B-ly-7, a monoclonal antibody labeling of activated lung lymphocytes.

A series of data, including those that recently appeared in Blood,’.* have focused the interest on the expression of the antigen recognized by the B-ly-7 monoclonal antibody (MoAb). Other antibodies with a pattern of reactivity similar to B-ly-7 have recently been produced, such as HMLl’ and Ber-ACTS4 MoAbs. The molecular structure recognized by these MoAbs appears to be a trimer made of 150-Kd, 125-Kd, and 105-Kd components, thus analogous to the integrin family! All these antibodies seem to selectively recognize intraepithelial T cells, particularly those of gut, whereas lymphocytes from other compartments are negative. Interestingly, these MoAbs strongly react with leukemic hairy cells and some lymphomas, notably the intestinal T-cell lymphomas? Recent data are accumulating on the expression of this antigen by in vitro activated T ~ells,z”*~ indicating the possibility that the presence of this marker correlates with a long lasting in vivo activation of T lymphocytes. The positivity of intraepithelial lymphocytes of small intestine for this marker is consistent with the evidence of a persistent activation state of these cell populations.’ This finding prompted us to investigate the expression of this B-LY-7, A MONOCLONAL ANTIBODY LABELING OF ACTIVATED LUNG LYMPHOCYTES