The humoral and cellular responses induced locally and systemically after parenteral influenza vaccination in man

Studies of the immune response after influenza vaccination in man, with focus on the immune activity occurring locally at mucosal surfaces and in associated lymphoid tissue, provide a valuable insight into immunity to influenza. The aim of influenza vaccination is to develop immunological memory resulting in enhanced rapid specific response upon subsequent influenza encounter. The tonsils are thought to play an important role as an activating, effector and memory site for immune responses against influenza. We have shown that normally high numbers of influenza-specific antibody secreting cells (ASC) are present in the nasal mucosa of healthy adults but upon parenteral vaccination the numbers remain stable. However, a rapid transient increase in influenza-specific ASC is observed in the tonsils and peripheral blood after vaccination. In the tonsils and blood, parenteral vaccination results in a significant decrease in CD4+ cells upon vaccination, which are probably recruited to the draining lymph node.