Introduction to Immunoglobulins: Structure and Research

Introduction to Immunoglobulins: Structure and Research Basharat ali OVERVIEW OF IMMUNOGLOBULINS INTRODUCTION The immunoglobulins or antibodies are a group of proteins present in the serum and tissue fluids of all mammals. Antibodies are produced by cells (B type) on interaction of membrane antibody with antigens. Secreted antibodies moves in the blood; and serve as the effectors of humoral immunity by neutralizing antigens. They therefore also constitute an element of the adaptive immune system. Secreted antibodies circulate in the blood stream where they acts as the effectors of humoral immune response by searching and neutralizing or eliminating antigens. The immunoglobulins are present in highest concentration and most easily obtained in large quantities from blood serum. The antibodies produced are specific to each of the epitope. BASIC IMMUNOGLOBULIN STRUCTURE PROCEDURES OF IMMUNOGLOBULIN MEASUREMENT: The development of Molecular Biology and production of mono-clonal antibodies have allowed us tohave diagnostic tools with a great sensitivity and specificity. They are known as KITS, which are both easy and simple to use and read. The techniques developed in recent years are: Among the above methods available now, we can point out,those that have more possibilities of performing serologic studies on a large scale level, and without the need of highly technical resources. The popular methods used are: ELISA IMMUNOELECTROTRANSFERENCE OR WESTERN BLOT INDIRECT IMMUNOFLUORESCENCEOR IMMUNOPEROXIDASE SERONEUTRALIZATION ELISA: Few types of ELISA are used for the detection of ANTIGENS and ANTIBODIES. So far the following types of ELISA are used for the detection of specific antibodies: INDIRECT ELISA. COMPETITIVE ELISA. INDIRECT ELISA It is the common method used for antibody detection.It involve thecoating of the ELISA plate with the antigen against the specific Ig’s that may be present in the serum. The antigens can be from viral or bacterial product, and or even whole virus molecules. It is more common to use only those proteins with immunological interest, instead of using all the antigenic mixture.Thenext steps will include the addition of serum, incubation and washing;addition of the conjugate, incubation and washing and at last, the addition of the substrate, stopping the reaction and reading the results. COMPETITIVE ELISA This technique is also very common for the detection of specific antibodies. We have an I.G (monoclonal of polyclonal) of a known antigen. This antigen has previously been bound to the plate.It is known as competitive ELISA because the serum is incubated with the antigen previous to its incubation with the antiserum bound to the plate. Therefore, both compete for the antigen. IMMUNOELECTROTRANSFERENCE / WESTERN BLOT Immunoelectrotransference, Immunoblotting or western blotis an immune-enzymatic technique used for the detectionof specific antibodies.This method is recommended whenever it is necessary tostudy a large number of sera which have not given proper results using other techniques. Fig. Required objects to perform Immunoelectrotransference Technique:antigen-nitrocellulose sheets, PBS tampon, +ve / -ve control sera, conjugate, substrate solution and plastic plate. In order to obtain the antigen-nitrocellulosesheets, proteins are first separated by polyacrylamide gel electrophoresis (SDS-PAGE). Later, these proteins are electrically transferred from the gel to the nitrocellulose sheets. These sheets are then cut and will act as the antigen substrate. Each one of these pieces are then incubated with the test sera and washed. Then, a labelled anti-immunoglobulin (IgG or IgM) is added. If there is any antibody bound to the antigenic protein, they will be revealed by the addition of the conjugate.One or more specific precipitation lines will be observed depending on the existence of specific Ig’s against one or more proteins. It is a very sensitive and easy technique to perform and to understand. No special equipment is needed. This technique is especially for the study of small numbers of sera.As it does not require special tools, it is possible to perform it in laboratories with little equipment. Fig. The last step of the method. We can observe thedifferent lines where testand control serum have reacted. INDIRECT IMMUNOFLUORESCENCEOR IMMUNOPEROXIDASE Indirect immunofluorescence or immune-peroxidase are techniques that use the specifity of histology and the sensitivity of the immunological methods. These techniques usually involve the use of cell cultures infected with the virus or bacteria from which we need to know whether or not the unknown sera have antibodies. In the case of Ig’s being present in the unknown sera, after an incubation period, those antibodies will bind to the infected cells. This reaction can be observed with a fluorescence or ordinary microscope after the addition of an anti-immunoglobulin labelled with peroxidase respectively. Fig. Indirect immunofluorescence technique. Mammalian cells infected by the swine fever virus. Antibodies bound to the infected cells can be seen, the areas of the cell with higher viral replication have more bound Ig’s and therefore, a higher light intensity. SERONEUTRALIZATION This method is known asthereference method for every serological study. The use of this technique has made it possible to measure the capability of Ig’s present in the test sera of neutralizing the biological activity of an antigen. Inseroneutralization, we go a step further, and the potential of the serum of neutralizing the biological activity of an antigen can also be known.These tests are very common in labs when theassessment of the capability of a serum against microbial toxins, or viruses is needed. They are however, highly specific and sensitive and are considered as reference methods for every serological evaluation. In the case of viruses, we can determine the capability of a given serumfor neutralizing the virus infectivity on a susceptible cell line.A viral solution, of a uniform concentration and which has previously been in contact with different dilutions of the test serum, is added to the cell culture. The observation of the cells at different times allows one to see if these cells are being infected or not by the virus, using either conjugated dyes or looking for the cytopatic effect. We can measure, in this way, the serumcapability for neutralizing the virus. Fig. Infected cell layer. Laboratory techniques for monoclonal immunoglobulin measurement Following arelaboratory methods used to identify and quantify monoclonal immunoglobulins. SERUM PROTEIN ELECTROPHORESIS The serum protein electrophoresis (SPEP) method determines specific proteinsin the blood to help identify some diseases. Serum protein electrophoresis uses an electrical field to separate the proteins in the blood seruminto groups of similar size, shape, and charge. Blood serum contains two major protein groups: albumin and globulin. Both carry substances through the bloodstream. Using protein electrophoresis, these two groups can be separated into five smaller groups: Albumin. Alpha-1 globulin. Alpha-2 globulin. Beta globulin. Gamma globulin. Each of these five protein groups moves at a different rate in an electrical field and together form a specific pattern. This pattern helps in identifying diseases. Fig.Schematic of serum protein electrophoresis.The position of polyclonal Ig’s in normal serum and the anode (+) and cathode (-) are indicated. CAPILLARY ZONE ELECTROPHORESIS This method is an alternative way to agarose gel electrophoresis for the measurement of serum proteins. Protein separation is performed in a liquid buffer system. The separated proteins pass an U.V detector that measures absorbance at 200 to 215 nm to determine the protein concentration. Fig. CZE.(A)Normal serum.(B)Monoclonal protein peak in ÃŽ ³-region, indicated by a small arrow on right. IMMUNOFIXATION ELECTROPHORESIS For this method, a patient’s serum is applied to several wells of an agarose gel, and after electrophoresis, specific antisera are overlaid on individual lanes of the gel. These antisera are typically against IgG, IgA, IgM, and ÃŽ », although other specificities may be useful for identifying unusual bands. A lane fixed with acid is also included for comparison. Following removal of the antisera, gels are washed and stained with Brilliant Blue or Amido Black. Although IFE is non-quantitative, it is regarded as the â€Å"gold standard† method to confirm the presence of a monoclonal protein and to distinguish its heavy and light chain type. Fig. Serum immunofixation electrophoresis. (A)Normal serum.(B)Monoclonal IgGÃŽ » intact immunoglobulin.(C, D)Monoclonal IgDÃŽ » intact immunoglobulin with ÃŽ » FLCs. FÃŽ »: anti-free ÃŽ » antisera. IMMUNOSUBTRACTION: Immunosubtraction can be used in place of IFE for typing the majority of monoclonal bands, but it is less sensitive. In this technique, Ig’s against IgG, IgA, IgM, are incubated with serum aliquots, then CZE is performed to determine which reagent remove an electrophoretic abnormality. Fig. IgGÃŽ º immunosubtraction example.The monoclonal protein peak is removed with addition of anti-IgG and -ÃŽ º antibodies. URINE CAPILLARY ZONE ELECTROPHORESIS The measuring of urine proteins by CZE is more challenging than serum analysis because urine have electrolytes, organic acids and other metabolites that can interfere with the test. To prevent this, urine samples need to be pre-treated by filtration, or dialysisand for this reason, the routine use of urine CZE is limited. Reason for Immunoglobulin Measurement Measurement of Ig’s is performed for two reasons: Detection of immunodeficiency Determination of the nature of a paraprotein in monoclonal gammopathies History of Procedures ELISA: Before 1970s, a radioimmunoassay using radioactively-labeled antigens or antibodies was the only test available. In a radioimmunoassay, the radioactivity provides the reporter signal indicating if a specific antigen or antibody is present in the sample. WESTERN BLOT Western blotting evolved from Southern blotting (Ref 1), invented byEdwin Southernat University of Edinburgh in 1975. BACTERIAL AGGLUTINATION: Two scientists, Herbert Edward Durham (-1945) andMax von Gruber(1853–1927), discovered specific agglutination in 1896. RIA: In 1950s, the radio-immunoassay (RIA) was developed by Rosalyn Yalow and Solomon Berson.  This group was later awarded the Nobel Prize in 1977 for developing an RIA to detect and measure blood glucose levels in diabetic patients. REFERENCES: http://autoimmunityblog.com/2011/09/28/orgentec-autoimmune-diagnostics-history-of-indirect-immunofluorescence-technology-ift/ http://www.sanidadanimal.info/cursos/inmun/quinto1.htm#ELISA https://ahdc.vet.cornell.edu/sects/clinpath/test/immun/igs.cfm http://chemwiki.ucdavis.edu/Analytical_Chemistry/Instrumental_Analysis/Capillary_Electrophoresis http://www.ncbi.nlm.nih.gov/mesh?term=Fluorescent+Antibody+Technique

Alfred Marshall

Alfred Marshall became one of the most influential economists of his time. His book, Principles of Political Economy (1890) brought together the theories of supply and demand, of marginal utility and of the costs of production into a coherent whole. It became the dominant economic textbook in England for a long period . Born in London, and educated at St John’s College, Cambridge, Marshall took the mathematics tripos.By 1868 he was college lecturer in moral sciences at St John’s College, with particular responsibility for teaching political economy. In 1885 he became professor at Cambridge University, retiring in 1908. Marshall was regarded as one of the founders of the neoclassical school in economics and the most influential figure in the marginalist tradition of British economics. He dominated economics at Cambridge University almost to his death with many disciples, including A. C. Pigou, the young J. M. Keynes, and D. H. Robertson.His major contributions related to the economics of the stationary state, welfare economics, and partial equilibrium analysis; although claims could be made on his behalf for much that became part of economics textbooks over generations, including innovations relating to utility theory, economies of scale, and supply curves. Marshall saw economics as concerned with those aspects of human behavior open to pecuniary influences and sufficiently regular and ubiquitous to permit statements of broad scope and some persistence.While maintaining that some heeded moral imperatives might be impervious to pecuniary considerations, he conceded that most behaviors lay within the ambit of the measuring rod of money. On the other hand, he emphasized that motivation was not merely a matter of pursuing pecuniary self interest, even broadly conceived to include interests of family and friends. He stressed the human desire for social approbation or distinction, and the pleasures of skilful activity. Marshall developed a number of econ omic theories that main of which are the following:Demand Theory Marshall’s treatment of the theory of demand is sketchy, concentrating on the demand for a single commodity, or commodity group, against a loosely defined background. One of the outcomes of his Demand Theory is that demand price and consumer surplus are proportional to the marginal utility and the utility benefit, respectively, the proportionality factor being the reciprocal of the individual's marginal utility of money. This result is fundamental for Marshall’s welfare analysis.The now-familiar concept of demand elasticity – propor ¬tional quantity change divided by proportional price change -was first defined by Marshall. Production and Long-Period Competitive Supply In deriving the long-period supply curve of a commodity, Marshall envisages production as organized by firms, typically family businesses. Each firm strives to minimize its production costs, substituting one productive factor or pr oduction method for another according to the Principle of Substitution.In its simpler forms this involves marginalist adjustment to bring relative marginal value products into line with relative marginal costs. But more generally, the Principle of Substitution is akin to a natural selection process, being â€Å"a special and limited application of the law of survival of the fittest† . Marshall’s firms do not have costless access to a common production function, but must grope and experiment their way to cost-reducing modifications. The long period supply curve is defined for a given state of general scientific and technical knowledge. But each firm must explore this to some extent anew.The conception of competition in Marshall’s manufacturing case is much closer to later ideas of imperfect or monopolistic competition than to modern notions of perfect competition. Products are differentiated and firms are not price takers. Even if the difficulties of rapidly buil ding up a firm’s internal organization can be overcome, the resulting enlarged output can not be sold at a price covering cost – even granted substantial scale economies in production – without going through the slow process of building up a clientele and shifting the firm's particular demand curve.The time this takes is assumed to be considerable relative to the duration of the firm's initial vitality. But in some cases the difficulties of rapid expansion may be overcome. They may not have been very severe, as when different firms' products are highly substitut ¬able, or the firm's founder may have unusual genius. In such cases the industry will pass into a monopoly or be dominated by a few, strategically-interacting firms, or ‘conditional monopolies’ as Marshall termed them . Price Determination and Period AnalysisThe long-period supply curve for any good indicates for each market quantity the least price at which that quantity will continue ind efinitely to be supplied. The equilibrium price and quantity (long period) are determined by the intersection of this supply curve with the negatively sloped market demand curve, indicating the highest uniform price at which any total quantity can be sold. In an agricultural case, equilibrium will be unique as the supply curve slopes positively. But in a manufacturing case, the supply curve, as well as the demand curve, will have negative slope, so that multiple equilibrium can occur.Equilibrium is adjudged locally stable if demand price is above (below) supply price at a quantity just below (above) the equilibrium quantity. The intuitive justification for this is that the actual price of any available quantity is determined by the demand price, while quantity produced tends to increase whenever an excess of market price over supply price promises high profits, while it tends to decrease in the opposite case. Period analysis is Marshall’s most explicit and self-conscious appl ication of the comparative-static, partial-equilibrium method with which his name will always be associated.As he observed, the most important among the many uses of this method is to classify forces with reference to the time which they require for their work; and to impound in Ceteris Paribus those forces which are of minor importance relatively to the particular time we have in view Normal Value and Normal Profit Normal value is defined as the value which would result â€Å"if the economic conditions under view had time to work out undisturbed their full effect† . It is contrasted with market value, which is â€Å"the actual value at any time† .Normal value is hypothetical, its role being to indicate underlying tendencies. The normal value of a commodity may approximate its average value over periods sufficiently long for the â€Å"fitful and irregular causes† , which dominate market value to cancel out, but this should not be presupposed automatically outsid e a hypothetical stationary state. Profit was viewed by Marshall as the residual income accruing to a firm’s owner, a return to the investment of his own capital and to the pains he suffers in exercising his â€Å"business power† in planning, supervision and control.Normal profit is essentially an opportunity cost, the minimum return necessary to secure the owner’s inputs to their current use, or rather to accomplish this for an owner of normal ability. Marshall presumes that there is a large and elastic supply of versatile actual or potential owner managers of normal ability. In long-period equilibrium each of these must just receive the same normal rates of return on his investment and exercise of business power whatever his line of business. The brief survey of economic theories constructed by Alfred Marshall provides the grounds to maintain that the main field of his activity was macroeconomics.His theories include most of Ten Principles of Economics. Specif ically such principles as ‘People face tradeoffs’ and ‘The cost of something is what you give up to get it’ and ‘Rational people think at the margin’ are considered in his Demand Theory, while principles ‘Markets are usually a good way to organize economic activity’ and ‘Governments can sometimes improve market outcomes’ are considered in interrelated markets and distribution theory; and finally the principle ‘Prices rise when the government prints too much money’ is included in his monetary theory.BibliographyMarshall, A. (1893) On Rent. In C. W. Guillebaud, A. Marshall (1961), Principles of Economics. Vol. II , 492 -512.Marshall, A. (1890) The Principles of Economics, Retrieved on Feb. 19, 2007 from http://www. ecn. bris. ac. uk/het/marshall/prin/.Medema, Steven G. , Samuels, Warren J. (Eds. ). (2003) The History of Economic Thought: A Reader. New York: Routledge.O’Brien, D. P. (1981) A. Marshall. In D. P. O’Brien and J. R. Presley (Eds. ), Pioneers of Modern Economics in Britain (36-71). London: Macmillan.Robertson, H. M. (1970) Alfred Marshall’s aims and methods illus ¬trated from his treatment of distribution. History of Political Economy, 2 (1), 1-65.Whitaker, J. K. (1986) The continuing relevance of Alfred Marshall. In R. D. C. Black (Ed. ) Ideas in Economies, London: Macmillan.

Life After Investigative Essay Samples

Life After Investigative Essay Samples Key Pieces of Investigative Essay Samples Therefore, many students and employees decide to purchase inexpensive essay rather than writing it themselves. Before starting to compose a visual analysis essay, you ought to carefully study the artwork for a great quantity of time. If you haven't written any narration essays before, you ought to read works of different students to comprehend how to develop a structure, the way to use your private narrative ideas, and what topics you may utilize. The key point to remember is an investigative essay needs to be unbiased. The previous paragraph is going to be an overview of the whole paper. A topic must be researchable with a couple sources to read you may use as a reference for your paper. A researchable topic is one where the writer can locate a wide variety of credible and current sources. What You Must Know About Investigative Essay Samples There's well-known that you aren't going to have the ability to write a fantastic insightful research paper if you're not interested in the subject overall and in the subject specifically. The people who will read your essay might not be proficient in this subject. You can both utilize personal experience and cover new nuances for you, dependent on the research of different authors and drawing your own personal conclusions. If you would like to dedicate yourself to research or you must do a project or work and you do not understand what subject to do, I bring you a few ideas about subjects that might be of interest to you and of which there is still muc h to understand. The entire research should be constructed around or from the subject. The most recent research in this region is closely about the emergence of the web. Do not be scared to conduct a comprehensive research. Do not quit at the overview of your research outcomes. Investigate what is necessary to find the job. There are particular funding programs out there. Students can find with new approaches to attain accessible clean water in developing countries. Many students wish to find out more about business operations. The principal rule you ought to keep in mind is that your investigation essay ought to be devoted to something you're really interested in. You should be considering the skeleton draft of your paper, a couple sentences and you'll have a rough draft. Writing about nuclear weapons is always an excellent idea. How people will act if there will not be any rules in any respect. Some tips that you can investigate are strange, while a number of them seem scary. There's one main reason for you could take any issue or issue which you do not understand and investigate it! There are some things to take into consideration when picking a topic. The Importance of Investigative Essay Samples The aim of genetic studies is to find a personalized medicine and adapted to the patient. Physical impacts of the medication on the body A. Weight gain results from antidepressants slowing down the metabolism. Many studies are conducted with respect to the reason behind infidelity and all of them have shown varied results. Research can uncover the history of deciding the basis for death, in addition to historic methodologies used to spot certain causes. As you include information regarding your topic provide detailed evidence to back up your investigation. If you're still interested in investigating med ical issues but don't wish to go a neighborhood morgue, you can see any hospital and learn the way the medical staff helps car collision victims. Forensic practices which range from old and easy to current and sophisticated are utilized to analyze the scene of the crime. These methods are applied in the procedure for criminal investigation step-by-step. You must understand completely that you're not writing a descriptive essay. It isn't always easy to select a very good topic and story for this kind of essay. You should be certain to understand everything clearly once you go for an essay topic. If you select a topic that is quite broad, you will be unable to cover this issue in the limited quantity of space the essay requires. Study groups are going to be a good assistance, especially at the early writing stages when you want to pick a topic and generate a thesis statement. In the procedure for writing research articles, it's essential to adhere to a specific topic. There are occasions when you're assigned with the topic but more frequently, you'll have to create a topic on your own. Locate an instance of an excellent topic of narrative essays of different students.

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