Biologic allergen assay for in vivo test allergens with an in vitro model of the murine type I reaction

J Allergy Clin Immunol. 1997 Feb;99(2):227-32. doi: 10.1016/s0091-6749(97)70101-5.

Abstract

Background: The determination of the biologic activity of allergenic extracts in human beings is limited for ethical and practical reasons. The establishment of a simplified in vitro model, which mimics a main event of the type I reaction, should provide true benefit for manufactures, researchers, and clinicians.

Objective: This study was designed to develop and evaluate a mediator release assay based on rat bosophil leukemia cells for the purpose of investigating allergenic extracts.

Methods: Rat basophil leukemia cells were passively sensitized with murine IgE raised against allergens and stimulated by serial dilutions of allergenic extracts in a dose-related manner. The allergen-specific degranulation was monitored by measuring the release of beta-hexosaminidase.

Results: The investigation of standardized commercial allergen products for in vivo diagnostics (birch pollen, cat dander, and bee venom) allowed a quantitative description of differences in biologic activity in accordance with the declared activity units. The Fel d 1 content was determined in 17 cat dander extracts and correlated well with the results of a two-site binding ELISA (r = 0.93, log/log). Extremely low allergen amounts in the range of 10 to 100 pg/ml could be easily detected. Moreover, the cross-reactivity pattern of patients allergic to birch pollen could be reproduced with extracts of hazel, alder, apple, and celery.

Conclusion: The assay is suitable for supplementing quality control of allergenic extracts and for the determination of biologic activity of final allergen products. As a research tool, it allows the study of IgE cross-linking properties of modified and recombinant allergens at an early stage before they are tested in human beings.

MeSH terms

  • Allergens / immunology*
  • Animals
  • Bee Venoms / immunology
  • Biological Assay / methods*
  • Cats
  • Cells, Cultured
  • Cross Reactions / immunology
  • Dose-Response Relationship, Immunologic
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Hypersensitivity / immunology*
  • Immunoglobulin E / immunology
  • Immunoglobulin G / immunology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred CBA
  • Pollen / immunology
  • Rats
  • Reproducibility of Results
  • beta-N-Acetylhexosaminidases / metabolism

Substances

  • Allergens
  • Bee Venoms
  • Immunoglobulin G
  • Immunoglobulin E
  • beta-N-Acetylhexosaminidases