Influence of dendritic cells on tumor growth.

Abstract

Dendritic cells (DC) exposed to antigen are potent initiators of immune responses, and the numbers of DC and the dose of antigen control the level of response. The influence of these variables was tested on the growth of mouse sarcoma cells in vivo. When normal syngeneic DC (100,000) were given to mice with palpable tumors, tumor regression or delay in tumor growth was obtained. DC exposed to increasing doses of tumor growth was obtained. DC exposed to increasing doses of tumor extract in vitro before administration had progressively less effect. DC exposed to antigen delayed tumor growth significantly only when given on the same day as 500 tumor cells. Apparently, low doses of antigen on DC elicit immune responses and high doses block them. The numbers of antigen-presenting cells and the dose of antigen modulate the degree of immunity to mouse sarcoma in vivo.