Longitudinal analysis of CD8(+) T-cell phenotype and IL-7, IL-15 and IL-16 mRNA expression in different tissues...

Area of Science:

• Immunology
• Virology
• Primatology

Background:

• Simian immunodeficiency virus (SIV) infection in macaques serves as a critical model for studying human immunodeficiency virus (HIV) infection.
• Investigating early changes in CD8(+) T-lymphocyte subsets and cytokines during lentiviral infection is crucial for understanding disease progression.

Purpose of the Study:

• To analyze early modifications in CD8(+) T-lymphocyte subsets and cytokine mRNA expression in macaques infected with SIV.
• To explore the relationship between viral replication, T-cell subset changes, and cytokine profiles in different tissues.

Main Methods:

• Three cynomolgus macaques were intravenously inoculated with SIVmac 251.
• Phenotypic analysis of CD8(+) T cells was performed on mononuclear cells from blood, lymph nodes, and bronchoalveolar lavage.
• Reverse transcription-polymerase chain reaction (RT-PCR) was used to monitor mRNA expression of Interleukin-7 (IL-7), Interleukin-15 (IL-15), and Interleukin-16 (IL-16).

Main Results:

• An expansion of CD8(+)CD28(-) T cells was observed in peripheral blood and lungs from the third week post-infection.
• CD8(+)CD28(+) T cells expanded in lymph nodes.
• Modulations in IL-16, IL-15, and IL-7 mRNA expression were detected across all studied compartments.
• Overexpression of IL-16 mRNA in the lung and peripheral blood correlated with containment of systemic viral replication.

Conclusions:

• Early SIV infection induces distinct CD8(+) T-cell subset expansions in different anatomical sites.
• Altered expression of IL-7, IL-15, and IL-16 suggests their involvement in early viral dissemination.
• These cytokine perturbations may play a significant role in the immunopathogenesis of HIV infection.