OX48, a monoclonal antibody against a 70,000 MW rat activation antigen expressed by T cells bearing the high-affinity interleukin-2 receptor.
The monoclonal antibody (mAb) OX48 recognizes a 70,000 MW cell-surface protein present in a small percentage of activated rat T cells and in CD8+ rat x BW5147 interleukin-2 (IL-2)-dependent T-cell hybridomas, but not in resting spleen cells or in IL-2-independent T-cell hybrids. OX48 antibody added simultaneously with concanavalin A (Con A) to resting spleen cells inhibits the cell proliferation and reduces the IL-2 production. However, addition of IL-2 does not restore the mitogenic response. Growth of rat blast T cells or IL-2-dependent hybrids is not affected by the OX48 antibody. There is a close correlation between the expression of high-affinity IL-2 receptors (IL-2R) and the OX48 antigen in T-cell hybridomas. In spite of this striking correlation, OX48 mAb does not inhibit the binding of 125I-IL-2 to the IL-2-dependent hybrids, and is unable to immunoprecipitate any of the proteins chemically cross-linked to 125I-IL-2. Therefore, the OX48 molecule represents a new rat activation antigen, undefined in other species, and probably involved in the early steps of T-cell activation.
Somoza
C
C
Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
Fernández-Ruiz
E
E
Rebollo
A
A
Sanz
E
E
Ramírez
F
F
Silva
A
A
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D003208:Concanavalin A / Q000494:pharmacology; D007700:Kinetics; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000276:immunology; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D000099192:CD69 Antigens
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D003208:Concanavalin A; D037181:Lectins, C-Type; D015375:Receptors, Interleukin-2; D000099192:CD69 Antigens