It enters two types of cells in the vaginal epithelium

Feb 16, 2007 08:41 GMT  ·  By

Human immunodeficiency virus (HIV) is the germ that provokes AIDS (acquired immunodeficiency syndrome).

AIDS is a serious, life-threatening illness that has a variety of symptoms, like swollen lymph nodes; fever, chills, and night sweats; diarrhea, weight loss, coughing and shortness of breath, persistent tiredness, skin sores, blurred vision and headaches, development of other infections, such as certain kinds of pneumonia.

All these happen because the immune system falls and the most banal germs trigger severe infections. HIV therapy can improve and prolong the life of the patients, but there is no cure for HIV infection.

That's why till now, about 25 million people have died of AIDS and other 40 million people are infected with HIV worldwide.

HIV is transmitted through body fluids, like semen and vaginal secretions (through sexual contact with an infected person) and blood, but no saliva; infected blood from shared drug injection needles or an accidental needle stick with a needle contaminated with infected blood or infected blood and blood products though transfusion (this still occurs in countries with inadequate blood donor testing programs).

HIV infected women can pass the virus to their babies during pregnancy or delivery or through their breast milk.

Researchers have imagined till now various types of vagina gels that would protect the women from being infected by sexual contact, but they failed by now.

These failures could have an explanation now that American researchers have detected the primary targets of HIV-1 infection in the human vagina. HIV is present under two varieties: the most common and virulent form, HIV-1 and HIV-2, located in West Africa and less easily transmitted. "The majority of HIV-1 infected individuals worldwide are women who acquire HIV infection following sexual contact. Blocking HIV transmission and local spread in the female lower genital tract is key to prevent infection and ultimately to ease the pandemic," wrote study authors Dr. Florian Hladik and Dr. M. Juliana McElrath, of the Fred Hutchinson Cancer Research Center in Seattle.

The researchers discovered that HIV-1 simultaneously penetrates two different kind of cells in the vaginal epithelium (outer lining of vaginal cells) linked to the immune system: Langerhans cells and CD4+ T-cells. Both of these cell types can move out of the vaginal epithelium. "Our findings provide exciting, definitive insights into the initial events of HIV-1 infection in the human vagina, which can guide the design of effective strategies to block local transmission and prevent HIV-1 spread," McElrath said.