HPV Humoral Response

This web page was produced as an assignment for an undergraduate course at Davidson College.

Monoclonal antibody binding of a papillomavirion John T. Schiller, Center for Cancer Research. 2001. Reproduced with permission. http://ccr.cancer.gov/staff/ gallery.asp?profileid=5637

Humoral immunity is part of the adaptive immune system, and it refers to the production of antibodies against the invading pathogen. Antibodies are produced by B cells that have been activated by effector T cells: naïve B cells internalize pathogens, then move to lymph nodes or the spleen. There, they present parts of the pathogen – antigens – to the effector T cells, which then stimulate the B cells to differentiate into antibody-producing plasma cells. These antibodies recognize and target the same pathogen internalized by the B cell; the antigen targeted by antibodies in an HPV humoral response is the capsid surface protein L1. When the antibodies contact L1 on the virus’s surface, they remain attached, preventing the virus from being taken up by keratinocytes. They also signal macrophages to ingest the virus and stimulate the release of inflammatory cytokines. However, antibodies can only attach to viruses that are free in the body, not those that have already infected the cell (Stanley 2006).

The majority of these antibodies are IgG1 class, which is a common class involved in viral infections since it helps natural killer cells identify and kill infected cells. The L1 protein they target is sufficiently different between types of HPV that infection with one type offers no cross-protection for the other types; in other words, the antibodies produced during an infection with one type of HPV will not recognize the L1 on another type of papillomavirus. (Stanley 2006).