Lifespan of HIV-infected cells might be shorter than previously anticipated

Jun 30 2009

Dutch-sponsored researcher Christian Althaus has used mathematical models to demonstrate that cells infected with HIV could live even shorter than was thought until now. If infected cells have a shorter lifespan then this increases the chances of the virus escaping the attention of the immune system.

Althaus used mathematical models and computer simulations to describe the dynamics of viral populations and immune responses. For example, he studied how chronic viral infections such as HIV are kept under control. The human immune system attempts to prevent the replication of viruses in various ways. The so-called cytotoxic T cells are capable of recognising and killing cells that have been infected with the virus. Althaus found that if cells are recognised and eliminated directly after infection before they start producing virus then the viral replication is considerably reduced.

Hiding from the immune response

Each time the virus infects a new cell it can change itself by mutating so that the newly infected cells are no longer recognised and destroyed. This process of 'immune escape' can reflect how strongly the immune system suppresses the virus. This is what led Althaus to study the speed at which these new and unrecognisable viral variants are generated and selected. He also found that HIV-infected cells might survive for a shorter period than expected until now, which means it is even more difficult for the immune system to recognise and destroy these cells.

This type of research is essential for an improved knowledge of viral infections. The models Althaus has developed provide a better understanding of why the immune system can sometimes effectively control viral infections and sometimes not. This opens up possibilities for further research into the immune system of people infected with HIV.

Christian Althaus has carried out this work as a member of Rob de Boer's research group. De Boer received a Vici grant from the NWO's Innovational Research Incentives Scheme in 2004. He aims to use this grant to set up a novel, quantitative approach to immunology.