Functional characterization of an antigen involved in an early step of T-cell activation.
An activation antigen, identified by the monoclonal antibody MLR3, is described that is present on activated T lymphocytes and thymocytes but not on resting T lymphocytes. Immunoprecipitation of radiolabeled membranes from an activated T-cell line showed that the MLR3-binding molecule has a molecular size of 28-34 kDa. Immunofluorescence analysis showed that the appearance of the MLR3 antigen is an early event and precedes that of the interleukin 2 receptor both in T lymphocytes and thymocytes. The proliferative response of resting T cells to OKT3-Sepharose and interleukin 1 or accessory cells, but not the interleukin 2-dependent proliferation, was inhibited by the addition of MLR3 monoclonal antibodies. Similar results wer also obtained in an interleukin 1-dependent human thymocyte proliferation assay. In addition when MLR3-positive cells were cultured with purified interleukin 1, MLR3 surface antigen expression was not observed. Thus MLR3 monoclonal antibody appears to recognize an antigen involved in an early step of T-cell activation related to interleukin 1-dependent functions and on both T lymphocytes and thymocytes.
Cosulich
M E
ME
Rubartelli
A
A
Risso
A
A
Cozzolino
F
F
Bargellesi
A
A
D000911:Antibodies, Monoclonal; D000941:Antigens / Q000032:analysis*; D002478:Cells, Cultured; D004261:DNA Replication; D005455:Fluorescent Antibody Technique; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000941:Antigens; D007375:Interleukin-1; D013755:Tetradecanoylphorbol Acetate