| Abstract: | Two murine monoclonal antibodies (MoAbs), LAM3 and LAM7 of the IgG1 isotype, which were produced by immunization with normal peripheral blood monocytes (PBM), were assayed in their specificity by indirect immunofluorescence against a panel of normal as well as leukemic cells. Both LAM3 and LAM7 were reactive with PBM while LAM3 also recognized platelets. Neither MoAb showed reactivity with erythrocytes, granulocytes, or resting and mitogen activated B and T lymphocytes. The reactivity with bone marrow cells correlated with the degree of monocyte contamination. Among the 62 cases of leukemia tested, which included three cases of B-CLL, 19 cases of ALL, and 40 cases of ANLL, both MoAbs reacted highly homogenously only with M5b ANLL cells. These findings indicate that the two MoAbs, which recognize two distinct epitopes, represent useful markers in the differential diagnosis of M5b ANLL. |
