Saturday, September 1, 2012

Partners in crime: T Follicular Helper Cells assist HIV in thwarting the immune system


Antibodies play an essential role in protecting against viral infection by preventing viral entry into host cells and eliminating cells infected with virus. A few viruses, including HIV and SIV, have developed mechanisms to evade the body's antibody response, allowing the virus to persist and making it very difficult to develop effective vaccines.
In this issue of the Journal of Clinical Investigation, two research groups report that accumulation of a type of immune cell known as T follicular helper (TFH) cells accumulate during HIV and SIV infection to help the viruses escape antibody-mediated immune responses.
Hendrick Streeck and his colleagues at Harvard Medical School found that there was significant increase in the number of TFH cells in patients with chronic HIV infections. The extra TFH cells were associated with alterations in the development of B cells, which are responsible for antibody production in response to viral infections.
Constantinos Petrovas's group at NIH discovered that the gene profile of TFH cells in SIV-infected rhesus macaques, demonstrating that TFH cells are highly susceptible to SIV infection.
In a companion piece, Carola Vinuesa of the Australian National University in Canberra, AU discusses the implications of these findings for the development of new HIV therapies.
TITLE: Expansion of HIV-specific T follicular helper cells in chronic HIV infection

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