Advanced System for Worldwide Surveillance of Rickettsial Disease Antibodies. Phase 1
Final rept. 15 Mar 1996-14 Sep 1996
INTEGRATED DIAGNOSTICS INC BALTIMORE MD
Pagination or Media Count:
Detection of newly emerging human ehilichioses would benefit greatly from the commercial availability of a simple, standardized, and economical confirming diagnostic test. A serological dot ELISA dipstick DS test meeting these criteria, produced by Integrated Diagnostics, detects anti-rickettsial antibodies with sensitivity and specificity comparable to IFA. We explored the feasibility of producing similar DS for recognizing antibodies to pathogenic ehrlichiae by developing methods for the bulk cultivation and purification of 2 elirlichia species E. sennetsu E chaffeensis and by producing and testing prototype DS. Large quantities of E. chaffeensis and E. sennetsu were successfully grown in Vero cells inhi bition of host cell division by daunomycin did not affect elirlichial replication and permitted harvest from cultures of 100, very heavily infected cells. Renogralin gradient purification of E. chanfeensis was refined to optimize DS antigen yields preliminary results suggest that antigen yields may be further increased by treating infected cells with Triton X- 100. DS made with purified E. chaffeensis and HUE human granulocytic ehrlichiae antigens evidenced some cross reactivity when tested with anti-Ep chaffeensis and -HGE convalescent sera, but reactions with control sera from normal and rickettsia-, flavivirus-, and auto-immune donors were largely negative. Thus we have demonstrated the technical feasibility of producing ehrlichial DS suitable for extensive field testing for sensitivity and specificity. These should provide a rapid, field-deployable, and easily performed and read alternative to IFA.