CD1d favors MHC neighborhood, GM₁ ganglioside proximity and low detergent sensitive membrane regions on the surface of B lymphocytes

详细信息    查看全文

• 作者：Dilip Shrestha ; Mark A. Exley ; Gy枚rgy Vereb ; J谩nos Sz枚ll艖si ; Attila Jenei
• 关键词：MHC ; major histocompatibility complex ; CD1 ; cluster of differentiation 1 ; NKT cells ; natural killer T cells ; iNKT ; invariant natural killer T cells ; 尾2m ; 尾2-microglobulin ; M尾CD ; methyl-尾-cyclodextrin ; FRET ; fluorescence resonance energy transfer ; NCS ; newborn calf serum ; Mabs ; monoclonal antibodies ; TfR ; transferrin receptor ; FCET ; flow-cytometric FRET ; CTxB ; cholera toxin subunit B ; FCDR test ; flow cytometric detergent resistance test ; TX100 ; Triton X-100 ; DRMs ; Detergent resistant membrane
• 刊名：Biochimica et Biophysica Acta (BBA)/General Subjects
• 出版年：January, 2014
• 年：2014
• 卷：1840
• 期：1
• 页码：667-680
• 全文大小：2186 K

文摘

Background

Cluster of differentiation 1 (CD1) represents a family of proteins which is involved in lipid-based antigen presentation. Primarily, antigen presenting cells, like B cells, express CD1 proteins. Here, we examined the cell-surface distribution of CD1d, a subtype of CD1 receptors, on B lymphocytes.

Methods

Fluorescence labeling methods, including fluorescence resonance energy transfer (FRET), were employed to investigate plasma membrane features of CD1d receptors.

Results

High FRET efficiency was observed between CD1d and MHC I heavy chain (MHC I-HC), 尾₂-microglobulin (尾₂m) and MHC II proteins in the plasma membrane. In addition, overexpression of CD1d reduced the expression of MHC II and increased the expression of MHC I-HC and 尾₂m proteins on the cell-surface. Surprisingly, 尾₂m dependent CD1d isoform constituted only ~ 15% of the total membrane CD1d proteins. Treatment of B cells with methyl-尾-cyclodextrin (M尾CD) / simvastatin caused protein rearrangement; however, FRET demonstrated only minimal effect of these chemicals on the association between CD1d and GM₁ ganglioside on cell-surface. Likewise, a modest effect was only observed in a co-culture assay between M尾CD/simvastatin treated C1R-CD1d cells and invariant natural killer T cells on measuring secreted cytokines (IFN纬 and IL4). Furthermore, CD1d rich regions were highly sensitive to low concentration of Triton X-100. Physical proximity between CD1d, MHC and GM₁ molecules was also detected in the plasma membrane.

Conclusions

An intricate relationship between CD1d, MHC, and lipid species was found on the membrane of human B cells.

General significance

Organization of CD1d on the plasma membrane might be critical for its biological functions.