Walker 256 tumor MHC class I expression during the shift from A variant to the immunogenic AR variant.

Novel tumor cell variants can be obtained by serially passaging tumor cells in different media and/or environments. Serial intraperitoneal (ip) passages of the Walker 256 tumor A variant was followed for studying the generation of its regressive AR variant. MHC class I molecule expression was assessed since variations in this molecule would explain changes in tumor cell immunogenicity and therefore, the shift from progressive A variant to the regressive AR variant.