Mechanism of action: HPV vaccine targets selective proteins found on the surface of the virus. These protein targets are grown in yeast cells cultured in the laboratory. The mature protein self-assembles to mimic the appearance of HPV virus. Because the HPV protein does not harbor any HPV genetic materials, the protein is incapable of replication and production, hence HPV vaccines that target the HPV proteins do not cause any HPV infections. As for how the HPV vaccine generates immunity, it follows the same logical developmental steps as other types of vaccines: (1) The “target” delivered by the vaccine is recognized by the host immune system as “non-self and dangerous”. (2) The “target” such as HPV 16 is processed and presented by antigen presentation cells (such as dendritic cells) to naive T helper cells in the lymph nodes. (3) The presentation activates T helper cells which then interact with B cells. (4) Activated B cells differentiate to become plasma cells that produce antibodies specific to the HPV protein. (5) If and when HPV appears under the radar of the prepared host immune system, the HPV-specific antibodies take immediate action to protect the host from HPV infection.
