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Intracellular expression and release of Fc epsilon RI alpha by human eosinophils.
J Immunol. 1999 Jun 01; 162(11):6893-900.JI

Abstract

Although Fc epsilon R have been detected on human eosinophils, levels varied from moderate to extremely low or undetectable depending on the donor and methods used. We have attempted to resolve the conflicting data by measuring levels of IgE, Fc epsilon RI, and Fc epsilon RII in or on human eosinophils from a variety of donors (n = 26) and late-phase bronchoalveolar lavage fluids (n = 5). Our results demonstrated little or no cell surface IgE or IgE receptors as analyzed by immunofluorescence and flow cytometry. Culture of eosinophils for up to 11 days in the presence or absence of IgE and/or IL-4 (conditions that enhance Fc epsilon R on other cells) failed to induce any detectable surface Fc epsilon R. However, immunoprecipitation and Western blot analysis of eosinophil lysates using mAb specific for Fc epsilon RI alpha showed a distinct band of approximately 50 kDa, similar to that found in basophils. Western blotting also showed the presence of FcR gamma-chain, but no Fc epsilon RI beta. Surface biotinylation followed by immunoprecipitation again failed to detect surface Fc epsilon RI alpha, although surface FcR gamma was easily detected. Since we were able to detect intracellular Fc epsilon RI alpha, we examined its release from eosinophils. Immunoprecipitation and Western blotting demonstrated the release of Fc epsilon RI alpha into the supernatant of cultured eosinophils, peaking at approximately 48 h. We conclude that eosinophils possess a sizable intracellular pool of Fc epsilon RI alpha that is available for release, with undetectable surface levels in a variety of subjects, including those with eosinophilia and elevated serum IgE. The biological relevance of this soluble form of Fc epsilon RI alpha remains to be determined.

Authors+Show Affiliations

Department of Medicine, Division of Clinical Immunology, Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10352311

Citation

Seminario, M C., et al. "Intracellular Expression and Release of Fc Epsilon RI Alpha By Human Eosinophils." Journal of Immunology (Baltimore, Md. : 1950), vol. 162, no. 11, 1999, pp. 6893-900.
Seminario MC, Saini SS, MacGlashan DW, et al. Intracellular expression and release of Fc epsilon RI alpha by human eosinophils. J Immunol. 1999;162(11):6893-900.
Seminario, M. C., Saini, S. S., MacGlashan, D. W., & Bochner, B. S. (1999). Intracellular expression and release of Fc epsilon RI alpha by human eosinophils. Journal of Immunology (Baltimore, Md. : 1950), 162(11), 6893-900.
Seminario MC, et al. Intracellular Expression and Release of Fc Epsilon RI Alpha By Human Eosinophils. J Immunol. 1999 Jun 1;162(11):6893-900. PubMed PMID: 10352311.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Intracellular expression and release of Fc epsilon RI alpha by human eosinophils. AU - Seminario,M C, AU - Saini,S S, AU - MacGlashan,D W,Jr AU - Bochner,B S, PY - 1999/6/3/pubmed PY - 2001/3/28/medline PY - 1999/6/3/entrez SP - 6893 EP - 900 JF - Journal of immunology (Baltimore, Md. : 1950) JO - J Immunol VL - 162 IS - 11 N2 - Although Fc epsilon R have been detected on human eosinophils, levels varied from moderate to extremely low or undetectable depending on the donor and methods used. We have attempted to resolve the conflicting data by measuring levels of IgE, Fc epsilon RI, and Fc epsilon RII in or on human eosinophils from a variety of donors (n = 26) and late-phase bronchoalveolar lavage fluids (n = 5). Our results demonstrated little or no cell surface IgE or IgE receptors as analyzed by immunofluorescence and flow cytometry. Culture of eosinophils for up to 11 days in the presence or absence of IgE and/or IL-4 (conditions that enhance Fc epsilon R on other cells) failed to induce any detectable surface Fc epsilon R. However, immunoprecipitation and Western blot analysis of eosinophil lysates using mAb specific for Fc epsilon RI alpha showed a distinct band of approximately 50 kDa, similar to that found in basophils. Western blotting also showed the presence of FcR gamma-chain, but no Fc epsilon RI beta. Surface biotinylation followed by immunoprecipitation again failed to detect surface Fc epsilon RI alpha, although surface FcR gamma was easily detected. Since we were able to detect intracellular Fc epsilon RI alpha, we examined its release from eosinophils. Immunoprecipitation and Western blotting demonstrated the release of Fc epsilon RI alpha into the supernatant of cultured eosinophils, peaking at approximately 48 h. We conclude that eosinophils possess a sizable intracellular pool of Fc epsilon RI alpha that is available for release, with undetectable surface levels in a variety of subjects, including those with eosinophilia and elevated serum IgE. The biological relevance of this soluble form of Fc epsilon RI alpha remains to be determined. SN - 0022-1767 UR - https://www.unboundmedicine.com/medline/citation/10352311/Intracellular_expression_and_release_of_Fc_epsilon_RI_alpha_by_human_eosinophils_ L2 - http://www.jimmunol.org/cgi/pmidlookup?view=long&pmid=10352311 DB - PRIME DP - Unbound Medicine ER -