Question

Immunization

Attentuated vaccines use modified microbes that have been treated to lessen virulence. This type of vaccine causes mild infections but usually not disease. Because the microbes are whole, they provide many epitopes that stimulate antibody production and cell mediated immune responses. Vaccinated individuals can transmitt the infection to other unvaccinated individuals providing contact immunity. A disadvantage of attenuated vaccines include the risk of the virus mutated to a virulent form and causing disease. Immunosuppressed or pregnant individuals should not recieve attenuated vaccines.

6. Some examples of attenuated vaccines are measles, mumps, rubella and the flu. Which type of microbe caused these infections? Give an example of an attenuated vaccine that is bacterial. (search the cdc website)

Inactivated vaccines include whole agent vaccines and subunit vaccines. Because the microbes used for inactivated vaccines cannot replicate, revert to wild type or mutate they are safer than attenuated vaccines in which the agents grow in the host to induce an immune response. In addition, inactivated vaccines do not confer contact immunity or as strong an immune response as attenuated vaccines. Inactivated vaccines require multiple doses and stimulate a humoral response by the immune system.  

Toxoid vaccines are chemically modifie8d toxins, i.e. tetanospasmin or botulinum toxin, that stimulate antibody production. Antibodies neutralize toxins by binding to the site the toxin would use to bind to its target cell and cause disease.

7. Describe one example of a combination vaccine that prevents tetanus.

Vaccines that use recombinant DNA technology to delete virulence genes from a pathogen to creat an attenuated pathogen that is avirulent, to insert a gene into a bacterial culture that expresses large quantities of antigen for use in a vaccine or injection of DNA into a cell that will then synthesize and process the antigen to stimulate an immune response.

8. List and explain three problems with vaccine safety. Why are vaccines considered the best prevention of certain diseases?

9. In 2014, 667 cases of measles were reported 27 states. Measles elimination in the US was documented in 2005. How is measles transmitted? Why did so many people have measles? Explain how a traveler from a different continent could cause so many cases of measles.

10. Explain how active immuniztion differs from passive immunization.

Answer 1

8.

Vaccine safety is a concern as it is necessary to maintain the integrity of the vaccine to keep it in its active form. There are several problems that challenge the vaccine safety.

1. Reversal effect of the live vaccines.
2. Change in temperature that can change the effect of the vaccine.
3. Mutation in the strain due to several environmental factors.

Vaccine is considered as the best prevention because vaccines protect the body by producing specific antibodies against the specific pathogen. The side effects are also not there like that of medicines. Vaccine protects the body for the long term and decrease the future risk of the pathogen.

10.

Active immunity involves your bodies direct response to an unknown pathogen. This response is the production of antibodies specific to the antigen of a particular pathogen. This type of immunity is not immediate as it takes time to have create enough of the correct antibodies to fight the pathogen. However, the response lasts for a long period of time and in some cases, where antibodies remain in the body as memory cells, immunity to the specific pathogen may be life long. Conversely, passive immunity is an immune response which involves antibodies obtained from outside the body. An example of this is the antibodies a mother passes to her infant through her breastmilk. Immunity to the pathogens which these antibodies are specific to is therefore immediate, as no time is needed to create them. However, this immunity is not long term and may only last a few days. Passive and active immunity both have natural and artificial forms. So, for example the natural form of passive immunity is antibodies transferred in breast milk as mentioned, however an artificial form of passive immunity is the use of antidotes such as that for rabies where specific antibodies are injected into an infected individual. Additionally, the natural form of active immunity is the normal process of an individual contracting an infection and their immune system responding, conversely the artificial form of active immunity is immunization, where an individual is deliberately exposed to a weakened form of a particular pathogen in order to elicit an immune response.