A virus strain related to HIV that can infect monkeys is designated as SIV.
In some strains of monkey (which are known as natural hosts) SIV does not cause disease, whereas it does in others (which are known as susceptible hosts). It is hoped that understanding why SIV does not cause disease in natural hosts will provide insight into how to control HIV infection of humans.
Two independent research teams, one led by Michaela C. Müller-Trutwin, and the other led by Guido Silvestri, Ashley Haase, and David Kelvin, have now determined that SIV induces vigorous activation of the immune system, in particular upregulation of genes stimulated by immune molecules known as IFNs, in both natural and susceptible hosts, but strikingly, the responses are later brought under control only in the former. In an accompanying commentary, Nina Bhardwaj and Olivier Manches, at New York University Langone Medical Center, New York, discuss how the lessons learned from these studies might impact HIV vaccine design and therapy.