Immune response of the draining and distal lymph nodes during the progressive grwoth of a chemically-induced transplantable rat hepatoma.

The immunological and histological changes occurring in the lymph node draining the site of a progressively growing intramuscular tumour (D192A) implant were monitored during a 4-week time course. Cell-mediated cytotoxicity against hepatoma-D192A and 15-day rat embryo cell targets, was detected with cells derived from the draining "lumbar" lymph node 4 days after tumour implantation and persisted up to the 2nd week of tumour growth, decreasing rapidly during the 3rd week. The observed lymph-node anergy demonstrated in cytotoxicity tests correlated with the histological findings, in that an initial marked paracortical (T-dependent) response also declined towards the end of the 3rd week of tumour growth. The B-dependent cortex showed active lymphocyte follicles in the 2nd week of the time course, and plasma-cell production continued until the experiment was terminated. These changes were shown to occur with the progressive increase in lymph-node mass. Serum antibody specific for the developing tumour was detected during the latter stages of tumour growth. The immunological and histological changes displayed were out of phase with those shown by the draining lymph node.