CD40 Colorimetric Cell-Based ELISA Kit

Designed for the detection of CD40 levels in cell lysates and tissue homogenates, this colorimetric cell-based ELISA from Assay Genie provides a high-throughput, lysate-free, and sensitive workflow. The kit uses an indirect ELISA format in which CD40 is captured by CD40-specific primary antibodies and HRP-conjugated secondary antibodies bind the Fc region of the primary antibody, allowing the HRP enzyme to catalyze a colorimetric reaction upon substrate addition. The signal is read at 450 nm, and determination of CD40 concentration is qualitative, requiring normalization to internal controls.

A monoclonal antibody specific for human GAPDH is included as an internal positive control for normalizing target absorbance values. Following colorimetric measurement of HRP activity, a Crystal Violet whole-cell staining step can be used to determine cell density and adjust for plating differences. The assay has a dynamic range of > 5000 Cells and is validated for adherent cells, with reactivity reported for Human and Mouse samples. It is supplied in a 96-well microplate format, with recommended storage at 4°C for 6 Months. It is intended for measuring relative CD40 expression in cultured cells and for screening the effects of treatments, inhibitors (such as siRNA or chemicals), or activators on CD40.

CD40 is a member of the TNF-receptor superfamily, acting as the receptor for CD40L and mediating immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. The protein is referenced under UniProt ID P25942 and NCBI Gene ID 958.