Stimulation of peripheral blood lymphocytes of children by influenza vaccine.

Cell cultures were performed with the blood of children, adults and umbilical cords in an examination of the effects of influenza vaccines. Commercially prepared whole virus vaccines containing swine +/- human virus antigens had a stimulatory effect upon peripheral blood lymphocytes of children but not adults. The stimulatory effect was shown to be retained by a fraction of whole influenza virus vaccine, but not subunit virus vaccine, is known to stimulation of blood lymphocytes by commercial subunit vaccines of either monovalent swine influenza or a trivalent composition. Immunization with whole influenza virus vaccine, but not subunit virus vaccine, is known to produce a high incidence of generalized reactions in children but not adults. The lymphocyte stimulation observed here may represent an in vitro counterpart of the in vivo reactions.