Persistence of Human Antibody to Venezuelan Equine Encephalomyelitis (VEE) Virus Subtypes after Immunization with Attenuated (TC-83) VEE Vaccine.

摘要

The persistence of serum antibody of Venezuelan equine encephalomyelitis (VEE) virus subtypes was studied in 20 volunteers inoculated 7 or 9 years previously with attenuated TC-83 VEE vaccine. Serological patterns were compared with those of 10 other persons bled 28 days after vaccination with TC-83. Vaccinees had no other known group A arbovirus exposure. Neutralizing antibody titers of > 1:10 were measured against the homologous TC-83 virus strain in all long- and short-term vaccinees. In both groups of vaccinees the percentage of antibody-positive persons and their geometric mean titers were higher against the epizootic subtypes I-A, I-B, I-C, than against the enzootic subtypes, I-D, I-E, II, III, and IV. However proportionally fewer long-term vaccinees than short-term vaccinees, had detectable neutralizing antibody reactive with enzootic strains. These results reveal long-lasting circulation of neutralizing antibody to TC-83 virus and closely related epizootic variants in 95-100% of vaccinees. The relatively lower antibody conversion rate and loss of antibody to more antigenically remote enzootic VEE subtypes suggests that vaccinees may be less well protected against infection by these strains.