IgE-mediated rat mast cell triggering with tryptic and synthetic peptides of bovine beta-lactoglobulin.
BACKGROUND
Immunoglobulin E (IgE) epitopes of beta-lactoglubulin (betaLG) have been identified by ELISA inhibition methods using sera from allergic patients. However, the functional capacity of these epitopes to stimulate mast cells is unknown. It is the goal of the present study to identify bivalent IgE epitopes of betaLG able to trigger target mast cells.


METHODS
Peptides were obtained either by purification from tryptic hydrolysates of betaLG or by synthesis. They were examined for their triggering activity in vitro on peritoneal 3H-serotonin-labeled rat mast cells passively sensitized with IgE anti-betaLG antibodies. In vivo, rats immunized with betaLG were administered peptides by gavage for intestinal rat mast cell protease II release.


RESULTS
Compared with intact betaLG, purified or synthetic tryptic-like betaLG peptides have a sharply decreased allergenicity. Peptide 149-162 retains the highest bivalent IgE epitope-mediated triggering capacity.


CONCLUSIONS
A functional bivalent IgE epitope was identified at the C terminal end of betaLG.
Fritsché
Rodolphe
R
Nestlé Research Center, Lausanne, Switzerland. rodolphe.fritsche@rdls.nestle.com
Adel-Patient
Karine
K
Bernard
Hervé
H
Martin-Paschoud
Christine
C
Schwarz
Catherine
C
Ah-Leung
Sandrine
S
Wal
Jean-Michel
JM
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D000939:Epitopes / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology*; D007782:Lactoglobulins / Q000276:immunology*; D008407:Mast Cells / Q000276:immunology*; D016269:Milk Hypersensitivity / Q000276:immunology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology*; D051381:Rats; D011914:Rats, Inbred BN; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases / Q000097:blood
D000939:Epitopes; D007782:Lactoglobulins; D010446:Peptide Fragments; D007073:Immunoglobulin E; D012697:Serine Endopeptidases; C057818:cytotoxic T lymphocyte-specific serine protease