Moloney virus (M-MuLV) leukemogenesis: virus spread, antibody production and antigenic expression in neonatally virus-inoculated young mice.

(A X C57BL) and (A X C57L)F1 hybrid mice were inoculated neonatally with M-MuLV. Virus spread, antigenic expression and antibody production were followed during the preleukemic period. M-MuLV was first detectable in the spleen and later in the thymus. Virus spread was faster and the level of viremia higher in A X C57L than in A X C57BL mice. Also, A X C57L mice had no or only low titers of virus neutralizing antibodies, whereas A X C57BL mice had high titers. Anti-MCSA antibodies, reacting with the surface of syngeneic M-MuLV-induced lymphoma cells, were present in a minority of the mice, but disappeared ultimately in all mice. The two groups of mice differed with regard to the length of the preleukemic latency period. High virus load and a low level of virus neutralizing and anti-MCSA antibodies were correlated with an earlier onset of leukemia.