S14: Immune Reactions (Cont'd)

Question 1

How does animal blood differ from human blood?

Answer 1

Each species has its own antigens. Isoantibodies are less common and less reactive in animal blood than in human blood.

Question 2

Why can tissue be transplanted from one identical twin to another?

Answer 2

Because they have identical tissue antigens

Question 3

What are the four different types of skin grafts?

Answer 3

1. Autograft
2. Isograft
3. Homograft (allograft)
4. Heterograft (xenograft)

Question 4

Describe autograft

Answer 4

Tissue (skin) taken from one site to another of the same individual. No foreign antibodies introduced to body

Question 5

Describe isograft

Answer 5

Tissue transplanted from one site to another of genetically identical individuals (twins)

Question 6

Describe homograft (allograft)

Answer 6

Tissue transplanted from one individual to a different individual, both of the same species. Is attacked by the immune system due to foreign antibodies on the tissue

Question 7

Describe heterograft (xenograft)

Answer 7

Tissue transplanted from one individual of one species, to another of a different species (e.g. dog to cat, pig to human). Stimulates immune response

Question 8

How can transplant reactions be prevented?

Answer 8

Drugs, like cyclosporine, paralyze the immune system by impairing T lymphocyte function, therefore preventing the rejection of a graft. Must be taken on a continuous basis