Rhodococcus equi-Infected Macrophages Are Recognized and Killed by CD8+ T Lymphocytes in a Major Histocompatibility Complex Class I-Unrestricted Fashion
AUTOR(ES)
Patton, Kristin M.
FONTE
American Society for Microbiology
RESUMO
The goal of this research was to examine the role of cytotoxic T lymphocytes (CTL) in the control of Rhodococcus equi and specifically to determine if R. equi-specific CD8+ CTL occurred in the blood of immune horses. Equine peripheral blood mononuclear cells stimulated with antigen-presenting cells either infected with R. equi or exposed to soluble R. equi antigen lysed R. equi-infected target cells. Lysis was decreased to background by depletion of either CD2+ or CD3+ cells, indicating that the effector cell had a T-lymphocyte, but not NK cell, phenotype. Stimulation induced an increased percentage of CD8+ T cells in the effector population, and depletion of CD8+ T cells resulted in significantly decreased lysis of infected targets. Killing of R. equi-infected macrophages by effector cells was equally effective against autologous and equine leukocyte antigen A (classical major histocompatibility complex [MHC] class I) mismatched targets. To evaluate potential target antigens, target cells were infected with either virulent (80.6-kb plasmid-containing) or avirulent (plasmid-cured) R. equi. The degree of lysis was not altered by the presence of the plasmid, providing evidence that the virulence plasmid, which is required for survival within macrophages, was not necessary for recognition and killing of R. equi-infected cells. These data indicate that immunocompetent adult horses develop R. equi-specific CD8+ CTL, which may play a role in immunity to R. equi. The apparent lack of restriction via classical MHC class I molecules suggests a novel or nonclassical method of antigen processing and presentation, such as presentation by CD1 or other nonclassical MHC molecules.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=529141Documentos Relacionados
- Necrotic Death of Rhodococcus equi-Infected Macrophages Is Regulated by Virulence-Associated Plasmids†
- Major histocompatibility complex class I-specific and -restricted killing of beta 2-microglobulin-deficient cells by CD8+ cytotoxic T lymphocytes.
- Virus-specific, CD8+ major histocompatibility complex class I-restricted cytotoxic T lymphocytes in lymphocytic choriomeningitis virus-infected beta2-microglobulin-deficient mice.
- Detection of Simian Immunodeficiency Virus Gag-Specific CD8+ T Lymphocytes in Semen of Chronically Infected Rhesus Monkeys by Cell Staining with a Tetrameric Major Histocompatibility Complex Class I-Peptide Complex
- Putative Immunodominant Human Immunodeficiency Virus-Specific CD8+ T-Cell Responses Cannot Be Predicted by Major Histocompatibility Complex Class I Haplotype