Related Experiment Videos
Characterization of simian immunodeficiency virus-specific T-cell-mediated cytotoxic response of infected rhesus
B R Vowels1, M E Gershwin, M B Gardner
1Department of Pathology, University of California, Davis 95616.
Abstract:
Four juvenile rhesus macaques were infected with simian immunodeficiency virus (SIV)MAC-Freshly isolated peripheral blood mononuclear cells (PBMC) from these SIVMAC-infected and from uninfected control macaques were assessed for cytotoxic T-lymphocyte (CTL) activity monthly for 7 consecutive months, beginning 2 months after infection. Target cells consisted of major histocompatibility complex (MHC) haploidentical parental PBMC which were stimulated with mitogen and then pulsed with heat-killed SIVMAC. CTL activity was demonstrated on all four infected animals. The effector cells are T cells which mediate cytotoxicity against SIVMAC-pulsed target cells in an MHC-restricted manner. Furthermore, the cytotoxicity is virus specific and predominantly, if not exclusively, mediated by CD8+ T cells; it is also MHC class-I restricted. Incubation of target cells with leupeptin prior to the cytotoxic assay inhibited target cell generation, suggesting that viral antigens are processed via an endocytic pathway.
Insights
This study shows that cytotoxic T-lymphocyte (CTL) activity develops in rhesus macaques infected with simian immunodeficiency virus (SIV). This immune response is virus-specific and primarily mediated by CD8+ T cells.
Area of Science:
- Immunology
- Virology
- Primate Models
Background:
- Simian immunodeficiency virus (SIV) infection in macaques serves as a model for human immunodeficiency virus (HIV) infection.
- Understanding the host immune response to SIV is crucial for developing effective vaccines and therapies.
Purpose of the Study:
- To investigate the development and characteristics of cytotoxic T-lymphocyte (CTL) activity following SIVMAC infection in juvenile rhesus macaques.
- To determine the specificity and cellular mediators of the anti-SIV immune response.
Main Methods:
- Peripheral blood mononuclear cells (PBMC) from SIVMAC-infected and control macaques were assessed for CTL activity over 7 months.
- Target cells were mitogen-stimulated, SIVMAC-pulsed PBMC, assessed for MHC restriction and cellular mediators (CD8+ T cells).
- Antigen processing pathways were investigated using leupeptin treatment of target cells.
Main Results:
- All four SIVMAC-infected macaques demonstrated significant CTL activity.
- The observed cytotoxicity was MHC-restricted, virus-specific, and predominantly mediated by CD8+ T cells.
- Leupeptin inhibition suggested viral antigen processing via an endocytic pathway.
Conclusions:
- Juvenile rhesus macaques develop robust, virus-specific CTL responses after SIVMAC infection.
- CD8+ T cells play a central role in mediating MHC class-I restricted cytotoxicity against SIV-infected cells.
- Viral antigens are likely processed through an endocytic pathway for presentation to cytotoxic T lymphocytes.