Effector CD4 T Cells Are Biochemically Distinct from the Memory Subset: Evidence for Long-Term Persistence of Effectors In Vivo

• Published in: The Journal of immunology (1950) Vol. 163; no. 6; pp. 3053 - 3063
• Main Authors: Ahmadzadeh, Mojgan, Hussain, S. Farzana, Farber, Donna L
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.09.1999
• Subjects: Adoptive Transfer; Animals; CD4-Positive T-Lymphocytes - chemistry; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - metabolism; CD4-Positive T-Lymphocytes - transplantation; Cell Differentiation - immunology; Cell Survival - immunology; Immunologic Memory; Immunophenotyping; Interphase - immunology; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Transgenic; Phosphorylation; T-Lymphocyte Subsets - chemistry; T-Lymphocyte Subsets - cytology; T-Lymphocyte Subsets - metabolism; T-Lymphocyte Subsets - transplantation
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.163.6.3053

Memory T cell responses are believed to be mediated by long-lived memory T cells that arise directly from a subset of short-lived, activated effector T cells that have reverted to the resting state. Although widely accepted, definitive proof that memory T cells arise from effectors is lacking because of the inability to reliably distinguish these subsets based on known phenotypic or functional parameters. We have used a biochemical approach to distinguish effector and memory CD4 T cell subsets and follow the differentiative fate of effector cells in vivo. When examined biochemically, effector and memory CD4 T cells are strikingly distinct and exhibit qualitative and quantitative differences in tyrosine phosphorylation. These effector-specific patterns were identical in effectors derived either from naive CD4 T cells (primary effectors) or memory CD4 T cells (memory effectors). To monitor the fate of effector cells in vivo, Ag-activated CD4+ TCR-transgenic T cells were transferred into irradiated BALB/c mice. These TCR-transgenic CD4 T cells persisted in adoptive hosts for several months, gave a recall response to Ag, yet exhibited effector-specific biochemical profiles. These results suggest that a subset of effector CD4 T cells can persist in vivo and contribute to long-term immunity by mediating secondary immune responses.