12.If you are a biology student at BU, what is most
probably your first choice after you finish reading the webpage?
A.Watch the video of the Discussion.
B.Buy the magazine Bostonia.
C.Watch the video of the Conference.
D.Book tickets for the Reunion Weekend.
D
American researchers say drinking tea may help strengthen
the body’s defense system against infection(感染). Doctors at Brigham and Women’s Hospital in Boston, Massachusetts,
did the study. The team studied a chemical found in black, green, oolong and
pekoe tea. This chemical is an amino acid(氨基酸)called L-theanine. The scientists say it may increase the strength of
gamma delta T cells. That’s the letter T, not the drink. Gamma delta T cells
are part of the body’s defenses.
First, the researchers mixed some of these cells with
antigens(抗原)found in the amino acid. Antigens help the body
react to infection. Then the scientists added some bacteria(细菌). Within
twenty-four hours, the cells produced a lot of interferon, a substance that
fights infection. Cells not mixed with the antigens did not produce interferon.
In the second part of the study, eleven people drank five
to six cups of black tea every day. Ten other people drank the same amount of
instant coffee. That is dried coffee mixed with hot water.
Two weeks later, and again two weeks after that, the
researchers tested the blood of all twenty-one people. They also looked at what
happened when they added bacteria to the blood cells. They found that the tea drinkers
produced five times more interferon after they started drinking tea. The coffee
drinkers did not produce interferon.
Doctor Jack Bukowski led the study. He says the antigens
added to the gamma delta T cells were responsible for the increased reaction to
the bacteria. He says the study also showed that the cells were able to
remember the bacteria and fight them again the next time.
Earlier research already has found that tea can help
prevent heart disease and cancer. Doctor Bukowski says the new study must be
repeated with more people. If the findings prove to be true, he says, then tea
drinking might also help protect against bacterial infections. He says the
amino acid L-theanine could be removed from tea and used as a drug to
strengthen the body’s defenses.