Saturday December 7, 2019

Researchers Develop a New Vaccine to Stop Bovine TB

The Bacille Calmette Guerin (BCG) vaccine, which is currently used to protect humans against TB and is effective in cattle, is incompatible with the PPD test

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Bovine TB
This potentially allows farmers and veterinarians to protect their animals with the new BCG vaccine, whilst still maintaining a diagnostic test that will detect Bovine TB. Pixabay

Researchers have developed a novel vaccine and complementary skin test to protect cattle against bovine tuberculosis also known as Bovine TB.

The study, published in the journal Scientific Reports, revealed that the research team from University of Surrey created a vaccine that is compatible with a synthetic form of the tuberculin skin test(PPD), a legally required test used for the surveillance of TB in cattle throughout the UK.

“This new vaccine provides protection against bovine TB and will help in the fight against this deadly disease which infects over 50 million cattle worldwide and is economically devastating to farmers,” said study researcher Johnjoe McFadden

Bovine TB is an infectious disease in cattle affecting their lungs, and those that test positive for the disease are culled.

The Bacille Calmette Guerin (BCG) vaccine, which is currently used to protect humans against TB and is effective in cattle, is incompatible with the PPD test.

Bovine TB
Bovine TB is an infectious disease in cattle affecting their lungs, and those that test positive for the disease are culled. Wikimedia Commons

During this study, researchers sought to make a new BCG vaccine strain that lacks some of the proteins that are shared with the pathogen Mycobacterium bovis by identifying genes that contain encoded immunogenic proteins that could be removed from BCG without affecting its ability to work as a live vaccine.

To do this, a collection of BCG strains that had each lost a single gene were injected into cows and survival rates measured. This allowed the team to identify genes that could be removed without compromising the BCG vaccine’s effectiveness.

These dispensable genes encoding immunogenic proteins were then deleted from the BCG chromosome to make a BCG-minus strain.

The deleted immunogenic proteins were then used to develop a new synthetic skin test that, like PPD, will be positive for animals that have been exposed to TB but, unlike PPD, will be negative for animals that have been vaccinated with the BCG-minus strain.

The protective efficiency of the new strain was tested in guinea pigs.

Bovine TB
Researchers have developed a novel vaccine and complementary skin test to protect cattle against bovine tuberculosis also known as Bovine TB. Pixabay

It was found that TB-infected guinea pigs tested positive for the disease using the synthetic skin test whilst guinea pigs vaccinated with the BCG-minus strain did not.

So, unlike PPD, the new skin test also works in animals that are protected from TB by BCG-minus vaccination.

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This potentially allows farmers and veterinarians to protect their animals with the new BCG vaccine, whilst still maintaining a diagnostic test that will detect TB. (IANS)

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Genetic Variations Influence Risk of Developing Cancer: Study

Study found that variations in the regions that regulate the expression of oncogenes and tumour suppressor genes affect cancer risk

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Cancer
While minor genetic changes only have a small impact on Cancer risk, the variations analysed in this study are numerous and common in the population. Pixabay

Shedding new light on why some people develop cancer while others do not, a new study has found that a person’s risk of developing cancer is affected by Genetic variations in regions of DNA that do not code for proteins, previously dismissed as “junk DNA”.

This study, published in the British Journal of Cancer, shows that inherited cancer risk is not only affected by mutations in key cancer genes, but that variations in the DNA that controls the expression of these genes can also drive the disease.

The researchers believe that understanding how non-coding DNA affects the development of this disease could one day improve genetic screening for cancer risk.

And in the future, this could lead to new prevention strategies, or help doctors diagnose the disease earlier, when it is more likely to be treated successfully.

“What we found surprised us as it had never been reported before — our results show that small genetic variations work collectively to subtly shift the activity of genes that drive cancer,” said lead researcher of the study John Quackenbush, Professor at Harvard T.H. Chan School of Public Health in the US.

Genetic
Shedding new light on why some people develop Cancer while others do not, a new study has found that a person’s risk of developing cancer is affected by genetic variations in regions of DNA that do not code for proteins, previously dismissed as “junk DNA”. Pixabay

“We hope that this approach could one day save lives by helping to identify people at risk of cancer, as well as other complex diseases,” Quackenbush said.

The researchers investigated 846 genetic changes within non-coding stretches of DNA, identified by previous studies as affecting cancer risk.

These Single Nucleotide Polymorphisms (SNPs) are particular positions in the human genome where a single letter of the genetic code varies between people.

Unlike mutations in coding DNA, such as BRCA, that are rare but significantly raise a person’s risk of developing cancer, non-coding SNPs are relatively common in the population but only slightly increase cancer risk.

The team analysed whether there was a correlation between the presence of a particular SNP and the expression of particular genes.

In total, they looked at over six million genetic variants across 13 different body tissues.

Genetic
The researchers believe that understanding how non-coding DNA affects the development of this disease could one day improve genetic screening for cancer risk. Pixabay

They found that variations in the regions that regulate the expression of oncogenes and tumour suppressor genes affect cancer risk.

The study also revealed that these cancer-risk SNPs tend to be specifically located in regions that regulate the immune system and tissue-specific processes — highlighting the importance of these cellular processes to the development of cancer.

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“While minor genetic changes only have a small impact on cancer risk, the variations analysed in this study are numerous and common in the population,” said Emily Farthing, senior research information manager at British charity Cancer Research UK. (IANS)