title: The role of I-region associated antigen (Ia)-bearing accessory cells in the generation of cytotoxic T cells in a subpopulation of thymocytes.
abstract: The roles of killer-helper factor (KHF) and accessory cells bearing I-region associated antigen (Ia) in the generation of cytotoxic T lymphocytes (CTL) were analyzed. Peanut agglutinin-binding (PNA+) thymocytes from C3H/HeN mice generated efficient CTL responses against 2,4,6-trinitrophenyl (TNP)-modified syngeneic spleen cells in the presence of cell-free supernatant (CFS) derived from purified protein derivatives (PPD)-stimulated Mycobacterium tuberculosis-primed BALB/c spleen cell culture (PPD-CFS). The KHF which is present in PPD-CFS devoid of the activities of IL-1 or IL-2 was required in conjunction with IL-2 for generation of CTL in PNA+ thymocytes. In contrast, PNA- thymocytes as well as spleen cells could generate CTL in the absence of helper factors. However, a significant CTL response against Ia-negative syngeneic tumor cells was not induced from either PNA+, PNA- thymocytes or spleen cells in the absence of Ia-positive accessory cells. Moreover, the treatment of spleen cells with relevant anti-Ia antiserum plus complement before TNP-modification abrogated the stimulatory capacity of TNP-spleen cells. In both cases, the addition of Ia-positive accessory cells restored the impaired capacity of TNP-modified stimulator cells. The addition of IL-1 to the culture of PNA- thymocytes or spleen cells stimulated with TNP-X5563 cells in the absence of accessory cells restored the CTL generation. In contrast, the addition of IL-1 to the culture of PNA+ thymocytes was ineffective. The role of Ia-positive accessory cells in the generation of CTL in a subpopulation of thymocytes is discussed.
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007375:Interleukin-1 / Q000502:physiology; D007376:Interleukin-2 / Q000502:physiology; D037102:Lectins; D051379:Mice; D008815:Mice, Inbred Strains; D019887:Peanut Agglutinin; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D007376:Interleukin-2; D037102:Lectins; D019887:Peanut Agglutinin; D014301:Trinitrobenzenes