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. 1975 Jun;29(6):776–779. doi: 10.1128/am.29.6.776-779.1975

Stability of 125I-Labeled Staphylococcal Enterotoxins in Solid-Phase Radioimmunoassay

Peter E Kauffman 1, Howard M Johnson 1
PMCID: PMC187078  PMID: 1155934

Abstract

Staphylococcal enterotoxins, Types A, B, and C, were labeled with 125I by the chloramine-T method at approximately two levels of specific activity, 40 and 4 μCi/μg of protein. Toxins labeled with high specific activity showed extensive dissociation of 125I when stored at different temperatures, including -23 C. In contrast, toxins labeled with low specific activity did not show any significant loss of 125I when stored at -23 C for as long as 2 months. Enterotoxins, whether labeled with high or low activities, formed aggregates immediately upon labeling. Aggregate formation increased in high-activity-labeled toxins on storage at -23 C, and low-activity-labeled toxins showed no significant increase in aggregate formation, even after 2 months at -23 C. The aggregated forms of the enterotoxins were either devoid of antigenic activity in solid-phase radioimmunoassay or they possessed significantly reduced antigenic activity. Thus, a decrease in binding of 125I-labeled enterotxin to specific antibody in solid-phase radioimmunoassay results mainly from (i) loss of 125I on storage, and (ii) formation of aggregates with reduced antigenic activity.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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