Comparison between the effects of Micrococcus lysodeikticus, bacterial cell wall and related polysaccharides in the nonspecific tumour immunotherapy of Ehrlich ascites tumour growth

By analyzing, at different times after grafting 300,000 Ehrlich ascites cells to BALB/c mice, the primary immune response to 2.10 8 sheep erythrocytes, the carcinoma monitored immunosuppression was outlined. The fact that murine ascites fluid contains less immunoglobulins and less pre-albumin migrating components than serum of tumour bearing mice suggests that the tumour site may be the consuming focus. When different treatment schedules were assayed, we found that the intraperitoneal route (intratumoral) was better than other treatment routes: for 30,000 initially grafted tumour cells, i.p. treatment with 0.08 and 0.4 mg heat-killed Micrococcus on day 1, 3, 5, 7 and 9 resulted respectively in a 120 and 148% increase in mean life span over control mice and 50 and 20% of long-term survivors were recorded. However, the administration of 1 mg Micrococcus on days 1, 5, 9 and 12 after grafting 300,000 Ehrlich carcinoma cells considerably enhanced tumour growth. The administration of 1 mg of Micrococcus, cell wall, cell wall conjugated chitin, chitin and zymosan A on days 1, 2, 3, 4 and 5 resulted in a 71, 45, 29.5, 68 and 82% increase in mean life span over control mice and 30, 20 and 30% of long-term survivors were recorded for chitin, cell wall conjugated chitin and zymosan A respectively.