title: Subpopulations of CD8+ cytotoxic T cell precursors collaborate in the absence of conventional CD4+ helper T cells.
abstract: Four different subpopulations (Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi) of CD8+ T cells were arbitrarily defined on the basis of differential expression of Ly6C Ag. By combining the processes of electronic cell sorting and automated cell deposition, small numbers of respective CD8+ T cell subpopulations were directly deposited into tissue culture wells in which mitogen-stimulated responses were studied. Anti-CD3-stimulated proliferation and IL-2 production were the strongest by Ly6Cneg/Ly6Clow T cells, moderate for Ly6Cint T cells, and highly deficient for Ly6Chi T cells. The level of IL-2 production for Ly6Cneg CD8+ T cells was comparable to that of conventional CD4+ Th cells. Allogeneic stimulator cells elicited a strong cytotoxic response by Ly6Cneg + low but not Ly6Chi CD8+ T cells in the absence of added lymphokines. When IL-2 was supplied in excess, anti-CD3 induced comparable levels of cell proliferation and cytotoxic activity in Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi CD8+ T cells whereas alloantigen stimulated an approximate fivefold higher cytotoxic response by Ly6Chi than Ly6Cneg + low CD8+ T cells. Stimulation of co-cultures of B10 (CD8b) Ly6Cneg + low and congenic B10.CD8a Ly6Chi CD8+ T cells in the absence of added lymphokines, followed by selective elimination of activated CD8.1+ (CD8.2+) T cells by anti-CD8.1 (anti-CD8.2) + C treatment, allowed the demonstration that help provided by Ly6Cneg + low T cells can be effectively used by both Ly6Cneg + low and Ly6Chi T cells in anti-CD3 and alloantigen induced proliferative and cytotoxic responses, respectively.
authors.affiliation: Department of Microbiology, University of Texas Health Science Center, San Antonio 78284.
authors.forename: J T
authors.initials: JT
authors.lastname: Kung
authors.forename: M
authors.initials: M
authors.lastname: Castillo
authors.forename: P
authors.initials: P
authors.lastname: Heard
authors.forename: K
authors.initials: K
authors.lastname: Kerbacher
authors.forename: C A
authors.initials: CA
authors.lastname: Thomas
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D000950:Antigens, Ly / Q000096:biosynthesis; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002450:Cell Communication / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D007376:Interleukin-2 / Q000096:biosynthesis / Q000502:physiology; D007519:Isoantigens / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013234:Stem Cells / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D017252:CD3 Complex; D007376:Interleukin-2; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell