Figure 2.

Immune responses against OVA in rats receiving fractions of serum. Serum was separated into two different fractions containing structures larger than 100 000 MW and smaller than 100 000 MW. All rats were immunized with OVA in Freund's complete adjuvant 1 week after serum fraction transfer and then booster immunized with OVA in Freund's incomplete adjuvant 5 weeks later. The bars represent the mean value of eight animals in each group and the standard error is indicated. Statistical analyses used the Mann–Whitney U-test. Solid bars, serum fractions from rats fed OVA; hatched bars, serum fractions from control-fed rats. (a) DTH reaction against OVA, measured as increase in ear thickness 24 hr after challenge with 50 µg OVA in 20 µl PBS. The challenge was performed 2 weeks after the primary immunization. (b) IgG anti-OVA antibodies in serum 3 weeks after serum transfer.