IMMUNOLOGY

Detailed explanation-1: -These antibodies bind to pathogens or to foreign substances, such as toxins, to neutralize them. For example, an antibody can bind to a virus, which prevents it from entering a normal cell and causing infection. B cells can also recruit other cells to help destroy an infected cell.

Detailed explanation-2: -Macrophages and neutrophils (phagocytes) are the front-line defenders in your body’s immune system. They seek out, ingest, and destroy pathogens and other debris through a process called phagocytosis.

Detailed explanation-3: -B-cells produce antibodies to fight bacteria and viruses. These antibodies are Y-shaped proteins that are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells.

Detailed explanation-4: -Antibodies. Antibodies help the body to fight microbes or the toxins (poisons) they produce. They do this by recognising substances called antigens on the surface of the microbe, or in the chemicals they produce, which mark the microbe or toxin as being foreign. The antibodies then mark these antigens for destruction.

Detailed explanation-5: -Each B cell produces a single species of antibody, each with a unique antigen-binding site. When a naïve or memory B cell is activated by antigen (with the aid of a helper T cell), it proliferates and differentiates into an antibody-secreting effector cell.

Detailed explanation-6: -Some microbial antigens can activate B cells directly in the absence of T-cell help. The ability of B cells to respond directly to these antigens provides a rapid response to many important bacterial pathogens.

Detailed explanation-7: -During immune responses, B cells are directly activated by invading microorganisms, either by detecting a specific antigen through their BCR or by detecting pathogen-associated molecular patterns (PAMPs) through general pattern recognition receptors (PRRs)4, 5, 6 (Fig.