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Updated: Oct 17, 2026
Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining
Published on: December 23, 2016
Feline CD8+ T cell non-cytolytic anti-feline immunodeficiency virus activity mediated by a soluble factor(s)
T Hohdatsu1, M Okubo, H Koyama
1Department of Veterinary Infectious Diseases, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori, Japan. hohdatsu@vmas.kitasato-u.ac.jp
Abstract:
Feline immunodeficiency virus (FIV) is more readily isolated from CD8+ T cell-depleted peripheral blood mononuclear cells (PBMC) of FIV-infected cats than from unfractionated PBMC cultures. However, it is not known whether feline CD8+ T cells down-regulate FIV expression by direct interaction with FIV-infected cells or via a soluble mediator. Furthermore, it is not known whether this anti-FIV activity involves a lytic or non-lytic mechanism. In the present study, we demonstrated that autologous and allogeneic CD8+ T cells from asymptomatic FIV-infected cats inhibited the replication of FIV in CD8+ T cell-depleted PBMC cultures in a dose-dependent manner. The inhibitory effect was mediated by a non-lytic mechanism, and was not dependent on direct cell-to-cell contact: an inhibitory effect was exerted by CD8+ T cells across a semi-permeable membrane, and an inhibitory activity was also present in cell-free supernatants from CD8+ T cells. These results suggest that this suppressive effect is mediated, at least in part, by soluble factors produced by CD8+ T cells.
Insights
Feline CD8+ T cells inhibit feline immunodeficiency virus (FIV) replication through soluble factors, not direct contact. This non-lytic mechanism suppresses FIV in infected cats.
Area of Science:
- Immunology
- Virology
- Veterinary Medicine
Background:
- Feline immunodeficiency virus (FIV) is often isolated from CD8+ T cell-depleted peripheral blood mononuclear cells (PBMC) of infected cats.
- The mechanism by which CD8+ T cells influence FIV replication (direct contact vs. soluble mediators, lytic vs. non-lytic) remains unclear.
Purpose of the Study:
- To investigate the mechanism by which feline CD8+ T cells suppress FIV replication.
- To determine if the anti-FIV activity involves direct cell-to-cell contact or soluble factors.
- To ascertain whether the mechanism is lytic or non-lytic.
Main Methods:
- Utilized CD8+ T cell-depleted PBMC cultures from FIV-infected cats.
- Assessed the inhibitory effect of autologous and allogeneic CD8+ T cells on FIV replication.
- Investigated the role of cell-to-cell contact using semi-permeable membranes.
- Analyzed cell-free supernatants from CD8+ T cells for inhibitory activity.
Main Results:
- CD8+ T cells from asymptomatic FIV-infected cats demonstrated a dose-dependent inhibition of FIV replication.
- The inhibitory effect was mediated by a non-lytic mechanism.
- Inhibition occurred independently of direct cell-to-cell contact, as evidenced by experiments using semi-permeable membranes and cell-free supernatants.
Conclusions:
- Feline CD8+ T cells suppress FIV replication in PBMC cultures.
- The suppressive effect is mediated, at least in part, by soluble factors released by CD8+ T cells.
- The mechanism of FIV suppression by CD8+ T cells is non-lytic and does not require direct cell-to-cell contact.
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