SEROLOGICAL REACTIVITY OF SERA FROM SCRUB TYPHUS PATIENTS AGAINST WEIL-FELIX TEST ANTIGENS

Sera from 17 patients of scrub typhus in the acute and convalescent ph ases were tested by indirect immunoperoxidase test, Weil-Felix (WF) te st, enzyme-linked immunosorbent assay (ELISA), and immunoblotting. In the comparison of antibody titers between acute- and convalescent-phas e sera, we recognized a parallelism of increment between the titers in WF test and titers of immunoglobulin M (IgM) in ELISA against Proteus mirabilis strain OXK-whole cells and OXK-lipopolysaccharides (Proteus OXK-LPS). Furthermore, IgM antibodies from almost all of WF test-posi tive sera recognized LPS from Proteus OXK in immunoblotting. Based on these results, it was concluded that IgM antibody rather than IgG may participate in WF test, and that Proteus OXK-LPS may have one of antig enic epitopes common to the components of R. tsutsugamushi.