Evaluation of commercial antibodies against human sphingosine-1-phosphate receptor 1.

Sphingosine-1-phosphate receptor 1 (S1P1), also called endothelial differentiation gene 1, plays an important role in migration, proliferation, and survival of several types of cells including endothelial cells and lymphocytes and is involved in multiple sclerosis. Two commercial rabbit anti-S1P1 antibodies (polyclonal and monoclonal) were tested on CHO cells expressing S1P1 receptors fused to the green fluorescent protein at the C-terminal end and on Pichia pastoris and HEK cells expressing cmyc-tagged S1P1. Polyclonal antibodies did not give any signal by Western blot, immunofluorescence, and flow cytofluorometry. Monoclonal antibodies were able to reveal an unspecific band by Western blot performed on various cell types. Consequently, in our hands and using our protocols, we show that these antibodies did not specifically detect S1P1 receptors.