title: Antigen-experienced CD4 T cells display a reduced capacity for clonal expansion in vivo that is imposed by factors present in the immune host.
abstract: It is thought that protective immunity is mediated in part by Ag-experienced T cells that respond more quickly and vigorously than naive T cells. Using adoptive transfer of OVA-specific CD4 T cells from TCR transgenic mice as a model system, we show that Ag-experienced CD4 T cells accumulate in lymph nodes more rapidly than naive T cells after in vivo challenge with Ag. However, the magnitude of clonal expansion by Ag-experienced T cells was much less than that of naive T cells, particularly at early times after primary immunization. Ag-experienced CD4 T cells quickly reverted to the slower but more robust clonal expansion behavior of naive T cells after transfer into a naive environment. Conversely, the capacity for rapid clonal expansion was acquired by naive CD4 T cells after transfer into passively immunized recipients. These results indicate that rapid in vivo response by Ag-experienced T cells is facilitated by Ag-specific Abs, whereas the limited capacity for clonal expansion is imposed by some other factor in the immune environment, perhaps residual Ag.
authors.affiliation: Department of Microbiology and Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: R
authors.initials: R
authors.lastname: Merica
authors.forename: A
authors.initials: A
authors.lastname: Khoruts
authors.forename: K A
authors.initials: KA
authors.lastname: Pape
authors.forename: R L
authors.initials: RL
authors.lastname: Reinhardt
authors.forename: M K
authors.initials: MK
authors.lastname: Jenkins
mesh_terms: D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000918:Antibody Specificity; D000941:Antigens / Q000008:administration & dosage* / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000637:transplantation*; D002999:Clone Cells; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D007117:Immunization, Secondary; D007275:Injections, Intravenous; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology
chemical_list: D000906:Antibodies; D000941:Antigens; D018984:Epitopes, T-Lymphocyte; D011948:Receptors, Antigen, T-Cell; D010047:Ovalbumin