Virus-specific CD4~+ and CD8~+ memory T-cells in young volunteers after immunization with pandemic live attenuated reassortant influenza vaccines A (H5N2) and A(H1N1)

摘要

It is well known that a primary goal of vaccination is to generate immunological memory against the targeted antigen to prevent disease in a vaccinated person. This ensures an accelerated immune response in the event of future contact with the pathogenic agent, such as a virus. Therefore, it is very important to develop criteria for the assessment of vaccine immunogenicity by measuring both T and B memory cell levels from the vaccinated host. In contrast to inactivated influenza vaccines, live attenuated influenza vaccines (LAIVs) have been shown to provide primarily cellular and local immune responses. To date, however, the hemagglutination-inhibition (HAI) test (i.e. detection of serum antibodies) remains the method widely accepted for evaluation of an influenza vaccine's immunogenicity. Improved understanding of the role of cellular and mucosal immunity and their contribution to protecting against severe illness caused by influenza infection has emphasized the need to reconsider methodologies used to evaluate the immunogenic impact of various influenza vaccines. Such new assays need to include methods to measure local antibodies and virus-specific lymphocytes, especially in the case of live attenuated influenza vaccines, because of their potential to induce such broad-based immune responses.