【正文】 as diseasecausing bacteria and viruses and other infectious agents, known as antigens, are recognized by the body39。 antigen determinants immunodominant 一種抗原通常具有多個不同的抗原決定族，因此能刺激多個 B淋巴細胞產(chǎn)生相應的單克隆抗體，因此血清中的抗體是針對不同抗原決定族的單克隆抗體混合物，稱為多克隆抗體。s immune system as invaders. Our natural defenses against these infectious agents are antibodies, proteins that seek out the antigens and help destroy them. ? Antibodies have two very useful characteristics: ? 1) extremely specific each antibody binds to and attacks one particular antigen. ? 2) some antibodies, once activated by the occurrence of a disease, continue to confer resistance against that 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 diseasefighting 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 (antibodycontaining blood serum is called antiserum). There are two problems with this method: It yields antiserum that contains undesired substances, and it provides a very small amount of usable antibody. Structure and function of IgG Amino terminal end Carboxy terminal end Variable regions. Constant regions Fab fratgments Fc fragment Antibody ? ( ) is not only the first class of antibody to appear on the surface of developing B cell but also the major class secreted into blood in the earlt stages of primary antibody response, on first exposure to antigen ? ( ) is the only antibody that can pass from mothrt to fetus via the placenta. ? ( ) is the precipal class of antibody in secretions including saliva, tears, milk and the respiratory and intestine secretions. 人體內(nèi)的五種抗體 單克隆抗體 (monoclonal antibody， McAb) 定義： 利用細胞融合技術， 將能夠產(chǎn)生抗體的 B淋巴細胞 （ antigen stimulated B lymphoblast)和具有無限增殖能力的骨髓瘤細胞 (myeloma)融合在一起，形成雜交瘤細胞(hybridoma cell)。這種 單一類型 的只針對某一特定抗原決定簇 的 抗體分子 ，就是單克隆抗體。 we also have available a class of cells that can grow continually in cell culture. If we form a hybrid that bines the characteristic of immortality with the ability to produce the desired substance, we would have, in effect, a factory to produce antibodies that worked around the clock. ? In monoclonal antibody technology, tumor cells that can replicate endlessly are fused with mammalian cells that produce an antibody. The result of this cell fusion is a hybridoma, which will continually produce antibodies. These antibodies are called monoclonal because they e from only one type of cell, the hybridoma cell。s own cells as well, sometimes producing undesirable side effects such as nausea and allergic reactions. Monoclonal antibodies attack the target molecule and only the target molecule, with no or greatly diminished side effects. Generation of Hybridomas: Permanent Cell Lines Secreting Monoclonal Antibodies 1. animal, immunized with the antigen of interest. sacrifice the mouse dissect the spleen and culture the lymphocytes from spleen. 2. prepare the culture of myeloma cells, 2 attributes:growing indefinitely in culture and does not produce immunoglobulins. 3. Fusion of 2 cells by PEG or electroporation 4. HAT medium used to support the growth of fused, hybrid cells but not of the parental cells. 5. The resulting clones of cells are screened for the production of antibody th the antigen of interest. 親本細胞的選擇 骨髓瘤細胞 myeloma：一般不分泌抗體，能在體外無限繁殖和連續(xù)繼代培養(yǎng)，且為 HPRT－（次黃嘌呤鳥嘌呤磷酰核糖轉(zhuǎn)移酶）或 TK－（胸腺嘧啶核苷激酶）。 淋巴細胞 lymphocytes：經(jīng)過免疫處理的淋巴細胞，多用大鼠或小鼠。 體內(nèi)法： 對細胞或微生物抗原可直接注射如小鼠體內(nèi)，可溶性蛋白抗原可與等量的福氏完全佐劑混合乳化后，注入到動物體內(nèi)。 體外法： 直接提取大、小鼠淋巴細胞，調(diào)整為 10^7個 /ml，加適當濃度抗原， 3－ 4天后，收集被刺激的淋巴細胞。 The generation of mAbproducing cells requires the use of animals, usuall