Interactions of murine leukemia virus (MuLV) with isolated lymphocytes. III. Alterations of splenic B and T cells in Friend virus-infected mice.

Lymphoid tissues of mice infected with murine leukemia virus (Friend) (MuLV-F) were examined for the presence of cellular markers of MuLV-F infection. The Friend virus-associated cell membrane antigen (FVMA) and the virus group-specific antigen (GSA) were detectable on cells from the spleen and, to a lesser degree, on cells from the bone-marrow. In contrast, neither FVMA nor GSA was found in cells from the thymus. Alterations in the B-cell and T-cell spleen populations of MuLV-F-infected mice were then studied. The proportion of Ig-positive cells declined from the initial 45% (in non-infected controls) to about 10% after 2 weeks of infection. A similar decline of theta-positive cells was noted. However, complement-bearing cells (EAC rosettes) declined even more rapidly and became undetectable in the second week after infection. The treatment of spleen cells from MuLV-F-infected mice with anti-FVMA serum plus complement in vitro reduced the number of detectable Ig-positive cells, specifically, whereas the number of theta-positive cells remained unchanged. Furthermore, B and T cells from spleens of infected mice were separated on an affinity column with anti-Ig antibody-coated beads. The initial cell suspension contained about 45% FVMA-positive cells, about 40% Ig-positive cells and about 40% theta-positive cells. Ig+ cells were retained on the column. The theta-positive cell fraction was collected in the eluate and contained very few FVMA-positive cells with some "null" cells. Most of the FVMA-positive cells were retained on the column, which strongly suggested that they were B cells. These results confirm the previous experiments which showed the selective infections of purified splenic B cells by MuLV-F in cultures.