We reported a retrospective study on hemagglutinin (HA) gene fragments of Avian Influenza (AI) viruses recovered between 2010 to 2012, using reverse transcriptase polymerase chain reaction (RT-PCR) followed by sequencing. The results provide information about the receptor binding sites (RBS) and antigenic sites character of HA gene of AI viruses in Indonesia. Viral RNA was extracted from allantoic fluid of specific pathogen free (SPF) of chicken embryonated eggs inoculated by AI suspected samples. Amplification was performed by using H5 specific primers to produce amplification target of 544 bp. The resulting sequences were analyzed with MEGA-5 consisting of multiple alignment, deductive amino acid prediction, and phylogenetic tree analysis. The results showed that out of the 12 samples amplified using RT-PCR technique, only 7 were detected to be avian influenza serotype H5 viruses. Sequence analysis of AIV H5 positive samples, showed a binding preference towards avian type receptors. Antigenic site analysis is consistent with the previous report, however, the antigenic site B at position 189 showed that the residue had undergone mutation from arginine to methionine. Phylogenetic tree analysis showed that these viruses were clustered into clade 2.1.3. Our report supports the importance of the previous study of RBS and antigenic properties of HPAI H5N1 in Indonesia.

Key words: Avian influenza virus, Hemagglutinin, Reverse transcriptase polymerase chain reaction