Specificity of the simultaneous cell-mediated immune reactivity to RIII murine mammary tumor virus glycoprotein 55 and human breast cancer tissues.

The leukocyte migration test (LMT) reactivity of breast cancer patients to Rill murine mammary tumor virus (MuMTV) gp55 was studied and compared with simulta neous reactivity to the following: (a) RIM gp55 prepared in another laboratory; (b) gp68, gp34, and p28 of Rill MuMTV; (c) gpSO of A-strain MuMTV; (d) gp70 and gp45 of Rauscher leukemia virus; and (e) autologous and homol ogous lymphoreticuloendothelial (L-RE)-positive and -negative breast cancer tissues and extracts of MCF-7 tissue culture cells. LMT reactivity against the two gp55 preparations was essentially identical. A similar correla tion was found in regard to LMT reactivity of L-RE-positive breast cancer patients, tested 11 months postoperatively against gpSS and autologous and homologous breast cancer tissues. Such a correlation was not demon strable between LMT reactivity to gpSS and reactivity to other Rill MuMTV protein fractions, gpSO of A-strain MuMTV, Rauscher leukemia virus protein fractions, or LRE-negative autologous breast cancer tissues. LMT reac tivity to MCF-7 extracts was essentially limited to patients who were responsive to gpSS. It appears that LMT reactivity of breast cancer patients to gpSS does not reflect a nonspecific increase in cellmediated immunity randomly directed against glycoproteins and breast cancer tissue. To the contrary, it appears that the observed simultaneous LMT reactivity to gpSS and L-RE-positive breast cancer tissues reflects antigenic similarity in their cell-mediated immunity determinants. Information regarding the molecular nature of the cellmediated immunity determinants should be of conceptual and clinical significance.