Proposals for quality control methods of bacterial vaccines for immunostimulation. III. Effect of BCG and C. parvum on in vivo Listeria clearance and tumor growth.

Two quality control methods for BCG and C. parvum are described. First, in vivo macrophage dependent-spleen clearance of Listeria monocytogenes in inbred B10LP mice. BCG and C. parvum were administered intravenously prior to listeria inoculation (a prophylactic model). Conditions for enhanced listeria clearance including dose, route and time interval were described for each vaccine. Next, a tumor model was developed: i.e. a fibrosarcoma, chemically induced by 20-methylcholanthrene in inbred Balb/c mice. Increase in footpad thickness was used as a criterion for tumor growth. Optimal dose, route and time interval were established both in prophylactic and therapeutic situations, including intratumoral application. Depending on the conditions chosen, both inhibition and enhancement of tumor growth were observed. General conclusions of these studies are: (a) both models yield information on the effect of bacterial vaccines for immunostimulation; (b) statements on the effectiveness of any product should be based on careful studies including all variables.