The antibodies bind to the antigens and form large macromolecular complexes. These complexes are formed due to the fact that each antibody can associate and bind with more than one antigen and each antigen can be bound by more than one antibody molecule. The noncovalent interactions that form the basis of antigen-antibody (Ag-Ab) binding include hydrogen bonds, ionic bonds, hydrophobic interactions, and Vander Waals interactions The formation of the large macromolecules results in their precipitation and the resulting precipitate is cleared by the body by various mechanisms. The interaction of antigen and antibody, resulting in precipitation, is also useful in research and diagnostics.