Study Guides (248,149)
Canada (121,345)
MIMM 466 (6)
Various (5)
Final

Solutions - MIMM 466 Final Examination, 2007.doc

39 Pages
173 Views
Unlock Document

Department
Microbiology and Immun (Sci)
Course
MIMM 466
Professor
Various
Semester
Winter

Description
SolutionsMIMM 466 Final Examination 200715All of the above25The price of antiviral drugs ahttpwwwavertorghivaidsafricahtm35All of the aboveaWhat are the major reasons why we do not have an HIVAIDS vaccinei1 A Tcell mediated response may be required to eliminate HIVinfected cells and currently it is hard to design vaccines that target the cellmediated immune response 1While this may be the case neutralizing antibodies may also be important in combating HIVii2 High mutation rate of HIV Like influenza HIV is considered a moving target and how do you conduct a vaccine against a moving target This is extremely difficult1This high mutation rates results in an instability of epitopesstable epitopes are required in order to have a safe longterm and efficacious vaccine2HIV drug resistance is also a large problem due to this high mutation rateiii3 It is largely unknown how to vaccinate well against sexuallytransmitted diseases There are not many vaccines that target STDs which have to cross mucosal barriers Some successful established vaccines targeting STDs include those against HPV Human papillomavirus and Hepatitis B can be sexually transmitted or transmitted in different ways4 There is still a lack of knowledgeiv44All vaccines developed to date against sexually transmitted agents have depended on strong mucosal immunityaWhat are the major reasons why we do not have an HIVAIDS vaccinei1 A Tcell mediated response may be required to eliminate HIVinfected cells and currently it is hard to design vaccines that target the cellmediated immune response 1While this may be the case neutralizing antibodies may also be important in combating HIVii2 High mutation rate of HIV Like influenza HIV is considered a moving target and how do you conduct a vaccine against a moving target This is extremely difficult1This high mutation rates results in an instability of epitopesstable epitopes are required in order to have a safe longterm and efficacious vaccine2HIV is also a large problem due to this high drug resistance mutation rateiii3 It is largely unknown how to vaccinate well against sexuallytransmitted diseases There are not many vaccines that target STDs which have to cross mucosal barriers Some successful established vaccines targeting STDs include those against HPV Human papillomavirus and Hepatitis B can be sexually transmitted or transmitted in different waysiv4 There is still a lack of knowledge52Elimination of the foreskin eliminates cells that can serve as portals of entry for HIV into the bodya3 CircumcisioniRecall the microbicide trial was effective at preventing HIV by 38 The PREP trial was gave 44 protectioniiEven better circumcision was shown to be 60 effective at preventing HIViiiWhy Studies show that Muslim men and Jewish men who both undergo circumcision at young ages have lower rate of HIV acquisition than the population at largeivTo test this hypothesis a group went to developing country settings in Africa where people get circumcised at later ages as a matter of routine at the age of about 1819 Scientists asked some of these men to delay circumcision by a yearvBy comparing these two groups they saw that the group that got circumcised right away had fewer cases of HIV infection than the group that deferred circumcision In fact there were 60 more infections in the group that deferred circumcision Therefore circumcision has a major protective effect Why The foreskin contains cells that are very susceptible to HIV as a portal of entry into the body These cells may not actually replicate the virus themselves but rather act as a purveyor of HIV into internal tissues where the virus can then start to replicateviThese cells within the foreskin are Langerhans epithelial cells that are very similar to dendritic cells making them effective portals of entry Getting rid of these portals seems to have a protective effect against HIV infection viiNote an issue that this brings up is that those in developingcountries may not have access to certain standards of cleanliness even just soap and hot water that results in higher HIV prevalence in developing countries than in the West 65None of the aboveaUsing drugs to prevent new infectionsiConcept if these drugs work in treatment shouldnt they also be used in prevention Why shouldnt those at high risk take these drugs before sexual intercourse in order to achieve levels of the drug in the plasma that are high enough so that if infection actually occurs the drugs will already be in the cells and when the virus comes in the drugs will interfere with the FIRST effort of the virus to infect and integrate into the genome thus effectively preventing infection from occurring since the drugs are inside the body in advanceiiThere have been several studies that have validated this concept1Dr Wainberg coauthored a paper published in Science in 2008 entitled Whither or Wither microbicides that discussed the lack of progress in this area2However a recent paper in Science by a South African group that used this microbicide approach They took women at high risk of HIV infection and got them to use a microbicide in the context of vaginal sponges daily The study showed that women who used this on a routine basis as opposed to those who used a placebo were protected by about 38 by the drug This was a major success in the field3Another recent paper in the NEJM showed that gay men who took one pill per day of Truvada coformulation of two drugs FTC nucleoside and Tenofovir nucleotide for two years as opposed to men who took placebo had 44 fewer HIV infections4These studies established an important principle these kinds of drugs can be used prophylactically as well as therapeutically5These studies raised ethical issues concerning the use of a placebo arm6A new concept that needs a placebo arm to prove taking a pill every day as a preventative measure might be cumbersome Therefore some suggest that instead of taking the pill daily simply take the pill in the morning in anticipation of sexual relations73AntialphaGal antibodiesaFour major hindrances to overcome in xenotransplantationiPhysiological compatibility1Pigs and humans have a wide phylogenetic disparity they are very different2Physiological compatibility is thus difficult to achieve for the majority of organs particularly for those performing complex biochemical and metabolic functions such as kidney and liver3Nonetheless this difficulty is relatively easier to overcome for those organs with dominant mechanical function such as heart and lungiiImmunological barriers where the answer comes from1Hyperacute rejection induced by naturally occurring antibodies against donor antigens mediated by complement activationaHuman and Old World monkeys have natural antibodies against galactose alpha13galactose Gal is sugar residue present only on the cell surface
More Less

Related notes for MIMM 466

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit