Antibody Responses to Vaccinia Membrane Proteins after Smallpox Vaccination

Background. Vaccinia virus (VV) membrane proteins are candidates for orthopoxvirus subunit vaccines and potential targets for therapeutic antibodies. Human antibody responses to these proteins after VV vaccination have not been well characterized. Methods. Pre- and postvaccination (day 26–30) serum specimens from 80 VV vaccine recipients were examined for immunoglobulin G antibodies specific for B5, A33, A27, and L1 by enzyme-linked immunosorbent assay (ELISA). Responses were compared between vaccinia-naive and previously vaccinated (nonnaive) recipients and between nonnaive recipients of undiluted or 1:10 diluted vaccine. Results. VV vaccination elicited anti-A33 and anti-A27 antibodies in nearly all vaccinia-naive subjects (100% and 93%, respectively). Preexisting antibodies were commonly detected in nonnaive subjects (for anti-B5, 68%; for anti-A33, 59%; for anti-A27, 38%; and for anti-L1, 10%). Anti-B5 antibodies were strongly boosted by undiluted vaccine (geometric mean titer [GMT], 151 vs. 1010 for pre- vs. postvaccination; P