Genetically Mutated Mice Capable of Avoiding HIV Infection
Mice that have been genetically reprogrammed to have human-like immune systems can be protected from HIV by boosting their production of certain broadly neutralizing antibodies, according to new research funded by US National Institutes of Health.
The mice in the study, referred to as "humanized mice" are capable of becoming infected with HIV and other human diseases. But by quieting certain antibodies in the humanized mice, researchers were able to prevent them from acquiring HIV in both instances of intravenous injection or vaginal infection.
California Institute of Technology researcher David Baltimore and his team discovered that by inserting the genes encoding the HIV-neutralizing antibody (known as VRC01) in to a vector, the virus infects the mice but does not cause the HIV disease.
Baltimore and his team used a tactic referred to as vectored immunoprophylaxis (VIP) to infect the mice with the altered HIV virus. The altered virus produced antibodies for an extended period of time.
In order to test how applicable this VIP approach would be on humans, the researchers tested the infecting the mice with HIV over a series of multiple low doses, which mimics the way humans would transmit the virus via sexual intercourse.
Over the course of two separate experiments, the researchers tested the humanized mice's ability to avoid HIV infection by a standard laboratory strain of the virus and a strain commonly transmitted among humans.
According to a news release: "Two of the 10 mice expressing VRC01 antibodies became infected with the laboratory strain of HIV after 13 to 15 exposures to the virus. In contrast, all nine mice without the antibodies were infected with HIV within six exposures. In the second experiment, researchers used a modified form of the VRC01 antibody, known as VRC07, and challenged the mice with an HIV strain known to be heterosexually transmitted among people. The mice expressing the VRC07 antibody were completely resistant to infection during repeated intravaginal challenge."
According to the researchers, these results, taken together, suggest that "VIP can protect mice from infection with strains of HIV that cause human disease and suggest that a similar strategy could be developed to reduce transmission in people."
The study appears in the journal Nature Medicine