Breaking News
December 17, 2017 - Breathing exercises help asthma patients with quality of life
December 17, 2017 - Researchers explore how toxic protein clusters linked to Parkinson’s disrupt brain cells
December 17, 2017 - Autism traits linked to risk of depression, suicidal thoughts in people with psychosis
December 17, 2017 - Jimmie Holland’s Long Medical Odyssey
December 17, 2017 - Controversial MS Treatment Found to Be Ineffective: MedlinePlus Health News
December 17, 2017 - Time of day affects test results for asthma, researchers find
December 17, 2017 - Scientists create atomic scale map that tracks how brain signals connect to neurons
December 17, 2017 - Tips for buying safe toys during the holidays – and year-round
December 17, 2017 - CardioBrief: Will Entresto Sell Big After All?
December 17, 2017 - Water baths as good as bleach baths for treating eczema
December 17, 2017 - Valley fever cases see sharp increase in November, say UVA experts
December 17, 2017 - New Insight on Killer Fungus Threatening Bats
December 17, 2017 - Early Atherosclerosis Defies ‘Normal’ Cholesterol
December 17, 2017 - CRF1 stress receptor is regulator of mast cell activity during stress
December 17, 2017 - CREST Failed to Dampen Enthusiasm for Carotid Stenting in Elderly
December 17, 2017 - Rising levels of HIV drug resistance
December 17, 2017 - Aging brain’s failure to coordinate deep-sleep brainwaves makes older adults forget
December 17, 2017 - Rural Workers Have Higher Exposures to COPD-Causing Pollutants
December 17, 2017 - Don’t Delay Hip Fracture Surgery. Here’s Why: MedlinePlus Health News
December 17, 2017 - NIH launches HIV prevention trial of long-acting injectable medication in women
December 17, 2017 - Op-Ed: Get Ready for a Tsunami of ECGs
December 17, 2017 - Observation care may save more than thought
December 17, 2017 - Scientists explore effectiveness of action video games to combat dyslexia
December 17, 2017 - Teens Acting Badly? Smog Could Be to Blame
December 17, 2017 - FDA Says ‘Yes’ to Short-Acting Insulin Admelog
December 17, 2017 - Vaping popular among teens; opioid misuse at historic lows
December 17, 2017 - Lower Urinary Symptoms Occur in Almost All Patients with SSc
December 17, 2017 - Genetic mutation in extended Amish family in Indiana protects against aging and increases longevity (Update)
December 16, 2017 - Butler Hospital launches international Alzheimer’s disease prevention study
December 16, 2017 - iMedicalApps: Virtual Reality Boosts Self-Confidence for Med Students
December 16, 2017 - Researchers validate five new genes responsible for Amyotrophic Lateral Sclerosis
December 16, 2017 - New genetic analysis of candidiasis reveals surprising fungal sex secrets
December 16, 2017 - New high precision machine-learning model could help accelerate drug discovery
December 16, 2017 - Groundbreaking gene therapy trial brings cure for hemophilia closer
December 16, 2017 - Racial Differences Seen in IgG4 Disease
December 16, 2017 - Treacher Collins Syndrome
December 16, 2017 - New approach to tracking how deadly ‘superbugs’ travel could slow their spread
December 16, 2017 - Muscle paralysis may promote breakdown of bones
December 16, 2017 - WSU scientists create injectable dye to track progression of diseases
December 16, 2017 - Kaiser Permanente delivers clot-busting drugs to stroke patients more than twice as fast as national rates
December 16, 2017 - Some Great Holiday Foods for Weight Loss
December 16, 2017 - Shared Decision-Making Strategies for Lung Ca Screening Get High Marks
December 16, 2017 - Lactic acid bacteria can protect against Influenza A virus, study finds
December 16, 2017 - Cancer immunotherapy’s effectiveness may depend on patient’s genetic makeup
December 16, 2017 - Researchers explore patient-doctor conversations, best practices linked to opioid tapering
December 16, 2017 - ‘Virtual child’ to help professionals learn key techniques to treat children with autism
December 16, 2017 - IU scientists discover way to make drug treatment more successful against malaria
December 16, 2017 - Prostate cancer researchers find significant disparities between two liquid biopsy providers
December 16, 2017 - ED-Diagnosed Lung Ca Patients Worse Off: Clin Onc News Report
December 16, 2017 - Calcium in Urine Test: MedlinePlus Lab Test Information
December 16, 2017 - Pregnancy-related conditions taken together leave moms—and dads—at risk
December 16, 2017 - Research uncovers mechanism implicated in defective function of tumor-associated dendritic cells
December 16, 2017 - OncoBreak: Stubborn Racial Disparities; Paid Medical Leave & Chemo; DIY Gene Tests
December 16, 2017 - Critical link between obesity and diabetes has been identified
December 16, 2017 - Transfusion dependence reduces access to high-quality end-of-life care for leukemia patients
December 16, 2017 - Porvair and Suzhou Tianlong Bio to develop epigenetic analysis technologies
December 16, 2017 - FDA Approves Ixifi (infliximab-qbtx), a Biosimilar to Remicade
December 16, 2017 - Morning Break: Trump to Get Check-Up; Cancerous Transplant; Death Knell for MIPS?
December 16, 2017 - First transcatheter implant for diastolic heart failure successful
December 16, 2017 - ‘Sushi-like’ nanodiscs provide structural snapshots of misfolding proteins
December 16, 2017 - Inherited gene variation may be to blame for poor survival of patients with early-onset breast cancer
December 16, 2017 - Sign-up deadline is Friday, but some people may get extra time
December 16, 2017 - Higher Booze Taxes Might Pay Off for Public Health
December 16, 2017 - Regular Activity in Midlife Spares Joints in Women
December 16, 2017 - Rain May Not Cause Achy Joints After All: MedlinePlus Health News
December 16, 2017 - MedDiet adherence doesn’t affect acute heart failure mortality
December 16, 2017 - HKBU experts develop new generation of smart anti-cancer drug molecules
December 16, 2017 - Chronic Kidney Disease Audit finds wide variations in coding of CKD patients in primary care
December 16, 2017 - Scientists use nanoparticles to fight Mucoviscidosis
December 16, 2017 - Increasing physical activity decreases risk of death from lymphoma
December 16, 2017 - Fear compromises the health, well-being of immigrant families, survey finds
December 16, 2017 - Rejected antibiotic candidate could be worth a second look, research finds
December 16, 2017 - Is Nation on the Right Track to Combat Opioid Crisis?
December 16, 2017 - Arthritis No Longer Just a Disease of the Old: MedlinePlus Health News
December 16, 2017 - Study reveals biology behind why muscle stem cells respond differently to aging or injury
December 16, 2017 - Family members without inherited mutation have increased risk of melanoma
December 16, 2017 - Researchers reveal previously unknown mechanism that inhibits cells’ ability to develop into tumors
December 16, 2017 - Studies highlight potential of fMRI applications to detect, treat epilepsy in children
December 16, 2017 - Active surveillance proposed as first-line approach to manage patients with low-risk PMC of the thyroid
December 16, 2017 - Patients’ life values affect their attendance at medical treatment for pelvic-floor dysfunction
Altering genetic mutation could enhance FluMist vaccine’s protective effect

Altering genetic mutation could enhance FluMist vaccine’s protective effect

image_pdfDownload PDFimage_print

Researchers at Johns Hopkins Bloomberg School of Public Health have discovered a genetic mutation in the FluMist intranasal flu vaccine that has the potential to be altered to enhance the vaccine’s protective effect.

This flu season marks the second that the panel that advises the Centers for Disease Control and Prevention (CDC) on vaccines has recommended that FluMist not be used in the U.S. The Advisory Committee on Immunization Practice found that the vaccine had grown less effective in recent years, possibly due to shifts in circulating flu strains, and researchers have been searching for ways to restore its effectiveness.

In the new study, the Bloomberg School researchers discovered a previously overlooked mutation, present within two of the viral strains used in the vaccine, that reduces virus production. When the researchers reversed the mutation in one of the viruses, the virus became more active, making copies of itself – which is known as replicating – more quickly in cultured human nasal cells and inducing a stronger production of immune proteins.

The findings appears in the journal Vaccine.

“Only one component of FluMist – the one targeting the Type A H1N1 virus – has been failing in the U.S. recently,” says Andrew S. Pekosz, PhD, professor in the Bloomberg School’s Department of Molecular Microbiology and Immunology. “It’s not clear exactly why it has failed but this mutation we identified could be used to make that component of the vaccine a little stronger, thereby improving vaccine efficacy. We now see the possibility of altering this mutation and perhaps others in the vaccine to optimize the vaccine’s protective effect, perhaps for different age groups.”

Three types of influenza viruses affect people, Type A, Type B and Type C, and flu vaccines include a mix of virus strains tailored to anticipate the upcoming flu season. The CDC estimates that over the past seven years, flu viruses have caused 9.2 million to 60.8 million illnesses, 140,000 to 710,000 hospitalizations, and 12,000 to 56,000 deaths annually in the U.S. Across the globe, there are an estimated three to five million cases of severe flu cases and about 250,000 to 500,000 deaths.

The FluMist vaccine, also known as LAIV (live, attenuated influenza vaccine) is made from four weakened flu virus strains, two representing the influenza A type, and two representing the influenza B type. Two segments of the strains used in the vaccine are altered periodically to match the strains of influenza circulating in the population.

The non-varying parts of the vaccine are made from a special, cold-adapted H2N2 strain that is known to contain mutations that slow its replication at the temperatures found in the human nose and throat. That slowing of activity is largely what keeps these vaccine strains from causing illness in people, although they remain active enough to induce at least partial immune protection against future influenza A infections.

Scientists in previous studies have linked the slower replication of this cold-adapted strain to changes in three virus genes. However, there have been hints in recent years, from Pekosz’s work and others’, that another gene encoding a viral protein called M2 may also contribute to this effect.

“We had studied M2 for years, but one day recently a student in my lab noticed that the M2 in the LAIV influenza A viruses contains a mutation in the same part of the protein that we had previously identified as affecting viral replication,” Pekosz says.

The researchers found that when they introduced this same mutation into a strain of influenza A virus that normally doesn’t have it, the replication rate of the virus dropped. Alternate mutations at the same site on the M2 gene also resulted in a slowing of viral replication.

The team then did the opposite experiment, starting with a FluMist influenza A strain and reversing the M2 mutation. They found that this enhanced the replication rate of the strain in human nasal cells.

The enhanced activity of the virus also led to a jump in production, in infected cells, of the immune protein interferon lambda, indicating an increased immune response. The result showed in principle that this mutation site, and perhaps others on the virus, may be used as “dimmer switches” to adjust the vaccine’s strength up or down–so that it induces a robustly protective immune response without also causing illness.

“What we’re trying to do now is make a panel of these LAIV viruses with different mutations to see if we can boost the replication rates to get vaccine formulations that protect children and other age groups better than LAIV has done in the past few years,” Pekosz says.

Source:

https://www.jhsph.edu/news/news-releases/2017/genetic-mutation-could-if-altered-boost-flumist-vaccine-effectiveness-research-suggests.html

Tagged with:

About author

Related Articles