Latex antigens.

Previous studies have demonstrated that some children with spina bifida have IgE to proteins in natural rubber. In this study we compare different sources of latex antigen and identify possible antigenic peptides by radioimmunoblotting technique. Sera were collected from 26 children with spina bifida, tested by RAST with ammoniated latex extract (AL), and frozen until use. Extracts were prepared from ammoniated and nonammoniated latex, and the proteins were separated by electrophoresis on a 15% sodium dodecyl suflate-polyacrylamide gel and transferred to polyvinylene difluoride (PVDF). Strips of PVDF were then incubated with individual sera and 125I-labeled rabbit antihuman IgE before development by autoradiography; 18/26 sera were AL RAST positive; 0/8 AL RAST-negative patients had any binding to the latex proteins on PVDF. Sera from all patients were tested in a RAST with a nonammoniated latex extract (NAL), and the results were comparable to the AL RAST. Liquid-phase AL and NAL were comparable in their ability to inhibit the binding of patient's IgE to solid-phase AL and NAL. Sera from 14 RAST-positive patients were tested by immunoblotting with separated, reduced, and nonreduced AL and NAL. All 14 sera demonstrated IgE binding to a 14 kd peptide, which was more pronounced in reduced NAL. These results suggest that the 14 kd peptide in NAL is a major antigen in rubber allergy but that AL is an acceptable antigen source for in vitro diagnostic studies.