Titration of individual strains in trivalent live-attenuated influenza vaccine without neutralization.
Formulation and quality control of trivalent live-attenuated influenza vaccine requires titration of infectivity of individual strains in the trivalent mix. This is usually performed by selective neutralization of two of the three strains and titration of the un-neutralized strain in cell culture or embryonated eggs. This procedure requires standard sera with high neutralizing titer against each of the three strains. Obtaining standard sera, which can specifically neutralize only the corresponding strain of influenza viruses and is able to completely neutralize high concentration of virus in the vaccine samples, can be a problem for many vaccine manufacturers as vaccine stocks usually have very high viral titers and complete neutralization may not be obtained. Here an alternative approach for titration of individual strain in trivalent vaccine without the selective neutralization is presented. This was done by detecting individual strains with specific antibodies in an end-point titration of a trivalent vaccine in cell culture. Similar titers were observed in monovalent and trivalent vaccines for influenza A H3N2 and influenza B strains, whereas the influenza A H1N1 strain did not grow well in cell culture. Viral interference among the vaccine strains was not observed. Therefore, providing that vaccine strains grow well in cell culture, this assay can reliably determine the potency of individual strains in trivalent live-attenuated influenza vaccines.
Institute of Molecular Biosciences (MB), Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand.
Naraporn
N
Sirinonthanawech
The Government Pharmaceutical Organization (GPO), 75/1 Rama VI Road, Ratchathewi, Bangkok 10400, Thailand.
Somchaiya
S
Surichan
The Government Pharmaceutical Organization (GPO), 75/1 Rama VI Road, Ratchathewi, Bangkok 10400, Thailand.
Aphinya
A
Namsai
Faculty of Medical Technology, Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand.
Pilaipan
P
Puthavathana
Institute of Molecular Biosciences (MB), Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand; Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Prannok Road, Bangkoknoi, Bangkok, 10700, Thailand.
Prasert
P
Auewarakul
Institute of Molecular Biosciences (MB), Mahidol University, 25/25 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170, Thailand. Electronic address: alita.kon@mahidol.ac.th.
Alita
A
Kongchanagul
D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D009981:Influenza B virus / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000276:immunology; D007251:Influenza, Human / Q000097:blood / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D009500:Neutralization Tests; D011786:Quality Control; D064166:Vaccine Potency
D000914:Antibodies, Viral; D007252:Influenza Vaccines
Influenza virus; Live-attenuated influenza vaccine; Trivalent vaccine titration