R tsutsugamushi is a obligate intracellular parsite, the causative agent of tsutsugamushi disease, whose surface proteins are suspected to involve its pathogenecity. Although large quantities of purified R. tsutsugamshi are
required
to
study rickettsial pathogenecity, it still remains technically and economically unfeasible to get large-scale growth and purificication of rickettsia for the isolation of individual antigens. We have expressed the rikettsial protein antigens
via
recombinant expression vecor system and examined their biological characteristics.A genomic library of R. Tsutsugamushi Kato strain was constructed using lambda ZAP II ovctor system. From this gene bank, three gees encoding 63-kDa,
47-kDa,
and
120-kDa rickettsial protein antigens were cloned and expressed in E. coli Expression of cloned proteins were shown to be independent of isopropyl beta-D-thiogalactopyranoside(IPTG) induction. Suggesting
that the
intact rikettsial promotors were operational in all clones.
Affinity-purified monospecific antisera against each cloned protein were used to identify the antigens in Western blost of extracted Kato and cloned proteins. Monospecific antisera against the recombinant 63-kDa protein reacted with
180-kDa
Kato protines, indicating pKT 1 has cloned the partial sequence of rickettsial gene expressing 180-kDa protein. And monospecific polysera against the recombinants 47-kDa and 120-kDa protein reocginzed the protients of 47-kDa in an
120-kDa
in
Kato strain respectively, suggesting these two clones have expressed the whole-sequeces of 47-kDa and 120-kDa rickettil antigen genes.
Three cloned proteins were reactive with serotype specific polysera against R. tsutsugamushi Kato, gilliam, Karp strains, indicating they have the common antigenic determinants of strains of R. tsutsugamushi.
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