Venezuelan equine encephalitis‐specific immunoglobulin responses: Live attenuated TC‐83 versus inactivated C‐84 vaccine

Abstract

Venezuelan equine encephalitis (VEE)-specific immunoglobulin responses to the two vaccines, TC-83 (a live attenuated vaccine) and C-84 (a formalin inactivated vaccine derived from the TC-83 strain of virus) were evaluated using an antigen and isotype-specific enzyme-linked immunoadsorbent assay (ELISA). The VEE-specific ELISA for IgG, IgG subclasses, IgA and IgM were developed and standardized using sera from vaccine-exposed and unexposed human subjects. Paired human sera (before and 28 days after immunization) were tested from laboratory workers vaccinated with either TC-83 (Group A: 20 paired sera from subjects receiving a single TC-83 vaccine and with no prior history of vaccination) or C-84 in varying schedules (Group B: 19 paired sera from subjects who had a distant vaccination history to TC-83 but no evidence of neutralizing antibody; Group C: 19 paired sera from subjects receiving their first C-84 vaccination and no prior documented history of vaccination; Group D: 15 paired sera from subjects receiving a C-84 booster vaccination with prior history of C-84 but no TC-83 exposure). Sera were all tested for viral neutralization in vitro using a Vero cell monolayer for culturing virus and establishing 80% plaque reduction for each serum tested. All pre-sera tested demonstrated no plaque reduction neutralization at a level of 80% for a dilution of 1:10. ELISA antibody titers for all pre-sera with no prior VEE exposure through vaccination or possible environmental factors were negative at a titer of 1:160 for IgM, 1:80 for IgG, IgA, and G subclasses.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and protective efficacy of INA-inactivated Venezuelan equine encephalitis virus: Implication in vaccine development

“…Formalin inactivated TC-83, known as C-84, is used as a booster following immunization with live, attenuated TC-83 vaccine. This vaccine is also used under IND status, has short-lived immunity and requires frequent boosts [14,15]. An attenuated strain, V3526, which has a deletion mutation at the furin cleavage site between the E2 and E3 glycoproteins of the Trinidad donkey strain of VEEV [16] has been extensively evaluated as a VEEV vaccine candidate [17][18][19][20].…”

Liposome-Antigen-Nucleic Acid Complexes Protect Mice from Lethal Challenge with Western and Eastern Equine Encephalitis Viruses

“…Moreover, same-day administration of WEEV/ EEEV vaccines can cause immune interference as measured by reduced antibody titers (3); thus, the development of vaccines that confer protection without immune interference is a goal of panalphavirus vaccine strategies. VEEV TC-83 is an attenuated vaccine with a response rate of 82%, and a single boost with formalininactivated C-84 vaccine increases the response rate to over 90%; however, adverse events are reported in 23% of recipients (5). Thus, TC-83 is considered reactogenic and moderately effective as measured by neutralizing antibody.…”

An Inactivated Ross River Virus Vaccine Is Well Tolerated and Immunogenic in an Adult Population in a Randomized Phase 3 Trial

“…There are no other reported clinical studies of RRV vaccines. Several other inactivated whole-virus candidate vaccines against other alphaviruses such as Venezuelan equine encephalomyelitis virus, Eastern equine encephalomyelitis virus, and Western equine encephalomyelitis virus have been developed (15)(16)(17)(18)(19)(20), but none have been licensed for human use and clinical data are limited. More extensive clinical data are available for inactivated, whole-virus vaccines to prevent diseases caused by flaviviruses, which structurally resemble alphaviruses, such as tick-borne encephalitis virus (TBEV), Japanese encephalitis virus, and yellow fever virus (21)(22)(23).…”