Osum, Kevin2025-02-142025-02-142024-09https://hdl.handle.net/11299/269961University of Minnesota Ph.D. dissertation. September 2024. Major: Microbiology, Immunology and Cancer Biology. Advisor: Marc Jenkins. 1 computer file (PDF); vi, 122 pages.It is not clear how CD4+ memory T cells are formed from a much larger pool of earlier effector cells. We found that transient systemic bacterial infection rapidly generates several antigen-specific Th1 and T follicular helper (Tfh) effector cell populations with different tissue residence behaviors. Each Th1 and Tfh effector cell type produced a similar memory cell type, which was maintained by IL-7, or in the case of germinal center Tfh cells, by the T cell antigen receptor (TCR). Although most cells of all varieties had transcriptomes indicative of cell stress and death at the peak of the response, some had already acquired a quiescence signature. This thesis demonstrates that acute infection induces differentiation of Th1 and Tfh effector cells, a minority of which quickly adopt a transcriptional program that allows escape from death and become memory cells that survive from sensing IL-7 or a TCR ligand.enCD4+ T cellMemoryTfhTh1Thesis or Dissertation