reactions The reaction between soluble antigen and antibody leads to visible precipitate formation, which is called precipitin reaction . Antibodies that bring about precipitate formation on reacting with antigens are called as precipitins . Whenever a particulate antigen interacts with its antibody, it would result in clumping or agglutination of the particulate antigen, which is called agglutination reaction . The antibody involved in bringing about agglutination reaction is called agglutinin .
Opsonisation or enhanced attachment is the process by which a pathogen is marked of ingestion and destruction by a phagocyte. Opsonisation involves the binding of an opsonin i.e., antibody, to a receptor on the pathogen’s cell membrane. After opsonin binds to the membrane, phagocytes are attracted to the pathogen. So, opsonisation is a process in which pathogens are coated with Each chain ( L and H ) has two terminals.
They are C - terminal (Carboxyl) and amino or N-terminal. Each chain ( L and H ) has two regions. They have variable ( V ) region at one end and a much larger constant ( C ) region at the other end. Antibodies responding to different antigens have very different (V) regions but their (C) regions are the same in all antibodies.
In each arm of the monomer antibody, the (V) regions of the heavy and light chains combines to form an antigen – binding site shaped to ‘fit’ a specific antigenic determinant. Consequently each antibody monomer has two such antigen – binding regions. The (C) regions that forms the stem of the antibody monomer determine the antibody class and serve common functions in all antibodies. The functions of immunoglobulin are agglutination, precipitation, opsonisation, neutralization etc.,