Immunotherapy of the rat 13762SC mammary adenocarcinoma by vaccinia virus augmentation of tumor immunity

Abstract

We studied whether vaccinia virus (VV) functioned as an immunogenic carrier in augmenting anti-tumor immunity in rats bearing a syngeneic metastatic tumor. The primary tumor was induced by injecting 10(6) 13762SC mammary adenocarcinoma cells subcutaneously into the right hind footpad of Fischer 344 rats. A concomitant anti-tumor response is induced by the tumor as demonstrated by the inhibited growth of a second tumor challenge given in the contralateral footpad 3-15 days later. Attempts were made to increase the concomitant immunity by injecting tumor-bearing animals intramuscularly with irradiated, VV-infected or uninfected 13762SC cells without adjuvant. Provided the immunotherapy was done within 5 days of the tumor challenge, administration of 10(6)-10(7) irradiated, VV-infected 13762SC cells resulted in significantly slower tumor growth, or led to complete tumor regression, compared to control animals given no treatment. In contrast, tumor growth in animals given only VV or given irradiated, uninfected 13762SC cells, alone or mixed with VV, was the same as that in control animals. Kinetics of early primary tumor growth were predictive of a longer-term anti-tumor effect. Rechallenge of 13762SC tumor-cured animals with either the homologous or with a heterologous syngeneic mammary adenocarcinoma showed the animals to be specifically 13762SC tumor-resistant, since only rats challenged with the heterologous mammary adenocarcinoma developed progressive tumors. We interpret these results to mean that early immunotherapy with irradiated, VV-infected 13762SC cells enhances an on-going anti-tumor immune response sufficiently to cause rejection of the primary tumor and any metastases that have occurred. We also believe that later immunotherapy with irradiated, VV-infected cells has no effect due to tumor-induced immunosuppression becoming paramount.

Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

“…During the experimental period, the tumor size was measured by a caliper. The breast cancer animal model was chosen since the model is a well-established animal model in breast cancer study (13762 MAT B-III breast cancer cell line is highly tumorigenic in Fischer 344 since the cell line is derived from the strain of Fischer 344 itself) [12][13][14]. Cyclophosphamide was used because the chemical has been used as a chemotherapeutic agent for treating human [15][16][17] and rat [14,18] breast tumors in previous researches.…”

Application of central immunologic concepts to cancer: Helping T cells and B cells become intolerant of tumors

“…A strategy that has long been considered to overcome this obstacle is the addition of foreign (e.g. xeno) antigens into cancer vaccines to boost immunity , and more recent studies have provided direct evidence that the beneficial effects of this procedure are through the provision of T‐cell help . A substantial advantage of employing foreign helper determinants physically linked to determinants recognized by CD8 + T cells, rather than tumor‐associated helper determinants, is that the tumor cannot use either downregulation of their own helper epitopes, or induction of tolerance against these foreign epitopes, as a means of escape.…”