False-colored scanning electron micrograph of HIV particles (yellow) infecting a human H9 T cell (blue, turquoise)
In some ways, HIV resembles a minimalist painter, using a few basic components to achieve dramatic effects. The virus contains just nine genes encoding 15 proteins, which wreak havoc on the human immune system. But this bare bones approach could have a fatal flaw. Lacking robust machinery, HIV hijacks human proteins to propagate, and these might represent powerful therapeutic targets.
Using a technique called RNA interference to screen thousands of genes, Harvard Medical School researchers have now identified 273 human proteins required for HIV propagation. The vast majority had not been connected to the virus by previous studies. The work appears online in Science Express on Jan. 10.
When ancient retroviruses slipped bits of their DNA into the primate genome millions of years ago, they successfully preserved their own genetic legacy. Today an estimated 8 percent of the human genetic code consists of endogenous retroviruses (ERVs)–the DNA remnants from these so-called “selfish parasites.”
Surprisingly, the infected hosts and their primate descendants also appear to have benefited from this genetic invasion, new evidence suggests. The ancient retroviruses–distant relatives of the human immunodeficiency virus (HIV)–helped a gene called p53 become an important “master gene regulator” in primates, according to a study published this week in the online early edition of Proceedings of the National Academy of Sciences.
In this cool animation the mode of action of a novel HIV drug, a protease inhibitor, is explained. Protease inhibitors revolutionized treatment of HIV infection by enabling drug combinations with inhibitors of another HIV enzyme the reverse transcription. Thus, this made it more difficult for virus to develop multiple mutations simultaneously to escape the effects of a single drug.
Amazing chemistry and rational drug design is involved in creating these new drugs.
Human resistance to a retrovirus that infected chimpanzees and other nonhuman primates 4 million years ago ironically may be at least partially responsible for the susceptibility of humans to HIV infection today.
“This ancient virus is a battle that humans have already won. Humans are not susceptible to it and have probably been resistant throughout millennia,” said senior author Michael Emerman, Ph.D., a member of the Human Biology and Basic Sciences divisions at the Hutchinson Center. “However, we found that during primate evolution, this innate immunity to one virus may have made us more vulnerable to HIV.”
A new category of drug has shown promising results for HIV/AIDS patients who failed to respond to other treatments, a study to be shows.
Especially when combined with other medications, raltegravir — the first in a new class of anti-retroviral drugs called integrase inhibitors — dramatically reduced the presence of the HIV virus and boosted immunity in clinical-trial patients, according to the study in the British journal The Lancet.
Continue reading “New HIV drug shows ‘unprecedented’ results”
This is an outstanding 3D animation of HIV replication cycle. I especially loved the entry part, which is like watching a science fiction movie.
The animation is fairly accurate representation of what we know about the this viruses life cycle today, except the part on entry of viral DNA into nucleus. Based on our current knowledge, import of viral DNA into nucleus is not dependent on integrase but other viral and host proteins that are still elusive. Integrase is however necessary for the integration of virus DNA into host genome.