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.
Antibodies protect against substances prior to cell infection. Antibodies are produced by a type of white blood cell called a B cell (B lymphocyte). B cells develop from stem cells in bone marrow.When B cells become activated due to the presence of a particular antigen, they develop into cells called plasma cells.ntibodies recognize specific antigens by identifying certain areas on the surface of the antigen known as antigenic determinants. Once the specific antigenic determinant is recognized, the antibody will bind to the determinant.