Helping the immune system thwart infections

Yale researchers have developed a set of synthetic molecules that may boost the strength of a key, virus-fighting protein. The protein, RIG-I, is an important sensor in the immune system of humans and other animals. It recognizes and responds to viral RNA by surrounding it, latching onto it, and launching the immune system into action.

The Yale team, led by biologists Anna Pyle and Akiko Iwasaki, has designed molecules that jump-start the process. These synthetic, stem-loop RNA (SLR) molecules can be visualized as short cords with a knot at one end. The configuration enables the SLRs to bind with RIG-I molecules in a way that prompts an aggressive response.

"When you tickle RIG-I with this small, RNA hairpin, it alerts the body that it's time to respond," said Pyle, professor of molecular, cellular, and developmental biology, and of chemistry. This gives a tool that can help with everything from the design of better vaccines to better antivirals and anti-cancer therapies.The new study represents the first time scientists have been able to specifically manipulate and analyze the RIG-I biosensor in a living animal-mice.
          haleplushearty.blogspot.com

Flu may be spread by breathing

It is easier to spread the influenza virus (flu) than previously thought, according to a new University of Maryland-led study. People commonly believe that they can catch the flu by exposure to droplets from an infected person's coughs, sneezes or by touching contaminated surfaces. But, new information about flu transmission reveals that flu may be pass to others by breathing.

Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community provides new evidence for the potential importance of airborne transmission because of the large quantities of infectious virus researchers found in the exhaled breath from people suffering from flu. Flu cases contaminated the air around them with infectious virus just by breathing, without coughing or sneezing.

People with flu generate infectious aerosols (tiny droplets that stay suspended in the air for a long time) even when they are not coughing, and especially during the first days of illness. Researchers from the University of Maryland, San Jose State University, Missouri Western State University and University of California, Berkeley contributed to this study.

Dr. Milton and his research team captured and characterized influenza virus in exhaled breath from people with influenza during natural breathing, prompted speech, spontaneous coughing, and sneezing, and assessed the infectivity of naturally occurring influenza aerosols. The participants provided nasopharyngeal swabs and 30-minute samples of exhaled breath, spontaneous coughing, and sneezing on the first, second, and third days after the onset of symptoms.

The analysis of the infectious virus recovered from these samples showed that a significant number of flu patients routinely shed infectious virus, not merely detectable RNA, into aerosol particles small enough to present a risk for airborne transmission. Surprisingly, 11 (48%) of the 23 fine aerosol samples acquired in the absence of coughing had detectable viral RNA and 8 of these 11 contained infectious virus, suggesting that coughing was not necessary for infectious aerosol generation in the fine aerosol droplets.

In addition, the few sneezes observed were not associated with greater viral RNA copy numbers in either coarse or fine aerosols, suggesting that sneezing does not make an important contribution to influenza virus shedding in aerosols. Keeping surfaces clean, washing of hands all the time, and avoiding people who are coughing does not provide complete protection from getting the flu. Isolation of infected people from public places can reduce the spread of  the influenza virus.
          haleplushearty.blogspot.com

Defective HIV proviruses prevent cure

Proteins created by defective forms of HIV associate with immune systems are monitored by cytotoxic T cells.

HIV proviruses are many in HIV patients, the faulty proteins they produce can hinder measurement of viral load, exhaust immune systems and prevent suppression of the virus.

Researchers are trying to hypermutate the proviruses and destroy defective HIV proviruses and develop cure for HIV infection.

Scientists collected defective HIV proviruses from 9 HIV patients and transfected cultures of human immune cells in laboratory.

It was discovered that the transfected human immune cells were capable of making HIV protein despite mutations.

Defective proviruses contribute to viral RNA and protein production and increase the viral load of HIV patients.