A simplified procedure for in vitro immunization of dispersed spleen cell cultures.

Dispersed spleen cell suspensions from normal mice were immunized with sheep erythrocytes in flat bottom vial tubes containing a relatively small amount of tissue culture medium fortified with a 'nutrient cocktail'. The magnitude of the number of antibody plaque forming cells appearing in such tube cultures was equivalent or greater than that obtained in Marbrook vessels in the Mishell--Dutton system. Omission of the nutrient cocktail on the day of culture initiation, or the use of round bottom vials, resulted in much lower PFC responses.