Soluble DC-SIGN isoforms: Ligands with unknown functions - A mini-review.

The present study aimed to perform a mini-review of the complete soluble isoforms of Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (sDC-SIGN), their functions, and their correlation with diseases. The present review reveals the lack of studies regarding these soluble isoforms and poor understanding of the importance of the topic, considering the concordant findings on the relevant influence of sDC-SIGN in the viral and bacterial infection process, in addition to its possible use as a cancer marker.

Development and evaluation of a double antibody sandwich ELISA for the detection of human sDC-SIGN.

sDC-SIGN is the soluble form of dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN, CD209), which is a molecule involved with pathogen recognition and immune regulation. However, there is no commercially available ELISA kit for detecting human sDC-SIGN, and the normal range of this molecule is unknown. Here, we describe an ELISA for detecting human sDC-SIGN with high specificity. First, sDC-SIGN protein was expressed and purified. Monoclonal and polyclonal antibodies were then raised against the purified protein and subsequently characterized. A sandwich ELISA was developed using polyclonal antibodies specific for sDC-SIGN for capture and a biotin-labeled monoclonal antibody specific for sDC-SIGN for detection of protein. This method has sensitivity up to 0.2 ng/ml. Using this ELISA, we found that the concentration of sDC-SIGN in sera of healthy volunteers ranges from 0-319 ng/ml with a mean concentration of 27.14 ng/ml. Interestingly, the concentration of sDC-SIGN in sera from patients with cancer or chronic hepatitis B virus (CHB) infection was lower than that of health controls. The mean concentrations of sDC-SIGN in cancer patients and chronic hepatitis B virus infection patients were 3.2 ng/ml and 3.8 ng/ml, respectively. We developed a sandwich ELISA for detecting human sDC-SIGN and demonstrated its use by assessing sera concentrations of sDC-SIGN in patients with cancer and chronic CHB infection compared to that of healthy controls.