Epitope specificity of bee venom phospholipase A2-specific suppressor T cells which produce antigen-binding glycosylation inhibiting factor

Aklo Morl, Peter Thomas, Yutaka Tagaya, Hiroshi Lijima, Howard Grey, Kimishige Ishizaka

Research output: Contribution to journalArticlepeer-review

Abstract

From the spleen cells of BALB/c mice primed with bee venom phospholipase A2(PLA2), we established seven T cell hybrldomas which constitutively secreted glycosylation inhibiting factor (GIF), expressed both CD3 and TCRαβ, 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 having affinity for native PLA2. The antigen-binding GIF could suppress the anti-hapten antibody response of BALB/c mice to dinitrophenyl (DNP)-PLA2 conjugates in a carrier-specific manner and bound to Immunosorbents coupled with either the mAb 14-12 or antl-TCRα chain, H28-710. Analysis of the epitope specificity of the TCR on the GIF-producing T hybridomas indicated that all of the hybridomas which could produce antigenbinding GIF upon antigenic stimulation recognized the synthetic peptide representing amino acid residues 19-34 in PLA2molecules in the context of the product of the I-Ad 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 moiecule and represents an external structure of the antigen, while peptide 25-37 forms an α helix. Evidence was obtained which suggests that the sequence of 25-34 contains amino acid residues interacting with la molecules, while peptide 19-24 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 Sepharose, while peptide 25-40 failed to do so. The results collectively indicate 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.

Original languageEnglish (US)
Pages (from-to)833-842
Number of pages10
JournalInternational Immunology
Volume5
Issue number8
DOIs
StatePublished - Aug 1 1993

Keywords

  • Bee venom
  • GIF
  • PLA2
  • Suppressor T cells

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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