Immunology 12: Synopsis: Relevance to Medical Problems

Question 1

Allergies

Answer 1

→ not allergic: produce IgG antibodies, not IgE ones
→ can immunize mice to produce an IgG response to an allergen via deviating the immune response to an IgG mode, and preventing induction of IgE antibody
→ promise for ppl

Question 2

Autoimmunity

Answer 2

→ different classes of antibody activate different effector functions
→ induction of IgA antibody is favoured by immunization through the gut (eating antigen)
→ IgA activates few effector functions, good since our intestines would be highly inflamed if they didn’t
→ approach for treatment of autoimmunity is based on this: deviate immune response against self-antigen into an IgA mode so its relatively harmless

Question 3

Vaccination against infectious diseases

Answer 3

→ many chronic diseases est foothold because of ineffective immune response
→ often ineffective because class of immunity is inappropriate
→ cell-mediated immunity can contain pathogens for leprosy, tuberculosis, probably HIV
→ recently, can immunize animal in a way to lock immune response into cell-mediated mode (deviation) which constitutes effective vaccination

Question 4

Transplantation

Answer 4

→ induction of CD4+ T cells needs interaction b/n phagocytic cell bearing MHC class 2 molecule-peptide complex and the T cells: this interaction mediated by molecule B7 on the macrophage, and CD28 on T cell
→ cells w/o B7 cannot induce T cells efficiently
→ organ grafts rejected bc grafts have donor macrophage-like cells that bear both graft antigens and B7
→ grafts without these "passenger leukocytes" are not rejected or rejected slower

Question 5

Cancer

Answer 5

→ same kinds of cancers in diff people share antigens
→ antigens used as target!
→ people w cancer have CD8+ T cells that can kill cancer cells aty INSUFFICIENT LEVELS
→ can make tumour cells express antigen B7 needed to stimulate T cells via transfecting an expression vector into cancer cells that encodes B7
→ administration of these inc the magnitude of CD8+ T cell cytotoxin so the transfected and untransfected cancer cells are killed more readily