Proliferation of spleen cells from immunodeficient mice in response to stimulation with HA. Spleen cells from nude or SCID mice were cultured in the presence of medium (control), T- or B-cell mitogens or with HA for 48 hours. Spleen cells from SCID mice were cultured in the presence of medium (control), T- or B-cell mitogens or with HA for 48 hours. The cell proliferation was measured as described in the legend to Fig 1.