Individuals with key variants in an important immune cell and a molecule that controls it show a slower progression to Aids after they are infected with the human immunodeficiency virus (HIV), a study released on Sunday says.
The paper focuses on "natural killer" cells, which are unleashed by the immune system to crush viral intruders.
Natural killers are switched on or off by receptors, or docking sites, on their surface. The receptors are activated by a molecule presented to the cell by the immune system's signallers.
Researchers led by Mary Carrington of the United States' National Cancer Institute, Maryland, looked at variants in two
genes - one that creates a receptor named KIR3DL1, and one that
creates a signalling molecule called HLA-B.
Genes tied to better immunity
In a study of 1 500 people with HIV, they found that individuals
who had specific variants in both genes were helped "significantly
and strongly," progressing to Aids much later than counterparts
without these variants and also having lower levels of virus in the
The study is released online by the journal Nature Genetics.
Meanwhile, work published in a sister journal, Nature Immunology, casts light on how HIV can foil the immune system by
stifling a sentry cell called a dendritic cell.
By latching onto the DC-SIGN receptor on this cell, the virus
blocked the signalling pathway, enabling itself to swarm around
nearby immune T-cells and penetrate them.
Around 39.5 million people were living with HIV or Aids at the
end of last year, according to the World Health Organisation (WHO)
and UNAIDS. – (Sapa-AFP)