Hope for an AIDS vaccine revived

More than 25 million dead and 33 million people are carriers of the virus : the AIDS virus , or HIV , is responsible for a global pandemic that started about thirty years ago. Its properties make this virus an impossible entity to eradicate once it has invaded target cells. The only means of control then consists of protection against infection. Preventive solutions exist such as wearing a condom , monitoring transfused blood … but contamination is increasing every year, especially in poor countries. The ultimate protection, the HIV vaccine, so far seemed unthinkable. However, two publications in the journal  Science suggest happy prospects.

The difficulty in finding an HIV vaccine consists in the variability of the virus: it is able to mutate very quickly and therefore to escape the immune system . It is also for this reason that multiple strains of the virus exist around the world. To successfully identify antibodies capable of targeting several strains, the researchers developed a new technique, based on the biological properties of the virus.

The particles of HIV are contained in an envelope where certain viral proteins are anchored , the famous peaks on the surface of the virus. The glycoprotein gp120 is one of them and is used to bind the virus to the receptor of human cells, called CD4. The gp120-CD4 interaction is therefore essential for infection and its inhibition would help fight against new infections.

Two research teams from the American National Institute of Allergies and Infectious Diseases (NIAID) have built a modified version of the gp120 protein with traits common to all strains. They then reacted this protein with B lymphocytes (immune cells secreting antibodies) extracted from the blood of a patient with HIV. The B lymphocytes activated by the modified gp120 protein were individualized, in order to determine the specific antibodies which they secreted.