Researchers discover how leukaemia virus spreads through the body

Researchers from Imperial College London, University of Oxford, Kagoshima University (Japan) and University of the Ryukyus (Japan) have discovered the mechanism by which human T-lymphotropic virus type 1 (HTLV-1), the virus which causes adult T-cell leukaemia, spreads through the body.

Previously it was not understood how HTLV-1 was able to spread between cells and pass between individuals, but according to research published today in Science, the virus spreads by subverting normal T-cell (a type of immune cell) behaviour, and without needing to release virus particles.

Professor Charles Bangham from Imperial College London at St Mary’s Hospital and senior author of the paper, comments: “The HTLV-1 virus affects between 10 and 20 million people worldwide with around two to three percent developing leukaemia. Although this research is not a cure, it does show how the virus is able to spread through the body, and infect other people. From this we hope to be able to develop more effective treatments for this fatal disease.”

The researchers used confocal microscopes to examine the distribution of HTLV-1 proteins and the genome in blood cells from HTLV-1 infected individuals, discovering that the HTLV-1 proteins and genome gather at the cell-cell junction, and are then transferred to the uninfected cell. This method of transfer is very efficient and helps the virus to avoid the immune system.

Most viruses spread through the body when an infected cell releases thousands of virus particles, which travel in the blood or other body fluids to infect other cells. HTLV-1 has evolved a different strategy of spreading: instead of releasing viruses, the infected cell itself moves round the body and transfers the virus to other cells when they make contact.

This new finding could also have implications for the development of new HIV/AIDS treatments. The HIV-1 virus is similar to HTLV-1, and HIV-1 may also be able to subvert immune cell physiology allowing the virus to spread between cells.

Professor Bangham adds: “HTLV-1 is a very similar virus to HIV. It is spread through the same methods, and if we can use this research to develop a way of treating HTLV-1, this research could be a crucial first step towards developing new, and more effective treatments to combat the global AIDS epidemic.”

The work was supported by the Wellcome Trust (UK).