The delayed-type hypersensitivity (DTH) response and lymphocyte-mediated angiogenesis were determined in mice bearing in vivo cultures of mammary tumor cells in diffusion chambers (DCs). Soluble tumor products which diffuse from the DCs were able to stimulate the immune system for both the DTH reaction and angiogenic activity by spleen cells.

No abstract

Mouse uterine draining lymph node (UDLN) cells, or soluble factors released by them in both phases of the estrous cycle were examined in the graft‐vs‐host (GVH) assay. The immune response during the estrous phase was significantly decreased as compared with diestrous phase; 24‐hour culture supernatant of UDLN cells was also able to decrease GVH activity mounted in F1 hybrids. This difference in reactivity was not found when peripheral nodes (PN) or spleen cells were tested. These results show that in physiological conditions it is possible to detect an hormonal influence on T lymphocyte function and would suggest that a nonspecific immunosuppression would appear even during the estrous phase.

At various stages during the progressive growth of a transplanted sarcoma in BALB/c mice, the delayed hypersensitivity response to tumor antigen was determined using the food-pad swelling test (FPS) and the leukocyte migration inhibition assay (LMI). A close correlation was observed between the in vivo and in vitro assays. "Early" recognition of tumor antigen was detected 24 h after tumor inoculation by both techniques and this positive response was maintained until day 15. As the tumor grew larger, the delayed hypersensitivity response in vivo vanished, while the delayed hypersensitivity response in vitro disappeared about 3 days later. This suppression or "eclipse" of the anti-tumor cellular immune response was specific for the type of tumor used, and could be reversed in vitro by means of a low pH treatment of lymphoid cells.

The periodicity of the estrual cycle in mice was studied by vaginal cytology during the growth of a hormone-independent mammary adenocarcinoma. A direct relationship between age progression and lengthening of estrual cycle was observed in control mice but not in tumor-bearing mice of the same age. These results suggest that hormone regulation of the estrual cycle may be affected in tumor-bearing hosts.