On Antibodies Substances foreign to the body, such as disease-causing bacteria and viruses and other infectious agents, are recognized by the body s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens (抗原) and help destroy them. Antibodies have two very useful characteristics. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen. Second, some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that disease. Classic example are the antibodies to the childhood diseases of chickenpox(水痘) and measles. The second characteristic of antibodies makes it possible to develop vaccines. A vaccine (痘苗) is a preparation of killed or weakened bacteria or viruses that, when introduced into the body, stimulates the production of antibodies against the antigens it contains. It is the first trait of antibodies, their specificity, that makes monoclonal antibody technology so valuable. Not only can antibodies be used therapeutically(在治疗上), to protect against disease; they can also help to .diagnose a wide variety of illnesses, and can detect the presence of drugs, viral and bacterial products, and other unusual or abnormal substances in the blood. Given such a diversity of uses for these diseased-fighting substances, their production in pure quantities has long been the focus of scientific investigation. The conventional method was to inject a laboratory animal with an antigen and then, after antibodies had been formed, collect those antibodies from the blood serum(血清) (Antibody containing blood serum is called antiserum (抗血清)). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Monoclonal antibody technology allows us to produce large amounts of pure antibodies. in the following way: we can obtain cells that produce antibodies naturally; we also have available a class of cells that can grow continually in cell culture (培养). If we form a hybrid (混血儿) that combines the characteristic of "immortality"(永生)with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that work around the clock. In monoclonal antibody technology, tumor cells that can replicate (重复) endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a "hybridoma" (杂交瘤), which will continually produce antibodies. These antibodies are called monoclonal because they come from only one type of cell, the hybridoma cell; antibodies produced by conventional methods, on the other hand, are derived from preparations containing many kinds of cells, and hence are called polyclonal. An example of how monoclonal antibodies are derived is described below. A myeloma is a tumor of the bone marrow (骨髓) that can be adapted to grow permanendy in cell culture. When myeloma cells were fused with antibody-producing mammalian spleen cells, it was found that the resulting hybrid cells, or hybridomas, produced large amounts of monoclonal(骨髓瘤) antibody. This product of cell fusion combined the desired qualities of the two different types of cells: the ability to grow continually, and the ability to produce large amounts of pure antibody. Because selected hybrid cells produce only one specific antibody, they are more pure than the polyclonal antibodies produced by conventional techniques. They are potentially more effective than conventional drugs in fighting disease, since drugs attack not only the foreign substance but the body’s own cells as well, sometimes producing undesirable side effects such as nausea(恶心) and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects. Which of the following substances is not an invader to the body’s immune system?

A:disease-causing bacteria B:disease-causing viruses C:antigens D:protein

Why India Needs Its Dying Vultures The vultures in question may look ugly and threatening, but the sudden sharp decline in three species of India’s vultures is producing alarm rather than celebration, and it presents the world with a new kind of environmental problem. The dramatic (51) in vulture numbers is causing widespread disruption to people living in the (52) areas as the birds. It is also causing serious public health problems (53) the Indian sub-continent. While their reputation and appearance may be unpleasant to many Indians, vultures have (54) played a very important role in keeping towns and villages all over India (55) . It is because they feed on dead cows. In India, cows are sacred animals and are (56) left in the open when they die in their thousands upon thousands every year. The disappearance of the vultures has (57) an explosion in the numbers of wild dogs feeding on the remains of these (58) animals. There are fears that rabies may increase as a result. And this terrifying disease may ultimately affect humans in the region, (59) wild dogs are its main carriers. Rabies could also spread to other animal species, (60) an even greater problem in the future. The need for action is (61) , so an emergency project has been launched to find a solution to this serious vulture problem. Scientists are trying to (62) the disease causing the birds’ deaths and, if possible, develop a cure. Large-scale vulture (63) were first noticed at the end of the 1980s in India. A population survey at that time showed that the three species of vultures had declined (64) over 90 per cent. All three species are now listed as “critically endangered”. As most vultures lay only single eggs and (65) about five years to reach maturity, reversing their population decline will be a long and difficult exercise.

A:improving B:causing C:predicting D:finding

Infections outside the brain may speed memory decline in Alzheimer’ s disease, UK researchers say. The Southampton University researchers studied 222 elderly people with Alzheimer’ s for six months, and they found that getting infections in places like the chest or urinary tract (尿道) could lead to higher level of an inflammatory (引发炎症的) protein called turnout necrosis factor (TNF) in the blood, and double memory loss.
There were 110 of the 222 subjects who developed a total of 150 infections, in areas such as the chest, stomach and intestines (肠) and the urinary tract, which led to the production of TNF proteins. These are collectively known as acute systemic inflammation events (SIEs).
Subjects with one or more SIEs during the six months follow - up had two times the rate of cognitive decline from their baseline score at the start of the study compared with those who had no SIE. And those patients who had high baseline levels of TNF and then suffered an SIE over the following six months had a 10 fold increase in the rate of cognitive decline compared to those who were SIE free.
Dr Susanne Sorensen, Head of Research, Alzheimer’ s Society said:
We know there might be a link between inflammatory processes and Alzheimer’ s but this is not yet fully understood.
"In the meantime it’ s important that older people, people with dementia treat any infection seriously and seek medical help in time. "Professor Clive Holmes at the University of Southampton, who led the research, said they had looked at patients with mild, moderate and severe Alzheimer’s disease.
"The worse the infection the worse the affect on the memory, but this is only an association at the moment. "
One might guess that people with a more rapid rate of cognitive decline are more susceptible to infections or injury, but we found no evidence to suggest that people with more severedementia (痴呆) were more likely to have infections or injuries.
"If further work proves that TNF is causing more brain inflammation it may be possible to use drugs that block TNF to help dementia sufferers. "
Professor Holmes said although common illnesses like colds and slight wounds could also set up an inflammatory response in the body, the data from his study did not support the idea that even these could cause memory loss.
Which one of the following statement is right about Professor Clive Holmes

A:Professor Clive Holmes believed that people with more severe dementia were more likely to have infections or injuries. B:Professor Clive Holmes introduced that they have only studied the people with more sever Alzheimer’ s disease. C:It is not certain yet whether TNF is causing more brain inflammation. D:It is always hold that the worse the infection the worse the affect on the memory.

On Antibodies Substances foreign to the body, such as disease-causing bacteria and viruses and other infectious agents, are recognized by the body s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens (抗原) and help destroy them. Antibodies have two very useful characteristics. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen. Second, some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that disease. Classic example are the antibodies to the childhood diseases of chickenpox(水痘) and measles. The second characteristic of antibodies makes it possible to develop vaccines. A vaccine (痘苗) is a preparation of killed or weakened bacteria or viruses that, when introduced into the body, stimulates the production of antibodies against the antigens it contains. It is the first trait of antibodies, their specificity, that makes monoclonal antibody technology so valuable. Not only can antibodies be used therapeutically(在治疗上), to protect against disease; they can also help to .diagnose a wide variety of illnesses, and can detect the presence of drugs, viral and bacterial products, and other unusual or abnormal substances in the blood. Given such a diversity of uses for these diseased-fighting substances, their production in pure quantities has long been the focus of scientific investigation. The conventional method was to inject a laboratory animal with an antigen and then, after antibodies had been formed, collect those antibodies from the blood serum(血清) (Antibody containing blood serum is called antiserum (抗血清)). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Monoclonal antibody technology allows us to produce large amounts of pure antibodies. in the following way: we can obtain cells that produce antibodies naturally; we also have available a class of cells that can grow continually in cell culture (培养). If we form a hybrid (混血儿) that combines the characteristic of "immortality"(永生)with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that work around the clock. In monoclonal antibody technology, tumor cells that can replicate (重复) endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a "hybridoma" (杂交瘤), which will continually produce antibodies. These antibodies are called monoclonal because they come from only one type of cell, the hybridoma cell; antibodies produced by conventional methods, on the other hand, are derived from preparations containing many kinds of cells, and hence are called polyclonal. An example of how monoclonal antibodies are derived is described below. A myeloma is a tumor of the bone marrow (骨髓) that can be adapted to grow permanendy in cell culture. When myeloma cells were fused with antibody-producing mammalian spleen cells, it was found that the resulting hybrid cells, or hybridomas, produced large amounts of monoclonal(骨髓瘤) antibody. This product of cell fusion combined the desired qualities of the two different types of cells: the ability to grow continually, and the ability to produce large amounts of pure antibody. Because selected hybrid cells produce only one specific antibody, they are more pure than the polyclonal antibodies produced by conventional techniques. They are potentially more effective than conventional drugs in fighting disease, since drugs attack not only the foreign substance but the body’s own cells as well, sometimes producing undesirable side effects such as nausea(恶心) and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects. Which of the following substances is not an invader to the body’s immune system?

A:disease-causing bacteria B:disease-causing viruses C:antigens D:protein

On Antibodies Substances foreign to the body, such as disease-causing bacteria and viruses and other infectious agents, are recognized by the body s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens (抗原) and help destroy them. Antibodies have two very useful characteristics. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen. Second, some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that disease. Classic example are the antibodies to the childhood diseases of chickenpox(水痘) and measles. The second characteristic of antibodies makes it possible to develop vaccines. A vaccine (痘苗) is a preparation of killed or weakened bacteria or viruses that, when introduced into the body, stimulates the production of antibodies against the antigens it contains. It is the first trait of antibodies, their specificity, that makes monoclonal antibody technology so valuable. Not only can antibodies be used therapeutically(在治疗上), to protect against disease; they can also help to .diagnose a wide variety of illnesses, and can detect the presence of drugs, viral and bacterial products, and other unusual or abnormal substances in the blood. Given such a diversity of uses for these diseased-fighting substances, their production in pure quantities has long been the focus of scientific investigation. The conventional method was to inject a laboratory animal with an antigen and then, after antibodies had been formed, collect those antibodies from the blood serum(血清) (Antibody containing blood serum is called antiserum (抗血清)). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Monoclonal antibody technology allows us to produce large amounts of pure antibodies. in the following way: we can obtain cells that produce antibodies naturally; we also have available a class of cells that can grow continually in cell culture (培养). If we form a hybrid (混血儿) that combines the characteristic of "immortality"(永生)with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that work around the clock. In monoclonal antibody technology, tumor cells that can replicate (重复) endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a "hybridoma" (杂交瘤), which will continually produce antibodies. These antibodies are called monoclonal because they come from only one type of cell, the hybridoma cell; antibodies produced by conventional methods, on the other hand, are derived from preparations containing many kinds of cells, and hence are called polyclonal. An example of how monoclonal antibodies are derived is described below. A myeloma is a tumor of the bone marrow (骨髓) that can be adapted to grow permanendy in cell culture. When myeloma cells were fused with antibody-producing mammalian spleen cells, it was found that the resulting hybrid cells, or hybridomas, produced large amounts of monoclonal(骨髓瘤) antibody. This product of cell fusion combined the desired qualities of the two different types of cells: the ability to grow continually, and the ability to produce large amounts of pure antibody. Because selected hybrid cells produce only one specific antibody, they are more pure than the polyclonal antibodies produced by conventional techniques. They are potentially more effective than conventional drugs in fighting disease, since drugs attack not only the foreign substance but the body’s own cells as well, sometimes producing undesirable side effects such as nausea(恶心) and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects. Which of the following substances is not an invader to the body’s immune system?

A:disease-causing bacteria B:disease-causing viruses C:antigens D:protein

On Antibodies Substances foreign to the body, such as disease-causing bacteria and viruses and other infectious agents, are recognized by the body s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens (抗原) and help destroy them. Antibodies have two very useful characteristics. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen. Second, some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that disease. Classic example are the antibodies to the childhood diseases of chickenpox(水痘) and measles. The second characteristic of antibodies makes it possible to develop vaccines. A vaccine (痘苗) is a preparation of killed or weakened bacteria or viruses that, when introduced into the body, stimulates the production of antibodies against the antigens it contains. It is the first trait of antibodies, their specificity, that makes monoclonal antibody technology so valuable. Not only can antibodies be used therapeutically(在治疗上), to protect against disease; they can also help to .diagnose a wide variety of illnesses, and can detect the presence of drugs, viral and bacterial products, and other unusual or abnormal substances in the blood. Given such a diversity of uses for these diseased-fighting substances, their production in pure quantities has long been the focus of scientific investigation. The conventional method was to inject a laboratory animal with an antigen and then, after antibodies had been formed, collect those antibodies from the blood serum(血清) (Antibody containing blood serum is called antiserum (抗血清)). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Monoclonal antibody technology allows us to produce large amounts of pure antibodies. in the following way: we can obtain cells that produce antibodies naturally; we also have available a class of cells that can grow continually in cell culture (培养). If we form a hybrid (混血儿) that combines the characteristic of "immortality"(永生)with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that work around the clock. In monoclonal antibody technology, tumor cells that can replicate (重复) endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a "hybridoma" (杂交瘤), which will continually produce antibodies. These antibodies are called monoclonal because they come from only one type of cell, the hybridoma cell; antibodies produced by conventional methods, on the other hand, are derived from preparations containing many kinds of cells, and hence are called polyclonal. An example of how monoclonal antibodies are derived is described below. A myeloma is a tumor of the bone marrow (骨髓) that can be adapted to grow permanendy in cell culture. When myeloma cells were fused with antibody-producing mammalian spleen cells, it was found that the resulting hybrid cells, or hybridomas, produced large amounts of monoclonal(骨髓瘤) antibody. This product of cell fusion combined the desired qualities of the two different types of cells: the ability to grow continually, and the ability to produce large amounts of pure antibody. Because selected hybrid cells produce only one specific antibody, they are more pure than the polyclonal antibodies produced by conventional techniques. They are potentially more effective than conventional drugs in fighting disease, since drugs attack not only the foreign substance but the body’s own cells as well, sometimes producing undesirable side effects such as nausea(恶心) and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects. Which of the following substances is not an invader to the body’s immune system?

A:disease-causing bacteria B:disease-causing viruses C:antigens D:protein