Induction of syngeneic cytotoxic T lymphocytes against a B cell tumor. II. Characterization of anti-idiotypic CTL lines and clones.
In an earlier communication we showed that idiotypic immunoglobulin (Id+ Ig) of a B cell hybrid, 2C3, can induce cytotoxic T lymphocytes (CTL) in the spleens of mice that are hyperimmunized with the irradiated tumor cells. To understand the extent of heterogeneity in the splenic CTL population, stable anti-idiotypic CTL lines and clones were established from 2C3-primed splenocytes. One representative CTL line A102 which exhibited the phenotype of CD3+, CD4-, and CD8+, has been maintained in long-term culture for more than 18 months. Cytotoxic specificity of A102 was determined by cold target inhibition assay using a panel of syngeneic and allogeneic B cell tumors. The CTL line A102 was highly cytotoxic to 2C3, only weakly to other syngeneic tumors, but not at all to allogeneic B cell tumor CH12. Furthermore, CTL-mediated cytolysis was significantly abrogated by blocking 2C3 cells with anti-idiotypic monoclonal and polyclonal antibodies. These results clearly show that 2C3 Id represents the immunodominant epitope(s) recognized by the CTL line A102. To isolate a highly Id-specific effector population, A102 was repeatedly subcloned by limiting dilution. One such clone 102.F5 exhibited considerable specificity toward Id+ 2C3 while another clone 102.E10 showed no such specificity in a competitive cytotoxicity assay. This was further confirmed by the inhibition studies with anti-Id mAb. Thus, hyperimmunization with irradiated 2C3 cells evokes a spectrum of anti-2C3 cytotoxic effector cells, of which a major population is reactive to the idiotypic determinants associated with 2C3 Ig.
Chakrabarti
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Department of Life Sciences, Indiana State University, Terre Haute 47809.
Ghosh
S K
SK
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000502:physiology; D002460:Cell Line; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D007130:Immunoglobulin Idiotypes / Q000276:immunology*; D016393:Lymphoma, B-Cell / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007130:Immunoglobulin Idiotypes