Histological and cytochemical studies on the distribution of schizophyllan glucan (SPG) in cancer-inoculated animals. I. Differences in distribution and antitumor activity of 3H-SPG in sarcoma-180 inoculated females between ICR and DBA mice.

Abstract

Purified schizophyllan (SPG), which was not labeled with radioactive isotopes, was administered intraperitoneally or intramuscularly to female mice of the ICR and DBA strains every third day from the 13th day afer sarcoma-180 inoculation to the 28th day. Four days after the last SPG administration, 400 .mu.Ci/head of 3H-SPG was injected intravenously. The liver, spleen, bone marrow, lymph nodes, thymus, and tumor were studied with whole-body, microscope, and electron microscope (EM) autoradiography (ARG). Anesthetized animals were used for whole-body ARG after tissue pieces were removed and fixed for micro-ARG and EM-ARG. These autoradiographic data suggest that the SPG granules (Fbs) containing activated macrophages in the ICR tumor nests play an important role in destroying the growing sarcoma cells, but there was no evidence of active macrophages in the DBA sarcoma nests. The Fbs in the macrophages in ICR mice probably produce a large amount of various lysosomal enzymes and act as activators of the destruction of sarcoma cells, but did not act in DBA mice. The reason for such a big difference between the two mouse strains was not clear, but some immunogenomic factors could be concerned.