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Summary Allergens and antigens of Bermuda grass pollen fractionated by SDS‐polyacrylamide gel electrophoresis and transferred to nitrocellulose membranes were identified using twenty‐one sera of Bermuda grass pollen‐allergic patients. The IgE‐ and IgG‐binding pollen components transferred to nitrocellulose were detected by reaction with enzyme‐labelled anti‐human IgE and anti‐human IgG, respectively. There was heterogeneity in both IgE‐ and IgG‐binding patterns of the allergic sera tested. Fourteen pollen components, ranging in molecular weight from 16000 to 88000 daltons, bound to IgE antibodies. Only two of the fourteen allergens identified reacted with IgE antibodies of more than 50% of the twenty‐one allergic sera. The pollen component with a molecular weight of 32000 daltons showed by far the highest frequency of IgE binding, being recognized by sixteen (76%) of the twenty‐one sera examined. Fifteen (71 %) of the twenty‐one sera tested had IgE antibodies that reacted with more than one of the fourteen allergenic components identified. Pollen components recognized by IgE antibodies also reacted with IgG antibodies, and there were components only recognized by IgG antibodies. Results obtained from this study should be useful both clinically and in research.

We have examined the effects of ingestion of chemically denatured ovalbumin (OVA) in mice. Both 8 M urea-denatured OVA (UD-OVA) and carboxymethylated UD-OVA (CM-OVA) were purified by gel filtration. Specific IgG antibody and systemic delayed-type hypersensitivity (DTH) responses to OVA were not suppressed by CM-OVA fed prior to or after immunization with OVA in complete Freund's adjuvant (CFA). When CM-OVA was used instead of OVA, for immunization, serum IgG and DTH responses to CM-OVA were orally tolerized by OVA, but not by UD-OVA or CM-OVA. Studies of antigen uptake in mice using sandwich ELISA tests showed that OVA, but not CM-OVA, was absorbed after antigen ingestion. In vitro studies further demonstrated that CM-OVA was digested much more rapidly than OVA. Moreover, studies using bovine serum albumin (BSA) demonstrated that both IgG and DTH responses to BSA were orally tolerant to BSA, but not to denatured BSA. Finally, studies using human gamma-globulin (HGG), a well-known tolerogen, also found that the IgG antibody response to HGG was not orally tolerized by denatured HGG. These results suggest that complete denaturation of globular proteins may affect their processing and absorption in the gut and thus abrogates oral tolerance induction.