Bringing Prevention Communities Together in Cape Town

HIV R4P organizers carry high hopes for the first conference attempting to knit together all HIV prevention efforts, says conference co-chair, Sharon Hillier, a University of Pittsburgh professor of obstetrics, gynecology, molecular genetics, and biochemistry.

“We’re hoping for cross-fertilization among fields,” Hillier says. An increasingly important focus as advances in each area will increasingly affect the other. On bringing vaccine, microbicide, and pre-exposure prophylaxis researchers together, Hillier says there were some tense times, but overall she says it’s been a pleasure. “We share many of the same goals.”

This confluence is prompted in part by advances such as increasing success in isolating broadly neutralizing monoclonal antibodies for vaccine research; the ongoing Phase III FACTS 001 trial, which if it confirms the results of an earlier microbicide trial (CAPRISA 004) may lead to the first topical microbicide gel licensed to prevent HIV infection and infection with the virus that causes genital herpes in women; and the recent approval of the pre-exposure prophylaxis drug Truvada.

Some 1,300 researchers are in Cape Town for HIV R4P, their eyes open for potential new data or information about the FACTS 001 trial, updates on follow-up studies to the RV144 vaccine trial of what remains the only vaccine candidate to show any success in preventing HIV infection, and updates on rolling out pre-exposure prophylaxis in different kinds of communities. “Some sex workers are against the use of it,” Hillier says. “They say it undermines their leverage when insisting on condom use.”

But before the official opening of the conference, delegates gathered for a series of satellite symposia. In one, Deborah Anderson, a Boston University professor of obstetrics and microbiology, led a group parsing the fine points of cell-associated transmission of HIV. For all the years and effort spent studying HIV, scientists are still not exactly certain how the virus is transmitted. After initial efforts examining whether the virus was contained inside cells and somehow breached and infected others, hiding from antibodies as if inside a wooden horse, most research focused on free virus mutating and disguising itself from antibodies while moving freely or lying dormant.

Anderson and a group of a little over a dozen researchers continue to consider cell-associated human transmission. “We’ve been doing this for 30 years,” she says. “We’re a hardcore lot.” The group held a workshop last year for the first time and is planning another. Boston University obstetrics and gynecology professor Joseph Politch, whose research examines the continued presence of HIV virus in the semen of even those on highly active antiretroviral regimens, argued that HIV infection of macrophages made genital secretions an environment favorable to virus transmission, while Gilda Tachedjian of the Burnet Institute shined light on varying levels of acidity in the vaginal environment and its effect on vaginal microbiota as a variable in providing a haven for HIV. Anderson and Boston University immunocytochemist Jeffery Pudney both made reference to mid-90’s work from former Population Council researcher David Phillips showing HIV-infected lymphocytes forming ‘pseudopods’ or ‘viral synapses’ between cells.

Perhaps this is one way HIV gets around, Anderson says, and failure to account for this could be a reason why HIV vaccine candidates have such a hard time of it. “Just putting it out there,” she says. – Michael Dumiak