AN EARLY HUMORAL IMMUNE-RESPONSE IN PERIPHERAL-BLOOD FOLLOWING PARENTERAL INACTIVATED INFLUENZA VACCINATION

The enzyme-linked immunospot assay was used to examine the humoral imm une response in 15 healthy volunteers immunized with either split or s ubunit inactivated trivalent influenza vaccine containing A/Beijing/35 3/89 (H3N2), A/Taiwan/1/86 (H1N1) and B/Yamagata/16/88. The rapidity o f the individual B-cell and serum antibody response was examined in ly mphocyte and serum samples collected at various time intervals after v accination. A rapid serological response was detected with increases i n antibody titre detected in the majority of volunteers by 7-8 days po stvaccination. Influenza-specific plasma cells were detected as early as 4 days postvaccination, higher numbers of IgA and IgG antibody-secr eting cells (ASC) were observed which peaked at 7-8 days postvaccinati on. The number of ASCs then declined with low numbers of cells detecte d at II days postvaccination. Influenza-specific IgA ASCs were predomi nantly of the IgA1 subclass. This rapid immune response may have a bea ring on future vaccination policies of unimmunized 'at risk groups' in times of high influenza activity.