PREVENTION OF CARCINOGENESIS BY MURINE SARCOMA VIRUS (HARVEY) FOLLOWING INJECTIONS OF IMMUNE SERA DURING LATENT PERIOD

Several immune sera were prepared by immunization of mice and rats with murine sarcoma virus (MSV‐Harvey) or with irradiated tissue of MSV‐induced tumours. Repeated injections of these sera into mice and rats which had been inoculated at birth with MSV (Harvey) effectively prevented MSV carcinogenesis. All the immune sera contained antibodies capable of neutralizing MSV. Sera containing the highest titres of virus‐neutralizing antibodies were also the most effective in prevention of MSV carcinogenesis. Passive transfer of some of these immune sera into adult and newborn mice did not influence the growth of MSV‐induced tumour cells transplanted into syngeneic recipients. Other sera either enhanced or inhibited tumour growth. Because of this no correlation could be established between the effect of sera on tumour growth and their capacity to prevent MSV carcinogenesis. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company