title: Mice deficient in stem cell antigen-1 (Sca1, Ly-6A/E) develop normal primary and memory CD4+ and CD8+ T-cell responses to virus infection.
abstract: Stem cell antigen-1 (Sca1, Ly-6A/E) is a well-established marker of murine hematopoietic stem cells, and also is expressed on memory T cells. It has been suggested that the functional maintenance of T-cell memory requires the expression of Sca1 on a specialized population of memory T cells termed "memory stem cells". Here, we evaluate the requirement for Sca1 in the primary T-cell response to virus infection, and in the establishment and maintenance of T-cell memory. We find that Sca1 expression increases on almost all CD4(+) and CD8(+) T cells during virus infection, and remains high on virus-specific memory cells. However, Sca1-deficient (Sca1KO) mice generate normal primary T-cell responses to infection; the kinetics, the immunodominance hierarchy, and the absolute numbers of CD4(+) and CD8(+) T cells are essentially indistinguishable from those observed in WT mice. Furthermore, by several criteria, primary and memory T cells in Sca1-deficient mice are phenotypically and functionally normal. These data indicate that Sca1, although perhaps a useful marker of virus-specific memory T cells, is not required for the regulation of T-cell quantity or quality, or for the development of a competent pool of memory cells.
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA. whitmire@scripps.edu
authors.forename: Jason K
authors.initials: JK
authors.lastname: Whitmire
authors.forename: Boreth
authors.initials: B
authors.lastname: Eam
authors.forename: J Lindsay
authors.initials: JL
authors.lastname: Whitton
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000502:physiology; D001117:Arenaviridae Infections / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002452:Cell Count; D018960:Hyaluronan Receptors / Q000378:metabolism; D007111:Immunity, Cellular / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007700:Kinetics; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D008565:Membrane Proteins / Q000172:deficiency* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017471:Receptors, Interferon / Q000235:genetics; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000950:Antigens, Ly; D018960:Hyaluronan Receptors; D007376:Interleukin-2; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D017471:Receptors, Interferon; D007371:Interferon-gamma