Cytolytic activity in vitro of lymph node cells after exposure in vivo to tumor cells suspended in blocking sera.

The in vivo effect of blocking sera (bs) on both tumor growth and subsequent in vitro cytolytic activity of regional lymph node cells was determined following injection of hepatoma cells suspended in normal sera (ns) or bs into the hind footpads of guinea pigs. Tumor growth was unaffected by bs but the primary response to tumor by LNC draining tumor/bs sites was significantly lower in 4/6 experiments as compared to cells from lymph nodes draining tumor/ns sites.