Human Defenses A gainst Infection. Fighting off the “Bad Guys”. The body possesses many mechanisms that impart nonspecific defense. The objectives of these mechanisms are to prevent microorganisms from gaining a foothold in the body and to destroy them if they penetrate to the deeper tissues.
whitish mass of cells, bacteria,
and debris called pus.
Five classes of antibodies (immunoglobulins)
4. IgD is found in extremely small quantities in the serum. IgD is found at the surface of B-lymphocytes and is believed to be an antigen receptor at this location.