Alterations in Fc[epsilon]RI induced by protoporphyrin plus long-wavelength ultraviolet light in mouse bone marrow-derived mast cells

Journal Article · Thu Jul 15 00:00:00 EDT 1993 · Journal of Immunology; (United States)

OSTI ID:5671779

Yen, A; Barrett, K E; Gigli, I ^[1]; Liu, F T ^[2]

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1. Univ. of California, San Diego, CA (United States)
2. Scripps Research Institutes, La Jolla, CA (United States)

As previously reported, protoporphyrin plus long-wavelength UV light (PP/UVA) inhibits IgE-mediated degranulation of mouse bone marrow-derived mast cells, as assessed by measurement of the release of [beta]-hexosaminidase. This inhibitory effect was seen with cells sensitized with IgE either before or after PP/UVA treatment (57.8 and 55.35 inhibition, respectively). PP/UVA did not dissociate IgE already bound to cells as assessed either by measure of release of bound [sup 125]I-IgE or by flow cytometric analysis. Results from immunoadsorption followed by SDS-PAGE analysis suggested that PP/UVA treatment may cause stable conjugation of IgE to its receptor. In unsensitized cells, PP/UVA did not cause conjugation of the unoccupied Fc[epsilon]RI to other proteins in the plasma membrane. Nevertheless, Scatchard analysis revealed that PP/UVA decreased the number of Fc[epsilon]Ri per cell by 37% (0.95 [times] 10[sup 5] vs 1.51 [times] 10[sup 5] cell), whereas affinity of the receptor for IgE was comparable between PP/UVA-treated and untreated cells (3.40 nM vs 3.27 nM). Flow cytometric analysis also confirmed the decrease in Fc[epsilon]RI number in PP/UVA-treated unsensitized mouse bone marrow-derived mast cells. Although 84% of PP/UVA-treated and 82% of untreated cells expressed positive fluorescence when stained with FITC-conjugated IgE, fluorescence intensity was reduced by 40% after PP/UVA treatment. The authors conclude that PP/UVA alters the conformational structure and/or number of Fc[epsilon]RI expressed on the mast cell surface. This effect could potentially explain the ability of PP/UVA to inhibit mast cell secretory function and may be related to an ability of PP/UVA to alter the properties of the plasma membrane. 29 refs., 8 figs.

• OSTI ID: 5671779
• Journal Information: Journal of Immunology; (United States), Vol. 151:2; ISSN 0022-1767
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
IMMUNOGLOBULINS
INHIBITION
MAST CELLS
NEAR ULTRAVIOLET RADIATION
BIOLOGICAL EFFECTS
RECEPTORS
PROTOPORPHYRINS
ANIMAL CELLS
CARBOXYLIC ACIDS
CONNECTIVE TISSUE CELLS
ELECTROMAGNETIC RADIATION
GLOBULINS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MEMBRANE PROTEINS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
RADIATIONS
SOMATIC CELLS
ULTRAVIOLET RADIATION
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture