Murine Mammary Tumor Virus Protein Vaccine: Induction of Antivirus Immunity and Inhibition or Acceleration of Growth of Transplanted Mammary Tumors 1. 2

ABSTRACT-BALB/c and DBAf mice were vaccinated with dif· ferent doses of a protein fraction of the murine mammary tumor virus (MuMTV), enriched for the major glycoprotein gp52. Twenty days after vaccination, the mice were challenged with live tumor cells: BALB/c with an MuMTV·induced mammary tumor, DBAf with the MuMTV·posltlve leukemia L 1210. Alum and an interphase material isolated from Mycobacterium smegma tis (IPM) were used as an adjuvant; control animals were treated with the adju· vant alone. In BALB/c mice treated with 1 /lg of the gp52·enriched protein fraction precipitated on alum, the onset of tumor growth was delayed 10 weeks; a dose of 10 /lg had no clear effect, whereas 100 /lg caused clear acceleration of tumor growth. Each of the vaccinated animals developed a tumor, as compared to 60 % of the control group. In DBAf mice low doses of the vaccine accelerated tumor growth. In general, acceleration was stronge