Immunology

Humans have a built-in weapon against HIV, but until recently no one knew how to unlock its potential. A study published in Nature reveals the atomic structure of this weapon, an enzyme known as APOBEC-3G, and suggests new directions for drug development. APOBEC-3G is present in every human cell. It is capable of stopping HIV at the first step of replication, when the retrovirus transcribes its RNA into viral DNA. The study's authors, led by Xiaojiang Chen of the University of Southern California, were able to show the atomic structure of the active portion of APOBEC-3G. The discovery…

It used to be that being buried under a pile of large, sweaty men was the worst thing that could happen to you playing Rugby - but then it turned out a herpes virus can cause a skin disease called "scrumpox" and it spreads through physical contact. Researchers have discovered that a new strain could be even more pathogenic - and it's now also found among sumo wrestlers in Japan. "Scrumpox", or herpes gladiatorum, is a skin infection caused by the herpes virus, which can cause coldsores. It is spread through direct skin-to-skin contact so it is common among rugby players. Symptoms can start…

For a long time scientists have been puzzled by the fact that the immune system in the gut is capable of fighting toxic bacterial infection while staying, at the same time, tolerant to its resident “friendly” bacteria. But an article now published in the journal Cell Host & Microbe(1) is starting to open the door to this mystery by revealing how a recently discovered gene - pims – is activated by the gut immune response against friendly bacteria to rapidly suppress it, effectively creating tolerance to the gut microbiota. In the same way pims is also shown to control the magnitude of…

Dr. Ed Corboy had no idea what was afflicting his 80-year-old mother, Joan Corboy. All he knew for certain was that since being treated for what was a routine diarrheal infection, she seemed to be wasting away and none of her doctors or other health specialists could explain why. Afraid that his mother was running out of time, Corboy called the Centers for Disease Control in Atlanta for advice. Dr. Clifford McDonald told him the infection his mother probably had was of the NAP1 type of the bacteria Clostridium difficile, a virulent strain of a common intestinal bacteria currently plaguing…

Researchers at Johns Hopkins say they have compelling evidence that some people with HIV who for years and even decades show extremely low levels of the virus in their blood never progress to full-blown AIDS and remain symptom free even without treatment, probably do so because of the strength of their immune systems, not any defects in the strain of HIV that infected them in the first place. They say this finding renews promise of vaccine against AIDS and disproves the theory of a defective virus. The theory about these so-called elite suppressors published in the Journal of Virology comes…

High levels of testosterone may be a key factor in spreading disease among mice, according to biologists. The findings could help explain why males in a population are often more likely to get infected, and transmit disease. Previous research has linked testosterone, the male sex hormone, to immune system suppression. Studies have shown that males, compared to females, experience more bouts of disease, and account for a larger share of disease transmission. However, it is not fully clear what makes males such super-spreaders of disease. "We know that testosterone makes males more…

University of Minnesota researchers have answered a key question as to why antiretroviral therapy isn't effective in restoring immunity in HIV-infected patients. Once a person is infected with the virus, fibrosis, or scarring, occurs in the lymph nodes – the home of T cells that fight infection. And once fibrosis occurs, T cells can't repopulate the lymph nodes when HIV therapy begins, said Timothy Schacker, M.D., professor of medicine and principal investigator on the study. "Importantly, we discovered that this fibrosis occurs more rapidly and to a greater extent in the portion of the gut…

Tijuana, with an estimated population of 1.4 million, is the largest city on the U.S./Mexican border. In addition to being a major transportation route for migrants headed to the United States, Tijuana is also situated on a major drug trafficking route. It is home to Mexico's largest number of drug users per capita and to a thriving zona roja (red light zone), work district of the city's estimated 5,000 female sex workers. These factors have contributed to Tijuana's growing epidemic of HIV and other sexually transmitted infections. The study compared HIV infection among male and female…

Scientists hope a vaccine is on the horizon for tularemia, a fatal disease caused by the pathogen Francisella tularensis, an organism of concern as a potential biological warfare agent. Until recently we knew very little about this bacterium. However, according to the August issue of the Journal of Medical Microbiology, research on the bacterium has been reinvigorated and rapid progress has been made in understanding how it causes disease. Infection with F. tularensis can result in a variety of symptoms, depending on the route of infection. For example, infection via an insect bite can lead…

Typhoid fever kills 10–30% of untreated people. One of the best-known cases was that of Mary Mallon, a healthy carrier of typhoid, who worked for many years in the food industry in New York and is thought to have infected almost 50 people. She was eventually forcibly quarantined by authorities and named Typhoid Mary. There are 17 million cases of Typhoid fever each year - although the World Health Organization cautions that this is a 'very conservative' estimate. Young people are most at risk: in Indonesia, nine out of ten cases occur in 3–19-year-olds. It has been controlled by vaccination…