Monoclonal antibodies recognizing normal human T lymphocytes and malignant human B lymphocytes: a comparative study.

We have undertaken a direct comparison of 8 different murine monoclonal antibodies that recognize antigens shared by human T cells and certain malignant B cells. Immune precipitation, lysostripping, and competitive binding experiments indicate that the antigenic determinants detected by antibodies Leu 1, T101, 17F12, SC1, A50, OKT1, and 10.2 are closely associated on the same molecular species and may in fact be identical. The antigenic determinant recognized by antibody 12.1, which has properties similar to the 1 detected by other antibodies, is present on a distinct cell-surface molecule. Our results emphasize the importance of a quantitative direct comparison of different monoclonal antibodies in distinguishing newly reported antibodies from those already described. Such a comparison can resolve apparent discrepancies that arise either from methodologic variations or from differences in antibody avidity.