MCQ IN MEDICINE

Detailed explanation-1: -That is how antibodies detect the matching germs to initiate a fast response from the adaptive immune system. Antibodies have three main functions: They neutralize germs, e.g. by directly attaching to the cell surfaces of viruses or bacteria, or by attaching to their toxins.

Detailed explanation-2: -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-3: -The immune system recognizes invaders by their antigens, which are proteins on the surface of the invading cells (see Figure 1). Every cell or substance has its own specific antigens, and a person’s cells carry “self-antigens” that are unique to that individual.

Detailed explanation-4: -That is, the immune system must be able to distinguish what is nonself (foreign) from what is self. The immune system can make this distinction because all cells have identification molecules (antigens) on their surface. Microorganisms are recognized because the identification molecules on their surface are foreign.

Detailed explanation-5: -Cells that belong in the body carry specific markers that identify them as “self” and tell the immune system not to attack them. Once the immune system recognizes a pathogen as “non-self, ‘’ it uses cellular and chemical defenses to attack it.