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Topic:Immunoglobulin M

Immunoglobulin M (IgM) is a type of antibody found in the blood and lymphatic fluid of horses, playing a significant role in the initial immune response to pathogens. It is the first antibody to be produced in response to an infection and is involved in the activation of the complement system, which aids in pathogen elimination. IgM is typically pentameric, allowing it to effectively bind to antigens and facilitate their removal from the body. The concentration and activity of IgM can provide insights into the immune status of horses and are relevant in the diagnosis and management of infectious diseases. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of Immunoglobulin M in equine immunology.
Isotype-specific antibodies in horses and dogs with immune-mediated hemolytic anemia.
Journal of veterinary internal medicine    April 20, 2000   Volume 14, Issue 2 190-196 doi: 10.1892/0891-6640(2000)0142.3.co;2
Wilkerson MJ, Davis E, Shuman W, Harkin K, Cox J, Rush B.Classes of antibody bound to erythrocytes were determined using direct immunofluorescence (DIF) flow cytometry in 3 horses and 12 dogs with immune-mediated hemolytic anemia (IMHA). Background levels of antibody binding were determined in samples from 12 horses and 12 dogs that were free of clinical disease. The range of nonspecific binding of a fluorescein isothiocyanate (FITC)-conjugated goat anti-equine immunoglobulin G (IgG) was 19.9-36.7%, but was eliminated by the use of the F(ab')2 fragment of FITC-conjugated goat anti-equine IgG. Background binding by other class-specific antibodies to ...
A case of interstitial pneumonia associated with Pneumocystis carinii in a foal.
Veterinary pathology    November 24, 1999   Volume 36, Issue 6 621-624 doi: 10.1354/vp.36-6-621
Perron Lepage MF, Gerber V, Suter MM.Subacute interstitial pneumonia with diffuse alveolar damage, marked macrophage infiltration, and intracellular Pneumocystis carinii cysts is described in a 3-month-old Swiss warmblood foal. Clinically, the disease was characterized by sudden onset of respiratory distress with fatal outcome. Based on serum immunoglobulin G (IgG), IgA, and IgM values, no humoral immunosuppression was detected. Spleen, thymus, and bronchial lymph nodes did not reveal lymphoid depletion, as assessed by immunohistochemical staining of CD-3-positive cells. Immunopathogenesis of pulmonary infections with intracellul...
Peripheral blood lymphocyte subpopulations and immunoglobulin concentrations in healthy foals and foals with Rhodococcus equi pneumonia.
Journal of veterinary internal medicine    June 5, 1999   Volume 13, Issue 3 206-212 doi: 10.1892/0891-6640(1999)0132.3.co;2
Flaminio MJ, Rush BR, Shuman W.Infectious diseases are common in foals aged 1-5 months. The objectives of this investigation were to evaluate immunologic parameters in foals from birth to weaning to establish reference values for the proportion of circulating lymphocytes that were helper (CD4+) or cytotoxic (CD8+) T cells, or B cells; to measure serum immunoglobulin (IgM and IgG) concentrations; and to compare these immunologic parameters to values in foals with naturally occurring Rhodococcus equi pneumonia and in adult horses. Peripheral blood lymphocyte subpopulations were determined by flow cytometric analysis, and seru...
The effect of nonspecific immunostimulation of pregnant mares with 1,3/1,6 glucan and levamisole on the immunoglobulins levels in colostrum, selected indices of nonspecific cellular and humoral immunity in foals in neonatal and postnatal period.
Veterinary immunology and immunopathology    May 8, 1999   Volume 68, Issue 1 1-11 doi: 10.1016/s0165-2427(99)00006-9
Krakowski L, Krzyzanowski J, Wrona Z, Siwicki AK.The objectives of the studies were to evaluate the effect of levamisole and 1,3/1,6 glucan applied in pregnant mares on parameters of non-specific cellular and humoral immunity of foals. Eighteen mares in three experimental groups (six animals in each) and their progeny were examined. Multiparous mares, crossbreed of Polish, full-blood and Hannover lines (400-500 kg), 4-9 years old, originated from four different farms. They were kept under identical zoohygienic and nutritional conditions. The animals were randomly chosen in experimental groups. None of mares had been previously vaccinated. In...
[Demonstration of immunoglobulin isotypes in the vitreous body as a contribution to the etiology of recurrent equine uveitis].
DTW. Deutsche tierarztliche Wochenschrift    February 21, 1998   Volume 104, Issue 11 467-470 
Wagner B, Brandt K, Sheoran A, Holmes MA, Deegen E, Leibold W.The functional properties of different immunoglobulin isotypes in equine recurrent uveitis (ERU) has not been investigated yet. Here, we describe the quantitative determination of total immunoglobulin levels and isotype differentiation in the vitreous of four horses with ERU as compared to that of seven healthy horses. In contrast to almost equal amounts of total immunoglobulin in the vitreous of both groups, remarkable differences were found: All four of the horses with ERU had significantly higher IgA contents in their vitreous as compared to the control group. However, the other isotypes mo...
Total protein and immunoglobulin concentrations in equine tears.
Zentralblatt fur Veterinarmedizin. Reihe A    January 9, 1998   Volume 44, Issue 8 461-465 doi: 10.1111/j.1439-0442.1997.tb01131.x
Martín E, Molleda JM, Ginel PJ, Novales M, Lucena R, López R.Lacrimal fluid represents a major ocular surface defensive mechanism providing different concentrations of all immunoglobulin classes. In this report, four classes of immunoglobulins (IgA, IgM, IgG and IgGT) have been measured in horse tears. As in others species, IgA is the main immunoglobulin responsible for local protection and constitutes quantitatively, 50% of all lacrimal proteins. The rest of immunoglobulins studied are normally present in equine tear fluid (though in lower concentration) and contribute to ocular surface immune protection. Female and adult horses showed significant high...
Acquired B lymphocyte deficiency and chronic enterocolitis in a 3-year-old quarter horse.
Veterinary immunology and immunopathology    June 1, 1997   Volume 57, Issue 1-2 49-57 doi: 10.1016/s0165-2427(96)05778-9
MacLeay JM, Ames TR, Hayden DW, Tumas DB.This case report describes a 3-year-old American Quarter Horse with acquired immunodeficiency. Clinical signs included chronic diarrhea due to Salmonella typhimurium and bacterial pneumonia. Characterization of the immunodeficiency involved in vivo phytohemagglutinin (PHA) intradermal testing, in vitro lymphocyte proliferation in response to concanavalin A, immunofluorescence flow cytometry data on blood lymphocytes, serum protein electrophoresis and immunoglobulin (Ig) quantification. A diagnosis of B lymphocyte deficiency with resulting deficiencies in serum IgG, IgA and IgM and a concurrent...
Borrelia burgdorferi infection in UK horses.
Equine veterinary journal    May 1, 1994   Volume 26, Issue 3 187-190 doi: 10.1111/j.2042-3306.1994.tb04367.x
Carter SD, May C, Barnes A, Bennett D.Antibody levels (IgG and IgM) to Borrelia burgdorferi were measured in the sera and synovial fluids of UK horses. Western blotting against B. burgdorferi was also used on samples from seropositive horses. A low incidence of seropositivity was shown in horses from most parts of the UK. This increased in areas that have a high incidence of human and canine borreliosis (Norfolk and south coast). Leptospira infections of horses did not cause cross reactions in the B. burgdorferi ELISA. Most horses did not display clinical signs of Lyme disease. As with dogs and man, it is apparent that B. burgdorf...
Diagnosis of eastern equine encephalomyelitis virus infection in horses by immunoglobulin M and G capture enzyme-linked immunosorbent assay. Sahu SP, Alstad AD, Pedersen DD, Pearson JE.Immunoglobulin M (IgM) and G (IgG) capture enzyme-linked immunosorbent assays (ELISAs) were used as possible adjuncts to hemagglutination inhibition (HI) and virus neutralization (VN) tests to differentiate between reaction to recent exposure to eastern equine encephalomyelitis (EEE) virus and those due to prior vaccination. Serum samples were evaluated by the IgM-capture ELISA, and the results were compared with those of HI and VN tests. Of 381 serum samples, 51% (195 samples) were positive by HI test (> or = 1:40) and 54% (205 samples) were positive by VN test (> or = 1:10), but only 3...
Immunologic studies of a horse with lymphosarcoma.
Veterinary immunology and immunopathology    October 1, 1993   Volume 38, Issue 3-4 229-239 doi: 10.1016/0165-2427(93)90083-g
Ansar Ahmed S, Furr M, Chickering WR, Sriranganathan N, Sponenberg DP.Immunological, clinical, and pathological investigations were conducted on a horse with lymphosarcoma. The immunological status was investigated by measuring the level of antibodies by single radial immunodiffusion test and the ability of lymphocytes to proliferate in response to mitogens. Multiple immunological abnormalities were noted in this horse. They were; (1) decreased IgM, IgG, and IgA levels in the serum despite hyperproteinemia; (2) increased in-vitro spontaneous lymphoproliferation which reflects augmented mitosis; (3) decreased lymphoproliferative response to T cell stimulants (e.g...
Selective IgM deficiency and abnormal B-cell response in a foal.
Journal of the American Veterinary Medical Association    November 1, 1992   Volume 201, Issue 9 1396-1398 
Weldon AD, Zhang C, Antczak DF, Rebhun WC.Selective IgM deficiency was diagnosed in a 3-month-old Standardbred colt that was referred for chronic respiratory tract disease. Immunoglobulin quantification revealed normal IgG and IgA concentrations, but undetectable IgM concentration. Stimulation of blood lymphocytes with the T-cell mitogens concanavalin A and phytohemagglutinin yielded results within the normal range. However, stimulation with the B-cell mitogen lipopolysaccharide produced no response. A B-cell defect similar to that associated with several immunodeficiency disorders in people was suggested as the cause of the IgM defic...
Serological responses of specific pathogen-free foals to equine herpesvirus-1: primary and secondary infection, and reactivation.
Veterinary microbiology    October 1, 1992   Volume 32, Issue 3-4 199-214 doi: 10.1016/0378-1135(92)90145-j
Gibson JS, O'Neill T, Thackray A, Hannant D, Field HJ.Serum antibody (virus neutralisation, complement fixation, IgM and IgG) responses to equine herpesvirus-1 (EHV-1) infection were measured in six foals which were initially free from EHV-1 and EHV-4 infection and maternally-derived antibodies. Following primary infection, high titres of virus neutralisation and complement fixation antibodies were detectable against EHV-1, however, corresponding antibody levels against EHV-4 were low or inapparent, although the two viruses share a number of cross-reactive epitopes. In addition, following the primary infection with EHV-1, IgM levels increased bef...
Unusual selective immunoglobulin deficiency in an Arabian foal.
Journal of veterinary internal medicine    July 1, 1992   Volume 6, Issue 4 201-205 doi: 10.1111/j.1939-1676.1992.tb00338.x
Boy MG, Zhang C, Antczak DF, Hamir AN, Whitlock RH.A 10-month-old Arabian foal was evaluated for a suspected immunoglobulin (Ig) M deficiency. Decreased to nondetectable concentrations of IgM, IgA, and IgG (T), and a normal concentration of IgG, were present. Results of in vitro testing of the blood lymphocyte blastogenesis showed a weak response to the B-cell mitogen, lipopolysaccharide (LPS), but normal responses to T-cell mitogens. Results of postmortem examination showed synovitis of the left tibiotarsal and both scapulohumeral joints. Atrophy and edema of the lymph nodes and lymphocyte depletion in the thymus and spleen were seen. A subac...
Immunohistochemical observations on pneumonic lesions caused by Rhodococcus equi in foals.
The Journal of veterinary medical science    June 1, 1992   Volume 54, Issue 3 509-515 doi: 10.1292/jvms.54.509
Ishino S, Kumagai K, Kuniyoshi S, Nakazawa M, Matsuda I, Oka M.An immunohistochemical analysis of Rhodococcus equi-induced pneumonia in 10 foals was performed by biotin-streptavidin system. The detection of R. equi was more sensitive in immuno-stain using anti-R. equi serum than in Gram's stain. This bacteria also reacted to anti-BCG serum. Lysozyme and alpha 1-antitrypsin were detectable in macrophages. A particularly intense staining was observed in association with intracellular bacteria. Though a degree of reaction for alpha 1-antichymotrypsin was very low in comparison with lysozyme and alpha 1-antitrypsin, it was also demonstrated in macrophages ing...
Immune-mediated thrombocytopenia in horses infected with equine infectious anemia virus.
Journal of virology    November 1, 1991   Volume 65, Issue 11 6242-6251 doi: 10.1128/JVI.65.11.6242-6251.1991
Clabough DL, Gebhard D, Flaherty MT, Whetter LE, Perry ST, Coggins L, Fuller FJ.An adult horse infected with a virulent, cell culture-adapted strain of equine infectious anemia virus (EIAV) developed cyclical thrombocytopenia in which the nadir of platelet counts coincided with peak febrile responses. In order to investigate the mechanism of thrombocytopenia during acute febrile episodes, four adult horses were experimentally infected with the wild-type Wyoming strain of EIAV. Platelet counts decreased from baseline as rectal temperature increased. Serum reverse transcriptase activity increased above background levels in all horses, coincident with increase in rectal temp...
Unusual patterns of serum antibodies to Streptococcus equi in two horses with purpura hemorrhagica.
Journal of veterinary internal medicine    September 1, 1991   Volume 5, Issue 5 263-267 doi: 10.1111/j.1939-1676.1991.tb03132.x
Heath SE, Geor RJ, Tabel H, McIntosh K.An enzyme-linked immunosorbent assay (ELISA) was developed for use in horses to determine serum titers of antibodies of the immunoglobulin classes IgA, IgG, and IgM to Streptococcus equi M-like protein and culture supernatant protein antigens. Serum antibodies were determined in 28 adult horses, including 9 horses with recent S. equi infections, 17 horses without known exposure to S. equi, but without a history of respiratory disease in the preceding 4 months, and 2 horses with clinical purpura hemorrhagica. Serum IgA titers to culture supernatant protein antigen were highest in recently infec...
Serosurvey of horses with evidence of equine monocytic ehrlichiosis.
Journal of the American Veterinary Medical Association    November 15, 1990   Volume 197, Issue 10 1327-1332 
Rikihisa Y, Reed SM, Sams RA, Gordon JC, Pretzman CI.In August 1986, an extensive serosurvey for prevalence of IgG and IgM antibodies against Ehrlichia risticii, the causative agent of equine monocytic ehrlichiosis (EME), was performed at 2 Ohio racetracks, River Downs (RD) and Beulah Park (BP). Of 840 horses at RD and 574 at BP, 13 and 20%, respectively, were IgG antibody-positive (by indirect fluorescent antibody test results), with antibody titer ranging from 1:20 to 1:10,240. The titer observed at highest frequency at both racetracks was 1:80. A higher proportion of horses was ill at RD (operating during the summer months) than at BP (winter...
Antibody response to Ehrlichia risticii and antibody reactivity to the component antigens in horses with induced Potomac horse fever.
Infection and immunity    October 1, 1989   Volume 57, Issue 10 2959-2962 doi: 10.1128/iai.57.10.2959-2962.1989
Dutta SK, Mattingly BL, Shankarappa B.The antibody response and the antibody reactivity to component antigens of Ehrlichia risticii were studied in horses with induced Potomac horse fever. These horses had no detectable antibodies to E. risticii in their preinoculation (PrI) sera by indirect fluorescent-antibody assay and enzyme-linked immunosorbent assay (ELISA). All the horses exhibited typical disease features following experimental infection and responded with specific antibodies, as measured by ELISA and indirect fluorescent-antibody assay. A primary antibody response was detected in 70% of the horses, while a secondary-type ...
Absorption of bovine colostral immunoglobulins G and M in newborn foals.
American journal of veterinary research    September 1, 1989   Volume 50, Issue 9 1598-1603 
Lavoie JP, Spensley MS, Smith BP, Mihalyi J.The uptake of colostral IgG and IgM, their serum half-lives, and the rates of endogenous synthesis of IgG and IgM were evaluated in 6 newborn foals fed bovine colostrum (principals) and 6 foals allowed to suckle their dams (controls). The principal foals were fed 400 ml of bovine colostrum (IgG, 10,000 mg/dl and IgM, 200 mg/dl) at 2-hour intervals, from 2 to 20 hours after foaling (total dose, 4 L). Serum IgG and IgM concentrations were determined by single radial immunodiffusion from birth to 98 days of age. At foaling, principal foals had no detectable serum equine IgG, but 1 control foal ha...
Rhodococcus equi foal pneumonia: protective effects of immune plasma in experimentally infected foals.
Equine veterinary journal    July 1, 1989   Volume 21, Issue 4 249-255 doi: 10.1111/j.2042-3306.1989.tb02161.x
Martens RJ, Martens JG, Fiske RA, Hietala SK.The immunoprophylactic capacity of specific immune plasma was evaluated in pony foals infected experimentally with Rhodococcus equi. Immune plasma, produced by repeated parenteral administration of viable R. equi to adult horses, was harvested and frozen. Group I (six control foals) and Group II (six principal foals) received lactated Ringers solution and immune plasma respectively at three and five days of age. R. equi were aerosolised into a caudal lung lobe of all foals at seven days of age. Clinical signs, haematological alterations, immune responses, thoracic radiographs and technetium99m...
Colostral and serum IgG, IgA, and IgM concentrations in Standardbred mares and their foals at parturition.
Journal of the American Veterinary Medical Association    July 1, 1989   Volume 195, Issue 1 64-68 
Kohn CW, Knight D, Hueston W, Jacobs R, Reed SM.Immunoglobulin G, IgM, and IgA concentrations were measured in serum collected from 36 Standardbred mares within 12 hours of foaling, in colostrum collected within 6 hours of foaling, and in serum collected from foals 24 to 48 hours after birth. In serum collected from mares after parturition, mean concentrations of IgG, IgM, and IgA were 2,463.9 +/- 1,337.3 mg/dl, 136.4 +/- 218 mg/dl, and 305.2 +/- 237.5 mg/dl, respectively. In serum from foals, mean concentrations of IgG, IgM, and IgA were 1,953.3 +/- 1,635 mg/dl, 33.8 +/- 30.4 mg/dl, and 58.4 +/- 42.2 mg/dl, respectively. In colostrum, mean...
Antibody isotype responses in the serum and respiratory tract to primary and secondary infections with equine influenza virus (H3N8).
Veterinary microbiology    April 1, 1989   Volume 19, Issue 4 293-303 doi: 10.1016/0378-1135(89)90095-3
Hannant D, Jessett DM, O'Neill T, Mumford JA.Serum antibody (IgGab, IgM and IgA) responses to primary and secondary infection with influenza A/equine/Newmarket/79 (H3N8) by nebulised aerosol were compared with local (nasopharyngeal and tracheal) antibody responses in ponies. Circulating IgGab antibody was of long duration after primary infection, whereas IgM responses were short-lived after both primary and secondary infections. The antigenic stimulation of secondary infection with equine influenza was sufficient to induce elevations of serum IgM and IgA in the presence of high levels of circulating IgGab. These results support the poten...
Colostral volume and immunoglobulin G and M determinations in mares.
American journal of veterinary research    April 1, 1989   Volume 50, Issue 4 466-470 
Lavoie JP, Spensley MS, Smith BP, Mihalyi J.Colostral volume and IgG and IgM concentrations were determined in 6 multiparous mares at foaling and them every 2 hours from 16 to 20 hours after parturition. Serum IgG and IgM concentrations at foaling also were determined in each mare. The rate of mammary secretion was 292 +/- 26 ml/h (range, 202 to 389 ml/h), and the colostral volume was 5.1 +/- 0.5 L (range, 3.2 to 7.0 L). The colostral IgG and IgM contents were 440 +/- 106 g (range, 199 to 855 g) and 3.1 +/- 0.9 g (range, 0.7 g to 7.1 g), respectively. There was no significant correlation between serum and initial colostral IgG and IgM c...
A monoclonal antibody against horse kidney (Na+ + K+)-ATPase inhibits sodium pump and E2K to E1 conversion of (Na+ + K+)-ATPase from outside of the cell membrane.
Biochimica et biophysica acta    February 2, 1989   Volume 994, Issue 2 104-113 doi: 10.1016/0167-4838(89)90149-0
Satoh K, Nakao T, Nagai F, Kano I, Nakagawa A, Ushiyama K, Urayama O, Hara Y, Nakao M.Monoclonal antibodies against horse kidney outer medulla (Na+ + K+)-ATPase were prepared. One of these antibodies (M45-80), was identified as an IgM, recognized the alpha subunit of the enzyme. M45-80 had the following effects on horse kidney (Na+ + K+)-ATPase: (1) it inhibited the enzyme activity by 50% in 140 mM Na+ and by 80% in 8.3 mM Na+; (2) it increased the Na+ concentration necessary for half-maximal activation (K0.5 for Na+) from 12.0 to 57.6 mM, but did not affect K0.5 for K+; (3) it slightly increased the K+-dependent p-nitrophenylphosphatase (K-pNPPase) activity; (4) it inhibited p...
Plasma cell numbers in uteri of mares with persistent endometritis and in ovariectomised mares treated with ovarian steroids.
Equine veterinary journal    November 1, 1988   Volume 20, Issue 6 424-425 doi: 10.1111/j.2042-3306.1988.tb01565.x
Watson ED, Stokes CR.Immunoglobulins A, G and M were localised by immunoperoxidase staining of endometrial sections from ovariectomised mares. Treatment with progesterone or oestradiol-17 beta did not significantly affect numbers of cells secreting any of the isotypes. Mares with persistent endometritis did not have significantly greater numbers of endometrial plasma cells than genitally-normal mares.
Immunohistochemical study of the local humoral immune system of the equine respiratory mucosa.
Research in veterinary science    September 1, 1988   Volume 45, Issue 2 160-165 
Mair TS, Stokes CR, Bourne FJ.An indirect immunoperoxidase technique was used to demonstrate both free immunoglobulin and immunoglobulin-containing plasma cells of IgG, IgA, and IgM classes in the mucosa of the equine respiratory tract. IgA-producing plasma cells predominated in the upper airways, whereas IgG-producing cells predominated in the lower respiratory tract. IgM-secreting cells were uncommon, but present in their highest numbers in the nasopharynx. Plasma cells specific for all of the immunoglobulin classes were identified in the surface epithelium, lamina propria connective tissue, glandular tissue and organise...
Borreliosis in equids in northeastern United States.
American journal of veterinary research    March 1, 1988   Volume 49, Issue 3 359-362 
Magnarelli LA, Anderson JF, Shaw E, Post JE, Palka FC.During 1982 and 1985, blood samples from 705 equids were examined for antibodies to Borrelia burgdorferi. By indirect immunofluorescence staining, IgM and total immunoglobulin (IgM and IgG) antibodies were detected in 37 (5.3%) and 90 (12.8%) serum specimens, respectively. The geometric mean titer for IgM antibody (140.4) was highest during July, whereas total immunoglobulin ranged from 94.1 in October to 338 in May. Eighty-six equids with total immunoglobulin to B burgdorferi lived in areas of Connecticut where the primary tick vector, Ixodes dammini, was present. Of the 86 equids, 9 from Lym...
Host responses to Borrelia burgdorferi in dogs and horses.
Annals of the New York Academy of Sciences    January 1, 1988   Volume 539 221-234 doi: 10.1111/j.1749-6632.1988.tb31856.x
Bosler EM, Cohen DP, Schulze TL, Olsen C, Bernard W, Lissman B.By using paired sera the IgM and IgG host responses were analyzed in dogs with ELISA and Western blot techniques. Antibodies in clinical seropositive dogs bound to 4-25 IgM and up to 40 or more IgG antigenic determinants. Early IgM response to the 41-kDa flagellin persisted for at least 9 months and involved as many as seven other peptides. IgG response expanded later in the disease and involved more immunogens than are currently recognized in late human disease. A percentage of asymptomatic dogs that later developed clinical symptoms were seropositive. Immunoblot studies suggested that B. bur...
Humoral immune response of foals to experimental infection with Rhodococcus equi.
Veterinary microbiology    August 1, 1987   Volume 14, Issue 3 321-327 doi: 10.1016/0378-1135(87)90119-2
Takai S, Kawazu S, Tsubaki S.Humoral immune response to Rhodococcus equi in experimentally infected foals was studied with the enzyme-linked immunosorbent assay (ELISA) method. Class-specific antibodies were measured by ELISA in the sera of foals after intratracheal or oral inoculation with R. equi ATCC 6939 or T 48 and in the lung washings of a foal after intratracheal inoculation or of normal horses. After intratracheal or oral inoculation with R. equi, serum antibodies were first detected in immunoglobulin G (IgG) followed by IgM and IgA classes, but significant levels of IgM and IgA developed only in the foal infected...
Acquired immunodeficiency in a seven-year-old horse.
Journal of the American Veterinary Medical Association    March 15, 1987   Volume 190, Issue 6 689-691 
Freestone JF, Hietala S, Moulton J, Vivrette S.A 7-year-old horse with no previous history of illness was determined to have a systemic infection of Rhodococcus equi. Rhodococcus equi was isolated from blood, tracheal fluid, and feces. Lymphopenia, failure to respond to concanavalin A and phytohemagglutinin lymphocyte stimulation testing, decreased concentrations of immunoglobulin (Ig)M, IgA, and IgG, low R equi antibody titer, histologic depletion of lymphoid tissue, and a failure to respond to antigenic stimulation led to the conclusion that both humoral and cell-mediated immunity were compromised. No cause for the acquired immunodeficie...