Give reasons for the following :
(a) Antibody mediated immunity is called humoral immunity.
(b) How is a child protected from a disease for which he/she is
vaccinated ?
(c) Name the type of cells the AIDS virus enters after getting into the
human body.
a) Antibody-mediated immunity is called humoral immunity because it is mediated by antibodies, macromolecules in the extracellular fluid, complement proteins present in the blood.
b) In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) is introduced into the body. The antibodies produced in the body against these antigens would neutralize the pathogenic agents during actual infection. The vaccines also generate memory – B and T-cells that recognize the pathogen quickly on subsequent exposure and overwhelm the invaders with a massive production of antibodies.
c) HIV enters into helper T-lymphocytes (TH), replicates and produces progeny viruses. The progeny viruses released in the blood attack other helper T-lymphocytes. This is repeated leading to a progressive decrease in the number of helper T-lymphocytes in the body of the infected person.