Membrane-associated alterations detected in poorly tumorigenic lectin-resistant variant sublines of a highly malignant and metastatic murine tumor.

A number of wheat germ agglutinin-resistant (WGAR) variants of a highly malignant and metastatic mouse tumor (called MDAY-D2) were selected. Two of these, MDW1 and MDW3, were poorly tumorigenic in the normal DBA/2 host but grew well in highly immunosuppressed recipients. In contrast, MDAY-D2, MDW4, and MDW5 were all highly tumorigenic in both normal and immunosuppressed hosts. Analysis of the WGAR variants by cytotoxic T-cell testing did not reveal any evidence for the acquisition of new tumor antigens by the MDW1 or MDW3 variant sublines, although they provoked a significantly stronger T killer cell response than did MDAY-D2, MDW4, or MDW5. Further studies indicated that the rate of tumor cell surface shedding in vitro correlated strongly with relative tumorigenicity and, furthermore, that changes in the cytoskeletal structure of MDW1 and MDW3 may have contributed to their reduced rate of shedding.