IMMUNOLOGY
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History Introduction Vaccine and immunization Type of vaccines and their characteristics Immune disorders Hypersensitivities Auto immune diseases Transplantation tissue) rejection Immunodeficiency's Antigen antibody interactions in vitro Agglutination www.indiandentalacademy.com
Complement fixation Enzyme linked immunosorbent assay Flow cytometry and flourosence Immunoblotting(western blot)
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Immunodiffusion Immunoelectrophoresis Immunoflouresence Immunoprecipitation Liposomes Neutralization Radioimmunoassay Serotyping www.indiandentalacademy.com Conclusion
History • • •
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First scientific attempts at artificial immunization were made in the late 18th century by edward jenner Jenner investigated the basis for the wide spread belief of the english peasants that anyone who had vaccine(cowpox)never contracted small pox It was on may14th ,1796, that jenner extracted he contents of a pustule from the arm of a cowpox –infected milkmaid,sarah nelmes,and injected it into the arm of 8yr old james phipps,as jenner expected immunization with the cowpox virus caused only mild symptoms in the boy.when he subesquently inoculated the boy with smallpox virus,the boy showed no symptoms of the disease Further work on immunization was carried out by louis pasteur www.indiandentalacademy.com
To a honour jennner,s work with cowpox,pasteur gave the name vaccine to any preperation of a weakend pathogen that was used(as was jenner,’s vaccine virus�)to immunize against infectious disease The three greatest discoveries of medicine in the last 200 yrs are antisepsis,antibiotics,and vaccines-stanley A. plotkin www.indiandentalacademy.com
Vaccine and immunizations • A vaccine(latin vacca ,cow) is a preperation from an •
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infectious agent that is adminstrated to humans and other animals to induce protective immunity. It may consits of preperation of killed microorganisms;living weakened (attentuated)microorganisms;inactivated bacterial toxins(toxoids);purifed macromolecules ;recombant vectors or DNA vaccines The modern era of vaccines and vaccination began in 1798 wiith edward jenner’s use of cowpox as a vaccine against smallpox and in 1881 with louis pasteur’s anthrax vaccine. Vaccinatin of most children should begin at about 2 months of age.before that age ,they are protected by www.indiandentalacademy.com passive natural immunity
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It is of two types Active immunization Passive immunization Active immunization is the protection of susceptible humans and domestic animals from communicable disease by the adminstration of vaccines Vaccination of most children should begin at about 2 months of age.before that age,they are protected by passive natural immunity Passive immunization,artifically acquired passive immunity,can be produced by injecting an animal or human with preformed antibodies that have produced in another animal ,in another human, or in vitro.This type of immunization is called passive because protection does not require participation of the recipient,s immune system. www.indiandentalacademy.com
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Bacterial diseases
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Immunoglobulins and antitoxins used for passive immunization against specific organisms
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Types of vaccines and their characterstics Whole organism vaccines Purified macromolecules as vaccines Recombant vector vaccines DNA vaccines
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Whole –organism vaccines Many of the currentvaccines in use for humans that are effective against viral and bacterial diseases consist of whole microorganisms that are either inactivated(killed) or attentuated (live but avirulent).These are termed whole-organism vaccines. Even though whole-organism vaccines are considered the “gold standard� of existing vaccines, they can be problematic in their own way
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Purified macromolecules as vaccines A few of the comon risks assosiated with wholeorganism vaccines can be avoided by using only specific, purified macromolecules derived from pathogenic microorganisms.
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Recombant-vector vaccines It is now possible to isolate genes that encoded major antigenes from a pathogen and insert them into nonvirulent viruses or bacteria.the vaccine are usually derived by needle injection or by a device called a gene gun Recently several microorganisms have been used in the production of the recombinant vector vaccines.examples include adenoviruses,vaccinia viruses,canarypox viruses,attentuated poliovirus and attentuated strains of salmonella and mycobacterium.
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DNA viruses A more complicated genetic vaccine to emerge in recent years is the DNA vaccine. DNA vaccine elicts protective immunity against a microbial pathogen by activating both branches of the immune systeam;humoral and celluar. At present,there are human trails under way several different DNA vaccines aganost malaria,AIDS,influenza,hepatitis B,and herpes virus.
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Immune disorders Immune disorders can be categoried as Hypersenstivities. Autoimmune diseases. Transplantation(tissue)rejection. Immunodeficiences.
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Hypersenstivities Hypersenstivity is an exaggerated immune response that results in tissue damage and is manifestated in the individual on second or subsequent contact with an antigen. Hypersenstivity can be classified as either immediate or delayed . Gell-coombs classification systeam divides hypersenstivity into four types;I,II,III,IV.
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Type I Hypersenstivity
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HypersenstivityI can be classfied as systemic and localized Localized is called an atopic allergy,eg.hay fever. Systemic incldes drugs(penicillin0,passively administerted antisera,peanuts, and insect venom from the stings or bites of wasps, bees.
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Skin prick test with grass pollen in a person with summer hay fever
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Type II Hypersenstivity
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Type III hypersenstivity
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Eg.systemic lupus erythematous,farmer’s lung and group A streptococcal infection.
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Type IV hypersenstivity
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Type IV involves delayed T-cell mediated immune reactions
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Autoimmune diseases
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Allograft Xenograft Immunosuppresion in organ transplant cases also can lead to garaft-versus-host disease.
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Transplantation(tissue) Rejection
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Immunodeficiencies
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ANTIGEN-ANTIBODY INTERACTIONS IN VITRO The branch of medical immunology concerned with antigen-antibody reactions in vitro is serology. In this section some more common serological tests employed in the diagnosis of microbial and immunological diseases are presented. Agglutination Complement fixation Enzyme-Linked Immunosorbent Assay Flow cytometry and Fluoresence Immunoblotting(western blot) Immunodiffusion Immunoelectrophoresis www.indiandentalacademy.com
Immunofluorescence Immunoprcipitation Liposomes Neutralization Radioimmunoassay Serotyping
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Agglutination When an immune complex is formed by cross-linking cells or particles with specific antibodies,it is called an aggutination reaction.
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Viral haemagglutination-widely used to diagnose influenza,measles,mumps,mononucleosis and other viral infection
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Complement fixation It is currently used in the diagnosis of certain viral,fungal rickettsial,chlamydial and protozoan disease and once used in the diagnosis of syphilis (the wassermann test). This technique is very senstive and can be usedto detect extremely small amount of antibody for suspactmicroorganism in an individual’s serum.
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Complement fixation
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Enzyme-Linked Immunosorbent Assay It is the most widely used serological tests for antibody or antigen detection This test involves the linking of various�label� enzymes to eother antigens or antibodies. Two basic methods are used Double antibodt sandwich assay-detection of antigens Indirect immunosorbent assay-detecting antibodies
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Flow cytometry and fluorescence It allows single or multiple-microorganism detection in clinical samples in an easy- reliable,fast way. In this, microorganisma are identified on the basis of their peciular cytometric parameters or by means of flurochromes that can be used either independently or bound to specific antibodies or oligonucleotides. Flow cytometer forces a suspension of cells through a laser beam and measures the light suspension of cels emit as they pass through beam .
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This technique has permitted the development of quantitative methods to access antimicrobial susceptibility and drug cytotoxicity in a rapid , accurate and highly reproducible way. It has ability to detect the presence of hetrogenous microbial populations wiyh different response to antimicrobial treatments.
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Immunoblotting(western blot) It involves polyacrylamide gel of the electrophoresis of a protein specimen followed by transfer of the seperated proteins to nitro cellulose sheets.
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Immunodiffusion It refers to a precipitation reaction that occurs between an antibody and antigen in an agar gel medium. Two techniques are routinely used Single radial immunodiffusion or mancini technique. Double diffusion in agar or ouchterlony technique.
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Single radial immnodiffusion assay
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Double diffusion agar
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immunoelectrophoresis
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immunoflurosence It is a process in which dyes called fluorochromed are exposed to uv,violet or blue light to make them fluoresce or emit visible light. Dyes such as rhodamine B or fluorescein isothiocyanate can be coupled to antibody molecules without changing the antibody,s capacity to bind a specific antigen. These are two kinds Direct immunofloresence Indirect immunofluorsence
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Direct immunofluorsence
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Indirect immunofluorsence
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immunoprecipitation It detects soluable anttigens that react with antibodies called precipitins.
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Precipitation reaction taking place in test tube
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liposomes
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Neutralization Neutralization tests are antigen-antibody reactions that determine whether the activity of a toxin or virus has been neutralized by antibody Laboratory animals or tissue culture cells are used as “indicator systeams� in these tests The toxin or virus to be assayed has known effects on the indicator systeam. The effect in the animal might be death , paralysis or skin lesions. Ex.C.botulinum
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Radioimmunoassay Rosalyn yalow won the noble prize in 1977 physiology or medicine for its development. It uses a purified antigen that is radioisotope-labeled and comoetes for antibody with labelled standard or antigen in expirement samples. A large amount of bound radiactivity indicates that there is little antigen present in the experimental sample.
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Serotyping It is a serological procedure used to differntiate strains of microorganisms that differ in the antigenic composition of a structure or product It is possible to identify the pathogen serologically by testing for cell wall antigens. In yhe early rebecca lancefield recognizied the importance of serological tests.she developed a classification systeam for the streptococci based on the antigenic nature of cell wall carbohydrates. Her systeam is now known as lancefield systeam www.indiandentalacademy.com
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