Structure-Function Implications of the Ability of Monoclonal Antibodies Against α-Galactosylceramide-CD1d Complex to Recognize β-Mannosylceramide Presentation by CD1d

Front Immunol. 2019 Oct 9;10:2355. doi: 10.3389/fimmu.2019.02355. eCollection 2019.

Abstract

iNKT cells are CD1d-restricted T cells recognizing lipid antigens. The prototypic iNKT cell-agonist α-galactosylceramide (α-GalCer) alongside compounds with similar structures induces robust proliferation and cytokine production of iNKT cells and protects against cancer in vivo. Monoclonal antibodies (mAbs) that detect CD1d-α-GalCer complexes have provided critical information for understanding of antigen presentation of iNKT cell agonists. Although most iNKT cell agonists with antitumor properties are α-linked glycosphingolipids that can be detected by anti-CD1d-α-GalCer mAbs, β-ManCer, a glycolipid with a β-linkage, induces strong antitumor immunity via mechanisms distinct from those of α-GalCer. In this study, we unexpectedly discovered that anti-CD1d-α-GalCer mAbs directly recognized β-ManCer-CD1d complexes and could inhibit β-ManCer stimulation of iNKT cells. The binding of anti-CD1d-α-GalCer mAb with β-ManCer-CD1d complexes was also confirmed by plasmon resonance and could not be explained by α-anomer contamination. The binding of anti-CD1d-α-GalCer mAb was also observed with CD1d loaded with another β-linked glycosylceramide, β-GalCer (C26:0). Detection with anti-CD1d-α-GalCer mAbs indicates that the interface of the β-ManCer-CD1d complex exposed to the iNKT cell TCR can assume a structure like that of CD1d-α-GalCer, despite its disparate carbohydrate structure. These results suggest that certain β-linked monoglycosylceramides can assume a structural display similar to that of CD1d-α-GalCer and that the data based on anti-CD1d-α-GalCer binding should be interpreted with caution.

Keywords: CD1d; L363; alpha-galactosylceramide; beta-mannosylceramide; natural killer T cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal, Murine-Derived / immunology*
  • Antigen Presentation / immunology*
  • Antigens, CD1d / chemistry
  • Antigens, CD1d / immunology*
  • Galactosylceramides* / chemistry
  • Galactosylceramides* / immunology
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Natural Killer T-Cells / immunology*
  • Natural Killer T-Cells / pathology
  • Structure-Activity Relationship

Substances

  • Antibodies, Monoclonal, Murine-Derived
  • Antigens, CD1d
  • CD1d antigen, mouse
  • Galactosylceramides
  • alpha-galactosylceramide