The correlation of the ongoing proliferative response to tumour in lymphoid organs with the anti-tumour activity of the lymphoid cells

Abstract

Anti-tumour activity of washed lymph node (LN) and spleen cells of mice bearing a transplanted methylcholanthrene-induced tumour (MC 1) for 10–14 or 25–28 days was compared and correlated with the stimulation of deoxyribonucleic acid (DNA) synthesis in the lymphoid organs. While the anti-tumour effect per lymph node cell (LNC) changed little if at all during this period, the stimulation of DNA synthesis in the total cell population of the nodes diminished significantly by the 25–28 day stage of tumour-bearing in contrast to the markedly high level seen at 10–14 days. In the spleen, however, stimulation of DNA synthesis in the total cell population increased throughout the period of study while the anti-tumour activity per cell significantly decreased. Depressed effector activity of spleen cells was shown to be associated with a decrease in anti-tumour activity of the T cell population. These observations provide evidence for a suppression of the immune response to tumour antigens operating at the level of sensitization of the immunocompetent cells and further suggest that proliferation in the tumour-bearing host of a cell clone(s) with suppressor function may have a direct or indirect role in controlling the specific response to tumours.