Potent Th2 Cytokine Bias of Natural Killer T Cell by CD1d Glycolipid Ligands: Anchoring Effect of Polar Groups in the Lipid Component

Abstract

Th2-biasing CD1d ligands are attractive potential candidates for adjuvants and therapeutic drugs. However, the number of potent ligands is limited, and their biasing mechanism remain unclear. Herein, a series of novel Th2-biasing CD1d glycolipid ligands, based on modification of their lipid part, have been identified. These have shown high binding affinities and efficient Th2 cytokine production. Importantly, the truncated acyl chain containing variants still retain their binding affinities and agonistic activities, which can be associated with an "anchoring effect," that is, formation of a buried hydrogen bond between a polar group on the acyl chain and the CD1d lipid-binding pocket. The analysis indicated that the appearance rates of ligand-CD1d complexes on the cell surface were involved in Th2-biasing responses. The designed ligands, having the anchor in the shorter lipid part, are one of the most potent Th2-biasing ligands among the known ligands.

Polar functional group-containing glycolipid CD1d ligands modulate cytokine-biasing responses and prevent experimental colitis

“…Interestingly, N-methyl amide-containing ligand 4a was more potent than the other derivatives (IFN-γ: 39,159 ± 4,960, IL-4: 599 ± 13 at 1 nM). In contrast, ligand 6a, with an amine as the polar functional group, showed slightly lower IFN-γ production and exhibited an IL-4-biasing response relative to corresponding amide-containing ligand 1a (IFN-γ; 1a: 16,907 ± 3,679 vs. 6a: 8,515 ± 1,016, IL-4; 1a: 247 ± 19 vs. 6a: 286 ± 12 at 1 nM), as previously reported 24 . Among C20:0-type ligands 4b-7b, the introduction of N-methyl amide and urea groups markedly increased the levels of IFN-γ, IL-4 and IL-17A production compared with the corresponding C20:0-α-GalCer Fig.…”

“…The introduction of amine or carbonyl groups, which are considered to be more flexible than amide or urea groups, resulted in potencies slightly higher than those of amide-or urea-containing derivatives at 10 nM concentration (1a: 177 ± 27 vs. 6a: 323 ± 41 and 7a: 424 ± 32). Next, we examined the binding potential of derivatives 1a, 4a, 6a and 7a using AlphaScreen system previously reported by our group 24 . The dose response curves and IC50 values of these compounds are shown in Fig.…”

“…In this context, we conducted SAR studies based on α-GalCer to obtain the potent and/or cytokine-biasing ligands [23][24][25] . In particular, we focused on a large hydrophobic pocket of CD1d (A' pocket) that recognizes long fatty acyl chains of glycolipid ligands and developed CD1d ligands with polar functional groups such as amides or amines that display potent cytokine induction levels and Th2 cytokine polarization.…”

Elucidation of Biological Mechanisms Using Synthetic Natural Products and Their Derivatives

“…got alkaloid 類の全合成， 5,6) スフィンゴシン類縁体 jaspine B の合成 7,8) と構造展開， 9,10) 糖脂質 a-GalCer に係わる生物有機化学研究 11,12)…”

Development of α-GalCer Analogues with an α-Fluorocarbonyl Moiety as Th2-Selective Ligands of CD1d

“…Recently, Fujimoto and co-workers introduced an amide group in the middle of the acyl chain ( Figure 1a) 18 and demonstrated that the interaction between amide group and hydrophilic residues in the A′ pocket induces the Th2-selective response of cytokines in NKT cells. 19 In this study, we focused our attention on the hydrophilic residues in the A′ pocket of CD1d. Based on the idea that using polar residues in the hydrophobic binding pocket could generate a different interaction, we rationally designed a new series of α-GalCer derivatives.…”