Characterization of a novel rat thymocyte costimulating antigen by the monoclonal antibody 1.3.
To define membrane-associated molecules that impart signals for the activation and expansion of double negative (DN) cells, mAb were raised against in vitro-cultured rat DN cells. One such mAb, 1.3, stimulated proliferation of DN cells along with submitogenic concentrations of PMA and IL-2 without affecting the mobilization of Ca2+. The 1.3 mAb precipitated a heterodimeric protein from DN cells and kidney (130/110 kDa). Although the tissue distribution and biochemical characteristics of the 1.3 determinant resemble the neutral aminopeptidase (AP-N) first described as the thymocyte activating molecule in the mouse, other data are contradictory; AP-N message was not detected in mRNA from 1.3 positive cells and the AP-N gene was absent in the genomic DNA from rat DN hybridomas expressing high levels of 1.3 Ag. In addition, the 1.3 mAb did not affect AP-N enzyme activity suggesting that 1.3 mAb does not function through this enzyme to transduce signals for proliferation. Thus, the 1.3 mAb defines a new and important thymocyte costimulating Ag.
Unit of Special Projects, National Institute on Alcoholism and Alcohol Abuse, ADAMHA, Rockville, MD 20852.
L A
LA
Bristol
L
L
Finch
E V
EV
Romm
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L
Takács
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis* / Q000235:genetics; D018826:CD13 Antigens; D002118:Calcium / Q000378:metabolism; D005260:Female; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D011915:Rats, Inbred BUF; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000954:Antigens, Surface; D007376:Interleukin-2; D018826:CD13 Antigens; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium