EPITOPE SPECIFICITY OF BEE VENOM PHOSPHOLIPASE-A(2)-SPECIFIC SUPPRESSOR T-CELLS WHICH PRODUCE ANTIGEN-BINDING GLYCOSYLATION INHIBITING FACTOR

Citation
A. Mori et al., EPITOPE SPECIFICITY OF BEE VENOM PHOSPHOLIPASE-A(2)-SPECIFIC SUPPRESSOR T-CELLS WHICH PRODUCE ANTIGEN-BINDING GLYCOSYLATION INHIBITING FACTOR, International immunology, 5(8), 1993, pp. 833-842
Citations number
46
Categorie Soggetti
Immunology
Journal title
ISSN journal
09538178
Volume
5
Issue
8
Year of publication
1993
Pages
833 - 842
Database
ISI
SICI code
0953-8178(1993)5:8<833:ESOBVP>2.0.ZU;2-W
Abstract
From the spleen cells of BALB/c mice primed with bee venom phospholipa se A2 (PLA2), we established seven T cell hybridomas which constitutiv ely secreted glycosylation inhibiting factor (GIF), expressed both CD3 and TCRalphabeta, and responded to antigen-pulsed antigen presenting cells (APC) for the formation of IgE-binding factor. Upon stimulation with antigen-pulsed APC, four of the seven hybridomas produced GIF hav ing affinity for native PLA2. The antigen-binding GIF could suppress t he anti-hapten antibody response of BALB/c mice to dinitrophenyl (DNP) - PLA2 conjugates in a carrier-specific manner and bound to immunosor bents coupled with either the mAb 14-12 or anti-TCRalpha chain, H28-71 0. Analysis of the epitope specificity of the TCR on the GIF-producing T hybridomas indicated that all of the hybridomas which could produce antigen-binding GIF upon antigenic stimulation recognized the synthet ic peptide representing amino acid residues 19 - 34 in PLA2 molecules in the context of the product of the I-A(d) subregion and the antigen- binding GIF formed by the cells had affinity for the peptide. The 3-D structure of bee venom PLA2 indicates that the sequence of amino acid 14 - 24 forms a loop in the PLA2 molecule and represents an external s tructure of the antigen, while peptide 25 - 37 forms an alpha helix. E vidence was obtained which suggests that the sequence of 25 - 34 conta ins amino acid residues interacting with la molecules, while peptide 1 9 - 24 contains residues involved in the interaction of p19 - 34 - la complexes with TCR on the hybridomas. It was also found that not only the synthetic peptide 19 - 34, but also the peptides 13 - 28 and 19 - 30 inhibited the binding of antigen-binding GIF to PLA2-coupled Sephar ose, while peptide 25 - 40 failed to do so. The results collectively i ndicate that the antigen-binding GIF and TCR on the cell source of the factor interact with a common epitope which is exposed on the surface of a nominal antigen.