Comparison of Nucleotide Sequences of Hantaan and Seoul viruses Passed in Suckling Mouse Brains

ABSTRACT

Hantaan (HTN) virus and Seoul (SEO) virus, two murid rodent-borne hantaviruses harbored by the striped-field mouse (Apodemus agrarius) and the Norway rat (Rattus norvegicus), respectively, were known to cause hemorrhagic fever with renal syndrome (HFRS). After inoculation of HTN and SEO viruses into suckling mice intracerebrally, mice became ill and were morbibund by 15 or 16 days postinfection. Viral antigens were present in brain, heart, lung, liver, kidney, spleen, pituitary gland, thymus, lymph nodes, adrenal, pancreas, salivary glands, trigeminal ganglia, adipose tissue, intestine and muscle. Moreover, the time period appearing illness and morbidity were gradually decreased from 15 or 16 days to 8 or 9 days postinfection increasing the passage number. Therefore to evaluate the relationship between these adaptation process and genomic change of HTN and SEO viruses, we sequenced corresponding regions of the 3' G1 and 5' G2 encoding M genomic segments of two HTN and six SEO virus strains, and compared the nucleotide changes between the original stocks and five to nine passed virus strains in suckling mice brains. There was no nucleotide changes in HTN virus strains and zero to four nucleotide changes in SEO virus strains. However, only one base change resulted in amino acid change at the position 1691 (Gln to Glu) of 5' G2 encoding M genomic segment. This amino acid change didn't effect any conformational change in the beta-sheet, hydrophilicity, antigenicity and surface probability of protein structure of G2 glycoprotein. Our present data suggested that the genomic changes in the 3' G1 and 5' G2 encoding M genomic segment was not related with adaptation process of HTN and SEO viruses passed in suckling mice brains.