Omalizumab is a recombinant humanized monoclonal antibody against IgE. Eculizumab is a recombinant humanized monoclonal antibody against the complement protein C5. Panitumumab is an IgG2 human monoclonal antibody. CA-125 was initially detected using the murine monoclonal antibody designated OC125. Multiple secondary antibodies can bind a single primary antibody. Nivolumab is a fully human monoclonal immunoglobulin G4 antibody to PD-1. Nivolumab is a human IgG4 monoclonal antibody that blocks PD-1. Cetuximab and panitumumab are examples of monoclonal antibody inhibitors. Daratumumab is an IgG1k monoclonal antibody directed against CD38. It is a humanized anti-CD20 monoclonal antibody. It is a fully human IgG2 monoclonal antibody. Ganitumab is a monoclonal antibody (mAb) directed antagonistically against IGF-1R. Labels are typically chemically linked or conjugated to the desired antibody or antigen. ELISA is a common means of determining antibody titers. The invention of antibody phage display revolutionised antibody drug discovery.