The Major Histocompatibility Complex (MHC) in horses is a group of genes that play a significant role in the immune system by encoding proteins responsible for antigen presentation. These proteins are essential for the recognition of foreign molecules by the immune system, facilitating the differentiation between self and non-self entities. In horses, the MHC is located on equine chromosome 20 and is divided into several regions, including class I and class II, which present antigens to different subsets of T cells. Variability in the MHC genes is associated with susceptibility or resistance to various diseases, influencing immune responses and vaccine efficacy. This page compiles peer-reviewed research studies and scholarly articles that explore the genetic diversity, expression patterns, and implications of MHC in equine health and disease.
Schnabel LV, Pezzanite LM, Antczak DF, Felippe MJ, Fortier LA.The horse is a valuable species to assess the effect of allogeneic mesenchymal stromal cells (MSCs) in regenerative treatments. No studies to date have examined recipient response to major histocompatibility complex (MHC)-mismatched equine MSCs. The purposes of this study were to immunophenotype MSCs from horses of known MHC haplotype and to compare the immunogenicity of MSCs with differing MHC class II expression. Methods: MSCs and peripheral blood leukocytes (PBLs) were obtained from Thoroughbred horses (n=10) of known MHC haplotype (ELA-A2, -A3, and -A9 homozygotes). MSCs were cultured thro...
Broeckx S, Zimmerman M, Crocetti S, Suls M, Mariën T, Ferguson SJ, Chiers K, Duchateau L, Franco-Obregón A, Wuertz K, Spaas JH.Degenerative joint disease (DJD) is a major cause of reduced athletic function and retirement in equine performers. For this reason, regenerative therapies for DJD have gained increasing interest. Platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) were isolated from a 6-year-old donor horse. MSCs were either used in their native state or after chondrogenic induction. In an initial study, 20 horses with naturally occurring DJD in the fetlock joint were divided in 4 groups and injected with the following: 1) PRP; 2) MSCs; 3) MSCs and PRP; or 4) chondrogenic induced MSCs and PRP. The ho...
Dossa RG, Alperin DC, Hines MT, Hines SA.The CD1 family is a group of non-polymorphic MHC class I-like molecules that present lipid-based antigens to T cells. Previous work in our laboratory demonstrated that cytotoxic T lymphocytes from immune adult horses recognize lipids from the cell wall of an important equine pathogen, Rhodococcus equi. These findings suggest an important role for the equine CD1 antigen presentation system in protective immune responses to microbial pathogens in the horse. In this study, we characterized and mapped the equine CD1 gene cluster. The equine genome was found to contain 13 complete CD1 genes; seven ...
Boudreaux MK, Humphries DM.Platelet alloantigens in horses may play an important role in the development of neonatal alloimmune thrombocytopenia (NAIT). Objective: The objective of this study was to evaluate genes encoding major platelet glycoproteins within the Equidae family in an effort to identify potential alloantigens. Methods: DNA was isolated from blood samples obtained from Equidae family members, including a Holsteiner-Oldenburg cross, a Quarter horse, a donkey, and a Plains zebra (Equus burchelli). Gene sequences encoding equine platelet membrane glycoproteins IIb, IIIa (integrin subunits αIIb and β3), Ia (...
Kailaanmäki A, Kinnunen T, Kwok WW, Rytkönen-Nissinen M, Randell J, Virtanen T.The responses of allergen-specific CD4(+) T cells of allergic and healthy individuals are still incompletely understood. Our objective was to investigate the functional and phenotypic properties of CD4(+) T cells of horse-allergic and healthy subjects specific to the immunodominant epitope region of the major horse allergen Equ c 1. Specific T-cell lines (TCLs) and clones were generated from peripheral blood mononuclear cells with Equ c 1(143-160), the peptide containing the immunodominant epitope region of Equ c 1. The frequency, proliferative response, cytokine production and HLA restriction...
Janova E, Futas J, Klumplerova M, Putnova L, Vrtkova I, Vyskocil M, Frolkova P, Horin P.The Old Kladruber horses arose in the 17th century as a breed used for ceremonial purposes. Currently, grey and black coat colour varieties exist as two sub-populations with different recent breeding history. As the population underwent historical bottlenecks and intensive inbreeding, loss of genetic variation is considered as the major threat. Therefore, genetic diversity in neutral and non-neutral molecular markers was examined in the current nucleus population. Fifty microsatellites, 13 single nucleotide polymorphisms (SNPs) in immunity-related genes, three mutations in coat colour genes an...
Vychodilova L, Matiasovic J, Bobrova O, Futas J, Klumplerova M, Stejskalova K, Cvanova M, Janova E, Osickova J, Vyskocil M, Sedlinska M, Dusek L....Equine insect bite hypersensitivity (IBH) is a seasonal IgE-mediated dermatosis caused by bites of insects of the genus Culicoides. A familial predisposition for the disease has been shown but, except for the MHC, the genes involved have not been identified so far. An immunogenomic analysis of IBH was performed in a model population of Old Kladruby horses, all living in the same environment. Clinical signs of IBH were used as phenotypic manifestation of IBH. Furthermore, total serum IgE levels were determined in the sera of these horses and used as an independent phenotypic marker for the immu...
Klumplerova M, Vychodilova L, Bobrova O, Cvanova M, Futas J, Janova E, Vyskocil M, Vrtkova I, Putnova L, Dusek L, Marti E, Horin P.Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of insects. IBH is a multifactorial disease with contribution of genetic and environmental factors. Candidate gene association analysis of IBH was performed in a group of 89 Icelandic horses all born in Iceland and imported to Europe. Horses were classified in IBH-affected and non-affected based on clinical signs and history of recurrent dermatitis, and on the results of an in vitro sulfidoleukotriene (sLT)-release assay with Culicoides nubeculosus and Simulium vittatum extract. Different genetic markers wer...
Schurink A, Wolc A, Ducro BJ, Frankena K, Garrick DJ, Dekkers JC, van Arendonk JA.Insect bite hypersensitivity is a common allergic disease in horse populations worldwide. Insect bite hypersensitivity is affected by both environmental and genetic factors. However, little is known about genes contributing to the genetic variance associated with insect bite hypersensitivity. Therefore, the aim of our study was to identify and quantify genomic associations with insect bite hypersensitivity in Shetland pony mares and Icelandic horses in the Netherlands. Methods: Data on 200 Shetland pony mares and 146 Icelandic horses were collected according to a matched case-control design. C...
Brinkmeyer-Langford CL, Cai JJ, Gill CA, Skow LC.Genes within the major histocompatibility complex (MHC) encode proteins involved in innate and adaptive immune responses. Genetic variation in this region can influence the immune response of an individual animal to challenges from a variety of pathogens; however, a complete documentation of genetic variation in the MHC is lacking for most domestic animals, including horses. To provide additional genetic markers for study of the horse MHC, or ELA (equine lymphocyte antigen), we identified 37 polymorphic microsatellite repeats in ELA and used these variations separately and together with publis...
Antczak DF.One of the most intriguing and dramatic examples of immunological tolerance is displayed by the mammalian foetal-placental unit, which thrives as a semi-allograft in the mother's uterus during pregnancy. The success of the so-called foetal allograft stands in stark contrast to the failure of most tissue and organ grafts to survive without genetic matching of donor and recipient or drastic immunosuppression of the recipient's immune system. Experiments conducted over the past 60 years have revealed multiple mechanisms that enable the conceptus to avoid immunological detection or destruction. Ma...
Noronha LE, Antczak DF.Pregnant mares demonstrate a reduction in cytotoxic T lymphocyte (CTL) reactivity against cells from the breeding stallion. We investigated whether this effect is limited to activity against paternal major histocompatibility complex (MHC) antigens, and whether it occurs during MHC-compatible pregnancy. Methods: Mares were mated to carry MHC-compatible or MHC-incompatible pregnancies. CTL activity of these mares when pregnant and non-pregnant was measured against cells from horses with MHC haplotypes unrelated to the mare or breeding stallion. Results: While carrying MHC-incompatible pregnancie...
Kalemkerian PB, Metz GE, Peral-Garcia P, Echeverria MG, Giovambattista G, Díaz S.Polymorphisms at Major Histocompatibility Complex (MHC) genes have been associated with resistance/susceptibility to infectious diseases in domestic animals. The aim of this investigation was to evaluate whether polymorphisms of the DRA gene the Equine Lymphocyte Antigen is associated with susceptibility to Equine Arteritis Virus (EAV) infection in horses in Argentina. The equine DRA gene was screened for polymorphisms using Pyrosequencing® Technology which allowed the detection of three ELA-DRA exon 2 alleles. Neither allele frequencies nor genotypic differentiation exhibited any statistical...
De Schauwer C, Piepers S, Van de Walle GR, Demeyere K, Hoogewijs MK, Govaere JL, Braeckmans K, Van Soom A, Meyer E.During recent years, cell-based therapies using mesenchymal stem cells (MSC) are reported in equine veterinary medicine with increasing frequency. In most cases, the isolation and in vitro differentiation of equine MSC are described, but their proper immunophenotypic characterization is rarely performed. The lack of a single marker specific for MSC and the limited availability of monoclonal antibodies (mAbs) for equine MSC in particular, strongly hamper this research. In this study, 30 commercial mAbs were screened with flow cytometry for recognizing equine epitopes using the appropriate posit...
Ma G, Feineis S, Osterrieder N, Van de Walle GR.Major histocompatibility complex class I (MHC-I) molecules play an important role in host immunity to infection by presenting antigenic peptides to cytotoxic T lymphocytes (CTLs), which recognize and destroy virus-infected cells. Members of the Herpesviridae have developed multiple mechanisms to avoid CTL recognition by virtue of downregulation of MHC-I on the cell surface. We report here on an immunomodulatory protein involved in this process, pUL56, which is encoded by ORF1 of equine herpesvirus type 1 (EHV-1), an alphaherpesvirus. We show that EHV-1 pUL56 is a phosphorylated early protein w...
Yao S, Qi J, Liu J, Chen R, Pan X, Li X, Gao F, Xia C.In order to clarify the structure and the peptide-presentation characteristics of the equine major histocompatibility complex (MHC) class I molecule, a complex of equine MHC class I molecule (ELA-A1 haplotype, 7-6 allele) with mouse β(2)-microglobulin and the cytotoxic T lymphocyte (CTL) epitope Env-RW12 (RVEDVTNTAEYW) derived from equine infectious anaemia virus (EIAV) envelope protein (residues 195-206) was refolded and crystallized. The crystal, which belonged to space group P2(1), diffracted to 2.3 Å resolution and had unit-cell parameters a = 82.5, b = 71.4, c = 99.8 Å, β = 102.9°. T...
Sasaki M, Kim E, Igarashi M, Ito K, Hasebe R, Fukushi H, Sawa H, Kimura T.Equine herpesvirus-1 (EHV-1), an α-herpesvirus of the family Herpesviridae, causes respiratory disease, abortion, and encephalomyelitis in horses. EHV-1 utilizes equine MHC class I molecules as entry receptors. However, hamster MHC class I molecules on EHV-1-susceptible CHO-K1 cells play no role in EHV-1 entry. To identify the MHC class I molecule region that is responsible for EHV-1 entry, domain exchange and site-directed mutagenesis experiments were performed, in which parts of the extracellular region of hamster MHC class I (clone C5) were replaced with corresponding sequences from equine...
Andersson LS, Swinburne JE, Meadows JR, Broström H, Eriksson S, Fikse WF, Frey R, Sundquist M, Tseng CT, Mikko S, Lindgren G.Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Sw...
Böer U, Lohrenz A, Klingenberg M, Pich A, Haverich A, Wilhelmi M.Decellularized equine carotid arteries (dEAC) may represent a reasonable alternative to alloplastic materials in vascular replacement therapy. Acellularity of the matrix is standardly evaluated by DNA quantification what however may not record sufficiently the degree of matrix immunogenicity. Thus, our aim was to analyze dEAC with a low DNA content for residual cellular proteins. A detergent-based decellularization protocol including endonuclease treatment resulted in dEAC with 0.6 ± 0.15 ng DNA/mg dry weight representing 0.33 ± 0.14% of native tissue DNA content. In contrast, when matrices ...
Kamath PL, Getz WM.Major Histocompatibility Complex (MHC) genes are central to vertebrate immune response and are believed to be under balancing selection by pathogens. This hypothesis has been supported by observations of extremely high polymorphism, elevated nonsynonymous to synonymous base pair substitution rates and trans-species polymorphisms at these loci. In equids, the organization and variability of this gene family has been described, however the full extent of diversity and selection is unknown. As selection is not expected to act uniformly on a functional gene, maximum likelihood codon-based models o...
Sasaki M, Hasebe R, Makino Y, Suzuki T, Fukushi H, Okamoto M, Matsuda K, Taniyama H, Sawa H, Kimura T.The endotheliotropism of equine herpesvirus-1 (EHV-1) leads to encephalomyelitis secondary to vasculitis and thrombosis in the infected horse central nervous system (CNS). To identify the host factors involved in EHV-1 infection of CNS endothelial cells, we performed functional cloning using an equine brain microvascular endothelial cell cDNA library. Exogenous expression of equine major histocompatibility complex (MHC) class I heavy chain genes conferred susceptibility to EHV-1 infection in mouse NIH3T3 cells, which are not naturally susceptible to EHV-1 infection. Equine MHC class I molecule...
Quintana AM, Landolt GA, Annis KM, Hussey GS.Our understanding of innate immunity within the equine respiratory tract is limited despite growing evidence for its key role in both the immediate defense and the shaping of downstream adaptive immune responses to respiratory disease. As the first interface to undergo pathogen invasion, the respiratory epithelium is a key player in these early events and our goal was to examine the innate immune characteristics of equine respiratory epithelia and compare them to an in vitro equine respiratory epithelial cell model cultured at the air-fluid interface (AFI). Respiratory epithelial tissues, isol...
Tseng CT, Miller D, Cassano J, Bailey E, Antczak DF.A system for identifying equine major histocompatibility complex (MHC) haplotypes was developed based on five polymorphic microsatellites located within the MHC region on ECA 20. Molecular signatures for 50 microsatellite haplotypes were recognized from typing 353 horses. Of these, 23 microsatellite haplotypes were associated with 12 established equine leucocyte antigen (ELA) haplotypes in Thoroughbreds and Standardbreds. Five ELA serotypes were associated with multiple microsatellite subhaplotypes, expanding the estimates of diversity in the equine MHC. The strong correlations between serolog...
Brinkmeyer-Langford CL, Murphy WJ, Childers CP, Skow LC.The assembled genomic sequence of the horse major histocompatibility complex (MHC) (equine lymphocyte antigen, ELA) is very similar to the homologous human HLA, with the notable exception of a large segmental duplication at the boundary of ELA class I and class III that is absent in HLA. The segmental duplication consists of a ∼ 710 kb region of at least 11 repeated blocks: 10 blocks each contain an MHC class I-like sequence and the helicase domain portion of a BAT1-like sequence, and the remaining unit contains the full-length BAT1 gene. Similar genomic features were found in other Perissod...
Carrade DD, Owens SD, Galuppo LD, Vidal MA, Ferraro GL, Librach F, Buerchler S, Friedman MS, Walker NJ, Borjesson DL.The development of an allogeneic mesenchymal stem cell (MSC) product to treat equine disorders would be useful; however, there are limited in vivo safety data for horses. We hypothesized that the injection of self (autologous) and non-self (related allogeneic or allogeneic) MSC would not elicit significant alterations in physical examination, gait or synovial fluid parameters when injected into the joints of healthy horses. Methods: Sixteen healthy horses were used in this study. Group 1 consisted of foals (n = 6), group 2 consisted of their dams (n = 5) and group 3 consisted of half-siblings ...
Ramsay JD, Leib SR, Orfe L, Call DR, Tallmadge RL, Fraser DG, Mealey RH.Development of an accurate and efficient molecular-based equine MHC class I typing method would facilitate the study of T lymphocyte immune responses in horses. Here, a DNA microarray was designed to detect expressed classical MHC class I genes comprising serologically defined equine leukocyte antigen (ELA)-A haplotypes represented in a closed Arabian horse breeding herd. Initially, cloning and sequencing of RT-PCR products were used to identify sequences associated with the ELA-A1, A4, and W11 haplotypes, and one undefined haplotype, in six horses. Subsequently, sequence-specific, conserved (...
Kurtz BM, Singletary LB, Kelly SD, Frampton AR.In this study, Equus caballus major histocompatibility complex class I (MHC-I) was identified as a cellular entry receptor for the alphaherpesvirus equine herpesvirus type 1 (EHV-1). This novel EHV-1 receptor was discovered using a cDNA library from equine macrophages. cDNAs from this EHV-1-susceptible cell type were inserted into EHV-1-resistant B78H1 murine melanoma cells, these cells were infected with an EHV-1 lacZ reporter virus, and cells that supported virus infection were identified by X-Gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside) staining. Positive cells were subjected t...
Noronha LE, Antczak DF.The horse has proven to be a distinctively informative species in the study of pregnancy immunology for several reasons. First, unique aspects of the anatomy and physiology of the equine conceptus facilitate approaches that are not possible in other model organisms, such as non-surgical recovery of early stage embryos and conceptuses and isolation of pure trophoblast cell populations. Second, pregnant mares make strong cytotoxic antibody responses to paternal major histocompatibility complex class I antigens expressed by the chorionic girdle cells, permitting detailed evaluation of the antigen...
Harris SP, Fujiwara N, Mealey RH, Alperin DC, Naka T, Goda R, Hines SA.Immune adult horses have CD8(+) cytotoxic T lymphocytes (CTLs) that recognize and lyse Rhodococcus equi-infected cells in an equine lymphocyte alloantigen (ELA)-A [classical major histocompatibility complex (MHC) class I]-unrestricted fashion. As protein antigens are MHC class I-restricted, the lack of restriction suggests that the bacterial antigens being recognized by the host are not proteins. The goals of this study were to test the hypothesis that these CTLs recognize unique R. equi cell-wall lipids related to mycobacterial lipids. Initial experiments showed that treatment of soluble R. e...
Tallmadge RL, Campbell JA, Miller DC, Antczak DF.The genomic sequences of 15 horse major histocompatibility complex (MHC) class I genes and a collection of MHC class I homozygous horses of five different haplotypes were used to investigate the genomic structure and polymorphism of the equine MHC. A combination of conserved and locus-specific primers was used to amplify horse MHC class I genes with classical and nonclassical characteristics. Multiple clones from each haplotype identified three to five classical sequences per homozygous animal and two to three nonclassical sequences. Phylogenetic analysis was applied to these sequences, and gr...
Caplazi P, Ehrensperger F.Borna disease (BD) has been recognized as a virally induced T-cell dependent immunopathological disorder of the central nervous system (CNS), as shown by experimental infection of rats with Borna disease virus (BDV). In contrast to the rat model, little is known about the pathogenesis of spontaneous BD in sheep and horses. The present study describes the brain lesions of 12 ovine and 11 equine cases of naturally occurring BD. A set of monoclonal and polyclonal antibodies was used in order to determine the cells operative in encephalitic lesions and to detect expression of MHC-I and MHC-II prod...
van der Meulen K, Caij B, Pensaert M, Nauwynck H.In vitro studies demonstrated that most equine herpesvirus 1 (EHV-1)-infected peripheral blood mononuclear cells (PBMC) do not expose viral envelope proteins on their surface. This protects them against antibody-dependent lysis. We examined whether viral envelope proteins are also undetectable on infected PBMC during cell-associated viremia. Further, surface expression of major histocompatibility complex (MHC)-I was examined, since MHC-I assists in making infected cells recognizable for cytotoxic T-lymphocytes (CTL). Four ponies, previously exposed to EHV, and two ponies that had no contact wi...
Flaminio MJ, Nydam DV, Marquis H, Matychak MB, Giguère S.Susceptibility of foals to Rhodococcus equi pneumonia is exclusive to the first few months of life. The objective of this study was to investigate the immediate immunologic response of foal and adult horse antigen-presenting cells (APCs) upon infection with R. equi. We measured the activation of the antigen-presenting major histocompatibility complex (MHC) class II molecule, costimulatory molecules CD40 and CD86, the cytokine interleukin-12 (IL-12), and the transcriptional factor interferon regulatory factor 1 (IRF-1) in monocyte-derived macrophages (mMOs) and dendritic cells (mDCs) of adult h...
Kydd JH, Case R, Winton C, MacRae S, Sharp E, Ricketts SL, Rash N, Newton JR.Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy ...
Brinkmeyer-Langford CL, Cai JJ, Gill CA, Skow LC.Genes within the major histocompatibility complex (MHC) encode proteins involved in innate and adaptive immune responses. Genetic variation in this region can influence the immune response of an individual animal to challenges from a variety of pathogens; however, a complete documentation of genetic variation in the MHC is lacking for most domestic animals, including horses. To provide additional genetic markers for study of the horse MHC, or ELA (equine lymphocyte antigen), we identified 37 polymorphic microsatellite repeats in ELA and used these variations separately and together with publis...
Eder C, Curik I, Brem G, Crameri R, Bodo I, Habe F, Lazary S, Sölkner J, Marti E.To investigate whether allergen-specific IgE production is influenced by environmental and genetic factors, IgE levels against 2 mould extracts (Alternaria alternata [Alt a] and Aspergillus fumigatus [Asp f]) and against recombinant (r) rAlt a 1, rAsp f 7 and rAsp f 8 were determined by ELISA in sera from 448 Lipizzan horses living in 6 studfarms. Statistical evaluation showed a significant effect of studfarm-specific environment on IgE levels against the different allergens, but genetic factors also influenced allergen-specific IgE production: an heritability of 0.33 was found for IgE levels ...
Aguiar C, Theoret C, Smith O, Segura M, Lemire P, Smith LC.Induced pluripotent stem cells (iPSC) have brought immense hope to cellular therapy and regenerative medicine. However, the antigenicity of iPSC has not been well documented and remains a hurdle for clinical applications. Expression of major histocompatibility complex (MHC) molecules by human and murine iPSC is downregulated, making these cells potentially safe for transplantation. No such data are available for any large animal model. Objective: To measure expression of MHC molecules on equine iPSC (eiPSC) and describe their antigenicity using intradermal testing. The hypothesis was that allo...
Dossa RG, Alperin DC, Hines MT, Hines SA.The CD1 family is a group of non-polymorphic MHC class I-like molecules that present lipid-based antigens to T cells. Previous work in our laboratory demonstrated that cytotoxic T lymphocytes from immune adult horses recognize lipids from the cell wall of an important equine pathogen, Rhodococcus equi. These findings suggest an important role for the equine CD1 antigen presentation system in protective immune responses to microbial pathogens in the horse. In this study, we characterized and mapped the equine CD1 gene cluster. The equine genome was found to contain 13 complete CD1 genes; seven ...
Bullido R, Doménech N, Alvarez B, Alonso F, Babín M, Ezquerra A, Ortuño E, Domínguez J.A set of five monoclonal antibodies (mAb) against porcine major histocompatibility complex (MHC), or swine leukocyte antigens (SLA), class II molecules has been characterized. These mAbs appear to recognize monomorphic determinants on SLA-DR (2F4, 1F12 and 2E9/13) and SLA-DQ (BL2H5 and BL4H2) molecules, as assessed by flow cytometry and immunoprecipitation. By Western blot, the 2F4, 1F12, BL2H5 and BL4H2 epitopes were located on the beta-chains of these molecules. mAbs 2F4 and 1F12 crossreact with leucocytes of dog, cattle, horse and human; mAbs 2E9/13, BL2H5 and BL4H2 bind leucocytes of cattl...
Jeannerat E, Marti E, Berney C, Janett F, Bollwein H, Sieme H, Burger D, Wedekind C.The major histocompatibility complex (MHC) has repeatedly been found to influence mate choice of vertebrates, with MHC-dissimilar mates typically being preferred over MHC-similar mates. We used horses (Equus caballus) to test whether MHC matching also affects male investment into ejaculates after short exposure to a female. Semen characteristics varied much among stallions. Controlling for this variance with a full-factorial within-subject experimental design, we found that a short exposure to an MHC-dissimilar mare enhanced male plasma testosterone and led to ejaculates with elevated sperm nu...
Kammerer R, Ballesteros A, Bonsor D, Warren J, Williams JM, Moore T, Dveksler G.In early equine pregnancy, a highly invasive trophoblast cell subpopulation, the chorionic girdle cells, invade the endometrium and form endometrial cups (EC). These cells express classical MHC molecules, thereby stimulating a humoral and cellular immune response, resulting in a massive accumulation of maternal CD4+ and CD8+ T cells around the EC. Nevertheless, no immediate destruction of endometrial cups by maternal lymphoid cells occurs, presumably due to immune tolerance. Although the environment of EC is rich in TGFB and in FOXP3+, CD4+ T cells, the mechanisms leading to tolerance have not...
Lew AM, Valas RB, Maloy WL, Coligan JE.Horse serum is shown to contain a soluble class I molecule analogous to the secreted Q10 molecule in the mouse. This molecule has several similarities to the recently described mouse Q10 molecule: it is smaller than membrane-bound equine class I molecules; it occurs in a high molecular mass complex of 200-300 kd in serum; and the serum levels of the equine molecule are similar to that of the Q10 molecule (about 30 micrograms/ml). A soluble molecule is also detected in the sera of species related to the horse; it has in fact been found in all the wild members of the order Perissodactyla so far ...
Donaldson WL, Oriol JG, Plavin A, Antczak DF.Between days 36-38 of pregnancy equine trophoblastic cells of the chorionic girdle migrate and form endometrial cups. Just prior to invasion, the chorionic girdle cells express high levels of polymorphic, paternally inherited, major histocompatibility complex (MHC) class I antigens. Their descendents, the mature, invasive trophoblast cells of the endometrial cups, however, express low or undetectable levels of MHC class I antigens by day 44 of pregnancy. Experiments with MHC compatible pregnancies, the study of residual chorionic girdle cells that had failed to invade the endometrium and remai...
Burger D, Meuwly C, Marti E, Sieme H, Oberthür M, Janda J, Meinecke-Tillmann S, Wedekind C.Genes of the major histocompatibility complex (MHC) have been shown to influence communication in many vertebrates, possibly with context-specific MHC-correlated reactions. Here we test for MHC-linked female preferences in the polygynous horse (Equus caballus) by repeatedly exposing 19 mares to a group of seven sexually experienced stallions. Each mare was tested four times during two consecutive reproductive cycles, twice during estrus and twice during diestrus. Male plasma testosterone concentrations were determined from weekly blood samples, and equine leukocyte antigen (ELA) class I and II...
Vychodilova L, Matiasovic J, Bobrova O, Futas J, Klumplerova M, Stejskalova K, Cvanova M, Janova E, Osickova J, Vyskocil M, Sedlinska M, Dusek L....Equine insect bite hypersensitivity (IBH) is a seasonal IgE-mediated dermatosis caused by bites of insects of the genus Culicoides. A familial predisposition for the disease has been shown but, except for the MHC, the genes involved have not been identified so far. An immunogenomic analysis of IBH was performed in a model population of Old Kladruby horses, all living in the same environment. Clinical signs of IBH were used as phenotypic manifestation of IBH. Furthermore, total serum IgE levels were determined in the sera of these horses and used as an independent phenotypic marker for the immu...
Lawler DF, Hopkins J, Watson ED.Recent evidence indicates that the cells of the immune system and their large network of secretory products, or cytokines, play an active role in the ovary throughout the oestrous cycle. In the present study, immune cell populations (T and B lymphocytes, macrophages, granulocytes and eosinophils) and expression of major histocompatibility complex (MHC) class II were investigated in corpora lutea from mares in early (days 2-4), mid- (days 7-10) and late (days 12-14) dioestrus, the post-luteolytic phase (days 16-17) and early pregnancy. The number of T lymphocytes within the corpus luteum increa...
Durward-Akhurst SA, Valberg SJ.In horses, immune-mediated muscle disorders can arise from an overzealous immune response to concurrent infections or potentially from an inherent immune response to host muscle antigens. Streptococcus equi ss. equi infection or vaccination can result in infarctive purpura hemorrhagica (IPH) in which vascular deposition of IgA-streptococcal M protein complexes produces ischemia and complete focal infarction of skeletal muscle and internal organs. In Quarter Horse-related breeds with immune-mediated myositis, an apparent abnormal immune response to muscle antigens results in upregulation of maj...
Kamm JL, Parlane NA, Riley CB, Gee EK, Dittmer KE, McIlwraith CW.As the search for an immune privileged allogeneic donor mesenchymal stem cell (MSC) line continues in equine medicine, the characterization of the cells between different sources becomes important. Our research seeks to more clearly define the MSC marker expression of different equine MSC donors. The bone marrow-derived MSCs from two equine breeds and different blood donor-types were compared over successive culture passages to determine the differential expression of important antigens. Eighteen Thoroughbreds and 18 Standardbreds, including 8 blood donor (erythrocyte Aa, Ca, and Qa antigen ne...
Lunn DP, Holmes MA, Duffus WP.This paper describes the characteristics of a monoclonal antibody (CVS10) that reacts with an equine leukocyte antigen. On the basis of tissue distribution and biochemical characteristics, this antigen is equine MHC II. The equine MHC II antigen was found on a large subset of T-lymphocytes in addition to all B-lymphocytes, as has been reported previously. In addition MHC II was found to be present on a large proportion of both the mutually exclusive equine T-lymphocyte subpopulations which express either the equine homologues of CD4, or CD8. In a study of changes in equine MHC II expression wi...
McGuire TC, Zhang W, Hines MT, Henney PJ, Byrne KM.Horses with equine infectious anemia virus (EIAV) have episodes of viremia and disease; however, most eventually become inapparent carriers. A possible mechanism of control is cytotoxic T lymphocytes (CTL). To evaluate CTL in inapparent carriers with low viral loads, peripheral blood mononuclear cells (PBMC) were stimulated in vitro with autologous EIAV-infected PBMC and human IL-2 to detect memory CTL (CTLm). In initial studies, three carriers had CTLm and one of these had low-level effector CTL (CTLe). The CTLm were restricted by equine lymphocyte alloantigen-A (ELA-A) locus encoded MHC clas...
Chapman HS, Gale AL, Dodson ME, Linardi RL, Ortved KF.Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are being investigated for their potential in the treatment of musculoskeletal injuries, including tendon and ligament lesions, and cartilage lesions. Culture expansion of cells has traditionally been performed in medium supplemented with fetal bovine serum (FBS), however, concerns regarding the antigenicity and potential viral or prion contamination of FBS have prompted interest in alternative medium supplements. Platelet lysate (PL) contains elevated concentrations of growth factors, including transforming growth factor-β (TGF-β), pla...
Brown JJ, Thomson W, Clegg P, Eyre S, Kennedy LJ, Matthews J, Carter S, Ollier WE.The full extent of the polymorphism of ELA-DRA in Equidae is not yet known. Given the apparent differences in DRA polymorphisms between Equidae and other species, the aims of this study were to more fully characterize ELA-DRA, determine the extent of gene polymorphism and establish the allele-frequency distribution. An allele reference panel for the second exon of ELA-DRA was established by sequence-based typing of 69 equine DNA samples consisting of various breeds of domestic horse (Equus caballus), together with donkeys (Equus asinus), Grant's zebras (Equus boehmi) and one onager (Equus hemi...
Baker JM, Bamford AI, Antczak DF.Maternal immune recognition of the developing conceptus in equine pregnancy is characterized by the strongest and most consistent alloantibody response described in any species, a response directed almost exclusively against paternal MHC class I Ags. This work investigated the cellular immune response to paternal MHC Ags in pregnant and nonpregnant horses and donkeys, and in horses carrying interspecies hybrid mule conceptuses. We observed profound decreases in classical, MHC-restricted, CTL activity to allogeneic paternal cells in peripheral blood lymphocytes from both horse mares and donkey ...
Burger D, Dolivo G, Marti E, Sieme H, Wedekind C.Odours of vertebrates often contain information about the major histocompatibility complex (MHC), and are used in kin recognition, mate choice or female investment in pregnancy. It is, however, still unclear whether MHC-linked signals can also affect male reproductive strategies. We used horses (Equus caballus) to study this question under experimental conditions. Twelve stallions were individually exposed either to an unfamiliar MHC-similar mare and then to an unfamiliar MHC-dissimilar mare, or vice versa. Each exposure lasted over a period of four weeks. Peripheral blood testosterone levels ...
Rowland AL, Xu JJ, Joswig AJ, Gregory CA, Antczak DF, Cummings KJ, Watts AE.We recently demonstrated that intracellular xenogen-contaminated autologous MSCs (FBS) and non-xenogen-contaminated allogeneic (ALLO) MSCs caused an adverse clinical response after repeated intra-articular injection in horses, whereas autologous (AUTO) MSCs did not. Our current objective was to use clinical data from the previous study to compare MSC stemness against adverse response indicated by synovial total nucleated cell count (TNCC) following intra-articular MSC injection. Stemness, quantified by a trilineage differentiation (TLD) score; immunomodulation, quantified by mixed lymphocyte ...
Cavatorta DJ, Erb HN, Flaminio MJ.Dendritic cells (DCs) are innate immune cells specialized in antigen detection and presentation. They perform an essential role in initiating and guiding the immune response, the direction of which largely depends upon the activation state of the DCs. The objective of this study was to generate mature equine monocyte-derived DCs and, in doing so, to develop a method for measuring the activation state of these cells. Equine DCs were stimulated with UV-inactivated Escherichia coli (E. coli), and the activation status was measured by analyzing cell surface marker expression, cytokine production, ...
Viveiros MM, Antczak DF.Natural killer (NK) cells are an important component of the innate immune system. Though intensively studied in humans and rodents. NK cells remain less well characterized in other species. Studies are often limited by the lack of specific cell markers; however, the mAb NK-5C6 has been suggested to recognize an evolutionarily conserved molecule on NK cells and reacts with cells from several species. This mAb was used in the current investigation to identify and characterize equine NK cells, and was found to label approximately 10% of peripheral blood lymphocytes (PBL). Two-color flow cytometry...
