tetano
Editor, Senior Moderator
WASHINGTON, D.C. Think you?ll easily survive a bout of H1N1 swine flu? Fat chance ? if you?re really fat. New research points to a likely explanation for this weighty vulnerability: a failure of the immune system to rev up as strongly as it should.
In 2009, obesity emerged for the first time as an independent risk factor for flu ? but only for the H1N1 pandemic strain. To see whether immunity was behind this risk, Heather Paich of the University of North Carolina at Chapel Hill and her colleagues recruited participants for a new study from among local residents who had stopped off at a university clinic to get their flu shots.
Thirty days after those vaccinations, each participant came back to give blood. White blood cells ? key players in fighting disease ? were separated out and then challenged with a small dose of live H1N1 virus. Two important classes of these cells responded differently in the obese, Paich and her colleagues reported April 11 at the Experimental Biology meeting.
.
Dendritic cells present a virus to other immune cells, inviting them to attack it. CD8-positive T-cells are an important class of germ killers that receive the virus from those dendritic cells.
In blood from the lean people, H1N1 stimulation activated both types of cells, turning them into infection-fighting warriors. In blood from the obese recruits, the response proved much more anemic -- only about 70 percent as robust. Consistent with these changes, the H1N1-stimulated CD8-positive T-cells from obese participants also made 25 to 30 percent less of two important immune-signaling proteins: granzyme-B and interferon-gamma.
..
http://www.sciencenews.org/view/gen...ity__compromises_ability_to_fend_off_H1N1_flu
In 2009, obesity emerged for the first time as an independent risk factor for flu ? but only for the H1N1 pandemic strain. To see whether immunity was behind this risk, Heather Paich of the University of North Carolina at Chapel Hill and her colleagues recruited participants for a new study from among local residents who had stopped off at a university clinic to get their flu shots.
Thirty days after those vaccinations, each participant came back to give blood. White blood cells ? key players in fighting disease ? were separated out and then challenged with a small dose of live H1N1 virus. Two important classes of these cells responded differently in the obese, Paich and her colleagues reported April 11 at the Experimental Biology meeting.
.
Dendritic cells present a virus to other immune cells, inviting them to attack it. CD8-positive T-cells are an important class of germ killers that receive the virus from those dendritic cells.
In blood from the lean people, H1N1 stimulation activated both types of cells, turning them into infection-fighting warriors. In blood from the obese recruits, the response proved much more anemic -- only about 70 percent as robust. Consistent with these changes, the H1N1-stimulated CD8-positive T-cells from obese participants also made 25 to 30 percent less of two important immune-signaling proteins: granzyme-B and interferon-gamma.
..
http://www.sciencenews.org/view/gen...ity__compromises_ability_to_fend_off_H1N1_flu