Write in detail about various types of antigen- antibody reactions

Explanation

The reaction between soluble antigen leads to visible precipitate formation,which is called percipitin reaction. Antibdies that bring about precipitate formation on reacting with antigens are called as precipitins.
Whenever a particulate antigen interacts with its antobody,it would result in clumping or agglutination of the particulate antigen,which is called agglutination reaction.The antibody involved in bringing about agglunation reaction is called agglutinin.
Opsonisation or enhanced attachment is the process by which a pathogen is marked of ingestion and destruction by a phaocyte,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 a substance called an opsonin,marking the pathogen out for destruction by the immune syste .This results in a much more efficient phagocytosis.
The neutralization reactions are the reactions of antigen-antibody that involve the eliminationof harmful effect of bacterial exotoxins or a virus by specific antibodies .These neutralizing substances i.e antibodies are known as antitoxins.This specific antibody is produced by a host cell in reponse to a bacterial exotoxin or corresponding toxoid (inactivated toxin).