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Liu L, Cai P, Gu W, Duan X, Gao S, Ma X, Ma Y, Ma S, Li G, Wang X, Cai K, Wang Y, Cai T, Zhao H. Evaluation of vaccine candidates against Rhodococcus equi in BALB/c mice infection model: cellular and humoral immune responses. BMC Microbiol 2024; 24:249. [PMID: 38977999 PMCID: PMC11229254 DOI: 10.1186/s12866-024-03408-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 07/02/2024] [Indexed: 07/10/2024] Open
Abstract
Rhodococcus equi (R. equi) is a zoonotic opportunistic pathogen that mainly causes fatal lung and extrapulmonary abscesses in foals and immunocompromised individuals. To date, no commercial vaccine against R. equi exists. We previously screened all potential vaccine candidates from the complete genome of R. equi using a reverse vaccinology approach. Five of these candidates, namely ABC transporter substrate-binding protein (ABC transporter), penicillin-binding protein 2 (PBD2), NlpC/P60 family protein (NlpC/P60), esterase family protein (Esterase), and M23 family metallopeptidase (M23) were selected for the evaluation of immunogenicity and immunoprotective effects in BALB/c mice model challenged with R. equi. The results showed that all five vaccine candidate-immunized mice experienced a significant increase in spleen antigen-specific IFN-γ- and TNF-α-positive CD4 + and CD8 + T lymphocytes and generated robust Th1- and Th2-type immune responses and antibody responses. Two weeks after the R. equi challenge, immunization with the five vaccine candidates reduced the bacterial load in the lungs and improved the pathological damage to the lungs and livers compared with those in the control group. NlpC/P60, Esterase, and M23 were more effective than the ABC transporter and PBD2 in inducing protective immunity against R. equi challenge in mice. In addition, these vaccine candidates have the potential to induce T lymphocyte memory immune responses in mice. In summary, these antigens are effective candidates for the development of protective vaccines against R. equi. The R. equi antigen library has been expanded and provides new ideas for the development of multivalent vaccines.
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Affiliation(s)
- Lu Liu
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China
| | - Peng Cai
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Weifang Gu
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xingxun Duan
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Shiwen Gao
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xuelian Ma
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China
| | - Yuhui Ma
- Zhaosu Xiyu Horse Industry Co., Ltd., Yining, China
| | - Siyuan Ma
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Guoqing Li
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Xiangyu Wang
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Kuojun Cai
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Yanfeng Wang
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Tao Cai
- Xinjiang Agricultural Vocational Technical College, Changji, China
| | - Hongqiong Zhao
- College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China.
- Xinjiang Key Laboratory of New Drug Study and Creation for Herbivorous Animal, Urumqi, China.
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Dossa RG, Alperin DC, Garzon D, Mealey RH, Brown WC, Jervis PJ, Besra GS, Cox LR, Hines SA. In contrast to other species, α-Galactosylceramide (α-GalCer) is not an immunostimulatory NKT cell agonist in horses. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2015; 49:49-58. [PMID: 25445911 DOI: 10.1016/j.dci.2014.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 11/06/2014] [Accepted: 11/06/2014] [Indexed: 06/04/2023]
Abstract
α-GalCer is a potent immunomodulatory molecule that is presented to NKT cells via the CD1 antigen-presenting system. We hypothesized that when used as an adjuvant α-GalCer would induce protective immune responses against Rhodococcus equi, an important pathogen of young horses. Here we demonstrate that the equine CD1d molecule shares most features found in CD1d from other species and has a suitable lipid-binding groove for presenting glycolipids to NKT cells. However, equine CTL stimulated with α-GalCer failed to kill cells infected with R. equi, and α-GalCer did not increase killing by CTL co-stimulated with R. equi antigen. Likewise, α-GalCer did not induce the lymphoproliferation of equine PBMC or increase the proliferation of R. equi-stimulated cells. Intradermal injection of α-GalCer in horses did not increase the recruitment of lymphocytes or cytokine production. Furthermore, α-GalCer-loaded CD1d tetramers, which have been shown to be broadly cross-reactive, did not bind equine lymphocytes. Altogether, our results demonstrate that in contrast to previously described species, horses are unable to respond to α-GalCer. This raises questions about the capabilities and function of NKT cells and other lipid-specific T lymphocytes in horses.
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Affiliation(s)
- Robson G Dossa
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, USA
| | - Debra C Alperin
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, USA
| | - Diana Garzon
- Unilever Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, USA
| | - Wendy C Brown
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, USA
| | - Peter J Jervis
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Liam R Cox
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Stephen A Hines
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, USA.
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The equine immune responses to infectious and allergic disease: a model for humans? Mol Immunol 2014; 66:89-96. [PMID: 25457878 DOI: 10.1016/j.molimm.2014.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/23/2014] [Accepted: 09/29/2014] [Indexed: 01/01/2023]
Abstract
The modern horse, Equus caballus has historically made important contributions to the field of immunology, dating back to Emil von Behring's description of curative antibodies in equine serum over a century ago. While the horse continues to play an important role in human serotherapy, the mouse has replaced the horse as the predominant experimental animal in immunology research. Nevertheless, continuing efforts have led to an improved understanding of the equine immune response in a variety of infectious and non-infectious diseases. Based on this information, we can begin to identify specific situations where the horse may provide a unique immunological model for certain human diseases.
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The equine CD1 gene family is the largest and most diverse yet identified. Immunogenetics 2013; 66:33-42. [DOI: 10.1007/s00251-013-0741-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
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Ramsay JD, Ueti MW, Johnson WC, Scoles GA, Knowles DP, Mealey RH. Lymphocytes and macrophages are infected by Theileria equi, but T cells and B cells are not required to establish infection in vivo. PLoS One 2013; 8:e76996. [PMID: 24116194 PMCID: PMC3792048 DOI: 10.1371/journal.pone.0076996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/04/2013] [Indexed: 11/18/2022] Open
Abstract
Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata), the intraleukocyte stage (schizont) of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis, breed susceptibility, and strain virulence.
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Affiliation(s)
- Joshua D. Ramsay
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
- * E-mail:
| | - Massaro W. Ueti
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Wendell C. Johnson
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Glen A. Scoles
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Donald P. Knowles
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Robert H. Mealey
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
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Sun L, Adams AA, Betancourt A, Stewart JC, Liu C, Horohov DW. The role of proliferation in the regulation of interferon gamma (IFNγ) expression in foals. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 36:534-539. [PMID: 22079897 DOI: 10.1016/j.dci.2011.09.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/16/2011] [Accepted: 09/19/2011] [Indexed: 05/31/2023]
Abstract
Interferon-gamma (IFNγ) plays an important role against viral and intracellular bacterial infections and its production is deficient in foals. Cellular proliferation provides an opportunity for de novo gene expression, though little is known about its role in regulating IFNγ expression in foals. While stimulation of foal peripheral blood mononuclear cells (PBMCs) with concanavalin A (ConA) increased the frequency of IFNγ(+) cells, the overall percentage of IFNγ(+) cells remained below that of adults. By contrast, the proliferative response of foal PBMC was significantly greater than that of the adults. In foals, IFNγ production was predominantly associated with those T cells that underwent proliferation, whereas in adults non-dividing cells also produced IFNγ. While treatment with hydroxyurea inhibited cellular division, it failed to completely block IFNγ production. This residual IFNγ production likely represented memory cells as the proportion of these proliferation-independent IFNγ(+) cells increased with foal age. However, memory cells may not account for all of the IFNγ production as ConA stimulation likely provided additional signals that can control IFNγ expression.
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Affiliation(s)
- Lingshuang Sun
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546-0099, USA
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Giguère S, Cohen N, Keith Chaffin M, Hines S, Hondalus M, Prescott J, Slovis N. Rhodococcus equi: Clinical Manifestations, Virulence, and Immunity. J Vet Intern Med 2011; 25:1221-30. [DOI: 10.1111/j.1939-1676.2011.00804.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/01/2011] [Accepted: 08/15/2011] [Indexed: 11/27/2022] Open
Affiliation(s)
- S. Giguère
- Department of Large Animal Medicine; University of Georgia; Athens; GA
| | - N.D. Cohen
- Department of Large Animal Clinical Sciences; College of Veterinary Medicine; Texas A&M University; College Station; TX
| | - M. Keith Chaffin
- Department of Large Animal Clinical Sciences; College of Veterinary Medicine; Texas A&M University; College Station; TX
| | - S.A. Hines
- Department of Veterinary Microbiology and Pathology; Washington State University; Pullman; WA
| | - M.K. Hondalus
- Department of Infectious Diseases; University of Georgia; Athens; GA
| | - J.F. Prescott
- Department of Pathobiology; University of Guelph; Guelph; ON; Canada
| | - N.M. Slovis
- Hagyard Equine Medical Institute; Lexington; KY
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Sturgill TL, Giguère S, Franklin RP, Cohen ND, Hagen J, Kalyuzhny AE. Effects of inactivated parapoxvirus ovis on the cumulative incidence of pneumonia and cytokine secretion in foals on a farm with endemic infections caused by Rhodococcus equi. Vet Immunol Immunopathol 2011; 140:237-43. [DOI: 10.1016/j.vetimm.2010.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 12/15/2010] [Accepted: 12/20/2010] [Indexed: 01/29/2023]
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Harris SP, Hines MT, Mealey RH, Alperin DC, Hines SA. Early development of cytotoxic T lymphocytes in neonatal foals following oral inoculation with Rhodococcus equi. Vet Immunol Immunopathol 2011; 141:312-6. [PMID: 21481947 DOI: 10.1016/j.vetimm.2011.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 02/28/2011] [Accepted: 03/14/2011] [Indexed: 11/28/2022]
Abstract
Rhodococcus equi is an important respiratory pathogen of young foals for which a vaccine has long been sought. Two major impediments to effective vaccination are the functionally immature type I immune responses of neonatal foals and early exposure to the bacterium via the environment. Despite these obstacles, it appears that under specific circumstances foals can develop a protective immune response. In this study we investigated the protective mechanisms behind oral inoculation of foals with virulent R. equi bacteria. Two foals receiving an oral inoculum demonstrated accelerated development of R. equi specific cytotoxic T lymphocytes (CTL) as evidenced by significant lysis of R. equi infected, ELA-A mismatched cells at 3 weeks of age. As in a previous study, CTL were not detected until 5-6 weeks of age in two control foals. At each time point the ability of foal peripheral blood mononuclear cells (PBMC) to produce IFN-γ following stimulation with live R. equi or extracted cell wall lipids was similar to that of an adult horse control and between foals, regardless of treatment. These results provide a potential mechanism of protection which has previously been shown to occur following oral inoculation, and suggest that the early detection of CTL may be a useful marker for induction of protective immunity.
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Affiliation(s)
- Seth P Harris
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, PO Box 647040, Pullman, WA 99164-7040, USA
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Nonhealing wound due to Rhodococcus equi in an apparently immunocompetent patient, revealing CD8+ T-lymphocyte deficiency. J Clin Microbiol 2010; 48:4658-60. [PMID: 20881171 DOI: 10.1128/jcm.01469-10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We describe a case of a nonhealing wound due to Rhodococcus equi. Failure of the wound to heal led to immunological investigations and the discovery of a previously unknown CD8+ T-lymphocyte deficit responsible for the chronic infection. The infection was cured after a 3-month course of a combination of antibiotics.
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Harris SP, Fujiwara N, Mealey RH, Alperin DC, Naka T, Goda R, Hines SA. Identification of Rhodococcus equi lipids recognized by host cytotoxic T lymphocytes. MICROBIOLOGY-SGM 2010; 156:1836-1847. [PMID: 20299405 DOI: 10.1099/mic.0.035915-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
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. equi antigen with broadly reactive proteases did not significantly diminish the ability of the antigen to stimulate R. equi-specific CTLs. R. equi-specific CTLs were also shown to lyse target cells (equine macrophages) pulsed with an R. equi lipid extract. Analysis of the R. equi lipid by TLC and MS (MALDI-TOF and ES) indicated that the extracted antigen consisted of three primary fractions: trehalose monomycolate (TMM), trehalose dimycolate (TDM) and cardiolipin (CL). ELA-A-mismatched cells pulsed with purified TMM and CL, but not the TDM fraction, were recognized and lysed by R. equi-specific CTLs. Because of their role in immune clearance and pathogenesis, transcription of the cytokines gamma interferon (IFN-gamma) and interleukin-4 (IL-4) was also measured in response to R. equi lipids by using real-time PCR; elevated IFN-gamma, but not IL-4, was associated with host clearance of the bacteria. The whole-cell R. equi lipid and all three R. equi lipid fractions resulted in marked increases in IFN-gamma transcription, but no increase in IL-4 transcription. Together, these data support the hypothesis that immune recognition of unique lipids in the bacterial cell wall is an important component of the protective immune response to R. equi. The results also identify potential lipid antigens not previously shown to be recognized by CTLs in an important, naturally occurring actinomycete bacterial pathogen.
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Affiliation(s)
- Seth P Harris
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, PO Box 647040, Pullman, WA 99164-7040, USA
| | - Nagatoshi Fujiwara
- Department of Bacteriology, Osaka City University, Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585, Japan
| | - Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, PO Box 647040, Pullman, WA 99164-7040, USA
| | - Debra C Alperin
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, PO Box 647040, Pullman, WA 99164-7040, USA
| | - Takashi Naka
- Department of Bacteriology, Osaka City University, Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585, Japan
| | - Reina Goda
- Department of Bacteriology, Osaka City University, Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585, Japan
| | - Stephen A Hines
- Department of Veterinary Microbiology and Pathology, Washington State University, College of Veterinary Medicine, PO Box 647040, Pullman, WA 99164-7040, USA
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Oliveira AF, Ruas LP, Cardoso SA, Soares SG, Roque-Barreira MC. Vaccination of mice with salmonella expressing VapA: mucosal and systemic Th1 responses provide protection against Rhodococcus equi infection. PLoS One 2010; 5:e8644. [PMID: 20072623 PMCID: PMC2800180 DOI: 10.1371/journal.pone.0008644] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 12/21/2009] [Indexed: 11/28/2022] Open
Abstract
Conventional vaccines to prevent the pneumonia caused by Rhodococcus equi have not been successful. We have recently demonstrated that immunization with Salmonella enterica Typhimurium expressing the VapA antigen protects mice against R. equi infection. We now report that oral vaccination of mice with this recombinant strain results in high and persistent fecal levels of antigen-specific IgA, and specific proliferation of the spleen cells of immunized mice in response to the in vitro stimulation with R. equi antigen. After in vitro stimulation, spleen cells of immunized mice produce high levels of Th1 cytokines and show a prominent mRNA expression of the Th1 transcription factor T-bet, in detriment of the Th2 transcription factor GATA-3. Following R. equi challenge, a high H2O2, NO, IL-12, and IFN-γ content is detected in the organs of immunized mice. On the other hand, TNF-α and IL-4 levels are markedly lower in the organs of vaccinated mice, compared with the non-vaccinated ones. The IL-10 content and the mRNA transcription level of TGF-β are also higher in the organs of immunized mice. A greater incidence of CD4+ and CD8+ T cells and B lymphocytes is verified in vaccinated mice. However, there is no difference between vaccinated and non-vaccinated mice in terms of the frequency of CD4+CD25+Foxp3+ T cells. Finally, we show that the vaccination confers a long-term protection against R. equi infection. Altogether, these data indicate that the oral vaccination of mice with S. enterica Typhimurium expressing VapA induces specific and long-lasting humoral and cellular responses against the pathogen, which are appropriately regulated and allow tissue integrity after challenge.
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Affiliation(s)
- Aline F. Oliveira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luciana P. Ruas
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Silvia A. Cardoso
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Sandro G. Soares
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Maria-Cristina Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail:
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Jacks S, Giguère S. Effects of inoculum size on cell-mediated and humoral immune responses of foals experimentally infected with Rhodococcus equi: a pilot study. Vet Immunol Immunopathol 2009; 133:282-6. [PMID: 19720402 DOI: 10.1016/j.vetimm.2009.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Revised: 05/15/2009] [Accepted: 08/03/2009] [Indexed: 11/18/2022]
Abstract
The objective of this pilot study was to compare the cytokine profile as well as cell-mediated and antibody responses of foals infected with a low inoculum of virulent Rhodococcus equi resulting in subclinical pneumonia to that of foals infected with a high inoculum resulting in severe clinical pneumonia. The mean (+/-SD) ratio of post-infection to pre-infection anti-R. equi IgG(T) concentration was significantly (P=0.002) higher in foals infected with the high inoculum (195+/-145; range 62-328) compared to foals infected with the low inoculum (3.9+/-4.5; range 0.5-11). Similarly, mean (+/-SD) ratio of post-infection to pre-infection IgM concentration was significantly (P=0.002) higher in foals infected with the high inoculum (12+/-4.0; range 7.4-14) compared to foals infected with the low inoculum (2.5+/-1.5; range 1.2-4.7). Proliferative responses to R. equi antigens as well as expression of mRNA for IL-2, IL-4, IL-10, and IFN-gamma in BLN were not significantly different between the two groups. There was a tendency (P=0.073) towards a higher IFN-gamma/IL-4 ratio in the low inoculum group. This study demonstrates that the size of inoculum modulates the IgG subisotype response and possibly the cytokine profile of foals.
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Affiliation(s)
- Stephanie Jacks
- Department Of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States
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The influence of age and Rhodococcus equi infection on CD1 expression by equine antigen presenting cells. Vet Immunol Immunopathol 2009; 130:197-209. [DOI: 10.1016/j.vetimm.2009.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 01/13/2009] [Accepted: 02/06/2009] [Indexed: 11/21/2022]
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Abstract
Assessment of peripheral blood leukocytes is the most common clinical pathology test in equine practice. It is always a part of complete body function assessment and frequently is used alone, or in conjunction with, fibrinogen to monitor response to treatment.
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Affiliation(s)
- Joan B Carrick
- Scone Veterinary Laboratory, Scone Veterinary Hospital, 106 Liverpool Street, Scone, NSW, Australia.
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Nerren JR, Martens RJ, Payne S, Murrell J, Butler JL, Cohen ND. Age-related changes in cytokine expression by neutrophils of foals stimulated with virulent Rhodococcus equi in vitro. Vet Immunol Immunopathol 2008; 127:212-9. [PMID: 19026456 DOI: 10.1016/j.vetimm.2008.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 09/22/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
Although evidence exists that neutrophils play a vital role in resistance to infection with Rhodococcus equi, the means by which neutrophils exert their effects have not been clearly defined. In the present study we evaluated differences in cytokine expression by unstimulated and R. equi-stimulated neutrophils obtained from newborn foals and subsequently at 2-, 4-, and 8-weeks of age. Stimulation with virulent R. equi induced significantly (P<0.05) greater expression of IFNgamma, TNFalpha, IL-6, IL-8, IL-12p40, IL-12p35, and IL-23p19 mRNA relative to expression by unstimulated neutrophils, and there were significant effects of age on expression of IL-6, IL-8, IL-12p40 and IL-23p19. Neutrophil expression of IL-6 and IL-8 in newborn foals was significantly greater than expression at 2-, 4-, and 8-weeks of age. Expression of IL-12p40 by R. equi-stimulated neutrophils from newborn and 2-week-old foals did not differ from that of unstimulated neutrophils; however, expression of IL-12p40 by neutrophils from 4- and 8-week-old foals was significantly greater when stimulated by R. equi than without stimulation. These results demonstrate that foal neutrophils increase mRNA expression of many pro-inflammatory cytokines, including IFNgamma, in response to in vitro stimulation with R. equi, and that the magnitude of this expression with respect to IL-6, IL-8, IL-12p40 and IL-23p19 is influenced by age. The clinical importance of the age-related difference in R. equi-induced expression of IL-12p40 to susceptibility to R. equi pneumonia remains to be determined.
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Affiliation(s)
- Jessica R Nerren
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4475, United States
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17
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T lymphocyte proliferative capacity and CD4+/CD8+ ratio in primiparous and pluriparous lactating cows. J DAIRY RES 2008; 75:457-65. [DOI: 10.1017/s0022029908003439] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
T cells play a central role in specific immunity; their populations and phenotypes could be affected by number of lactation in high-yielding dairy cows. To investigate the effects of parity on the dynamics of T lymphocytes, lymphoproliferative capacity, T lymphocyte subsets and CD4+/CD8+ ratio were studied in peripheral blood of primiparous and pluriparous dairy cows during mid–late lactation. A non-radioactive technique was also adapted for a detailed lymphoproliferation assay. Compared with the primiparous cows, the pluriparous cows exhibited weaker lymphoproliferative activity, larger number of CD4+ cells and substantially greater CD4+/CD8+ ratio in their blood circulation. The increase of the CD4+/CD8+ ratio in the blood of pluriparous dairy cows was mainly due to the rise in the proportion of CD4+ cells and decline in the proportion of CD8+ cells. This increase of the CD4+/CD8+ ratio coincided with the decrease of mitogen-induced proliferation capacity of T lymphocytes. Of four lymphocyte divisions or generations during the lymphoproliferation assay, maximal lymphocyte proliferation capacity at generation 3 in primiparous cows was markedly greater than in pluriparous cows. With an alternatively safer, faster and more reproducible assay (compared with 3H-thymidine scintillation assay) we showed for the first time that aging in dairy cows leads to a decreased mitogen-induced lymphoproliferation and disturbed proportion between CD4+ and CD8+ T cells. This CD4+-CD8+ imbalance together with diminished lymphoproliferative capacity may lead to a weaker T cytotoxic-mediated immunity and increased susceptibility to infectious diseases in pluriparous lactating cows. Our study also emphasizes further application of the methods in farm animals.
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18
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Zhang YW, Davis EG, Blecha F, Wilkerson MJ. Molecular cloning and characterization of equine Toll-like receptor 9. Vet Immunol Immunopathol 2008; 124:209-19. [DOI: 10.1016/j.vetimm.2008.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 03/13/2008] [Accepted: 03/14/2008] [Indexed: 11/17/2022]
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19
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Liu T, Nerren J, Murrell J, Juillard V, El Garch H, Martens R, Cohen N. CpG-Induced Stimulation of Cytokine Expression by Peripheral Blood Mononuclear Cells of Foals and Their Dams. J Equine Vet Sci 2008. [DOI: 10.1016/j.jevs.2008.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Lopez A, Townsend H, Allen A, Hondalus M. Safety and immunogenicity of a live-attenuated auxotrophic candidate vaccine against the intracellular pathogen Rhodococcus equi. Vaccine 2008; 26:998-1009. [DOI: 10.1016/j.vaccine.2007.10.069] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/26/2007] [Accepted: 10/30/2007] [Indexed: 11/15/2022]
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21
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Mealey R, Stone D, Hines M, Alperin D, Littke M, Leib S, Leach S, Hines S. Experimental Rhodococcus equi and equine infectious anemia virus DNA vaccination in adult and neonatal horses: effect of IL-12, dose, and route. Vaccine 2007; 25:7582-97. [PMID: 17889970 PMCID: PMC3342688 DOI: 10.1016/j.vaccine.2007.07.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2007] [Revised: 07/24/2007] [Accepted: 07/28/2007] [Indexed: 11/15/2022]
Abstract
Improving the ability of DNA-based vaccines to induce potent Type1/Th1 responses against intracellular pathogens in large outbred species is essential. Rhodoccocus equi and equine infectious anemia virus (EIAV) are two naturally occurring equine pathogens that also serve as important large animal models of neonatal immunity and lentiviral immune control. Neonates present a unique challenge for immunization due to their diminished immunologic capabilities and apparent Th2 bias. In an effort to augment R. equi- and EIAV-specific Th1 responses induced by DNA vaccination, we hypothesized that a dual promoter plasmid encoding recombinant equine IL-12 (rEqIL-12) would function as a molecular adjuvant. In adult horses, DNA vaccines induced R. equi- and EIAV-specific antibody and lymphoproliferative responses, and EIAV-specific CTL and tetramer-positive CD8+ T lymphocytes. These responses were not enhanced by the rEqIL-12 plasmid. In neonatal foals, DNA immunization induced EIAV-specific antibody and lymphoproliferative responses, but not CTL. The R. equi vapA vaccine was poorly immunogenic in foals even when co-administered with the IL-12 plasmid. It was concluded that DNA immunization was capable of inducing Th1 responses in horses; dose and route were significant variables, but rEqIL-12 was not an effective molecular adjuvant. Additional work is needed to optimize DNA vaccine-induced Th1 responses in horses, especially in neonates.
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Affiliation(s)
- R.H. Mealey
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - D.M. Stone
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - M.T. Hines
- Department of Veterinary Clinical Sciences, Washington State University, College of Veterinary Medicine, P.O. Box 646010, Pullman, WA 99164-6010, United States
| | - D.C. Alperin
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - M.H. Littke
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - S.R. Leib
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - S.E. Leach
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
| | - S.A. Hines
- Department of Veterinary Microbiology & Pathology, Washington State University, College of Veterinary Medicine, P.O. Box 647040, Pullman, WA 99164-7040, United States
- Corresponding author. Tel.: +1 509 335 6030; fax: +1 509 335 8529. (S.A. Hines)
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22
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Mealey RH, Littke MH, Leib SR, Davis WC, McGuire TC. Cloning and large-scale expansion of epitope-specific equine cytotoxic T lymphocytes using an anti-equine CD3 monoclonal antibody and human recombinant IL-2. Vet Immunol Immunopathol 2007; 118:121-8. [PMID: 17498813 PMCID: PMC2002571 DOI: 10.1016/j.vetimm.2007.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2007] [Revised: 03/20/2007] [Accepted: 04/05/2007] [Indexed: 11/20/2022]
Abstract
Cytotoxic T lymphocytes are involved in controlling intracellular pathogens in many species, including horses. Particularly, CTL are critical for the control of equine infectious anemia virus (EIAV), a lentivirus that infects horses world-wide. In humans and animal models, CTL clones are valuable for evaluating the fine specificity of epitope recognition, and for adoptive immunotherapy against infectious and neoplastic diseases. Cloned CTL would be equally useful for similar studies in the horse. Here we present the first analysis of a method to generate equine CTL clones. Peripheral blood mononuclear cells were obtained from an EIAV-infected horse and stimulated with the EIAV Rev-QW11 peptide. Sorted CD8+ T cells were cloned by limiting dilution, and expanded without further antigen addition using irradiated PBMC, anti-equine CD3, and human recombinant IL-2. Clones could be frozen and thawed without detrimental effects, and could be subsequently expanded to numbers exceeding 2 x 10(9)cells. Flow cytometry of expanded clones confirmed the CD3+/CD8+ phenotype, and chromium release assays confirmed CTL activity. Finally, sequencing TCR beta chain genes confirmed clonality. Our results provide a reliable means to generate large numbers of epitope-specific equine CTL clones that are suitable for use in downstream applications, including functional assays and adoptive transfer studies.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- CD3 Complex/immunology
- Clone Cells/cytology
- Clone Cells/drug effects
- Epitopes, T-Lymphocyte/immunology
- Horses/immunology
- Humans
- Interleukin-2/immunology
- Interleukin-2/pharmacology
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Recombinant Proteins
- T-Lymphocytes, Cytotoxic/cytology
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- Time Factors
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Affiliation(s)
- Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA.
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Jacks S, Giguère S, Crawford PC, Castleman WL. Experimental infection of neonatal foals with Rhodococcus equi triggers adult-like gamma interferon induction. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:669-77. [PMID: 17409222 PMCID: PMC1951072 DOI: 10.1128/cvi.00042-07] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rhodococcus equi is a facultative intracellular pathogen that causes pneumonia in young foals but does not induce disease in immunocompetent adult horses. Clearance of R. equi depends mainly on gamma interferon (IFN-gamma) production by T lymphocytes, whereas the predominance of interleukin 4 (IL-4) is detrimental. Young foals, like neonates of many other species, are generally deficient in the ability to produce IFN-gamma. The objective of this study was to compare the cytokine profiles, as well as cell-mediated and antibody responses, of young foals to those of adult horses following intrabronchial challenge with R. equi. The lymphoproliferative responses of bronchial lymph node (BLN) cells to concanavalin A were significantly higher in foals than in adult horses. In contrast, adult horses had significantly higher lymphoproliferative responses to R. equi antigens than did foals. Infected foals had significantly lower IL-4 mRNA expression but significantly higher IFN-gamma expression and IFN-gamma/IL-4 ratio in R. equi-stimulated BLN lymphocytes than did infected adults. Infection with R. equi in foals resulted in a significant increase in the percentage of T lymphocytes and CD4(+) T lymphocytes in bronchoalveolar lavage fluid in association with a significant decrease in the percentage of these cell populations in BLNs. Infection of foals also resulted in a marked increase in serum immunoglobulin Ga (IgGa) and IgGb levels, resulting in concentrations in serum that were significantly higher than those of adult horses. This study demonstrates that the immune response to R. equi in foals is not biased toward IL-4 and is characterized by the predominant induction of IFN-gamma.
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Affiliation(s)
- Stephanie Jacks
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, P.O. Box 100136, 2015 S.W. 16th Ave., Gainesville, FL 32610, USA
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24
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Jacks S, Giguère S, Prescott JF. In vivo expression of and cell-mediated immune responses to the plasmid-encoded virulence-associated proteins of Rhodococcus equi in foals. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2007; 14:369-74. [PMID: 17301216 PMCID: PMC1865619 DOI: 10.1128/cvi.00448-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rhodococcus equi is a facultative intracellular pathogen that causes pneumonia in foals but does not induce disease in adult horses. Virulence of R. equi depends on the presence of a large plasmid, which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH). Eradication of R. equi from the lungs depends on gamma interferon (IFN-gamma) production by T lymphocytes. The objectives of the present study were to determine the relative in vivo expression of the vap genes of R. equi in the lungs of infected foals, to determine the recall response of bronchial lymph node (BLN) lymphocytes from foals and adult horses to each of the Vap proteins, and to compare the cytokine profiles of proliferating lymphocytes between foals and adult horses. vapA, vapD, and vapG were preferentially expressed in the lungs of infected foals, and expression of these genes in the lungs was significantly (P < 0.05) higher than that achieved during in vitro growth. VapA and VapC induced the strongest lymphoproliferative responses for foals and adult horses. There was no significant difference in recall lymphoproliferative responses or IFN-gamma mRNA expression by bronchial lymph node lymphocytes between foals and adults. In contrast, interleukin 4 (IL-4) expression was significantly higher for adults than for foals for each of the Vap proteins. The ratio of IFN-gamma to IL-4 was significantly higher for foals than for adult horses for most Vap proteins. Therefore, foals are immunocompetent and are capable of mounting lymphoproliferative responses of the same magnitude and cytokine phenotype as those of adult horses.
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Affiliation(s)
- Stephanie Jacks
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
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25
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Breathnach CC, Sturgill-Wright T, Stiltner JL, Adams AA, Lunn DP, Horohov DW. Foals are interferon gamma-deficient at birth. Vet Immunol Immunopathol 2006; 112:199-209. [PMID: 16621024 DOI: 10.1016/j.vetimm.2006.02.010] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 02/17/2006] [Accepted: 02/20/2006] [Indexed: 11/23/2022]
Abstract
The increased vulnerability of foals to specific pathogens such as Rhodococcus equi is believed to reflect an innate immunodeficiency, the nature of which remains poorly understood. Previous studies have demonstrated that neonates of many species fail to mount potent Th1 responses. The current research investigates the ability of circulating and pulmonary lymphocytes of developing foals to produce interferon gamma (IFNgamma). Peripheral blood mononuclear cells (PBMC) were prepared from up to 10 horse foals at regular intervals throughout the first 6 months of life. Bronchoalveolar lavage (BAL) samples were collected at 1, 3 or 6 months of age from three groups of five foals. The PBMC and BAL cells were stimulated in vitro and IFNgamma production was measured by intracellular staining. In addition, RNA was extracted from freshly isolated and in vitro stimulated PBMC and BAL cells for quantitation of IFNgamma gene expression by real time PCR. Newborn foals exhibited a marked inability to express the IFNgamma gene and produce IFNgamma protein. This deficiency was observed in both circulating and pulmonary lymphocytes. However, IFNgamma gene expression and protein production increased steadily throughout the first 6 months of life, reaching adult levels within the first year of life. These findings suggest that foals are born with an inherent inability to mount a Th1-based cell mediated immune response which may contribute to their susceptibility to intracellular pathogens.
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Affiliation(s)
- C C Breathnach
- Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40546-0099, USA
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26
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Patton KM, McGuire TC, Hines MT, Mealey RH, Hines SA. Rhodococcus equi-specific cytotoxic T lymphocytes in immune horses and development in asymptomatic foals. Infect Immun 2005; 73:2083-93. [PMID: 15784549 PMCID: PMC1087435 DOI: 10.1128/iai.73.4.2083-2093.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rhodococcus equi is an important cause of pneumonia in young horses; however, adult horses are immune due to their ability to mount protective recall responses. In this study, the hypothesis that R. equi-specific cytotoxic T lymphocytes (CTL) are present in the lung of immune horses was tested. Bronchoalveolar lavage (BAL)-derived pulmonary T lymphocytes stimulated with R. equi lysed infected alveolar macrophages and peripheral blood adherent cells (PBAC). As with CTL obtained from the blood, killing of R. equi-infected targets by pulmonary effectors was not restricted by equine lymphocyte alloantigen-A (ELA-A; classical major histocompatibility complex class I), suggesting a novel or nonclassical method of antigen presentation. To determine whether or not CTL activity coincided with the age-associated susceptibility to rhodococcal pneumonia, CTL were evaluated in foals. R. equi-stimulated peripheral blood mononuclear cells (PBMC) from 3-week-old foals were unable to lyse either autologous perinatal or mismatched adult PBAC targets. The defect was not with the perinatal targets, as adult CTL effectors efficiently killed infected targets from 3-week-old foals. In contrast, significant CTL activity was present in three of five foals at 6 weeks of age, and significant specific lysis was induced by PBMC from all foals at 8 weeks of age. As with adults, lysis was ELA-A unrestricted. Two previously described monoclonal antibodies, BCD1b3 and CD1F2/1B12.1, were used to examine the expression of CD1, a nonclassical antigen-presenting molecule, on CTL targets. These antibodies cross-reacted with both foal and adult PBAC. However, neither antibody bound alveolar macrophages, suggesting that the R. equi-specific, major histocompatibility complex-unrestricted lysis is not restricted by a surface molecule identified by these antibodies.
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Affiliation(s)
- Kristin M Patton
- Department of Veterinary Microbiology and Pathology, Washington State University, Bustad Hall, Room 402, Pullman, Washington 99164-7040, USA
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