MHC proteins in organ transplants

Question 1

More often successful with advances in
humoral/cellular immune regulation and
immunosuppressive drugs, plus a greater
understanding of MHC antigens

Answer 1

Transplantation Immunopathology

Question 2

Transplanted organs of MHC antigens include Allogenic, syngeneic, and autologous donor

Answer 2

Allogenic donor: donor + recipient related or share similar
HLA types

Syngeneic; donor + recipient are identical twins

Autologous: donor + recipient are same person

Question 3

MHC proteins are divided into class 1 and 2 describe each class

Answer 3

Class 1- Found in membranes of nucleated cells

Class 2-  Found in membranes of antigen-presenting cells (APCs) typically the
phagocytosing cells
 Found in lymphocytes

Question 4

, are specific types of molecules
found on the surface of cells that help differentiate one cell type from
another.
- They are on T cell membranes

Answer 4

What are CD markers? What are they on?

Question 5

CD8 vs CD4

Answer 5

1. CD8 Markers
    Found on cytotoxic T cells and suppressor T cells
    Respond to antigens on Class I MHC proteins
2. CD4 Markers
    Found on helper T cells

 Respond to antigens on Class II MHC protein

Question 6

The MHC class I proteins take up small peptides (antigens) that are in the infected cell and carry them to the surface. The antigens are from waht pathogens? What happens once on the surface?

Answer 6

These antigens are from intracellular pathogens
 Once on the surface, cytotoxic T cells can bind to the antigen and
ultimately be activated

Question 7

Once formed cytotoxic T (TC) Cells Seek out and immediately destroy target cell. How?

Answer 7

1. Release perforin
    To destroy antigenic plasma membrane
2. Secrete poisonous lymphotoxin
    To destroy target cell
3. Activate genes in target cell 

Question 8

Activation of cytotoxic T Cells leads to clonal selection with effector
cells and memory cells being formed.
 Activation by exposure to antigens on MHC proteins to:

Answer 8

 Production of cytotoxic T cells and memory T cells via clonal selection

 Production of suppressor T cell

Question 9

Suppressor T Cells

Answer 9

Secrete suppression factors
 Inhibit responses of T and B cells
 Act after initial immune response
 Limit immune reaction to single stimulus
 Put a break on the response

Question 10

T Helper Cell Activation require

Answer 10

APC’s, MHC class 2 proteins and CD 4 markers

Question 11

 Class II MHC Proteins found only on

Answer 11

APC’s (dendritic, macrophages
and B cells)
 Antigenic fragments are broken down and processed after being taken in by the APC cells

Question 12

Active helper T cells (TH1 cells and TH2 cells ) andMemory helper (TH) cell

Answer 12

 Active helper T cells (TH1 cells and TH2 cells): Secrete cytokines, which coordinate many specific and nonspecific responses

 Memory helper (TH) cells; Remain in reserve

Question 13

What do Th1 cells stimulate?

Answer 13

cellular immune response, participate in the inhibition of macrophage activation and stimulate B cells to produce
IgM, IgG1.

Question 14

What do Th2 cells stimulate?

Answer 14

humoral immune response, promotes B cell proliferation and induces antibody production (IL-4

Question 15

 Four Functions of Cytokines particularly IL-2

Answer 15

1. Stimulate T cell divisions
    Produce memory TH cells
    Accelerate cytotoxic T cell maturation
2. Attract and stimulate macrophages
3. Attract and stimulate activity of cytotoxic T cells
4. Promote activation of B cells