Epidemiology and Infection



Amino-acid change on the antigenic region B1 of H3 haemagglutinin may be a trigger for the emergence of drift strain of influenza A virus


K. SATO a1, T. MORISHITA a1, E. NOBUSAWA a2, K. TONEGAWA a2, K. SAKAE a1, S. NAKAJIMA a2 and K. NAKAJIMA a2c1
a1 Department of Microbiology, Aichi Prefectural Institute of Public Health, Nagoya 462-8576, Japan
a2 Department of Virology, Medical School, Nagoya City University, Nagoya 467-8601, Japan

Article author query
sato k   [PubMed][Google Scholar] 
morishita t   [PubMed][Google Scholar] 
nobusawa e   [PubMed][Google Scholar] 
tonegawa k   [PubMed][Google Scholar] 
sakae k   [PubMed][Google Scholar] 
nakajima s   [PubMed][Google Scholar] 
nakajima k   [PubMed][Google Scholar] 

Abstract

Sera from 27 children and eight older persons, which had been collected in 1998 and 1999 and showed haemagglutination–inhibition (HI) activity against influenza A/Sydney/5/97 (H3N2) strain, were characterized with a binding assay using chimeric haemagglutinin (HA) proteins between A/Aichi/2/68 (A/AI/68) and A/Sydney/5/97 (A/SD/97) strains. Sera from the young children had a tendency to recognize only the antigenic site B1 of the HA1 region. On the other hand, sera of the older individuals were fully reactive to all antigenic sites of HA1 except antigenic site D. Recent epidemic strains, A/Panama/2007/99 (A/PM/99)-like viruses have differences in amino acids in antigenic sites A, C, and B2 but not B1. However, human antisera obtained even from young children had HI activity to Panama-like viruses. The limited epidemic of A/PM/99-like viruses may have been due to the existence of antibody against B1, which had been produced in response to infection by the A/SD/97-like viruses.

(Accepted November 3 2003)


Correspondence:
c1 Dr K. Nakajima, Department of Virology, Medical School, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.


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