PRODUCTION AND CHARACTERIZATION OF MONOCLONAL-ANTIBODIES RAISED AGAINST RECOMBINANT HUMAN GRANZYME-A AND GRANZYME-B AND SHOWING CROSS-REACTIONS WITH THE NATURAL PROTEINS

The human serine proteases granzymes A and B are expressed in cytotopl asmic granules of activated cytotoxic T lymphocytes and natural killer cells. Recombinant granzyme A and granzyme B proteins were produced i n bacteria, purified and then used to raise specific mouse monoclonal antibodies. Seven monoclonal antibodies (mAb) were raised against gran zyme A, which all recognized the same or overlapping epitopes. They re acted specifically in an immunoblot of interleukin-2 (IL-2) stimulated PBMNC with a disulfide-linked homodimer of 43 kDa consisting of 28 kD a subunits. Seven mAb against granzyme B were obtained, which could be divided into two groups, each recognizing a different epitope. On an immunoblot, all mAb reacted with a monomer of 33 kDa protein. By immun ohistochemistry, these mAb could be used to detect granzymes A and B e xpression in activated CTL and NK cells. The availability of these mAb may facilitate studies on the role of human cytotoxic cells in variou s immune reactions and may contribute to a better understanding of the role of granzymes A and B in the cytotoxic response in vivo.