COMBINED USE OF COMPLEMENT AND ANTIIMMUNOGLOBULIN IN AN ENHANCED NEUTRALIZATION ASSAY FOR ANTIBODIES TO VARICELLA-ZOSTER VIRUS

An enhanced neutralization assay was developed to permit the sensitive , specific, and reproducible measurement of antibodies to varicella-zo ster virus (VZV). Optimal neutralization was achieved using a combinat ion of guinea pig complement (C') and rabbit anti-human IgG. This prov ided 625-, 160- and 13- to 64-fold increases in dilution endpoints of human post-tester serum, varicella-zoster immune globulin and represen tative sera from recipients of live attenuated varicella vaccine, resp ectively, above those measured in the absence of C' and anti-IgG. The specificity of the assay was shown by the absorption of serum neutrali zation capacity with VZV-specific antigen and the lack of concordance between antibody titers to VZV with those to either herpes simplex vir us type-2 or cytomegalovirus. The antibody status of recipients of liv e attenuated varicella vaccine was established from the amount of neut ralizing activity produced at a single optimal serum dilution (1:64).