National Institute of Animal Health (NIAH)

Topics in Animal Health Research 2005

14. Molecular and immunological characterization of Histophilus somni high molecular weight-immunoglobulin binding proteins

Japanese

  Analysis of the 5’-flanking nucleotide sequence of the gene for Histophilus somni p76 virulence-associated immunoglobulin binding protein (IgBP) indicated that the gene (immunoglobulin binding protein A, ibpA) encoding the high molecular weight (HMW) and p76 IgBPs comprised a single open reading frame of 12,285 base pairs (bp). The ibpA gene is flanked by an upstream ORF of 1,758 bp, designated ibpB. The predicted amino acid sequences of these two genes demonstrate similarity to virulence exoproteins and their transporter proteins that comprise a two-partner secretion pathway in various Gram-negative bacteria. Expression plasmids for glutathione S-transferase (GST)-fused recombinant fragments covered amino acid residues 972 to 3,201. IgG2 Fc binding studies identified fragment 972-1,515 (GST-IbpA3) as an Fc binding peptide. This peptide and GST-IbpA5 (aa2,071-2,730) reacted strongly with convalescent phase serum. In a preliminary study, calves immunized with the purified GST-IbpA3 peptide were protected against an intrabronchial H. somni challenge.
(Research Team for Bacterial/Parasitic Diseases, TEL +81-29-838-7739)

Reference:

Tagawa et al. (2005) Microb. Pathog. 39:159-170.

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