Question

*The answer is C.* Antibodies generated by the vaccination are produced by antigen-specific memory B cells which reside in the bone marrow. These antibodies (most likely IgG) can promote opsonization (choice A), Fc receptor-mediated phago-cytosis, and complement activation (choice D) as well as ADCC (choice E). However, the infectious agent in most cases will have colonized tissues by the time these mechanisms act to limit growth. The most critical function of a vaccine-mediated humoral response is to generate antibodies which block attachment of infectious agents to host cell surfaces or neutralization. This blockade completely inhibits microbial colonization and ensures protection from the pathogen. Extravasation (choice B) refers to the process whereby immune cells can leave the circulation and enter tis-sues generally to migrate into areas of inflammation in order to destroy pathogens invading host tissues.

Answer 1

Vaccines stimulate the humoral immune system by introducing specific antigens to generate a protective antibody response. These antibodies neutralize pathogens by preventing their attachment to host cells and mark them for destruction by phagocytes through opsonization, hence providing immunity.

Step-by-step explanation:

The Role of Vaccines in Humoral Immunity

Vaccines play a crucial role in the prevention of infectious diseases by stimulating the humoral immune response. The process starts when a vaccine introduces antigens specific to a pathogen into the bloodstream. These antigens are then presented on the surface of antigen-presenting cells, which leads to the activation of helper T cells. The activated helper T cells then help B lymphocytes to produce antibodies.

Memory B cells that develop post-vaccination are key as they ensure long-term protection. Once the immune system is exposed to the genuine pathogen, these memory cells quickly generate a robust antibody response, thus providing immunity. The antibodies produced can neutralize pathogens by blocking their attachment sites, which prevents colonization and infection of host cells. They mark the pathogens for destruction by phagocytes in a process known as opsonization and can also stimulate complement activation leading to pathogen lysis.

Overall, the generation of specific antibodies by B cells is essential for long-lasting defense against many infectious diseases, which is the primary goal of vaccination.