Specific IgE antibody responses to ragweed allergens Ra5S and Ra5G associated with distinct HLA-DR beta genes.

Previous studies have established that sensitivity (IgE antibody response) to Ra5S, a 5000 mol. wt protein of short ragweed pollen, is significantly associated with host possession of HLA-DR2. The same allele was implicated [Goodfriend et al. (1985) Molec. Immun. 22, 899-906] in sensitivity to Ra5G, a 4400 mol. wt homologue of Ra5S in giant ragweed pollen, based on frequency of co-sensitivity to both proteins. However, data reported here generated in HLA-DR assays of mono-sensitive individuals demonstrate that sensitivity to Ra5S and Ra5G is associated with separate alleles: DR2 and DRw52 respectively. Results consistent with the same sensitivity/DR associations were obtained in immunoabsorption studies with sera from co-sensitive individuals. As HLA-DR2 and DRw52 have identical alpha but different beta chain types (beta 1 and beta 3), it was considered that IgE antibody responses to Ra5S and Ra5G are associated with distinct DR-beta genes.