1 Most of these diseases are infections, caused by a variety of bacteria, viruses, and parasites that can be foodborne. 2  Other diseases are poisonings, caused by harmful toxins or chemicals that have contaminated the food, for example, poisonous mushrooms.
(cluster designation 4) symbol for a glycoprotein expressed on the surface of helper T lymphocytes and other immune cells. CD4 serves as a receptor for human immunodeficiency virus envelope glycoprotein gp120.
CD4 is a protein on the surface of the T cell. HIV's gp120 antigen is a mirror image of the CD4 protein. If HIV bumps into the right place on the T cell's surface, the gp120 of the virus will lock onto the CD4 site of the T cell (Figure 4). Because of this, CD4 is called the receptor site or docking port for HIV.