Melanoma antigen expression and metastatic ability of mutant B16 melanoma clones.

The biological functions of murine melanoma-associated antigens recognized by monoclonal antibodies (MAbs) (M562, M622 and M2590) were examined by using mutant clones which differed in their degree of expression of these antigens. Four clones of high expressors of 3 types of antigen (MEA group), 5 clones of low or non-expressors of M562- and M622-recognizing antigens (MEB group) and 4 clones of non-expressor of GM3 recognized by M2590 (MEC group) were used. Attachment of these clones to components of extracellular matrix was different between the groups. Two clones of the MEA group showed the highest ability to adhere to laminin and type-IV collagen, whereas the clones of the MEB and MEC groups significantly lost their ability to attach to laminin and type-IV collagen. In experimental lung metastasis, metastasizing ability of MEA-group cells was higher than that of MEB- and MEC-group cells. Our results suggest that these antigens play some functional role in metastasis mediated by increasing capacity for attachment to laminin and type-IV collagen.