Abstract
To elucidate immunological mechanisms in the development of experimental liver cancer, 59 guinea pigs were fed 0.0042% (W/V) diethylnitrosoamine (DEN) in drinking water for 12 months. Liver cancer was induced in all animals during the 4th month. Anti-liver cell membrane antibody (LMA), anti-smooth muscle antibody (SMA), anti-nuclear antibody (ANA) and anti-mitochondrial antibody (AMA) were detected by the indirect immunofluorescent technique, and rheumatoid factor (RF) by the RA test kit as indicators of humoral antibodies. Circulating soluble immune complex-like substances were determined by Clq binding activity (Clq-BA). Peripheral lymphocyte counts and the purified phytohemagglutinin (PHA-P) skin test were performed as indicators of cellular immunity.
The incidence of seropositivity for LMA (P<0.05) and RF (P<0.01) was increased in animals with liver cancer compared with non-cancer bearing animals. The incidence of LMA was higher in early cancer than in late. AMA was observed in the precancerous and early cancerous stages. ANA was not found during the course of the experiment. Clq-BA was elevated in association with seropositivity of LMA (P<0.05) and RF (P<0.02). The absolute and relative peripheral lymphocyte counts were increased after DEN feeding. Reactivity to the PHA-P skin test was decreased only at the 3rd and 4th month, irrespective of the presence of the cancer.
These results suggest that some immune responses occur in early cancer, which are associated with the development of cancer.
