Transplacental tumor-preventive effects of polyclonal antibodies generated against the soluble 53 kDa antigen on mammary tumorigenesis in offspring.

This study was designed to determine whether immunizing females with polyclonal antibodies generated against the soluble 53 kDa tumor-associated antigen (s53 TAA) has a tumor-preventive effect on their progeny and whether this effect is manifested in some biochemical characteristics. Rat females were immunized before mating with anti-s53 IgG (50 microg/rat in Freund's complete and incomplete adjuvant, three times during a month) and their 5-week-old offspring was exposed to the carcinogen (dimethylbenz(a)antracene, 10 mg/rat). Results of these experiments were studied 4 months later. Vaccination of mothers decreased the tumorigenic effects of DMBA on their offspring. Blood levels of soluble TAA were analyzed in offspring of different groups. Two TAA were isolated from the blood, with molecular masses of 64 and 53 kDa. Their concentrations differed in offspring obtained from different maternal groups. Vaccination itself resulted in a marked increase in the blood levels of TAA, not only in the mothers but also in their offspring, however, this increase was not significant in tumor-bearing animals. In offspring from non-vaccinated mothers, tumorigenesis resulted in high overexpression of s53. In offspring from vaccinated mothers, a high blood level of s53 was shown even in tumor-free animals, probably due to maternal vaccination. We conclude that maternal vaccination before pregnancy increases immunoreactivity in offspring and can reduce risk of tumors in those progeny.