Lymphocyte nucleoli activation and changes of the mononuclear phagocytic system in mice during 3-methylcholanthrene carcinogenesis.

After an intra-muscular application of 3-methylcholanthrene (MCA) in a dose of 0.2 mg/animal to SPF mice, strain C57B1/10, changes in the lymphocyte nucleoli activation (LNA) and changes of the mononuclear phagocytic system (MPS) in blood and tissues were monitored. The tests were carried out after the first and sixth weeks of the MCA administration, when the tumours were not yet palpable, and 12 weeks after the MCA injection, when the tumours were manifest in 100% of animals. In the first and sixth week after MCA application, the number of non-activable lymphocytes with micronucleoli increased at the expense of the resting ring-shaped forms. In the 12th week, a highly significant drop of active lymphocytes with nucleolonemas and compact nucleoli and particularly a high number of afunctional lymphocytes with micronucleoli were observed in tumour-bearing mice. The phagocytic activity of peripheral mononuclears was significantly increased in the same time interval. MPS activity, monitored on the basis of the colloidal carbon clearance, was stepwise inhibited in animals with originating tumours. It should be pointed out that the LNA test and probably the changes in carbon clearance were early indicators of involvement in chemical carcinogenesis.