Description Application Coating a plate well (6 well plate) with this recombinant CD40 protein in neuronal cell specific medium at 1-10 μg/well (6 well plate) allows for 1) human neuronal cell / receptor interaction studies or 2) use as a culture matrix protein for human neuronal axon connection studies in vitro. Use this procedure as a guideline to determine optimal coating conditions for the culture system of choice. 1. Thaw CD40 and dilute to desired concentration using serum-free medium or PBS. The final solution should be sufficiently dilute so the volume added covers the surface evenly (1-10 μg/well, 6 well plate). 2. Add appropriate amount of diluted material to culture surface. 3. Incubate at room temperature for approximately 1.5 hours. 4. Aspirate remaining material. 5. Rinse plates carefully with water and avoid scratching bottom surface of plates. 6. Plates are ready for use. They may also be stored at 2-8 °C damp or air dried if sterility is maintained. Sequence MASMTGGQQMGRGHHHHHHGNLYFQGGEFELEPPTACREKQYLINSQCCSLCQPGQKLVSDCTEFTETECLPCGESEFLDTWNRETHCHQHKYCDPNLGLRVQQKGTSETDTICTCEEGWHCTSEACESCVLHRSCSPGFGVKQIATGVSDTICEPCPVGFFSNVSSAFEKCHPWTRSPGSAESPGGDPHHLRDPVCHPLGAGL Preparation Note The full-length extracellular domain of the human CD40 gene (54-608 aa) was constructed with 29 N-terminal T7/HIS-tag and expressed in E. coli as inclusion bodies. The final product was refolded using our unique “temperature shift inclusion body refolding” technology and chromatographically purified.