RESUMO
Vaccination is the practiced and accessible measure for preventing influenza infection. Because chicken embryos used for vaccine production have various insufficiencies, more efficient methods are needed. African green monkey kidney (Vero) cells are recommended by the World Health Organization (WHO) as a safe substitute for influenza vaccine production for humans. However, the influenza virus usually had low-yield in Vero cells, which limits the usage of Vero cellular vaccines. This study used 2 high-yield influenza viruses in Vero cells: A/Yunnan/1/2005Va (H3N2) and B/Yunnan/2/2005Va (B) as donor viruses. It used 3 wild strain viruses to reassort new adaptation viruses, including: A/Tianjin/15/2009(H1N1), A/Fujian/196/2009(H3N2), and B/Chongqing/1384/2010(B). These three new viruses could maintain the characteristic of high-yield in Vero cells. Furthermore, they could keep the immunogenic characteristics of the original wild influenza viruses. Importantly, these viruses were shown as safe in chicken embryo and guinea pigs assessment systems. These results provide an alternative method to produce influenza vaccine based on Vero cells.
Assuntos
Técnicas de Cultura de Células , Vírus da Influenza A Subtipo H1N1/patogenicidade , Vírus da Influenza A Subtipo H3N2/patogenicidade , Vírus da Influenza B/patogenicidade , Vacinas contra Influenza/efeitos adversos , Vírus Reordenados/patogenicidade , Tecnologia Farmacêutica , Animais , Chlorocebus aethiops , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Feminino , Furões , Cobaias , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza B/genética , Vírus da Influenza B/crescimento & desenvolvimento , Vírus da Influenza B/imunologia , Vacinas contra Influenza/administração & dosagem , Camundongos Endogâmicos BALB C , Vírus Reordenados/genética , Vírus Reordenados/crescimento & desenvolvimento , Vírus Reordenados/imunologia , Células VeroRESUMO
Influenza pandemics occur periodically and the subtype of the next pandemic strain cannot be predicted. Vaccination remains a critical intervention during pandemics, but current production technology requires several months to develop sufficient vaccine to meet anticipated worldwide need. Candidate prepandemic vaccines for use in population priming or rapid deployment during an epidemic are in development but are subtype specific and logistical obstacles to timely distribution exist. Intensive research is underway to identify a universal vaccine, providing protection against all known influenza strains based on shared epitopes. Vaccine access is expected to be limited during early response to a pandemic, necessitating ethical vaccine distribution plans for within-country and global allocation. Mass vaccination plans must be in place prior to an event to ensure appropriate infrastructures are in place. Carefully crafted education campaigns regarding pandemic vaccine safety and efficacy should aid in maximizing pandemic vaccine uptake during a future event.
Assuntos
Programas de Imunização/organização & administração , Vacinas contra Influenza/provisão & distribuição , Influenza Humana/prevenção & controle , Vacinação em Massa/métodos , Pandemias/prevenção & controle , Variação Antigênica , Transmissão de Doença Infecciosa/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Política de Saúde/legislação & jurisprudência , Humanos , Programas de Imunização/legislação & jurisprudência , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/patogenicidade , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Vacinação em Massa/ética , Vacinação em Massa/legislação & jurisprudência , Ensaios Clínicos Controlados Aleatórios como Assunto , Vírus Reordenados/imunologia , Vírus Reordenados/patogenicidadeRESUMO
PURPOSE: The main purpose of vaccination is to generate immunological memory providing enhanced immune responses against infectious pathogens. The standard and most commonly used assay for influenza vaccine immunogenicity evaluation is a hemagglutination inhibition assay (HAI). It is clear now that HAI assay is unable to properly assess the proven protective immunity elicited by live attenuated influenza vaccines (LAIV). New methods need to be developed for more accurate LAIV immunogenicity assessment and prediction of vaccine efficacy among target populations. OBJECTIVE: Randomized placebo-controlled study of memory B- and T-cell responses to intranasal LAIV in young adults. METHODS: A total of 56 healthy young adults 18-20 years old received seasonal monovalent LAIV. Mucosal memory B-cell responses were measured by IgA avidity assessment in nasal swabs. CD4 memory T cells in peripheral blood were examined by the expression of CD45RO marker and in functional test by the ability of virus-specific T cells to maintain the trogocytosis with antigen-loaded target cells. RESULTS: Intranasal LAIV immunization enhances mucosal IgA avidity even without reliable increases in antibody titers. At the day 21 after vaccination, up to 40% of subjects demonstrated significant increases in both total and virus-specific CD4 memory T cells that were observed regardless of seroconversion rate measured by HAI assay. CONCLUSION: The data suggest that immunogenicity of LAIV vaccines should be evaluated on the mucosal and cellular immunity basis. The assays applied could be used to support influenza clinical trials through preliminary screening of volunteers and subsequent measurement of anti-influenza in immunity.
Assuntos
Apresentação de Antígeno , Linfócitos B/imunologia , Memória Imunológica , Vacinas contra Influenza/imunologia , Orthomyxoviridae/imunologia , Vírus Reordenados/imunologia , Linfócitos T/imunologia , Administração Intranasal , Adolescente , Anticorpos Antivirais/imunologia , Afinidade de Anticorpos , Antígenos CD4/análise , Experimentação Humana , Humanos , Imunidade nas Mucosas , Imunoglobulina A/imunologia , Vacinas contra Influenza/administração & dosagem , Antígenos Comuns de Leucócito/análise , Placebos/administração & dosagem , Subpopulações de Linfócitos T/química , Subpopulações de Linfócitos T/imunologia , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Adulto JovemAssuntos
Vacinas contra Influenza/provisão & distribuição , Influenza Humana/prevenção & controle , Adjuvantes Imunológicos , Animais , Galinhas , Ensaios Clínicos como Assunto , Engenharia Genética , Humanos , Vacinas contra Influenza/economia , Vacinas contra Influenza/imunologia , Influenza Humana/economia , Influenza Humana/epidemiologia , Influenza Humana/imunologia , Orthomyxoviridae/genética , Orthomyxoviridae/imunologia , Orthomyxoviridae/patogenicidade , Vírus Reordenados/genética , Vírus Reordenados/crescimento & desenvolvimento , Vírus Reordenados/imunologia , Fatores de TempoRESUMO
Japanese encephalitis is a disease of the CNS, endemic in Asia and Oceania. The disease is refractory to drug treatments and whilst the rural economies remain heavily dependent on agriculture, conditions for propagation of the disease will persist. Thus, there is a need for effective vaccines. Although some currently exist, they have their shortcomings. ChimeriVax-JE (Acambis Inc.) is a chimeric, live attenuated vaccine which expresses protective Japanese encephalitis antigens and to date has proven to be safe, effective and well-tolerated in clinical trials. It therefore appears to be a cost-effective prophylactic vaccine against this debilitating disease.