At the time of acute infection with HIV, the body has not yet made antibodies to HIV. Antibodies, proteins produced primarily by certain white blood cells called B lymphocytes, attack substances foreign to the body, including viruses. The fact that symptoms are present even though the blood test to detect antibodies to HIV is negative is not unusual. In most other infections, symptoms precede the body’s production of antibodies, and the symptoms disappear once antibodies are produced. The body usually takes several days or weeks to recognize a foreign substance like a virus, and then produces antibodies to attack it. Six to twelve weeks after HIV has entered the body, antibodies to HIV appear in the blood. Physicians call this appearance of antibodies seroconversion. That is, the result of a test for antibodies in the blood serum converts from negative to positive. Occasionally, seroconversion may take up to a year or longer. The reason for the delay in some people is not known. For some reason, the virus is dormant; that is, it is not actively reproducing, so the immune system is not manufacturing antibodies against it. Antibodies against most viral infections, once they appear, eliminate the virus and then stay in the body to protect against future infections by the same virus. Virtually all people with HIV infection eventually develop antibodies against HIV. These antibodies, for reasons no one yet understands, do not eliminate HIV. As a result, the person with HIV remains infected and capable of transmitting the virus for life.