Question

Part II – The Choice

Dr. Stanley said that now that the students answered questions to make sure they knew a little about the immune system, it was time to figure out which vaccine to use.

              Inactivated (“killed) vaccine

                        w    Intact, non-living organisms

                                    −Physical inactivation: UV, heat, gamma-irradiation

                                    −Chemical inactivation: formalin, phenol, iodoacetate

              Subunit vaccine

                        w    Highly concentrated purified versions of molecules from microorganisms,                                     including toxoids (detoxified toxins)

                        w    Typically given with an adjuvant

      w Conjugate vaccines: linking of a polysaccharide to a protein to stimulate

                               T-cell processing of the antigen

              Modified live vaccine (live, attenuated)

                        w    Live organisms modified so they cannot cause disease

                                    −Attenuated during in vitro serial passage by base=pair mutations or                                                deletions

                                    −Genetic engineering to provide more rational methods to develop live                                            attenuated vaccines

Dr. Stanley reminded the students that people get infected with S. Typhi either by eating food or by drinking water contaminated with the bacteria. These bacteria then cross through the intestinal epithelium and are taken up by macrophages in which they multiply. The bacteria then spread via the bloodstream to other tissues.

Questions

1. What is an adjuvant?

2.  What kind(s) of an immune response (antibody-mediated [humoral], cytotoxic T cells [cell-mediated] or both, systemic and/or mucosal) would exposure to a subunit vaccine delivered by intramuscular injection likely give?

3. What kind(s) of an immune response (antibody-mediated [humoral], cytotoxic T cells [cell- mediated] or both, systemic and/or mucosal) would exposure to a modified live vaccine given orally as enteric-coated capsules likely give?

4. What kind(s) of immune response (antibody-mediated [humoral], cytotoxic T cells [cell-mediated] or both, systemic and/or mucosal) would a killed vaccine given by subcutaneous injection likely give?

5. Name two disadvantages of a subunit vaccine.

6. Name two disadvantages of a modified live vaccine.

7. Name two disadvantages of a killed vaccine.

8. Which typhoid fever vaccine would you recommend the students get before going off to Nepal? Justify your choice.

Answer 1

Biology

1. An adjuvant is a substance that is co-injected with antigen in order to stimulate and enhance the immune system into producing the antibodies against the antigens. In people, recieving the vaccine, adjuvant helps in creating a strong immune response.

2. A subunit vaccine delivered by intramuscular injection has both cellular(cell-mediated) and humoral immune responses.

3.The modified live vaccine given orally shows mucosal immune response.The oral vaccines work through mucosal route.

4. Killed vacccine subcutaneouslyy leads to humoral immune response. Little or No cell mediate immunity is seen in this.

Following the guidelines, i am supposed to answer only the starting 4 parts. Kindly post other questions separately.