Researchers learn how Ebola virus disables the body’s immune defenses
A NEW STUDY BY UTMB RESEARCHERS HAS UNCOVERED new information on why the Ebola virus can exert such catastrophic effects on the infected person.
Researchers have described for the first time how the virus disables T-cells, an important line of immune defense, thus rendering the infected person less able to combat the disease.
Ebola virus disease is one of the most devastating infectious diseases known to exist, with previous outbreaks resulting in high fatality rates. The particularly aggressive nature of Ebola virus stems from its ability to rapidly disarm the infected person’s immune system by blocking the development of a virus-specific adaptive immune response.
White blood cells are an important part of our immune system and when
the T-cell count in the bloodstream is lower than normal, that condition
is referred to as lymphopenia. The extent of lymphopenia is one of the
strongest indicators of how severe the Ebola infection will become.
“People who survive an Ebola infection are able to maintain their T-cell
levels over the course of the infection, whereas low T-cell levels are
nearly universally seen in fatalities,” said senior author Dr. Alex Bukreyev, a UTMB virologist in the departments of Pathology and Microbiology and
Immunology. “The trouble is that we’ve never understood how this T-cell
depletion occurs, so we set out to answer this question.”
Using cellular biology and genetic approaches, the researchers demonstrated for the first time how the Ebola virus can attach to, enter and infect T-cells and what happens afterward. Although the virus is confined
within the infected T-cells, those cells become stressed to the point where the body destroys them. This contributes to the lymphopenia that’s linked to
disease severity.
“With this new information, we’re planning to investigate the role of these processes in Ebola-induced white blood cell death, immunosuppression and disease development in general,” said Bukreyev.
Other authors include UTMB Drs. Patrick Younan, Rodrigo Santos, Palaniappan Ramanathan, Mathieu Iampietro, Michelle Meyer and Vsevolod
Popov, as well as Drs. Andrew Nishida and Mukta Dutta from the University
of Washington. Additional contributors included Drs. Tatiana Ammosova
and Sergei Nekhai from Howard University and Dr. Michael Katze from
the National Primate Research Center.