Volume 72, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


A partial gene sequence encoding the 56-kD scrub typhus antigen (Sta56) was amplified from genomic DNA of the Karp strain by a polymerase chain reaction (PCR). The PCR product was ligated with the 47-kD scrub typhus antigen (Sta47) gene in the pQE30/47 expression vector, and the resulting recombinant expression vector was designated pQE30/56-47. A fusion antigen (Sta56-47) was expressed in cells transformed with pQE30/56-47 after induction with isopropyl-β--thiogalactopyranoside. The Sta56-47 antigen was recognized by both Sta47 and Sta56 immune sera and by immune serum to Sta56-47 in an immunoblot assay. This antigen was purified and used to immunize BALB/c mice. The animals immunized with Sta56-47 exhibited profound humoral and cellular immune responses, as well as increased resistance to Karp compared with mice immunized with Sta56 or Sta47. These results strongly suggest that Sta56-47 contains antigenic epitopes of the Sta56 and Sta47 antigens of Karp, and is a more suitable candidate for replacing whole-cell antigen of Karp to induce protective immunity against scrub typhus.


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  • Received : 25 Mar 2004
  • Accepted : 21 Oct 2004

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