The terms monoclonal and recombinant antibodies are often used interchangeably, but in reality, they represent two different types of antibodies. Monoclonal antibodies refer to IgG molecules generated and produced in hybridoma cell lines. In contrast, recombinant antibodies can be IgG immunoglobulins or any other antibody format (scFv, Fab, IgM, etc.) produced in vitro via a recombinant expression system such as bacteria, yeast, insect, plant, and mammalian cells.
Nevertheless, both monoclonal and recombinant antibodies possess antigen-specificity given that they derive from a single plasma cell clone or a single antibody sequence, respectively. In contrast, polyclonal antibodies are exclusively generated by hyperimmunizing animal hosts and harvesting their IgG-enriched plasma for downstream purification. In their essence, polyclonal antibodies contain a mixture of monoclonal antibodies derived from different B cell lineages and consequently displaying different epitope-specificity.