Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Jun;13(6):367-75.
doi: 10.1089/vbz.2012.1112. Epub 2013 Apr 16.

Diversity of the 47-kD HtrA nucleic acid and translated amino acid sequences from 17 recent human isolates of Orientia

Ju Jiang  1 , Daniel H Paris, Stuart D Blacksell, Nuntipa Aukkanit, Paul N Newton, Rattanaphone Phetsouvanh, Leonard Izzard, John Stenos, Stephen R Graves, Nicholas P J Day, Allen L Richards
Affiliations

Diversity of the 47-kD HtrA nucleic acid and translated amino acid sequences from 17 recent human isolates of Orientia

Ju Jiang et al. Vector Borne Zoonotic Dis. 2013 Jun.

Abstract

Orientia tsutsugamushi, the etiologic agent of potentially fatal scrub typhus, is characterized by a high antigenic diversity, which complicates the development of a broadly protective vaccine. Efficacy studies in murine and nonhuman primate models demonstrated the DNA vaccine candidate pKarp47, based upon the O. tsutsugamushi Karp 47-kD HtrA protein gene, to be a successful immunoprophylactic against scrub typhus. To characterize 47-kD HtrA protein diversity among human isolates of Orientia, we sequenced the full open reading frame (ORF) of the 47-kD HtrA gene and analyzed the translated amino acid sequences of 17 patient isolates from Thailand (n=13), Laos (n=2), Australia (n=1), and the United Arab Emirates (UAE) (n=1) and 9 reference strains: Karp (New Guinea), Kato (Japan), Ikeda (Japan), Gilliam (Burma), Boryong (Korea), TA763, TH1811 and TH1817 (Thailand), and MAK243 (China). The percentage identity (similarity) of translated amino acid sequences between 16 new isolates and 9 reference strains of O. tsutsugamushi ranged from 96.4% to 100% (97.4% to 100%). However, inclusion of the recently identified Orientia chuto sp. nov. reduced identity (similarity) values to 82.2% to 83.3% (90.4% to 91.4%). These results demonstrate the diversity of Orientia 47-kD HtrA among isolates encountered by humans and therefore provide support for the necessity of developing a broadly protective scrub typhus vaccine that takes this diversity into account.

PubMed Disclaimer

Figures

FIG. 1.
FIG. 1.
Heat maps of percent identities of the 47-kD HtrA DNA (A) and amino acid (B) sequences among 25 Orientia isolates (without O. chuto). Heat maps were generated using the pairwise identity matrix tables with hierarchical clustering method. The name of each isolate was labeled on the right side of the graphs with its corresponding number code, which was used at the bottom of the graphs. Dendrograms were placed to the left side and on top of the graphs.
FIG. 1.
FIG. 1.
Heat maps of percent identities of the 47-kD HtrA DNA (A) and amino acid (B) sequences among 25 Orientia isolates (without O. chuto). Heat maps were generated using the pairwise identity matrix tables with hierarchical clustering method. The name of each isolate was labeled on the right side of the graphs with its corresponding number code, which was used at the bottom of the graphs. Dendrograms were placed to the left side and on top of the graphs.
FIG. 2.
FIG. 2.
Evolutionary relationships among 17 new Orientia isolates and 9 reference strains. Phylogenetic trees were constructed based on multiple sequence alignment of 47-kD HtrA gene open reading frame (ORF) (A) and calculated amino acid sequence of the 47-kD HtrA (B) using the maximum likelihood method. Bootstrap values above 50 are labeled at the nodes.
See this image and copyright information in PMC

References

    1. Balcells ME. Rabagliati R. Garcia P. Poggi H, et al. Endemic scrub typhus-like illness, Chile. Emerg Infect Dis. 2011;17:1659–1663. - PMC - PubMed
    1. Blacksell SD. Luksameetanasan R. Kalambaheti T. Aukkanit N, et al. Genetic typing of the 56-kDa type-specific antigen gene of contemporary Orientia tsutsugamushi isolates causing human scrub typhus at two sites in north-eastern and western Thailand. FEMS Immunol Med Microbiol. 2008;52:335–342. - PubMed
    1. Brown GW. Robinson DM. Huxsoll DL. Ng TS, et al. Scrub typhus: A common cause of illness in indigenous populations. Trans Royal Soc Trop Med Hyg. 1976;70:444–448. - PubMed
    1. Chattopadhyay S. Richards AL. Scrub typhus vaccines: Past history and recent developments. Hum Vaccines. 2007;3:73–80. - PubMed
    1. Ge H. Tong M. Li A. Mehta R. Ching WM. Cloning and sequence analysis of the 22-kDa antigen genes of Orientia tsutsugamushi strains Kato, TA763, AFSC 7, 18-032460, TH1814, and MAK 119. Ann NY Acad Sci. 2005;1063:231–238. - PubMed

Publication types

MeSH terms