Laboratory-produced antibodies of identical specificity.

Antibody responses to pathogens are typically polyclonal – a mixture of different antibodies are produced specific for different structures. To create monoclonal antibodies, immune cells called B cells producing an antibody of interest are isolated and fused with actively dividing myeloma cells (these are derived from a blood cancer cell), creating immortal hybridoma cells that continuously secrete the antibody of interest.

mAbs have been extensively used in oncology and in autoimmune diseases. In the field of infectious diseases, mAb development has focused primarily on viral infections. mAbs targeting anthrax (raxibacumab, obiltoxaximab) and to prevent recurrence of Clostridium difficile infections (bezlotoxumab) have been approved by the US FDA. mAbs are in clinical development for infections such as Staphylococcus aureus and Pseudomonas aeruginosa.

Monoclonal antibodies have been developed that bind to a pathogen, or to its virulence factors or toxins, rendering it non-pathogenic. They have the potential to be used both prophylactically (to prevent infection) or therapeutically (to treat infection).

Although innovative production methods are being developed for mAbs, they are complex therapeutics and are unlikely to replace conventional antibiotics. However, they have advantages – for example, they are highly specific, so would have less impact on the host microbiome, and long-lasting, so can contribute to prevention. As more antibiotics are affected by resistance, the need for mAbs may increase.