COCIRCULATION OF 2 DISTINCT GROUPS OF INFLUENZA-C VIRUS IN YAMAGATA-CITY, JAPAN

The antigenic and genetic relationships among 15 strains of influenza C virus isolated between August, 1988, and May, 1990, in Yamagata City , Japan, were investigated. Based on the results of antigenic analysis with monoclonal antibodies to the hemagglutinin-esterase (HE) glycopr oteins and oligonucleotide mapping of total vRNA, the isolates were di vided into two distinct groups closely related to either C/Yamagata/26 /81 or C/Aichi/1/81. Antigenic differences between two groups could be detected clearly with heterogeneous antiviral sera. Comparison of the HE gene sequences between the representative Yamagata isolates and th e previous isolates from other countries showed that C/Yamagata/26/81- like and C/Aichi/1/81-like viruses had high degrees of nucleotide sequ ence homology with C/pig/Beijing/115/81 and C/Johannesburg/1/66, respe ctively. These observations suggest that two lineages of influenza C v irus, markedly different from each other in both antigenic and genetic structures, were simultaneously present in Yamagata City during 1988- 1990 and that vi ruses belonging to each of the two lineages may also be prevalent in other areas of Japan and even in other countries. (C) 1994 Academic Press, Inc.