New double staining technology allows for easier staining protocols and faster turnaround time. The "cocktail" approach can be used when two primary antibodies are from different host species, as is the example of these two antibodies (mouse monoclonal antibody against HBsAg and rabbit polyclonal antibody against HBcAg). A secondary antibody or detection system can also be a cocktail of horseradish peroxidase (HRP) labeled anti-rabbit and alkaline phosphatase (AP) labeled anti-mouse. This allows simultaneous incubation of both primary antibodies, followed by simultaneous incubation of the cocktailed secondary detection reagents. This is a huge time saver compared to sequential staining techniques. The only sequential step in the "cocktail" approach is the application of DAB chromogen followed by application of fast red (FR) chromogen.
Both images show hepatitis infected hepatocytes. HBsAg is demonstrated by red cytoplasmic staining and HBcAg is shown by brown nuclear and lighter brown cytoplasmic staining. Many of the infected cells show co-localization of both antibodies.