The<br/>major role of the complement system is to work in conjunction with: A: antibodies to lyse cells via the C8 and C9 components B: the<br/>major histocompatibility complex for cell recognition C: antibodies to opsonize cells D: the<br/>T-cell receptor for production of lymphokines E: antibodies to lyse cells via the perforin molecules

Antibodies are made by a class of white blood cells called ___ lymphocytes.

food is to nourish as () A: organ is to secrete B: fluids is to circulate C: cells is to degenerate D: antibodies is to protect E: fats is to saturate

Which of the following is Trueabout the new research A: 12,290 infected British healthcare workers were involved in the research. B: 89 of 11,052 healthcare workers without antibodies got a symptomatic infection. C: Only few of the 1,246 healthcare workers with antibodies got a symptomatic infection. D: Nonew symptomatic infections in any of the workers who had tested positive for antibodies.

Which of the following are the three lines of defense against human infection A: Complete skin and mucous membrane B: Bactericidal substances and phagocytes in body fluids C: Antibodies and lymphocytes D: Antibiotics E: Vaccines

The basic principle of radioimmunoassay is A: The radiolabeled antigen reacted with excessive specific antibody B: The radiolabeled antigen reacted with a limited number of specific antibodies C: Radiolabeled antigen and unlabeled antigen reacted competitively with limited amount of specific antibody D: Radiolabeled antigen and unlabeled antigen reacted with excessive specific antibody

Assuming that a vaccine against hepatitis C was developed. To evaluate the effectiveness of this vaccine, the population that should be selected as the research object is A: People infected with hepatitis C B: People with low incidence of hepatitis C C: People who have been infected with hepatitis C and have antibodies in their bodies D: High-risk population of hepatitis C E: People who have been infected with hepatitis B

The ____1____（novelty）coronavirus(冠状病毒) has much in common ____2___ seasonal flu.They are both viral infections, share similar symptoms and crucially(关键地） can spread from human to human. In the midst of flu season in much of the northern hemisphere, ____3___(tell) the difference between the two will be vital in stopping its spread. Human coronaviruses, of which there are four, can cause respiratory (呼吸道)infections similar to flu: while many symptoms are mild, both can lead to pneumonia（肺炎） and become lethal（致命的）. ___4___, the novel coronavirus is more serious than __5__ "typical influenza infection,(流感)"says Ian Jones, a professor of virology at the University of Reading. "This virus appears to go___6___(far) down into the lungs than would generally be the case. Therefore, it will give you___7___ (symptom) of pneumonia(肺炎): the lungs becoming flooded, they don't function very well and the patient gets into breathing difficulty." While the mortality rates and symptoms of flu and novel coronavirus may end up being similar, humans' ability ___8____(fight) off the viruses differs greatly. Humans have naturally built up antibodies to seasonal flu and annual vaccines____9____(develop) to fight it. During a pandemic (流行病), which the new coronavirus has the potential to become, "there is no immunity (免疫性) in the population so you have potential for a ___10___(globe) spread," warns Jones.