• 1 April 1970
    • journal article
    • Vol. 18  (4) , 599-610
Abstract
Guinea-pigs were immunized with emulsions of protein antigens in Freund's complete adjuvant. Draining lymph node cells were cultured for 20 hours together with the immunizing antigen; after harvesting, the culture supernatants were added to fresh lymphocytes from allogeneic or autochthonous guinea-pigs, and these `recipient' cells were maintained in culture for 3 days. Uptake of [3H]thymidine was measured during the last 18 hours of culture, and revealed that the lymphocyte culture supernatants induced greater thymidine uptake by the `recipient' lymphocytes than could be expected from the amount of antigen present in the cultures. The soluble factor which mediates this effect was termed `mitogenic factor'.