Age-related change of the absolute number of IgG-, and IgM-bearing B-lymphocytes and T-lymphocytes in human peripheral blood following influenza vaccination.

The absolute number of IgG-, and IgM-bearing B lymphocytes and of T lymphocytes was determined in the peripheral blood of 12 old (over 60 years) and 11 young (20 to 40 years) healthy persons before vaccination and 6 days and 6 weeks, respectively after vaccination. It has been found that as opposed to an approximately fivefold increase of IgG bearing cells in young persons, the increase did hardly reach double of the original value in old individuals. The absolute number of T lymphocytes participating in the immune reaction showed a transitory increase in young persons, while a gradual decrease has been observed in old individuals. In healthy elderly persons the administration of 10 U Honkong 5/72-B killed influenza virus as in vivo antigen stimulus resulted in a reduced proliferation of IgG carrier lymphocytes participating in antibody production.