Effects of Corynebacterium granulosum on weight and histology of lymphoid organs, response to mitogens, skin allografts, and a syngeneic fibrosarcoma in mice.

We studied the effect of single and multiple injections of Corynebacterium granulosum on weight and histology of lymph nodes and spleen, on peripheral white blood cell count, response of peripheral blood lymphocytes, lymph node, and spleen cells to phytohemagglutinin and pokeweed mitogen, survival of skin allografts, and lung metastases of a syngeneic fibrosarcoma in C3Hf/Bu mice. Corynebacterium parvum was used in some studies on antitumor activity. The weight of lymph nodes and spleen was markedly increased by single and multiple i.p. injections of C. granulosum, the peak enlargement occurring at Day 7 in lymph nodes and at Day 16 in spleen. Histologically, there was an extensive proliferation of nucleated cells in the enlarged organs. C. granulosum did not change the total white blood cell count but caused a temporary lymphopenia. In general, in vitro response to phytohemagglutinin and pokeweed mitogen of blood lymphocytes and spleen cells was decreased. Lymph node cell response to phytohemagglutinin was increased by small doses (0.025 mg) of C. granulosum, was not altered by a single large dose (0.5 mg), and was decreased by multiple doses. The response of lymph node cells to pokeweed mitogen was increased by all treatments. These changes in response to mitogens were demonstrable for about 2 months after treatment. Treatment i.v. with 0.1 or 0.25 mg of C. granulosum given before but not after grafting significantly prolonged the survival of grafted BALB/c skin. Smaller doses of this bacterium were not effective. Splenectomy of skin graft recipients did not prevent the effect of C. granulosum. Treatment i.p. or i.v. with this bacterium significantly decreased the number of lung metastases from i.v.-injected fibrosarcoma cells, even if the cells were injected 3 to 4 months later. The magnitude of this effect varied with the dose and frequency of injection of C. granulosum and C. parvum.