Constitutive expression of IL-7 receptor alpha does not support increased expansion or prevent contraction of antigen-specific CD4 or CD8 T cells following Listeria monocytogenes infection

• Published in: The Journal of immunology (1950) 2008-03, Vol.180 (5), p.2855-2862
• Main Authors: Haring, Jodie S, Jing, Xuefang, Bollenbacher-Reilley, Julie, Xue, Hai-Hui, Leonard, Warren J, Harty, John T
• Format: Article
• Language: English
• Subjects: Animals; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; Cell Death - genetics; Cell Death - immunology; Cell Proliferation; Cell Survival - genetics; Cell Survival - immunology; Epitopes, T-Lymphocyte - genetics; Epitopes, T-Lymphocyte - immunology; Growth Inhibitors - biosynthesis; Growth Inhibitors - genetics; Growth Inhibitors - physiology; Immunologic Memory - genetics; Listeria monocytogenes; Listeria monocytogenes - immunology; Listeriosis - genetics; Listeriosis - immunology; Listeriosis - pathology; Lymphocyte Activation - genetics; Lymphocyte Count; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptors, Interleukin-7 - biosynthesis; Receptors, Interleukin-7 - genetics; Receptors, Interleukin-7 - physiology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.180.5.2855

Expression of IL-7Ralpha (CD127) has been suggested as a major determinant in the survival of memory T cell precursors. We investigated whether constitutive expression of IL-7Ralpha on T cells increased expansion and/or decreased contraction of endogenous Ag-specific CD4 and CD8 T cells following infection with Listeria monocytogenes. The results indicate that constitutive expression of IL-7Ralpha alone was not enough to impart an expansion or survival advantage to CD8 T cells responding to infection, and did not increase memory CD8 T cell numbers over those observed in wild-type controls. Constitutive expression of IL-7Ralpha did allow for slightly prolonged expansion of Ag-specific CD4 T cells; however, it did not alter the contraction phase or protect against the waning of memory T cell numbers at later times after infection. Memory CD4 and CD8 T cells generated in IL-7Ralpha transgenic mice expanded similarly to wild-type T cells after secondary infection, and immunized IL-7Ralpha transgenic mice were fully protected against lethal bacterial challenge demonstrating that constitutive expression of IL-7Ralpha does not impair, or markedly improve memory/secondary effector T cell function. These results indicate that expression of IL-7Ralpha alone does not support increased survival of effector Ag-specific CD4 or CD8 T cells into the memory phase following bacterial infection.