AIDS breakthrough - vaccine strengthens the body’s immune system againts HIV

Dec 28 2004

A Hadassah University Medical Center research team has developed a vaccine that significantly strengthens the body’s immune system against the autoimmune sequela of HIV infection, a breakthrough that could dramatically make an impact in the treatment of AIDS patients.

It is now evident that although treatment with the cocktail of medications kills the virus, the immune system continues to kill healthy cells; this research focuses on developing a vaccine that would arrest this autoimmune destructive process. The results of this study were published in the latest issue of the prestigious Journal of Clinical Virology.

The research group is headed by Dr. Rivka Abulafia-Lapid and assisted by Yael Keren-Zur, at the Human Biology Research Center directed by Prof. Henri Atlan, associated with the Department of Biophysics and Nuclear Medicine, Ein Karem, Jerusalem. This study was done in collaboration with Prof. Zvi Bentwich, Prof. Irun Cohen from the Weizmann Institute of Science.

HIV, the human immunodeficiency virus, infects a type of white blood cell called CD4, an integral component in the body’s immune system. As HIV attacks and destroys CD4 cells, the weakened immune system becomes less able to fight infection and disease. HIV can also cause AIDS, the last and most severe stage of HIV infection.

The Hadassah study was conducted between 1998 and 2002 with an additional two-year monitoring period. Seven patients participated in the study; five of the seven patients responded positively to the vaccine developed by this research team.

The research was based on a suggestion made by Prof. Atlan some ten years ago. This was based on the hypothesis that in addition to HIV causing AIDS by invading and killing CD4 blood cells, HIV causes the body’s central immune system to start killing these cells independently of the virus as a consequence of an autoimmune process. For most AIDS patients, the central immune system does not recover even if the HIV virus is almost eliminated through treatment with the cocktail of medications. The Hadassah vaccine was designed to stop the continuation of the autoimmune process.

Initially, the researchers identified CD8 cells which are involved in the autoimmune process and are supposedly responsible for destroying CD4 cells in the immune system. In the laboratory, the scientists isolated the CD8 cells from a sample of the patient’s white blood cells and mixed them with CD4 cells, and showed that these CD8 cells were involved in the killing process. At this stage, preparation of the vaccine involved neutralization of these CD8 cells and preparation of portions of ten million cells each to be used by injection under the skin in order to trigger a vaccination against these harmful cells.

Seven patients were treated with the new therapeutic vaccine. Each received between three and four injections in a six-month period. Following treatment, the patients CD4 cell count was continually monitored for another two years from their initial vaccination to determine if the number of CD4 cells increased in the peripheral blood, and subsequently, reinforced the strength of the immune system. In five of the seven vaccinated patients, the CD4 cells increased by more than 50 percent.

“Our aim was not to prevent infection by the virus but to strengthen the immune system and use our vaccination treatment as a complement to the antiviral medication (HAART)", said Dr. Rivka Abulafia-Lapid. "Since the autoimmune process continues even after elimination of the virus, the vaccine that we have developed is directed to stop this destructive process. In other words, our vaccine complements the cocktail of medications, to stop the body from continuing to destroy itself.”

The researchers are continuing to develop the vaccine funded by a grant from Hadasit, the Hadassah subsidiary that promotes and commercializes the intellectual properties generated at Hadassah and by the Center for the Study of Emerging Diseases.