title: Cutting edge: CD4+ T cell help can be essential for primary CD8+ T cell responses in vivo.
abstract: Recent studies have shown that CD4(+) T cell help is required for the generation of memory CD8(+) T cells that can proliferate and differentiate into effector cells on Ag restimulation. The importance of help for primary CD8(+) T cell responses remains controversial. It has been suggested that help is not required for the initial proliferation and differentiation of CD8(+) T cells in vivo and that classical models of helper-dependent responses describe impaired secondary responses to Ag in vitro. We have measured primary CD8(+) T cell responses to peptide-pulsed dendritic cells in mice by cytokine ELISPOT and tetramer staining. No responses were detected in the absence of help, either when normal dendritic cells were injected into MHC II-deficient mice or when MHC II-deficient dendritic cells were injected into normal mice. Thus, the primary in vivo CD8(+) T cell response depends absolutely on help from CD4(+) T cells in our experimental system.
authors.affiliation: David H. Smith Center for Vaccine Biology and Immunology, Aab Institute of Biomedical Sciences, and Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Jyh-Chiang E
authors.initials: JC
authors.lastname: Wang
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Livingstone
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism / Q000637:transplantation; D004797:Enzyme-Linked Immunosorbent Assay; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D007111:Immunity, Cellular / Q000235:genetics; D007156:Immunologic Memory / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000637:transplantation
chemical_list: D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D007371:Interferon-gamma; D010047:Ovalbumin