therapies. the entry of hiv into human immune cells requires the binding of the gp120 (an envelope glycoprotein on the surface of hiv) to cd4 (a receptor on the immune cell surface) to induce the structural shift in the gp120. ibalizumab binds to the cd4 receptor to prevent the post-attachment conformational changes in cd4-hiv envelope gp120 complex and therefore hinders the viral entry into host cells and prevents the hiv-infected cells from infecting other normal cells. the advantages of using ibalizumab as hiv therapy are low toxicity, good drug resistance, high antiviral effect and synergy with other antiviral drugs. perspective and future opportunities although passive administration of antibodies was used to treat infectious diseases 100 years ago, there are only a few therapeutic antibodies approved for the clinical treatments of infectious diseases currently. however, there are an increasing number of ongoing research and clinical developments on the applications of monoclonal antibodies in the therapy of viral infections without available vaccines, such as ebola, mers, and zika, and infectious diseases without effective anti-viral drugs such as influenza and rabies. the most recent research focuses on the development of monoclonal antibody therapy for treating covid-19.