Immune System is made up of cells, tissue and organs that work together to protect the body. These cells are white blood cells or leukocytes. Two types of leukocytes: 1. phagocytes (chew up invading organisms) 2. lymphocytes (remember and recognize previous invaders and help the body to destroy them) PHAGOCYTES LYMPHO

There are 2 kinds of lymphocytes: B Lymphocytes (mature in bone marrow) “T Cells” T Lymphocytes (mature in thymus) “B Cells” Military intelligence system: seeks out enemy and sends defenses to lock on to them Soldiers: destroys invaders that the intelligence system has identified

B cells also produce antibodies. Antibodies: proteins that lock on to certain antigens (the bad guys) This is how vaccines work. (become immune) HIV CHICKEN POX MEASLES SHINGLES

Antibodies can lock on to an antigen but they can not destroy it without help. That is the job of the T cells. Antibodies tag the bad guys. T-cells find the bad guys with the heap of the tag. T-cells destroy the antigen. TAG….YOU ARE IT! MEASLES ANTIBODIES

How the HIV Virus takes over the body?

HIV BODYBODY BLOOD SEMEN VAGINAL SECRETIONS MOTHER TO CHILD

HIV virus enters the blood stream attacking the T-helper cells. HIV T-HELPER CELL ATTACKS

HIV VIRUS GETS YOUR T-CELL TO REPLICATE THE VIRUS. T-CELL IS DESTROYED

HIV

Epidemiology of HIV Infection through 2011 Epidemiology of HIV Infection through 2011