SYSTEMIC AND MUCOSAL IMMUNE-RESPONSES IN YOUNG-CHILDREN AND ADULTS AFTER PARENTERAL INFLUENZA VACCINATION

The effect of natural mucosal priming on systemic and mucosal immune r esponses was investigated in young children after parenteral influenza vaccination, Eighteen young children and 8 adults were vaccinated wit h trivalent influenza vaccine at various time intervals before tonsill ectomy, The influenza-specific IgG, IgA, and IgM immune responses were examined in tonsillar lymphocytes and frequent samples of peripheral blood and oral fluid, Young children were divided into primed and unpr imed groups on the basis of presence of prevaccination serum antibodie s. In peripheral blood, adults and primed children had significantly h igher Ige and IgA antibody responses than did unprimed children. Irres pective of priming, children elicited weaker IgA responses than adults in both tonsils and oral fluid. While natural priming was essential t o elicit strong systemic response in young children after parenteral i nfluenza vaccination, it did not influence the local responses, which were significantly lower in both primed and unprimed children than in adults.