IMMUNOLOGY

Detailed explanation-1: -Introduction. Antibodies (Abs) have two distinct functions: one is to bind specifically to their target antigens (Ags); the other is to elicit an immune response against the bound Ag by recruiting other cells and molecules.

Detailed explanation-2: -An insoluble precipitate of Ag-Ab complex is produced when a soluble Ag and its Ab combine in the presence of an electrolyte (NaCl) at a specific pH and temperature. Precipitin is the Ab that causes precipitation, and the reaction is termed a precipitation reaction.

Detailed explanation-3: -Antibodies attach to a specific antigen and make it easier for the immune cells to destroy the antigen. T lymphocytes attack antigens directly and help control the immune response. They also release chemicals, known as cytokines, which control the entire immune response.

Detailed explanation-4: -The agglutination of red cells in this way is correctly called haemagglutination, although it is often simply referred to as agglutination. It takes place when serum/plasma antibody (e.g. anti-A) is mixed with red cells carrying the corresponding antigen (i.e. A antigen).

Detailed explanation-5: -An immune complex, sometimes called an antigen-antibody complex or antigen-bound antibody, is a molecule formed from the binding of multiple antigens to antibodies. The bound antigen and antibody act as a unitary object, effectively an antigen of its own with a specific epitope.

Detailed explanation-6: -The antigen-antibody bond occurs through multiple noncovalent bonds-electrostatic, hydrogen, hydrophobic, and Van der Waals. Long-range forces such as electrostatic and hydrogen bonds are important in the rate of formation of antigen-antibody complexes at the points of contact.