CD4, CD8 and Treg lymphocytes in the tumor microenvironment of M-406 murine triple negative mammary tumor growing in hosts with different susceptibilities

CAPITANI M. CELESTE; DEL GIÚDICE ANTONELA; FUSINI MATÍAS E.; MAINETTI LEANDRO E.; SCHAROVSKY OLGA GRACIELA; RICO MARÍA JOSÉ; ROZADOS VIVIANA R.

Mar del Plata

Congreso; LXIV Reunión Anual de SAIC, LI SAFE, XXI SAB, XXXI SAP; 2019

The tumor microenvironment contributes to several aspects of carcinogenesis and, therefore, offers promising targets for cancer therapy. CBi- mice was artificially selected for body conformation from CBi mice. The M-406 mammary adenocarcinoma appeared spontaneously in an inbred CBi female mouse and it is maintained in vivo in mice of the same line. Previously, we observed that when inbred CBi- mice were s.c. challenged with M-406 they showed 100% takes and 100% regressions (resistance). In contrast, the tumor grew exponentially (susceptibility) in CBi mice and in F1 hybrids (CBi x CBi- and CBi- x CBi). Our aim was to determine the participation of CD4, CD8 and Treg lymphocytes in tumors growing in hosts with different susceptibilities. Mice of the three genotypes were s.c. challenged with M-406 and when growing tumors reached the maximum size ethically allowed, they were sacrificed, tumor samples were obtained, fixed and included in paraffin. Also, tumors being rejected (CBi-) were excised at 12-17 days. CD4, CD8 and Treg cells were quantified by immunohistochemistry with antibodies for CD4, CD8 and Foxp3 in 30 fields of 1000X. The number of CD4+ and CD8+ cells were higher and the number of Treg lower in CBi- than in CBi and F1, being CBi- > F1 for CD4 (P