Immunity to Rhodococcus equi.
Abstract: Rhodococcal pneumonia is an important, life threatening disease of foals and immunosuppressed humans. Increased knowledge of the mechanisms of protective immunity are required in order to develop an effective immunoprophylaxis strategy for horses and immunotherapeutic regiments for people. Both humoral and cellular components of the immune system may be involved in immune clearance of R. equi. The susceptibility of foals less than 4-6 months of age is postulated to reflect waning maternal antibody, and passive transfer of hyperimmune plasma can provide protection on endemic farms. However, effective clearance is likely to require appropriate cellular responses, including the secretion of cytokines. In murine models, both CD4+ and CD8+ T lymphocytes can reduce bacterial counts in the lung. CD4+ cells appear to be both required and sufficient, and IFN-gamma is a primary mediator. Clearance appears to be a type 1 immune response while type 2 responses may lead to a failure to clear and lesion development. It remains to be determined how the cellular immunity experiments reported in mice relate to horses and humans. Likewise, the role of specific R. equi antigens in protective immunity has not been determined.
Publication Date: 1997-06-16 PubMed ID: 9226832DOI: 10.1016/s0378-1135(97)00086-2Google Scholar: Lookup
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Summary
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The research focuses on understanding the immune response to Rhodococcal pneumonia, a lethal disease affecting young foals and immunosuppressed humans, in order to develop effective vaccine and treatment strategies.
Overview of Rhodococcal Pneumonia and Immune Response
- Rhodococcal pneumonia is a serious and potentially fatal disease that affects young horses (foals) and humans with weakened immune systems.
- The study emphasizes the need to comprehend the components involved in the body’s immune response against the disease, which includes both humoral and cellular elements.
Role of Humoral Component in Immune Response
- The susceptibility of foals less than 4-6 months old to this disease is postulated to be due to a decrease in maternal antibodies.
- It is suggested that passive transfer of hyperimmune plasma, which is an immunity that is acquired from an outside source, protects foals in areas where the disease is prevalent.
Cellular Component in Immune Clearance
- The research suggests effective clearance of R. equi, the bacteria causing the disease, requires appropriate cellular responses, including the secretion of cytokines – proteins vital for cellular communication during immune responses.
- The study has inferred from experiments on mice that both CD4+ and CD8+ T lymphocytes (types of white blood cells) decrease bacterial counts in the lungs. It is not yet determined how these findings could apply to horses and humans.
- The CD4+ cells seem to be both needed and sufficient for effective clearance of the bacteria, with Interferon-gamma (IFN-gamma) being the key mediator. This indicates that IFN-gamma may play a significant role in the immune response against the disease.
Type 1 and Type 2 Immune Responses
- The study theorizes that clearance of the bacteria corresponds with a type 1 immune response, while type 2 immune responses could lead to inability to clear the infection and the development of lesions, implying an unsuccessful immune response.
Role of Specific R. equi Antigens
- The role of specific R. equi antigens (substances that induce an immune response) in protective immunity remains uncertain, and is highlighted as an area for future research.
Cite This Article
APA
Hines SA, Kanaly ST, Byrne BA, Palmer GH.
(1997).
Immunity to Rhodococcus equi.
Vet Microbiol, 56(3-4), 177-185.
https://doi.org/10.1016/s0378-1135(97)00086-2 Publication
Researcher Affiliations
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA. shines@vetmed.wsu.edu
MeSH Terms
- Actinomycetales Infections / immunology
- Actinomycetales Infections / prevention & control
- Actinomycetales Infections / veterinary
- Animals
- Antibody Formation
- Disease Susceptibility
- Female
- Horse Diseases
- Horses
- Humans
- Immunity, Cellular
- Immunity, Maternally-Acquired
- Mice
- Pregnancy
- Rhodococcus equi / immunology
Citations
This article has been cited 8 times.- Erganis O, Sayin Z, Hadimli HH, Sakmanoglu A, Pinarkara Y, Ozdemir O, Maden M. The effectiveness of anti-R. equi hyperimmune plasma against R. equi challenge in thoroughbred Arabian foals of mares vaccinated with R. equi vaccine. ScientificWorldJournal 2014;2014:480732.
- van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L. The steroid catabolic pathway of the intracellular pathogen Rhodococcus equi is important for pathogenesis and a target for vaccine development. PLoS Pathog 2011 Aug;7(8):e1002181.
- Denes E, Peignon-Orsoni D, Terrade FX. Nonhealing wound due to Rhodococcus equi in an apparently immunocompetent patient, revealing CD8+ T-lymphocyte deficiency. J Clin Microbiol 2010 Dec;48(12):4658-60.
- Prando C, Boisson-Dupuis S, Grant AV, Kong XF, Bustamante J, Feinberg J, Chapgier A, Rose Y, Jannière L, Rizzardi E, Zhang Q, Shanahan CM, Viollet L, Lyonnet S, Abel L, Ruga EM, Casanova JL. Paternal uniparental isodisomy of chromosome 6 causing a complex syndrome including complete IFN-gamma receptor 1 deficiency. Am J Med Genet A 2010 Mar;152A(3):622-9.
- 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 Jan 13;5(1):e8644.
- Kohler AK, Stone DM, Hines MT, Byrne BA, Alperin DC, Norton LK, Hines SA. Rhodococcus equi secreted antigens are immunogenic and stimulate a type 1 recall response in the lungs of horses immune to R. equi infection. Infect Immun 2003 Nov;71(11):6329-37.
- Kasuga-Aoki H, Takai S, Sasaki Y, Tsubaki S, Madarame H, Nakane A. Tumour necrosis factor and interferon-gamma are required in host resistance against virulent Rhodococcus equi infection in mice: cytokine production depends on the virulence levels of R. equi. Immunology 1999 Jan;96(1):122-7.
- Mizuguchi Y, Tsuzuki N, Ebana MD, Suzuki Y, Kakuda T. IgG Subtype Response against Virulence-Associated Protein A in Foals Naturally Infected with Rhodococcus equi. Vet Sci 2024 Sep 9;11(9).
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