Antibodies

 

Antibodies can work in several ways, depending on the nature of the antigen.
	Agglutination - clumping of particulate matter, including bacteria and viruses. IgM is particularly suitable for this, as each molecule can attach to more than one particle - resulting in a lattice type structure.
	Interlock with toxins produced by certain bacteria causing their precipitation and thus disabling them directy (antitoxins) - Precipitation and Neutralization.
	Coat (opsonize) bacteria, slowing their movement and thus aiding scavenger cells to destroy and engulf them - Opsonization and Immobilization .
	Antigen-antibody complex can ininiate a cascade of serum enzymes called complement - Complement activation .
	Antibodies can also block viruses from entering into cells (a quality that is exploited in making vaccines).
	Cells coated with antibody become vulnerable to attack by several types of white blood cells - antibody-dependent cell-mediated cytotoxicity (ADCC).