Variations in the phenotypic expression of an H-2-linked gene contributing to the control of IgE and haemagglutinating antibody responses to ovalbumin.

The genetic control of IgE- and HA-antibody responses to ovalbumin (OV) was investigated in H and L antibody responder lines of mice and in their hybrids. After immunization with threshold doses of OV (0.5 and 0.05 microgram OV) H mice were responder in terms of both HA and IgE antibody whereas L mice were non-responder. This trait was under monogenic control and the relevant gene was H-2-linked. The dominance direction depended on the antigen dose since high response was dominant for 0.5 microgram and recessive for 0.05 microgram. After immunization with a higher dose (10 microgram OV), the intervention of non-H-2 genes in the genetic control of the antibody response becomes manifest. The quantitative effect of the H-2 locus was greater for IgE- than for HA-antibody response, suggesting a less complex genetic control at the IgE-antibody level.