Killer T cells for better dengue protection
A team of researchers led by Associate Professor Sylvie Alonso from the NUS Yong Loo Lin School of Medicine (NUS Medicine) has found that a dengue vaccine that stimulates a strong T cell response in babies can provide better and broader protection for children of dengue vaccinated mothers than those that rely mainly on antibodies such as Dengvaxia, the only vaccine currently on the market.
The findings, published in scientific journal JCI insight on 21 December 2017, are significant as more children are being born to mothers who have been vaccinated against dengue infection.
A dengue vaccinated mother passes down antibodies to her child, which protects the latter against infection from a similar strain of the disease. However, a mother's antibodies, while offering no protection against different strains of the virus, could also worsen a dengue infection in her baby in some situations or interfere with the child’s immunisation by preventing the child from producing antibodies, a phenomenon known as “maternal antibody interference”.
The team discovered that introducing a dengue vaccine which induces an effective killer T cell response offers these children greater protection against dengue, even from different strains of the virus.
“We hope that our work will further convince the dengue vaccine community that it is of utmost importance to include a protective T cell response in their vaccine design. Too many efforts are currently being devoted to looking at an antibody-mediated protection while the T cell responses are being overlooked,” said Assoc Prof Alonso.
NUS Medicine Professor Paul Tambyah, who is also Senior Consultant at the National University Hospital’s Division of Infectious Diseases, added that the team’s findings shed clarity on the role played by different parts of our immune system in response to dengue and other viral infections.
“They emphasise the fact that we cannot just look at one measure — for example the antibody levels — but need to comprehensively ensure that individuals who are vaccinated by any candidate vaccine are truly protected from infection. It would be unfortunate if a vaccine actually made the situation worse by triggering off one part of the immune system to overreact instead of completely eliminating the virus,” he said.
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