Effect of anti-mouse type-1 interferon globulin on the evolution of Moloney sarcoma virus induced disease in mice.

The prolonged administration of potent sheep anti-mouse type-1 interferon globulin (anti-IF IgG) had a marked potentiating effect on Moloney sarcoma virus (MSV) infection in mice. The extent of resistance to the MSV-induced disease was age-related. In 4-week-old BALB/c mice, anti-IF IgG consistently induced 70-80% mortality due to the progression of early or late tumours and erythroleukaemia, whereas mortality of control mice was significantly lower. The same effect was obtained in 1-year-old BALB/c mice. However, in 4-week-old C57BL/6 or 6-week old BALB/c mice, anti-IF IgG enhanced only the growth of early tumours but had no effect on their regression. Antigenic stimulation with normal sheep globulin suppressed the growth of early tumours in suckling BALB/c or C57BL/6 mice and enhanced the evolution of late MSV-induced disease in older mice.