antibody reactions

antibody 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 . XII Std Biology-Zoology Chapter- XII Std Biology-Zoology Chapter- Human Health and Diseases 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 a substance called an opsonin , marking the pathogen out for destruction by the immune system. This results in a much more efficient phagocytosis . The neutralization reactions are the reactions of antigen-antibody that involve the elimination of harmful effects 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 response to a bacterial exotoxin or corresponding toxoid (inactivated toxin).