The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
Wadsworth AB, Kirkbride MB.Horses immunized to Type I pneumococci developed serum, 0.1 cc. of which protected against 0.5 cc. of a virulent culture, 0.000001 cc. of which killed mice in less than 40 hours. Protective tests of serum from horses immunized to Type II organisms varied, 0.1 cc. protecting, however, in certain instances against 0.1 and 0.01 cc. of virulent homologous culture. Types I and II sera obtained in our experiments with culture sediment and whole culture did not vary markedly for a given type and corresponded closely in their protective titer with samples of sera received from The Rockefeller Institut...
Wollstein M.The parameningococci of Dopter are culturally indistinguishable from true or normal meningococci, but serologically they exhibit differences as regards agglutination, opsonization, and complement deviation. Because of the variations and irregularities of serum reactions existing among otherwise normal strains of meningococci it does not seem either possible or desirable to separate the parameningococci into a strictly definite class. It appears desirable to consider them as constituting a special strain among meningococci not, however, wholly consistent in itself. The distinctions in serum rea...
Lintz W.This research article focuses on the study of distemper, also known as influenza or shipping fever, in horses, specifically focusing on its bacteriology and potential vaccine therapies. The research was [...]
Smith T.The foregoing and earlier data taken together demonstrate that an active immunity lasting several years can be produced in guinea-pigs, by the injection of toxin-antitoxin mixtures which have no recognizable harmful effect either immediate or remote. They also show, what might have been anticipated, that under the same conditions mixtures which produce local lesions and which, therefore, contain an excess of toxin produce a much higher degree of immunity than the neutral mixtures, and that an excess of antitoxin reduces the possibility of producing an active immunity, and may extinguish it alt...
Hubbert WR.1. Better results in the production of diphtheria antitoxin can be obtained with greater experience in the selection of the most suitable type of horses to be used. Young animals are usually to be preferred. Over one-half of all such horses can be made to yield 300-unit serum, while a third will yield (5)oo-unit serum. 2. High-test horses require a shorter time to immunize and will yield a potent serum for a longer period than will low-test horses. 3. The period of usefulness of an antitoxin horse is short, and on an average endures only a few months. 4. A horse having attained a maximal antit...
Atkinson JP.1. The globulins of both normal and diphtheria antitoxic serum exhibit chemically toward reagents the same reactions, being precipitated by magnesium sulphate and split up into fractions in precisely the same way. 2. All of the diphtheric antitoxic power of both normal and immunized serum is always carried by the globulin and its fractional precipitates. 3. During the fractional precipitation of the serum globulin of horses immunized from diphtheria toxin and horses not immunized from diphtheria toxin, some of the globulin is lost, likewise at the same time some of the antitoxic power of the g...
Although equine herpesvirus myeloencephalopathy (EHM) is a relatively uncommon manifestation of equine herpesvirus-1 (EHV-1) infection, it can cause devastating losses during outbreaks. Antemortem diagnosis of EHM relies mainly on the molecular detection of EHV-1 in nasal secretions and blood. Management of horses affected by EHM is aimed at supportive nursing and nutritional care, at reducing central nervous system inflammation and preventing thromboembolic sequelae. Horses exhibiting sudden and severe neurologic signs consistent with a diagnosis of EHM pose a definite risk to the surrounding...
Respiratory diseases are a major cause of morbidity and mortality in the horses of all ages including foals. There is limited understanding of the expression of immune molecules such as tetraspanins and surfactant proteins (SP) and the regulation of the immune responses in the lungs of the foals. Therefore, the expression of CD9, SP-A and SP-D in foal lungs was examined. Results: Lungs from one day old (n = 6) and 30 days old (n = 5) foals were examined for the expression of CD9, SP-A, and SP-D with immunohistology and Western blots. Western blot data showed significant increase in the...
Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize cur...
Equine recurrent uveitis serves as a spontaneous model for human autoimmune uveitis. Unpredictable relapses and ongoing inflammation in the eyes of diseased horses as well as in humans lead to destruction of the retina and finally result in blindness. However, the molecular mechanisms leading to inflammation and retinal degeneration are not well understood. An initial screening for differentially regulated proteins in sera of uveitic cases compared to healthy controls revealed an increase of the alternative pathway complement component factor B in ERU cases. To determine the activation status ...
Tehrani AH, Toth K, Osinchuk N, Dufour A, Krawetz R, Sen A, Sparks H.Adult bone marrow-derived mesenchymal stromal cells (BM-MSCs) hold significant therapeutic potential in human and veterinary medicine. Traditionally, BM-MSC cultures use fetal bovine serum (FBS) to promote growth, but this practice introduces batch variability and xenogeneic contamination that complicate clinical translation. While serum-free medium (SFM) alternatives have been optimized for human MSCs, limited options have been explored for alternative or veterinary species. Here, we compared a chemically defined, customizable SFM formulation with conventional serum-containing medium (SCM) fo...
de Santana Evangelista K, de Castro Barbosa E, de Souza Andrade A, Ardisson L, Martins AA, Boasquivis PF, Duarte MM, de Oliveira Ribeiro B....This study establishes an integrated workflow linking antibody production, neutralization assessment, and epitope mapping, supporting the identification of antigenic regions recognized by polyclonal antibodies generated in vivo. The viral suspension was inactivated with β-propiolactone under biosafety level 3 (BSL-3) conditions, with no cytopathic effect or plaque formation observed, confirming loss of viral replicative capacity. The produced immunogen retained antigenic activity, as demonstrated by reactivity with IgG antibodies from vaccinated and previously infected individuals. Protein an...
Junuzović M, Troillet A, Burk J.Osteoarthritis (OA) is a cross-species, multifactorial joint disease characterized by the progressive degeneration of articular cartilage, morphological remodeling of the subchondral bone, and inflammatory and fibrotic changes of the joint capsule. These alterations arise from chronic, often subclinical, inflammatory processes and dysregulated cellular homeostasis, leading to profound shifts in the cellular and extracellular composition of the joint organ. Although the mechanisms driving persistent inflammation are only partially understood, their impact on all joint-associated tissues is well...
Van Reusel Y, Broeckx SY, Carolo A, Patruno M, Steenbrugge J, Saunders J, Gugliandolo E, Spaas JH.Orthobiologics such as platelet-rich plasma (PRP) and alpha-2-macroglobulin (A2MG) are increasingly used for equine musculoskeletal injuries. However, their composition and safety with repeated allogeneic intra-articular administration remain poorly investigated. Objective: To characterise orthobiological preparations with or without 1 h incubation at 37°C (PRP, PRP + Inc, A2MG, A2MG + Inc) and evaluate immunological safety following repeated intra-articular administration (autologous and allogeneic) of PRP combined with A2MG + Inc in healthy horses. Methods: In vivo experiments...
Eertink LG, Jacob O, Adam EN, Page AE, Wang D, Li F.Despite a monovalent G3P[12] ('G3') vaccine being available for horses, equine rotavirus A (ERVA) is still the predominant infectious pathogen causing diarrhea in foals in the United States of America (U.S.). Previous research has shown that maternal neutralizing antibody (NAb) titers are too high and will interfere with the vaccination of foals at 30 and 45 days of age. We aimed to determine if it is possible to increase NAb titers in foals through vaccination before they are vulnerable to ERVA infection. We immunized two foals with the commercially available vaccine (G3) at solely three mont...
Liso G, Winter K, Triebe TJ, Ulrich R, Brehm W, Wagner B, Schnabel CL, Troillet A, Roth SP.Synovial macrophages' role in equine osteoarthritis (OA) is not well understood, despite horses being a model for human degenerative joint disorders. Equine synovial macrophages' characterization is limited and age-related changes are not described. This study aimed to evaluate surface marker distribution and expression from potential synovial tissue macrophages in foals, adult non-affected, and OA-affected horses. Unassigned: Surface markers (CD14, CD16, CD206) were quantitatively evaluated on dorsal villous synovial biopsies from the metacarpophalangeal joint of foals (F), non-affected (cont...
Paillot R, Newton JR, Gonzalez Medina S, Frosth S, Frykberg L, Flock M, Guss B, Flock JI, Waller AS.Streptococcus equi subspecies zooepidemicus is a highly diverse opportunistic pathogen of horses, associated with respiratory disease and endometritis. Objective: To characterise S. zooepidemicus isolates recovered from young ponies during a natural episode of respiratory disease, and to determine if vaccination with Strangvac®, a vaccine against Streptococcus equi subspecies equi, conferred cross-protection. Methods: Retrospective analysis of a double-blinded placebo-controlled study involving 32 ponies (16 vaccinates and 16 placebo controls) that experienced a natural episode of respiratory...
Hamm PJ.This essay offers a psycho-spiritual and psychoanalytic meditation on the horse-human relationship as a nonverbal site of attunement, regulation, and meaning-making. Drawing on autobiographical clinical narrative, it explores how horseback riding became a medium for experiencing and reflecting upon embodied connection, mutual responsiveness, and contemplative presence. Encounters with horses illuminate forms of reciprocity that preceded and exceed speech, while also opening reflection on maternal attachment, separation, loss, and the emergence of selfhood. In dialogue with Freud, Winnicott, Pi...
Magalhães VLP, Pinho FA, Souza FN, Santos KR, Santos AS, Hlavac N, Libera AMPD, Massoco CO, Barrouin-Melo SM.There are diverse uses for equine peripheral blood mononuclear cells (PBMC) in research. Studies have shown that PBMC isolation protocols can affect immune parameters of diagnostic and research assays. We aimed to assess the impact of equine blood handling techniques on cell yield, viability, and proliferation under mitogen stimulation. Whole blood (WB) samples were collected from eight healthy adult horses into heparinized tubes for PBMC isolation by comparing method 1 (M1) where freshly collected WB was layered directly over a density gradient medium for centrifugation, followed by PBMC harv...
Ren H, Chen K, Zhou B, Zhang W, Wang XF, Wang X.Type I interferons (IFNs) play a pivotal role in antiviral defence by inducing interferon-stimulated genes (ISGs) that target multiple stages of viral replication. Equine infectious anemia virus (EIAV) is an ancient lentivirus that establishes long-term asymptomatic infections in equids, suggesting its exceptional immune evasion capabilities. However, the mechanisms by which EIAV modulates IFN responses remain unclear. Here, we demonstrate that EIAV infection attenuates ISG expression at the post-transcriptional level. The viral Rev protein plays a central role by interacting with the stress g...
Pinto JEL, Gervásio JHB, Ng JC, Gomes-Silva A, de Matos Guedes HL, Cunha L, Castilho LR, da Silva JL, Franco GR, Navas C, Felicori LF.The humoral immune response relies on a diverse antibody repertoire, which is expanded through processes such as somatic hypermutation, class-switch recombination and gene conversion. These processes are primarily mediated by activation-induced cytidine deaminase (AID). Gene conversion generates diversity in immunoglobulin heavy and light chains (IGHVs) in species such as chickens and rabbits, though it has not been widely studied. Since 80% of the equine IGHV repertoire originates from only three functional gene segments, we examined gene conversion events in horses to assess their role in an...
Armillotta G, Capista S, Rodomonti D, Traini S, Testa L, Serroni A, Laguardia C, Palucci C, Di Pancrazio C, Di Febo T, Puglielli O, Ronchi GF....The protozoan Trypanosoma equiperdum is the causative agent of Dourine, a contagious sexually transmitted disease of equines that can manifest itself in chronic or acute form. Dourine has serious veterinary and economic implications, as there are no vaccines available for prevention and the management of the disease requires the culling of infected animals, together with rigorous sanitary control measures. This study compares the traditional production of T. equiperdum antigen grown in vivo, with an in vitro cultivation methodology developed to eliminate the use of animals. The in vitro and in...
Del Prado Soriano-Campos M, Muñoz-García CC, Luis-Calero M, Gallardo-Soler A, González-Fernández L, Macías-García B.Mesenchymal stromal cells (MSCs) are widely used in human cell-based therapies and recent research is focused on the use of MSCs in equine regenerative medicine. Recently, MSCs have been isolated from equine follicular aspirates; however, a major concern during isolation is the potential contamination with fibroblasts, the predominant stromal cell type in many tissues. Furthermore, both cell types share the minimal criteria established by the International Society for Cellular Therapy (ISCT) for MSCs identification. Hence, our study aimed to compare the morphological characteristics, expansion...
Shen CK, Liu J, Xu K, Xu P, Li Z, Wang L, Li C, Ding F, Xiao C, Yao X, Jing Y.Therapeutic F(ab') fragments derived from polyclonal equine antisera remain essential emergency biologics for addressing snake envenomation, tetanus, and viral infections. Traditional production methods rely on pepsin digestion, which is limited by non-specific proteolysis, harsh acidic conditions (pH 2.0-4.0), risk of contamination from animal sources, and significant batch variability, often complicating downstream preparative separations. In this study, we introduce a synergistic dual-endopeptidase platform that integrates hinge-specific biocatalysis with affinity chromatography to facilit...
da Silva Martins A, Silva TA, Heinemann MB, Guedes IB, Soares RR, Dias RA, Passos RF, Braga RM, Santos FCCD, Borsanelli AC.Leptospirosis is a neglected zoonosis with significant impact on public and veterinary health, with equines acting as potential maintenance hosts of infection. This study aimed to investigate the seroprevalence of Leptospira in Lavradeiro horses under semi-feral conditions in Indigenous communities in the state of Roraima, Brazil. A total of 387 serum samples were subjected to the microscopic agglutination test (MAT), using antigens of Leptospira spp. from 18 serogroups. The overall prevalence was 15.8% (95% CI: 12.3-19.8%), with the most frequent serogroups being Australis, Tarassovi, Autumna...
Durham AE, Gautam SS, Huber L.This study compared the in vitro stability of equine plasma adrenocorticotrophic hormone (ACTH) and serum insulin measured by chemiluminescent assay (CLA; Siemens Immulite 2000XPi) and immunofluorescent assay (IFA; Tosoh AIA-900) after storage at 4°C or room temperature (approximately 21°C) for clinically relevant periods. Fresh equine EDTA blood for ACTH and coagulated blood for insulin were aliquoted and analysed immediately (T0) and after storage. ACTH was assessed at 24, 48 and 72 hours; insulin was assessed at 24 hours, 72 hours and 7 days. Percentage recovery relative to T0 was analyse...
