The age related responses of New Zealand mice to a murine sarcoma virus.

The Moloney strain of murine sarcoma virus (MSV-M) rapidly induces soft tissue tumours in mice of all ages. Immunologically competent mice can spontaneously regress these tumours, and the regression time is an indication of the degree of immunologic reactivity. Using these parameters, New Zealand Black (NZB), New Zealand White × New Zealand Black F (B/W), and NIH Swiss mice develop cell mediated immune responses at an early age compared to five other mouse strains. 8–11-month-old NZB and B/W mice of both sexes show depressed immune responses when compared to 6-week-old controls. The responses of 10–11 month old female BALB/c mice were identical to 6-week-old controls. Older NZB and B/W mice spontaneously develop autoimmune disease. Measurement of autoimmune parameters in the older New Zealand mouse strains indicates that immune depression precedes the onset of detectable autoimmune disease.