Sartorisu-Sowmya eBook - 25

DECIPHERING THE IMMUNE RESPONSE TO VIRAL INFECTION

is not associated with the altered phenotypic or functional
attributes of double-positive cells," the article's authors
continued. "Overall, this study revealed a dengue-virus-specific
double-positive cell subset in patients with acute dengue
disease and argues against altered double-positive cells as a
determinant of dengue hemorrhagic fever."
These findings are important because they improve our
understanding of dengue fever - the world's most common
mosquito-borne illness. Also, they promise to narrow the hunt
for an effective vaccine for dengue.
The findings also demonstrate the power of whole
transcriptome analysis. In the current study, this approach was
used to evaluate dengue-specific CD4 T cells obtained from
patients who were being treated for either mild or for severe
dengue infection. (These patients were hospitalized in Sri Lanka,
where dengue fever is endemic.)
"This is a very powerful approach to detect gene expression
activity because all genes upregulated in response to the
virus can be identified," noted Weiskopf, the current study's
senior author. "It is completely unbiased and does not rely on
preselected genes."
The research team, to their surprise, detected no difference

25 | GENengnews.com

in the genomic profile of dengue-virus specific CD4 T cells
regardless if they isolated them from patients with mild or
severe dengue infection.
"The CD4 T cell response in the severe disease does not look
different so that cannot be the switch we are all looking for,"
Tian elaborated. "In fact, based on some intriguing preliminary
findings, we speculate that to counteract the severe immune
response occurring in acute cases, these dengue-specific CD4
cells may have gradually acquired the ability to produce more
IL-10 by converting IFN- γ. It is as if they are trying to calm
themselves, calm the inflammation. The double-positive CD4 T
cells could actually be helping, rather than hurting."
Tian added that he hopes these findings will serve to "help
guide efforts to develop effective dengue vaccines by improving
our understanding of this novel T-cell response."
Such an outcome would be most welcome. Dengue fever is
spreading. Infected mosquitos have expanded beyond their
established tropical and subtropical territories in South East Asia
and Latin America to new continents, including Europe and the
United States. More than half of the world's population is now at
risk; already, 390 million infections occur annually, according to
public health experts. n
http://www.GENengnews.com
Sartorisu-Sowmya eBook

Table of Contents for the Digital Edition of Sartorisu-Sowmya eBook
