Up-regulation of cell surface Toll-like receptor 4-MD2 expression on dendritic epidermal T cells after the emigration from epidermis during cutaneous inflammation.
BACKGROUND
Mouse epidermis contains a population of gammadelta T cells, termed dendritic epidermal T cells (DETCs), which uniformly express the invariant Vgamma3 T cell receptor. Certain DETC lines were reported to respond to Gram-negative bacteria in the presence of immobilized anti-CD3 monoclonal antibody or to lipopolysaccharide (LPS) in the presence of B cell lines.


OBJECTIVE
To determine whether DETCs express the primary signaling receptor for LPS, Toll-like receptor (TLR) 4-MD2.


METHODS
We analyzed expression of TLR4-MD2 in three independent DETC lines as well as in freshly isolated DETCs.


RESULTS
All DETC lines expressed TLR4 and MD2 transcripts and TLR4-MD2 protein complex intracellularly, but none expressed TLR4-MD2 on the cell surface. By immunoblotting, only the immature form of TLR4 protein was detected in the DETC lines. The DETC lines did not respond to LPS even in the presence of immobilized anti-CD3 monoclonal antibody. Freshly isolated DETCs and their fetal thymic precursors also lacked cell surface expression of TLR4-MD2, but a small subpopulation of dermal Vgamma3 T cells isolated from croton oil-painted skin expressed TLR4-MD2 on the cell surface. Similarly, Vgamma3 T cells emigrated from organ-cultured epidermis expressed cell surface TLR4-MD2.


CONCLUSIONS
These results demonstrate that DETCs do not constitutively express cell surface TLR4-MD2, but TLR4-MD2 expression may be up-regulated when DETCs emigrate from epidermis during cutaneous inflammation.
Shimura
Hideki
H
Division of Dermatology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
Nitahara
Ayano
A
Ito
Akiko
A
Tomiyama
Katsuhiro
K
Ito
Masaaki
M
Kawai
Kazuhiro
K
D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism*; D003872:Dermatitis / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D015151:Immunoblotting; D007249:Inflammation; D008070:Lipopolysaccharides / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D011971:Receptors, Immunologic / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000473:pathology*; D013601:T-Lymphocytes / Q000166:cytology*; D051197:Toll-Like Receptor 4; D015854:Up-Regulation
D016207:Cytokines; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C502579:TLR4-MD2 protein complex, mouse; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4