Biological Sciences
Vaccines
Vaccines are biological preparations that provide immunity to specific diseases. They work by stimulating the immune system to recognize and fight off pathogens, such as viruses or bacteria, without causing the disease itself. Vaccines have been instrumental in preventing the spread of infectious diseases and have significantly reduced the global burden of illness and death.
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8 Key excerpts on "Vaccines"
eBook - PDF- Julius M. Cruse, MD, PhD, Robert E. Lewis(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
769 A vaccine may contain live attenuated or killed microorgan- isms or parts or products from them capable of stimulating a specific immune response comprised of protective antibodies and T cell immunity. A vaccine should stimulate a sufficient number of memory T and B lymphocytes to yield effector T cells and antibody-producing B cells from memory cells. Viral vac- cine should also be able to stimulate high titers of neutralizing antibodies. Injection of a vaccine into a nonimmune subject induces active immunity against the modified pathogens. Other than macromolecular components, a vaccine may con- sist of a plasmid that contains a cDNA encoding an antigen of a microorangism. Other Vaccines include antiinsect vector Vaccines, fertility-control Vaccines, peptide-based prepara- tions, antiidiotype preparations and DNA Vaccines, among others. There is no antiparasite vaccine manufactured by con- ventional technology in use at present. Vaccines can be pre- pared from weakened or killed microorganisms, inactivated toxins, toxoids derived from microorganisms, or immunolog- ically active surface markers extracted from microorganisms. They can be administered intramuscularly, subcutaneously, intradermally, orally, or intranasally; as single agents or in combination. An ideal vaccine should be effective, well tol- erated, easy and inexpensive to produce, easy to administer, and convenient to store. Vaccine side effects include fever, muscle aches and injection site pain, but these are usually mild. Reportable adverse reactions to Vaccines include ana- phylaxis, shock, seizures, active infection, and death. Vaccination is immunization against infectious disease through the administration of Vaccines for the production of active (protective) immunity in humans or other animals.
eBook - PDFTruth, Lies, and Public Health
How We Are Affected When Science and Politics Collide
- Madelon L. Finkel(Author)
- 2007(Publication Date)
- Praeger(Publisher)
Although highly controversial when first proposed in the nineteenth century, it is now a cornerstone of modern medicine and clinical microbiology. Put simply, disease-causing organisms, be they viruses, microbes, or bacteria, attack the body and produce illness. The immune system, if working correctly, prevents illness by destroying disease- causing microorganisms that threaten the body. Vaccines, from the Latin word “vacca,” or cow, trigger one’s immune sys- tem’s infection-fighting ability and memory without exposure to the actual disease-producing germs. Instead, the person is injected with a dead or much weakened (and not dangerous) version of the pathogen. Vaccines stimulate the body’s immune system by triggering an immune response; the immune system goes into high gear to destroy the invader. The immunity one develops follow- ing vaccination is similar to the immunity acquired from natural infection. For some diseases, several doses of a vaccine (a booster) may be needed for a full immune response. For others, one shot is sufficient. One’s body can become immune to bacteria or viruses by either developing a natural immunity to the disease or by vaccine-induced immunity. Natural immunity develops after one has been exposed to an organism, and one’s immune system develops a defense (from antibodies and memory cells) to pre- vent one from getting sick again from that particular type of virus or bacte- rium. Vaccine-induced immunity results after one receives a vaccine, which makes the body think that it is being invaded by a specific organism and the Disease Prevention through Vaccination 175 immune system reacts by destroying the “invader” and preventing it from infecting the person again. The immunity one develops following vaccination is similar to the immunity acquired from natural infection. The goal is the same: to stimulate an immune response without causing disease.
eBook - PDF- Ronald W. Ellis(Author)
- 2001(Publication Date)
- CRC Press(Publisher)
C hapter 1 New Technologies for Making Vaccines Ronald W. Ellis Introduction T he past two decades have witnessed an explosion in the number of technological and immunological approaches for making new Vaccines. These developments have flowed from advances in a broad range of scientific fields. Some of the earliest applications of the newer technologies were to improving previously existing Vaccines. However, most recent applications have been directed toward the development of new Vaccines for diseases not previously approachable. The protective immunity elicited by a vaccine ideally would be life long and robust after one or a few doses with minimal side effects (reactogenicity). Available Vaccines and those under development fall short o f this ideal, thus stimulating new research in the field. There are two broad categories of Vaccines, active and passive. An active vaccine stimulates the host’s immune system to produce specific antibodies or cellular immune responses or both, which would protect against or eliminate a disease. A passive vaccine is a preparation o f anti bodies that neutralizes a pathogen and is administered before or around the time of known or potential exposure. Most references to the term vaccine are to active Vaccines, which are the object of the vast majority of research and development activities in the field as well as the subject of this chapter. Although it is desirable or essential to administer a passive vaccine in specific instances (particularly if no active vaccine is available or sometimes for immuno compromised individuals), establishing lasting immunity through the administration of an active vaccine is a very important means of preventive medicine. This chapter summarizes the major technologies, key issues and immunological objectives for making different kinds of active Vaccines.
eBook - PDF- James Swarbrick(Author)
- 2013(Publication Date)
- CRC Press(Publisher)
Unit–Vali dation Vaccines and Other Immunological Products Suresh K. Mittal Harm HogenEsch Department of Veterinary Pathobiology, Purdue University, West Lafayette, Indiana, U.S.A. Kinam Park Departments of Pharmaceutics and Biomedical Engineering, Purdue University, West Lafayette, Indiana, U.S.A. INTRODUCTION The concept of vaccination was introduced in the late 18th century by Edward Jenner when he used cowpox virus as a vaccine to protect humans against smallpox virus infections. This led to the develop-ment of Vaccines over the next 2 centuries to provide protection against various bacterial and viral patho-gens. Undoubtedly, the effective vaccination against infectious diseases is the best method of reducing suffering of human and animals caused by viral, bacterial, and parasitic infections. Over the last 200 years, the technology of vaccine development and production has not changed significantly. This usually involves the use of either a killed pathogen combined with an adjuvant or a livepathogen with reduced virulence. Apart from the tremendous suc-cess of killed and attenuated virus Vaccines over the years, many of such Vaccines do not provide satisfactory protection, and there are a number of other disadvantages associated with these Vaccines. Additionally, there are important pathogens against which attempts to develop effective Vaccines using traditional approaches were unsuccessful. Various protective viral antigens (envelope and/or capsid proteins or glycoproteins and other viral proteins) and bacterial antigens (surface, internal, or fimbria proteins; bacterial polysaccharides; bacterial toxins; and other proteins involved in bacterial metabolism) have been identified as potential vaccine candidates. These protective antigens are used by various means to develop effective Vaccines.
eBook - PDF- Firdos Alam Khan(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
97 Chapter four: Virology and Vaccines 4.8.1.5 Other Vaccines Recently, various efforts have been made to make Vaccines in different ways. An immune response can be achieved by introducing a protein subunit rather than introducing an inactivated or attenuated microorganism. Examples include the subunit vaccine against hepatitis B virus that is composed of only the surface proteins of the virus (previously extracted from the blood serum of chronically infected patients, but now produced by recombination of the viral genes into yeast), the virus-like particle (VLP) vaccine against HPV that is composed of the virus capsid protein, and the hemagglutinin and neuramini-dase subunits of the influenza virus. The vaccine can also be prepared by conjugating certain bacteria that have polysaccha-ride outer coats that are poorly immunogenic. Moreover, by connecting these outer coats to proteins, for example, toxins, the immune system can be led to recognize the polysaccha-ride as if it were a protein antigen. Interestingly, this approach is used in the Haemophilus influenzae type B vaccine development. Furthermore, by similar methods, dendritic cell vac-cines can also be made by combining dendritic cells with antigens in order to present the antigens to the body’s white blood cells, thus stimulating an immune reaction. These vac-cines have shown certain positive preliminary results for treating brain tumors. Moreover, Vaccines can be monovalent or univalent or multivalent in nature. A monovalent vaccine can immunize against a single antigen or single microorganism, whereas a multivalent vaccine is developed to immunize against two or more strains of the same microorganism, or against two or more microorganisms, respectively. In certain cases, it has been observed that a monovalent vaccine may be preferable for rapidly developing a strong immune response.
eBook - PDFPharmaceutical Biotechnology
Fundamentals and Applications, Third Edition
- Daan J. A. Crommelin, Robert D. Sindelar, Bernd Meibohm, Daan J. A. Crommelin, Robert D. Sindelar, Bernd Meibohm(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
This is effectuated by administration of antigenic components that (1) consist of, (2) are derived from, or (3) are related to the pathogen. The success of vaccination relies on the induction of a long-lasting immunological memory. Vaccination is also referred to as active immunization, because the host’s immune system is activated to respond to the “infection” through humoral and cellular immune responses, resulting in adaptive immunity against the particular pathogen. The immune response is generally highly specific: it discriminates not only between pathogen species, but often also between different strains within one species (e.g., strains of meningococci, poliovirus, influenza virus). Albeit sometimes a hurdle for vaccine developers, this high specificity of the immune system allows an almost perfect balance between response to foreign antigens and tolerance with respect to self-antigens. Apart from active immunization, administration of specific antibodies can be utilized for short-lived immunological protec-tion of the host. This is termed passive immunization (Fig. 2). Traditionally, active immunization has mainly served to prevent infectious diseases, whereas passive immunization has been applied for both prevention and therapy of infectious diseases.
eBook - PDFViruses
Biology, Applications, and Control
- David Harper(Author)
- 2011(Publication Date)
- Garland Science(Publisher)
While the mechanisms involved are not understood, this approach could be promising for the generation of muco-sal immunity if the other issues related to the use of this vector are resolved. Slow release Slow release systems are also under investigation for vaccine delivery. These are extensions of the existing depot effect provided by adjuvants. Such sys-tems would prevent the need for multiple vaccinations by delivering anti-gen over a period of weeks from within a biodegradable implant at the site of the initial vaccination. Many problems remain in this area, such as how to ensure the stability of the antigen in a warm environment perfused by body fluids, and the possibility of severe localized immune reactions. It is clear that many of the Vaccines now under development will be tailored to produce a spectrum of immunity providing maximum protection against a particular route of infection by an individual pathogen. This will involve careful selection and evaluation of multiple antigens, vector systems, adju-vants, and routes of delivery. All of this will need to be based on a more complete understanding of events at all levels. It is debatable whether such understanding exists at a useful level at the present time, as discussed in Section 5.5. 5.7 THERAPEUTIC VACCINATION While vaccination traditionally is considered as a method of preventing dis-ease ( prophylaxis ), it is also possible to use vaccination to moderate the effects of a pathogen that is already present (therapy). Some Vaccines, such as that for rabies, may be used after exposure, but this relies on establish-ing an immune response before infection becomes established rather than being a true therapeutic vaccination. There are a number of diseases where the organism responsible remains present at low levels or in an inactive form and causes disease at a later date; examples include herpesvirus infections and papillomavirus-induced cancers of the cervix.
eBook - PDF- Edouard Kurstak(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
These include (1) stimulation with a sufficient quan-tity of antigen, (2) use of a suitably specific antigen, and (3) the induction of an appropriate immune response for the prevention of the pathological consequences of infection. The first effective virus Vaccines (for smallpox, rabies, and yellow fever) were made of attenuated, infectious viruses. Because adequate techniques for growing and purifying viruses were not available prior to the 1940s, it was necessary that the virus reproduce within the host in order to supply a sufficient quantity of suitably specific antigen to stimu-late the immune mechanism. The effectiveness of toxoids (bacterial toxins treated with formaldehyde) for immunization against diphtheria and tetanus suggested that it might also be possible to inactivate viruses to produce Vaccines against virus diseases. Technical advances allowed for the large-scale production of virus that could be concentrated, purified, and rendered noninfectious without destroying immunogenicity. More recent advances permit the splitting of viruses chemically and the selec-tion of specific antigenic subunits for use in vaccine preparation (Bach-rach et al., 1975). Application of the principles of effective immunization against a par-ticular disease requires an understanding of its etiologic agents and pathogenic mechanisms. In the case of diphtheria and tetanus, for exam-ple, an appropriate immune response is one that neutralizes the toxin produced in the course of infection. The prevention of infection is not essential for the prevention of pathology. A similar understanding is required for other diseases (Mims, 1976). Evidence now suggests that immunity induced by natural infection with either wild virus or an attenuated (live) virus is not necessarily inherently superior to artificial immunization with an inactivated (killed) virus. Different problems are encountered with different methods.
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