Class II antigen-specific murine cytolytic T lymphocytes (CTL). II. Genuine class II specificity of Lyt-2+ CTL clones.
Class II-specific allogeneic cytolytic T lymphocytes (CTL) consist of two types of cells, i.e., Lyt-2+L3T4- and Lyt-2-L3T4 T cells. The Lyt-2+L3T4- class II-specific CTL population constitutes a conspicuous exception to the general correlation observed between the class of major histocompatibility complex antigen recognized and the type of accessory molecules expressed by T cells. In order to examine the specificity of such an exceptional T cell population, CTL clones were established by limiting dilution of a bulk CTL line developed in an I region incompatible combination of mouse strains, B10.QBR anti-B10.MBR. These CTL lines showed single genetic specificity indicating their clonal nature with respect to CTL activities. Lyt-2+L3T4- (2+4-), Lyt-2-L3T4+ (2-4+) and Lyt-2-L3T4- (2-4-) clones were obtained. Among many CTL clones showing a spectrum of genetic specificities, 2+4- and 2-4+ clones with apparent I-Ak-specificity, were studied further and four lines of evidence confirmed their class II specificity: 1) genes encoding the target antigen for these CTL clones were mapped within the I-A subregion by simple genetics; 2) an I-Ak-specific monoclonal antibody readily blocked specific cytolysis by these clones; 3) the clones failed to react with cells expressing mutated I-Ak antigens; and 4) a B cell tumor transfected with alpha- and beta-chain genes of I-Ak was specifically lysed by these CTL clones. These data therefore establish the existence of Lyt-2+ CTL with genuine class II specificity. All 2-4+ CTL were sensitive to the blocking effect of an antibody to L3T4, whereas none of the 2+4- class II-specific CTL were sensitive to blocking by an anti-Lyt-2 antibody, indicating that class II-specific CTL with "wrong phenotype" is not dependent on the function of the accessory molecule. Besides true class II-specific CTL clones, 2+4- clones with a spectrum of genetic specificities were obtained, including clones recognizing a combination of an I-Ak product and the Kb molecule. Two 2-4- clones were also specific for the combination of Kb + I-Ak. These clones most likely recognize an allogeneic class II antigen in the context of a class I antigen and therefore would more appropriately be included in the class I-restricted T cell population.
Shinohara
N
N
Transplantation Biology Section, National Cancer Institute, Bethesda, MD 20892.
Hozumi
N
N
Watanabe
M
M
Bluestone
J A
JA
Johnson-Leva
R
R
Sachs
D H
DH
D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000950:Antigens, Ly / Q000032:analysis*; D002460:Cell Line; D002999:Clone Cells / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D006649:Histocompatibility Antigens / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008297:Male; D051379:Mice; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D006649:Histocompatibility Antigens; D000949:Histocompatibility Antigens Class II