Immunohistochemistry analysis of hCG was performed on human placenta tissue and is showing positive staining in extra cellular spaces. To expose target proteins, antigen retrieval was performed by microwaving tissues for 20 minutes in 10mM sodium citrate buffer (pH 6.0). Tissue slides were probed with hCG monoclonal antibody at a dilution of 1:20, overnight at 4C in a humidified chamber without (left panel) or with hCG antibody control (right panel). Tissues were washed, and incubated with secondary antibody (conjugated with HRP) for 30 min at room temperature in a humidified chamber. Detection was performed using DAB substrate kit. Tissues were counterstained with hematoxylin and dehydrated to prep for mounting. Images were taken at 20x magnification.