VATIS UPDATE Article

According to researchers at University of Adelaide’s Basil Hetzel Institute for Translational Health Research, Australia, a recombinant rhinovirus (common cold virus) used along with an injection of DNA-based vaccine can activate the immune system against transmission of human immunodeficiency virus (HIV) via mucosal sites. Results from a mouse model trial may help develop effective mucosal HIV-1 vaccines in the future. Unlike previous vaccine trials, the new approach offers protection at mucosal sites – vaginal or rectal – that are most likely to encounter the virus first.

“Our vaccine approach aims at making the antibodies inhibit the HIV Tat (Transactivator of HIV gene expression) effect, thereby preventing the HIV virus from replicating. We believe that our strategy may be more effective than other studies for three reasons: Our vaccine will elicit mucosal immunity to Gag (The capsid proteins or group specific antigens) and Tat; systemic immunity to Tat; and cell-mediated immunity to Gag and Tat,” said lead researcher Eric Gowans. This approach may provide a novel strategy to prevent HIV infection.

Approximately 80 per cent of HIV infections are the result of mucosal transmission. A recent study from Switzerland suggested that although broadly neutralising antibodies to Env (envelope proteins) developed in a small number of patients, these were dependent on a high viral antigen load for many years and viral diversity criteria that cannot be achieved with current vaccine strategies. “Most HIV vaccines are designed to elicit systemic immunity to the Env, which can mutate rapidly. The Gag and Tat proteins are more highly conserved,” Gowan added.