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Title: Explain how a vaccine provides immunity against infection. What problems are associated with the use Post by: rppatton on Dec 11, 2013 1. Why are some bacteria resistant to the effects of penicillin? Explain. How would you genetically engineer a strain of Bacillus anthracis (the etiological agent of anthrax) to be resistant to penicillin? Describe the process.
2. Describe the potential problems that would arise if a person had an acquired inability to phagocytize pathogens. Could the person survive in a normal environment such as a college campus? What defects in the phagocyte might cause lack of phagocytosis? 3. Explain how a vaccine provides immunity against infection. What problems are associated with the use of a live attenuated vaccine? Many infectious diseases have no effective vaccines-what might be the reason(s) for this? 4. Design an experiment to increase the virulence and pathogenicity of Streptococcus pneumoniae. (Hint: S. pneumonia that is transferred for several passages in vitro loses its capsule and virulence for mice.) Would an increase in virulence confer a selective advantage for the microbe? Thanks!! Title: Explain how a vaccine provides immunity against infection. What problems are associated with the use Post by: padre on Dec 15, 2013 Did you get the answer to the other questions? If you did, could you post them? I found this one online :down:
3. Explain how a vaccine provides immunity against infection. What problems are associated with the use of a live attenuated vaccine? Many infectious diseases have no effective vaccines-what might be the reason(s) for this? An effective vaccine contains a modified virus or bacterial substance that will result in a person's developing immunity against getting a severe disease. Particles from the infectious material are treated and weakened or killed before being made into a vaccine. These particles are called antigens. Hopefully injected antigens will cause the body to develop antibodies against a severe infection or maybe prevent that infection altogether if the person later gets exposed to the dangerous infectious virus or bacteria. "Attenuated" vaccines do contain live infectious agents that have been greatly weakened (attenuated) and may cause a mild for of the infection which allows the body to develop protective antibodies without getting a severe illness. New vaccines are constantly being developed. Right now being tested are new vaccines against malaria and hepatitis C. It's a matter of trying to make and successfully test new vaccines = an effort that can take many, many years. Title: Re: Explain how a vaccine provides immunity against infection. What problems are associated with the Post by: agelessperson on Jan 31, 2015 2. Describe the potential problems that would arise if a person had an acquired inability to phagocytize pathogens. Could the person survive in a normal environment such as a college campus? What defects in the phagocyte might cause lack of phagocytosis? Phagocytes like neutrophils and macrophages are the front line of defense against bacteria. The adaptive response takes many days to fully activate. Without the ability to phagocytose bacteria a person would be at an increased risk from bacterial infections. On a college campus the dangers would come from bacteria such as S. aureus and N. meningitidis. The defect may come in receptors to antigens that signal the cell to phagocytose or in the ability of the phagocyte to lyse the ingested cell. These are just a few examples. Some pathogens can withstand the lysing because they actually thrive in the acidic environment of a phagolysosome. Some pathogens prevent the phagosome and lysosome from fusing. An example would be L. pneumophila. And finally some pathogens avoid phagocytosis by preventing it in the first place. S. pneumoniae has a polysaccharide capsule that prevents the phagocyte from ingesting the bacterium. |