Cytogenetic analysis of an immunogenic mutant of the L5178Y lymphoma.

A mutant of the uniformly lethal L5178Y lymphoma, called the L5178Y/Manitoba (L5178Y/M), was rejected after subcutaneous challenge in syngeneic DBA/2 mice. Karyotypic analysis revealed that the parent L5178Y lymphoma had four chromosome markers, with the mutant L5178Y/M sharing one of them as well as possessing two distinguishing markers. One diploid and two hypotetraploid clones were isolated from the L5178Y/M; they contained all the marker chromosomes and were also rejected by the syngeneic host. In addition to the shared chromosome markers, the L5178Y/M possessed antigens in common with the parent L5278Y. DBA/2 mice made immune to the mutant by subcutaneous immunization were able to slow the growth of the parent tumor but not the unrelated P-815-X2 mastocytoma.