Molecules of the immune system of AIDS resistant humans and chimpanzees recognise similar parts of HIV

Most humans infected by the Human Immunodeficiency Virus (HIV) develop the disease AIDS. However, a small number of individuals do not contract AIDS after infection. Resistance against the development of AIDS in these people is associated with genetic variations in a certain part of the immune system: the Major Histocompatibility Complex (MHC). MHC molecules display a lot of variation and play an important role in the control of viral infections

In contrast to humans, most chimpanzees that are infected with HIV do not contract AIDS. Characterisation of the chimpanzee MHC system has revealed that some parts of the system are less variable than the human MHC system. It appears that specific MHC molecules have been selected for. This may have been caused by a pandemic with an HIV-like virus 2-3 millions of years ago. Animals with AIDS resistant MHC molecules would have survived and these MHC molecules may have remained in the population under pressure of the virus

In collaboration with the LUMC, researchers of the BPRC have tested the hypothesis described above by investigating whether frequently occurring chimpanzee MHC molecules can recognise similar parts of the virus as AIDS resistant humans. The results of this research, published in the leading journal PNAS, revealed that almost all studied chimpanzees contained at least one MHC molecule with the same characteristics as the molecule that has been associated with AIDS resistance in humans. In addition, a lot of animals possessed multiple MHC molecules of this kind. In summary, in respect to both quality as well as quantity chimpanzees are well armed against HIV-like virusses.