FIG. 8.
Binding of MHV-68 and gp150 to cells. (A and B) Cells (106/well) were incubated with equimolar concentrations (20 μM) of fusion protein (gp150-His or GST-His), 107 PFU MHV-68, or BHK cell lysate (BHK) as a virus-negative control for 1.5 h at 37°C in the presence of sodium azide. Binding was detected by using a combination of rabbit anti-gp150-GST antibody, followed by swine anti-rabbit fluorescein isothiocyanate-conjugated antibody. Cells were formaldehyde fixed and analyzed by FACS. The marker for positive staining was positioned at 1% of staining with primary and secondary antibody alone. The bars denote the standard deviation of triplicate samples. (A) C127 murine epithelial cells; (B) primary B cells. (C) A total of 2 × 106 fresh mouse spleen cells were incubated with the indicated viruses at either 4°C or 37°C. After a washing step, the DNA copy number of bound virus was determined by quantitative PCR analysis. Numbers represent the mean of three determinations.