CD4+ T cells are required for the maintenance, not programming, of memory CD8+ T cells after acute infection.
Immunization in the absence of CD4(+) T cell help results in defective CD8(+) T cell memory, deficient recall responses and diminished protective immunity. Here we investigated at what stage during the immune response to pathogen CD4(+) T cells are essential in the promotion of functional CD8(+) T cell memory. Memory CD8(+) T cell numbers decreased gradually in the absence of CD4(+) T cells despite the presence of similar numbers of memory cell precursors at the peak of the effector phase. Adoptive transfer of effector or memory CD8(+) T cells into wild-type or CD4(+) T cell-deficient mice demonstrated that the presence of CD4(+) T cells was important only after, not during, the early CD8(+) T cell programming phase. In the absence of CD4(+) T cells, memory CD8(+) T cells became functionally impaired and decreased in quantity over time. We conclude that in the context of an acute infection, CD4(+) T cells are required only during the maintenance phase of long-lived memory CD8(+) T cells.
Department of Immunology and the Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA.
Joseph C
JC
Sun
Matthew A
MA
Williams
Michael J
MJ
Bevan
D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D000949:Histocompatibility Antigens Class II; D007156:Immunologic Memory; D008089:Listeria monocytogenes / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology*; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D051379:Mice; D008822:Mice, Transgenic; D020395:Receptors, Interleukin-7 / Q000096:biosynthesis / Q000276:immunology
D000949:Histocompatibility Antigens Class II; D020395:Receptors, Interleukin-7; C415350:interleukin-7 receptor, alpha chain