Figure 3.

Anti-F protein and neutralizing RSV antibodies. Blood was collected at day 0, 28, and 49 post vaccination/infection. (A) The anti-F protein IgG binding antibody was determined by ELISA as described in the materials and methods. The anti-F antibody response is indicated by absorbance for F minus absorbance at a 1:500 dilution. (B) The neutralizing antibodies were determined by a 60% plaque reduction assay. The serum specimens were heat inactivated and incubated with RSV A2 (25–50 PFU) at serial 4-fold dilutions beginning at a 1:10 dilution followed by inoculation in duplicates onto confluent HEp-2 monolayers in 24-well plates as described in materials and methods. The reciprocal neutralizing antibody titer is the highest titer with >60% reduction in plaque number as compared with the virus control.