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Updated: May 29, 2026

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function
Published on: October 15, 2013
HIV infection of thymocytes inhibits IL-7 activity without altering CD127 expression
Charlene D Young1, Jonathan B Angel
1Ottawa Hospital Research Institute, 501 Smyth Rd, Ottawa, Canada.
Background:
Thymic function is altered in HIV infection and characterized by dysregulation of the thymic epithelial network, reduced thymic output and ultimately an impaired naïve T-cell pool. The IL-7/IL-7 receptor (IL-7R) signalling pathway is critical for the maturation and differentiation of thymocytes. HIV infection is associated with a decrease in IL-7Rα (CD127) expression and impaired CD127 signalling in circulating CD8+ T-cells; however, little is known about the effect of HIV on CD127 expression and IL-7 activity in the thymus. Therefore, the effect of in vitro HIV infection on CD127 expression and IL-7-mediated function in thymocytes was investigated.
Findings:
In vitro HIV infection of thymocytes did not affect CD127 expression on either total thymocytes or on single positive CD4 or single positive CD8 subsets. However, HIV infection resulted in a decrease in the level of IL-7-induced STAT-5 phosphorylation and Bcl-2 expression in unfractionated thymocytes.
Conclusion:
These findings indicate that HIV infection alters IL-7 responsiveness of thymocytes by a mechanism other than CD127 downregulation and potentially explain the disruption in thymopoiesis observed in HIV infection.
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