The variations in antibody responses (total IgG and IgGl, IgG2a, IgG2b, and IgG2c subclasses) were studied in two groups of rats infected with metacercariae of the trematode Fasciola hepatica L. Animals of group 1 were 4 weeks old, and rats of group 2 were 13 weeks old. All IgG subclasses increased during the course of infection except IgG2c, which decreased. The younger rats reached more marked responses than the older, at least during the period of this trial. IgGl and IgG2a antibodies reached the highest levels, and among these two, IgG2a response was slightly superior to IgGl,
Sulfite, at concentrations from 0.05 to 5.0 mM, inhibited the uptake of sucrose into stripped tissue disks and enzymatically isolated vein networks from mature pea leaves. Sulfite affected the rate of sucrose uptake, while the value was not influenced. The isolated vein networks were much more sensitive to sulfite action than stripped leaf disks.