FIG. 4.

Permeability of B lymphocytes from BLV-negative and BLV-positive cattle. PBMC from BLV-negative or BLV-positive cattle were incubated for 1 h with 40- or 70-kDa fluorescein-conjugated dextrans (green fluorescence) and analyzed by flow cytometry. On the basis of staining with Tricolor labeled monoclonal antibodies (red fluorescence), lymphocyte subpopulations were identified in separate samples as B cells (positive for CD21-like antigen) and as BLV-expressing cells (positive for viral gp51 antigen) and assessed for dextran content by measuring green fluorescence. Cells exhibiting fluorescence above 1.1 log were considered dextran positive and were divided into groups of cells exhibiting low fluorescence (1.1 to 2.05 log) or high fluorescence (2.05 log to 3.7 log). Results are percentages of cells in each category exhibiting green fluorescence + SE. Data are from a representative experiment performed in triplicate.