HPV Immunization Program: Understanding Immune Response

SCENARIO 2 Vaccines as Specific Antigens The government is holding an HPV (Human Papilloma Virus) immunization program for girls aged at least 11 years. The HPV vaccine is an active immunization that aims to induce the body's immunity to prevent infection with certain diseases. The vaccine is given by being injected intramuscularly several times at certain intervals. The HPV vaccine is a type of recombinant vaccine Know the body's immune response to immunization (active and passive). LO 4 Tutor Instruction Questions: a. How does the body's immune response to immunization? As with stimulation of the immune system, the body must first detect a threat, be it a pathogenic agent or immunization. This initial detection is usually carried out by the innate immune system; although, B-cells can also perform this function. This detection process begins when the immune system recognizes an epitope on an antigen. Epitopes are small subregions on an antigen that simulate recognition by the immune system.Several components of the innate immune system will then capture these antigens. This component of innate immunity will opsonize or bind to the agent and stimulate phagocytosis by APCs such as macrophages or monocytes. These APC cells will then process the antigens from these pathogenic agents and present the processed antigens together with MHC proteins to the surface of the APC cells.If it is a viral antigen, the antigen will bind to the MHC I protein and be presented by the antigenpresenting cell to CD8 cells which is likely to trigger cell-mediated immunity. If it is a bacterial or parasitic antigen, the antigen will bind to the MHC II protein and be presented by antigen-presenting cells to CD4 cells possibly triggering antibodymediated immunity. The vaccine is injected into the muscle and the protein antigen is taken up by the dendritic cells, which are activated viaPattern Recognition Receptors(PRR) by signals produced by adjuvants, and then migrate to the lymph nodes. Presentation of vaccine protein antigen peptides by MHC molecules in dendritic cells activates T cells viaT cell receptors(TCR). The combination of signals by soluble antigen via the B cell receptor (BCR), T cells increases the developmental ability of B cells in the lymph nodes. T celldependent development of B cells results in the maturation of antibody responses to increase antibody affinity and induce different antibody isotypes. Production of shortlived plasma cells, which actively secrete antibodies specific for the vaccine protein, results in a rapid increase in serum antibody levels over the next 2 weeks. Memory B cells are also produced, which function to mediate immune system memory. Longlived plasma cells that can continue producing antibodies for decades travel to reside in the bone marrow. CD8+ memory T cells can proliferate rapidly when they recognize pathogens and CD8+ effector T cells are important for the elimination of infected cells.In polysaccharide vaccines without conjugate a, it induces antibody-producing plasma cells by binding toB cell receptors(BCR). However, affinity maturation of the antibody response and induction of memory B cells did not occur. Meanwhile, proteinpolysaccharide conjugate vaccines can involve T cells that recognize proteinscarriers, as well as B cells that recognize polysaccharides. T cells provide assistance to B cells, leading to affinity maturation and production of plasma cells and memory B cells.As previously explained, passive immunization does not stimulate the body's immune response from the vaccine recipient, so the vaccine works directly to recognize the antigen and neutralize the target antigen in the patient's body.