Effect of regional or distant lymph node removal and of splenectomy on immunologic responses in Ehrlich tumor-bearing mice.

To study the role of regional (RLN) and distant (DLN) lymph nodes and of the spleen in the regulation of tumor immunity, we monitored tumor growth in mice subjected to lymph node removal or splenectomy. We found that tumor growth was facilitated when RLN were removed before or soon after tumor inoculation and that RLN removal after extirpation of the immunizing tumor decreased the host resistance to a subsequent challenge. When splenectomy preceded tumor inoculation, tumor growth was not affected, however, marked growth inhibition was observed when splenectomy was performed 5 days after tumor inoculation. Furthermore, splenectomy combined with extirpation of the immunizing tumor increased the host resistance to a subsequent challenge. We conclude from these studies that RLN or the spleen may be of immunologic importance in the host's tumor resistance.