Absence of Cell-Mediated Immunologic Tolerance to Leukemia Virus in Carrier Mice

Abstract

Several viruses have been reported to induce immunologic tolerance in mice when infection occurs in the prenatal or immediate postnatal period. Among these are lymphocytic choriomeningitis (LCM) ³ virus (1–3) and murine leukemia viruses (MuLV) (4–6). Although Moloney murine leukemia virus (MuLV-M) can induce leukemia in both newborn and adult mice (7), there is a marked difference in host response in these two age groups. Inoculation into adults results in development of both humoral and cell-mediated immune responses to the virus, whereas in neonatally infected mice these responses appear to be either greatly reduced or undetectable (5, 8). Recent results have cast doubt on the validity of the concept of immunologic tolerance to viruses. It now is generally accepted that humoral antibodies can be formed after neonatal infection with LCM virus (9), MuLV-M (10), Harvey murine sarcoma virus (MuSV-H) (10), and Gross murine leukemia virus (MuLV-G) (11, 12).