Bioinformatics analysis of HA antigenic areas in influenza A viruses

• Main Authors: Ju-Jiun Wei, 魏竹君
• Other Authors: 高振益
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/66436622963048312803

碩士 === 國立中興大學 === 生命科學院碩士在職專班 === 97 === Influenza A is a serious respiratory infectious disease. In the past century, three times of serious influenza pandemics occurred. “Spanish influenza” caused by influenza A virus in 1918 was the most serious one and killed at least 50 million people. Generally, influenza epidemics cause severe illness in 3000000－5000000 people and kill 30000－50000 people worldwide every year. New epidemic influenza A strains arise every 1 to 2 years by the introduction of variation within surface antigen. The new variants are able to elude human host immune system and there is therefore no lasting immunity against the virus. Flu vaccine is the most effective prevention method. It can reduce effectively the morbidity and the mortality. Every year, WHO must predict influenza virus strains beforehand, and then flu vaccine can be made in advance. If the decided influenza virus strains were not correct, there should be significant impact on the people''s health and the economy globally. To develop and make universal vaccine is then very important. One of influenza virus surface antigen that easiest occurs variants is HA. We analyzed HA protein sequences of H1~H6 six subtypes by multiple sequence alignments and attempted to find conserved segments. We observed structures of these conserved segments by 3D crystal structure, and used ProtScale tool to analysze the hydrophilic and hydrophobic scale for HA protein sequences. The conserved segments were compared using UniProtKB database via the Blast to confirm the similar sequences. The 11 amino acid sequence “GXFGAIAGFIE” (X: I or L) is present in all H1~H6 subtype virus strains. The sequence is in hydrophilic region in HA protein sequence. Besides the influenza viruses, Blast analysis result only in Archaea having 3 sequences to be similar, Identities ranged from 69% to 81%. We do not find similar sequence as to “GLFGAIAGFIE” in other species and in human. We presume that “GLFGAIAGFIE” sequence may be used as the antigen for universal influenza vaccine.