Measurement of antibody responses to Modified Vaccinia virus Ankara (MVA) and Dryvax(®) using proteome microarrays and development of recombinant protein ELISAs.

Modified Vaccinia virus Ankara (MVA) is an attenuated strain of vaccinia virus that is being considered as a safer alternative to replicating vaccinia vaccine strains such as Dryvax(®) and ACAM2000. Its excellent safety profile and large genome also make it an attractive vector for the delivery of heterologous genes from other pathogens. MVA was attenuated by prolonged passage through chick embryonic fibroblasts in vitro. In human and most mammalian cells, production of infectious progeny is aborted in the late stage of infection. Despite this, MVA provides high-level gene expression and is immunogenic in humans and other animals. A key issue for vaccine developers is the ability to be able to monitor an immune response to MVA in both vaccinia naïve and previously vaccinated individuals. To this end we have used antibody profiling by proteome microarray to compare profiles before and after MVA and Dryvax vaccination to identify candidate serodiagnostic antigens. Six antigens with diagnostic utility, comprising three membrane and three non-membrane proteins from the intracellular mature virion, were purified and evaluated in ELISAs. The membrane protein WR113/D8L provided the best sensitivity and specificity of the six antigens tested for monitoring both MVA and Dryvax vaccination, whereas the A-type inclusion protein homolog, WR148, provided the best discrimination. The ratio of responses to membrane protein WR132/A13L and core protein WR070/I1L also provided good discrimination between primary and secondary responses to Dryvax, whereas membrane protein WR101/H3L and virion assembly protein WR118/D13L together provided the best sensitivity for detecting antibody in previously vaccinated individuals. These data will aid the development novel MVA-based vaccines.