people health life 25

Now, a team of scientists at UC Santa Cruz and the National Institutes of Health has obtained the first glimpse of the molecular mechanism by which recognition of an antigen (such as a viral protein) by the T cell receptor triggers the first steps leading to an immune response. The new findings, published May 16 in  Nature Communications , implicate changes in the molecular structure of the T cell receptor that propagate from the antigen recognition site on the outside of the cell to a signaling site inside the cell. The activation signal then triggers a complex "signaling cascade" within the T cell, leading to a range of possible responses by the cell. "This provides the first hint of the mechanism that triggers that signaling cascade," said Nikolaos Sgourakis, assistant professor of chemistry and biochemistry  at UC Santa Cruz and co-senior author of the paper. "We don't yet have a full reconstruction of the signaling system, but for the first time ...

"Our study suggests that HLA-B*46:01 may provide protection against severe leprosy because it is better adapted to present pathogen-derived peptide antigens for immunosurveillance by the immune system," says lead author Hugo Hilton of Stanford University School of Medicine . "The findings may explain why HLA-B*46:01 evolved 50,000 years ago and spread to become one of the most prevalent immunity gene variants in Southeast Asia." Population expansion, cultural changes, and migration during the last 100,000 years exposed humans to pathogens against which they had not evolved effective resistance. Due to strong selective pressure, human leukocyte antigen (HLA) genes have evolved to provide immunity against diverse and rapidly evolving pathogens. "New HLA gene variants, or alleles, are thought to arise in human populations during episodes of Darwinian selection, but there is little direct evidence for the nature of this process," says senior study author ...

This new research paves the way for vaccines that, as opposed to conventional methods, boosting the parts of the immune system attacking the viral genes, which are the least active during the infection. This prolongs the resistance of the immune system to the virus. Traditional vaccines typically cause a strong stimulation of the parts of the immune system, that are most responsive to the specific virus. But the reaction to the vaccine and the infection is often so intense that the immune system 'loses momentum' and consequently is not able to completely eliminate the virus. Researchers have therefore designed a vaccine which boosts the cells of the immune system responsible for the less exposed parts of the virus. As a result, the cells are able to distribute the 'work load' and retain the defense against the virus attack for a longer period of time. This gives the immune system time to build a more efficient defense, which may then defeat the remaining of the vir...

In a new, follow-up study published in the journal  Prevention Science , Ayers and colleagues found that not only did Sheen's disclosure lead people to seek information about HIV, it also corresponded with record levels of at-home rapid HIV testing sales. The team collected data on weekly sales of OraQuick, the only rapid in-home HIV test kit available in the United States, to investigate whether Internet queries (based on Google Trends data on searches with "test," "tests," or "testing" and "HIV") could be correlated with any uptick in HIV testing. "Our strategy allowed us to provide a real-world estimation of the 'Charlie Sheen effect' on HIV prevention and contrast that effect with our past formative assessment using Internet searches," said study coauthor Eric Leas, a research associate in the SDSU-UCSD joint doctoral program in public health. The week of Sheen's disclosure coincided with a near doubling in O...

DOT is a strategy to ensure that people with TB adhere to a long and challenging drug regimen by having someone observe and record the taking of all medicines. MDR TB is resistant to at least isoniazid and rifampin, two of the main therapeutic agents used to treat TB. "Directly observed therapy is already recommended to treat all forms of TB, but it's valuable to have this data on the effectiveness among patients with MDR TB," said Jorge Salinas, MD, lead study author and epidemic intelligence service officer in the Centers for Disease Control and Prevention's Division of Tuberculosis Elimination. "We wanted to assess whether the strategy influenced mortality in MDR TB patients." The researchers analyzed data from 1993-2013 for 3,434 MDR TB patients, 709 of whom died during the follow-up period. The proportion of patients on DOT increased from 74 percent during 1993-2002 to 95 percent during 2002-2013. Among MDR TB patients in the study: 34 percent...

"There's an opioid epidemic in our country, and there's a real public health crisis associated with injecting," said Cora Bernard, a graduate student in management science and engineering. "We think it's important to understand what investments give highest value because HIV prevention programs, and especially programs that reduce the prevalence of injection drug use, can have outsized, positive impact on individuals, families and public safety." Bernard is the lead author of a study on prevention programs that could head off a resurgence of HIV and perhaps decrease the effects of the opioid crisis. The study will be published online May 24 in  PLOS Medicine . The senior author is Margaret Brandeau, PhD, professor of management science and engineering. In July 2016, Bernard and her co-authors published a different study examining pre-exposure prophylaxis, or PrEP, a pill that reduces a person's risk of infection when they come into contact with...