Antibodies lipid bilayer CGI image.  The lipid bilayer of a cell membrane serves as a barrier.  It separates the inside of the cell from the outside environment.  Antibodies are proteins that are produced by the immune system in response a virus.  Antibodies are able to bind to specific sites on the surface of the invader, marking it for destruction by other parts of the immune system.  When an antibody binds to a virus, it can also interfere with the virus's ability to enter host cells by blocking endocytosis.  Endocytosis is a crucial step in the infectious cycle of many viruses.  In this way, the antibody can prevent the virus from accessing the interior of host cells and replicating, effectively neutralizing the virus. Polymime is a UK based animation company offering royalty free medical stock images and medical stock videos. Other services including 3D rending, medical animation interactive 3D, vfx and more.