title: Biological potency of German cockroach allergen extracts determined in an inner city population.
abstract: BACKGROUND
  Cockroach allergy is an important cause of inner city asthma. To perform valid studies on the diagnosis and treatment of cockroach allergy, biological potencies of test extracts need to be established, and a surrogate in vitro test for biological potency should be chosen.
  
  
  METHODS
  Sixty-two cockroach-allergic adult subjects were recruited for quantitative skin testing with three commercial German cockroach extracts. The intradermal D50 values were determined using linear interpolation, and the biologic potencies were determined from D50 data. The extracts were also analysed for relative potency, using a competition ELISA, and for specific allergen content, using a two-site ELISA.
  
  
  RESULTS
  Estimates of each extract's D50 were analysable in 48-55 subjects, with D50s between 10.3 and 11.8. All three extracts were bioequivalent using pre-set criteria. The biological potencies of the extracts were 1738-8570 bioequivalent allergy units (BAU)/mL (geometric mean=3300), and these relative potencies were similar to those estimated by competition ELISA and specific allergen content. IgE against cockroach allergens were detected in sera from 34 subjects with analysable D50s, and 17 subjects had IgE directed against specific cockroach allergens. Although the presence of anti-Bla g 5 correlated with the subjects' skin test responses for 2/3 extracts, no single allergen was immunodominant. Antibody responses among the subjects were heterogeneous.
  
  
  CONCLUSIONS
  Although commercial cockroach extracts are relatively low in potency, immunotherapeutic doses should be achievable. Biological potency may be estimated using D50 testing, a combination of specific allergen determinations, or by an overall potency assay such as the competition ELISA.
  
  
  CONCLUSIONS
  The biological potency of three German cockroach allergen extracts, determined in an inner city population, was 1738-8570 BAU/mL. No one allergen was immunodominant, and surrogate in vitro testing methods were examined.
authors.affiliation: Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Bethesda, MD, USA. jay.slater@fda.hhs.gov
authors.forename: J E
authors.initials: JE
authors.lastname: Slater
authors.forename: R
authors.initials: R
authors.lastname: James
authors.forename: J A
authors.initials: JA
authors.lastname: Pongracic
authors.forename: A H
authors.initials: AH
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Sarpong
authors.forename: H A
authors.initials: HA
authors.lastname: Sampson
authors.forename: S M
authors.initials: SM
authors.lastname: Satinover
authors.forename: J A
authors.initials: JA
authors.lastname: Woodfolk
authors.forename: H E
authors.initials: HE
authors.lastname: Mitchell
authors.forename: P J
authors.initials: PJ
authors.lastname: Gergen
authors.forename: P A
authors.initials: PA
authors.lastname: Eggleston
mesh_terms: D000328:Adult; D000485:Allergens / Q000008:administration & dosage* / Q000032:analysis; D000818:Animals; D052179:Antigens, Plant; D016282:Aspartic Acid Endopeptidases / Q000032:analysis; D003058:Cockroaches / Q000276:immunology*; D003888:Desensitization, Immunologic / Q000379:methods*; D004306:Dose-Response Relationship, Immunologic; D004890:Erythema / Q000276:immunology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000628:therapy*; D007073:Immunoglobulin E / Q000097:blood; D007271:Injections, Intradermal; D019476:Insect Proteins / Q000276:immunology*; D007428:Intradermal Tests; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D014481:United States; D014504:Urban Health
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D019476:Insect Proteins; C105482:allergen Bla g 1; D007073:Immunoglobulin E; D016282:Aspartic Acid Endopeptidases; C094699:allergen Bla g 2