Melanoma associated antigen, Human, mAb NKI/beteb

Melanoma associated antigen (MAA) is dispersed in the cytoplasma of melanoma cells, and is more concentrated inside vacuoles and sometimes on the melanosomes. Occasionally the antigen is seen on the cell surface. The antigen is actively shed from living cells. Although the antigen is associated with melanomas, it is not codistributed with the tyrosinase activity associated with melagonesis. The antigen shows codistribution with cathepsin D, which is a marker for lysosomal functions. The antibody NKI/beteb recognizes a (pre)melanosomal 100 kD and 7 kD antigen (glycoprotein). The antibody reacts with melanomas, clear cells sarcomas (melanoma of soft tissue), nevocellular nevi, and normal melanocytes. Except for one case of non-Hodgkin’s lymphoma in which macrophages were positive, no reactions with other tumors or tissues have been observed.