HIV genome helps determine antibodies formed in people with the virus

Sept. 11 (UPI) -- Researchers found that HIV itself plays a major role in determining which antibodies are formed in people, which may be important for developing a vaccine against it.

A Swiss research team led by the University of Zurich and University Hospital Zurich has been searching for the factors that play a role in these antibodies' production. Their findings were published Monday in the journal Nature.

HIV, which stands for human immunodeficiency virus, spreads through certain body fluids that attack the body's immune system, including T cells. Over time, these infections take advantage of a weak immune system and become acquired immunodeficiency syndrome, or AIDS.

Previously identified factors that played a role in the body's immune response were: the virus load and the diversity of the viruses, the duration of the infection and the ethnicity of the affected person.

"In our new study, we were able to identify another factor: The genome of the HI virus," Dr. Huldrych Günthard, deputy director of the Department of Infectious Diseases and Hospital Epidemiology at University Hospital Zurich, said in a press release.

They studied data and biobanked blood samples from around 4,500 HIV-infected people from the Swiss HIV Cohort Study and the Zurich Primary HIV Infection Study.

Analyzing 53 measured parameters of HIV-1-binding and neutralizing antibody responses, they found 303 potential transmission pairs of patients with similar genomic RNA, meaning they were probably infected with the same virus strain.

"By comparing the immune response of these pairs of patients, we were able to show that the HI virus itself has an influence on the extent and specificity of the antibody reactions," said Dr. Roger Kouyos, research group leader at the Department of Infectious Diseases and Hospital Epidemiology at University Hospital Zurich.

When antibodies act against HIV, they bind to proteins on the surface of the virus. The antibodies also differ based on virus strain and subtype.

The researchers studied patient pairs with similar virus genomes but had strong activity of broadly neutralizing antibodies.

"We discovered that there must be a special envelope protein that causes an efficient defense," said Dr. Alexandra Trkola, virologist and head of the Institute of Medical Virology at the Zurich hospital.

The envelope proteins and virus strains that lead to the formation of broadly acting antibodies must be identified to develop an effective vaccine against HIV-1.

"We have found one candidate. Based on that, we now want to begin developing an immunogen ourselves," Trkola said.