LIFE SCIENCE

Detailed explanation-1: -Antibodies are proteins made by the body’s natural defence system (immune system) to fight foreign substances, such as bacteria. Antibodies attach themselves to the foreign substance, allowing other immune system cells to attack and destroy the substance.

Detailed explanation-2: -Antibodies act against viruses primarily by binding to and neutralizing virions and by directing the lysis of infected cells by complement or killer leukocytes.

Detailed explanation-3: -The spleen is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells. It also makes disease-fighting components of the immune system (including antibodies and lymphocytes).

Detailed explanation-4: -Cells bound by such antibodies can then be killed by a specialized non-T, non-B lymphoid cell called a natural killer cell (NK cell), which we met earlier in Chapter 2. NK cells are large lymphoid cells with prominent intracellular granules; they make up a small fraction of peripheral blood lymphoid cells.