Early Indus Valley Civilization ... their Geograhpy, their customs and Indo-Aryan civilization with the earliest caste system.
Antibodies contribute to immunity in three main ways: they can prevent pathogens from entering or damaging cells by binding to them; they can stimulate removal of a pathogen by macrophages and other cells by coating the pathogen; and they can trigger direct pathogen destruction by stimulating other immune responses such as the complement pathway.
Antigens are chemicals on the surface of a cell. All cells have these. The immune system checks cells and identifies them as self or non-self. Antibodies are proteins produced by certain lymphocytes in response to a specific antigen.B-lymphocytes and T-lymphocytes produce the antibodies. B-lymphocytes become plasma cells which then generate antibodies. T-lymphocytes attack cells which bear antigens they recognize.ntigens are chemicals on the surface of a cell. All cells have these. The immune system checks cells and identifies them as self or non-self. Antibodies are proteins produced by certain lymphocytes in response to a specific antigen.