FIG. 1.

HA titers of human type O RBCs by rNV VLPs. Fifty microliters of rNV VLPs (400 ng/ml) (♦), influenza A/TX/36/91 virus grown in eggs (▪), or PBS-H (○) was serially diluted in PBS-H and mixed with 50 μl of 0.5% RBCs. (A) The PBS-H was at pH 7.2, and the HA assay incubation times, as determined by sedimentation of RBCs in negative control wells, were 30 min at 37°C, 40 min at 25°C, and 90 min at 4°C. (B) The pH of the PBS-H ranged from 5.0 to 8.0 as indicated, and the HA assay incubation time was 90 min at 4°C.