Scientists Develop New Vaccine Candidates Against Deadly Plague

New vaccine candidates are developed using mutant versions of Yersinia pestis bacteria for treatment of plague.

A research team from the University of Texas Medical Branch at Galveston have developed new vaccines which is capable of protecting animals from the deadly plague bacteria.

Yersinia pestis, the bacteria that is responsible for plague infection is considered as a re-emerging pathogen by the World Health Organization (WHO) due to increased number of plague cases in the world. Bubonic, septicemic and pneumonic are the three different kinds of plague caused by the bacteria in the lymph nodes, blood vessels and in the lungs respectively.

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‘Mutant bacterial strains of Yersinia pestis can be used for developing new vaccine candidates against plague.’

Select agents are usually potential agents used in bioterrorism and warfare and Tier 1 is labeled for agents that pose risk to the public health. The Centers for Disease Control and Prevention has classified Yersinia pestis strains as a Tier - 1 select agent since antibiotic- resistant Y.pestis strains from plague patients can be used as bioweapons.

Ashok Chopra, professor of microbiology and immunology at the Univeristy of Texas at Medical Branch said that "The optimal strategy for protecting people and animals against this deadly disease would be through vaccination, but there are no FDA-licensed plague vaccines available in the U.S."

"We've been working to develop a vaccine that will generate long-term immunity and protection against the plague" he said.

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New strains of Y.pestis bacteria were designed by scientists to provide immunity against plague without causing any illness. This was mainly done by deleting and modifying few genes. The immune response was examined after immunization and the duration of immune protection in mice and rats against the plague was tested.

The findings suggested that all three possible vaccines were found to produce long-lasting immune response for a period of 4 -5 months after immunization.

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Chopra said that,"In addition to how well a vaccine works to protect against disease, safety is another important aspect for vaccine development."

The researchers also said that the mutant versions of the bacteria were found to be safe vaccine candidates as there was no sign of tissue damage in vaccinated animals.

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Source-Medindia