RESEARCH NOTES
PREVENTION
(ALL IMAGES) THINKSTOCK
Genetically Tooled Antibodies Fight HIV
Engineering immune cells to produce what are known as broadly neutralizing antibodies (BNAs) protects against HIV infection in mice that have immune systems tooled to resemble those of humans. BNAs prevent infection by blocking the receptors HIV uses to latch onto human cells. About one in five people produce them in response to HIV, but usually do so too late to thwart a lifelong infection. The researchers in this study infected mice with a harmless virus, called a vector, that had been developed to deliver a genetic code to the animals’ immune cells, prompting them to produce BNAs over an extended period. The mice were then repeatedly exposed to HIV. One experiment was partially successful at preventing infection with a laboratory strain of HIV. In another, the researchers used a modified form of the vector and found that it was totally successful at preventing infection with a strain of HIV known to transmit heterosexually in humans.
TREATMENT
Benefit of Counseling With Computers A computerized counseling program for people with HIV improves treatment adherence and reduces viral load and risky sexual behavior. A Seattle study looked at a computer-based program called CARE+ that counseled study participants about treatment adherence, HIV disclosure, safer sex, condoms, substance abuse and the way that adherence affects viral load. After a nine-month period, there were various modest but significant differences between those who received the counseling and the control group who did not. The greatest benefits were found among those starting the study with a detectable virus, who were more likely to reach full suppression if they used CARE+. The counseling group’s adherence rate was 13 points higher than the control group on a scale of 0 to 100, while the control group appeared to dip slightly in adherence. The counseling group also appeared to nearly cut in half their number of risky sexual acts.
BY BENJAMIN RYAN
CURE
CONCERNS
Long-living, HIV-infected immune cells that have stem-cell-like properties— meaning they self-renew and produce new cells— appear to be a bedrock of the viral reservoir that prevents antiretroviral (ARV) treatment from clearing the virus. Scientists examined blood samples taken from people newly infected with HIV and again after six to 10 years of treatment. Comparing the genetics of the T memory stem cells between the samples, they found no great difference in the viral sequences. This suggested that the otherwise fast-mutating virus remained in these cells without significant changes for years. Also, the amount of HIV DNA found in these cells remained essentially constant over time, regardless of HIV treatment’s success at depleting viral levels in other types of immune cells. In fact, in those taking ARVs the amount of HIV DNA was the highest in their T memory stem cells. The conclusion is that these cells can continuously produce new HIVinfected immune cells while dodging ARV treatment.
Teens and young adults with HIV often delay entering medical care for the virus until late in the course of their disease. Combing the records of nearly 1,500 HIV-positive 12- to 24-yearolds seen in clinics between 2002 and 2010, researchers found that 30 to 45 percent of them sought treatment after their CD4 levels had dropped below 350. Recent research has found manifold benefits to starting HIV therapy before crossing that threshold. This new study found that those entering care with lower CD4 counts tended to have higher viral loads, making them more likely to pass along the virus. Black youths were more than twice as likely as white ones to start care with low CD4s, and Latinos were 1.7-times as likely to do so as whites. Males were more likely than females to seek care late. And men infected heterosexually tended to enter care later than those infected through sex with men.
Memory Stem Cells: Reservoir Backbone?
Youths With HIV Enter Care Late
poz.com JUNE 2014 POZ 27