Evaluation of recombinant type-specific antigens of Orientia tsutsugamushi which were expressed by baculovirus-insect cell system as antigens for indirect immunofluorescent assay in the serological diagnosis of scrub typhus.

In this study, sf-9 insect cells infected with the recombinant type-specific antigens (rTSA)-expressing baculovirus were applied for IFA. The paired sera samples of 15 scrub typhus-patients, 10 rickettsiosis-patients, and 10 control individuals were used. Both IgM and IgG IFA titers determined by the rTSA based IFA were correlated with those determined with the OTS-infected cell-based IFA (R 2 = 0.7319 to 0.7956). Based on the criteria for serological diagnosis, such as the suitable cutoff for single serum (IgM ≥ 1:160) and/or significant increase in IgG titer between paired sera (≥ 4 times), all of the 15 scrub typhus patients diagnosed as positive with OTS-infected cell-based IFA were also diagnosed as positive by the rTSA-based IFA, whereas all 10 rickettsiosis patients and 10 control individuals were not. The rTSAs, which can be prepared in BSL-2 laboratories, are efficacious in the serological diagnosis of scrub typhus. PMID: 32350215 [PubMed - as supplied by publisher]
Source: Japanese Journal of Infectious Diseases - Category: Infectious Diseases Authors: Tags: Jpn J Infect Dis Source Type: research