STANDARDIZATION AND SURVEILLANCE OF ALLERGENIC EXTRACTS

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ABSTRACT: A. Standardization of Allergenic Extracts Labeled "No U.S.Standard of Potency" Eight grasses (timothy, june, perennial rye, bermuda, redtop, orchard, sweet vernal, and meadow fescue) were standardized. Allergenic extract manufacturers have been submitting samples of their standardized grass pollen extracts to LAIB for testing prior to approval of the Product License Application Supplements. Efforts continue for the standardization of three cockroaches (American, German, and Oriental), latex and peanut. B. In Vitro Testing of Standardized Allergenic Extracts All grass pollen extracts submitted for approval under a PLA supplement are tested in vitro for relative potency by ELISA Competition Assay for similarity to the CBER reference by IEF and BIEF Light and for protein content by the Modified Ninhydrin Method. Samples of all lots of standardized allergenic extracts are submitted to CBER for approval before duplication. LAIB reviews the sample protocols, tests the samples for potency and identifies and accepts/re the sample as appropriate. LAIB is investigating a new method for evaluating venom lot release samples; the research has been completed and testing will begin shortly. A new method for measuring potency is being evaluated. This method would quantitatively and qualitatively measure the amount of antibody bound to the extract. The Laboratory is also considering the use of SDS-PAGE and Western Blot in the evaluation of current references, lots in support of PLA and lot release samples. C. Management of Standardized Allergenic Extract References LAIB provides the reference extracts used by the manufacturers to produce standardized allergenic extracts. Periodic replenishment of each reference is necessary. Candidate references are selected by comparing the potency and identity of commercially available extracts to the current reference. The candidates are subjected to a battery of tests and statistical analysis for comparability to the current reference. A replacement reference is then chosen. Replacement reference extracts established during this fiscal year: Df Mite, Perennial Rye Grass, Bermuda Grass, Cat Pelt and Cat RID Calibrators. Replacement reference extracts currently undergoing evaluation: Df Mite and Short Ragweed RID Calibrators. The process for a replacement serum pool for Short Ragweed has begun. A lyophilized Mite reference is being investigated for increased stability.