Lecture 24

Question 1

Thymus is:

Answer 1

a primary lymphoid organ. Largest at birth then shrinks with age. Sits at the top of the pericardium above the heart.

Question 2

T lymphocytes express both:

Answer 2

CD4 and CD8 surface antigens

Question 3

The MHC is:

Answer 3

group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances. MHC proteins are found in all higher vertebrates. In human beings the complex is also called the human leukocyte antigen (HLA) system.

MHC refers to the genetic locus that regulates histocompatibility

Question 4

CTL is:

Answer 4

Cytotoxic T cells react to you own cells when there is a change in MHC class 1 molecules i.e. when they express a neo antigen picked up from inside the cell. Killing non-self tumor cells.

Question 5

Functional subset of CD4 helper T cells control the immune response:

Answer 5

Treg, Th1, Th2, Th17

Question 6

Treg:

Answer 6

suppresses the immune response

Question 7

Th1

Answer 7

promotes cell mediated immunity

Question 8

Th2:

Answer 8

Promotes antibody mediated immunity

Question 9

Th17

Answer 9

Promotes inflammation

Question 10

MHC restriction: Viral immunity requires two antigens:

Answer 10

Self: antigen encoded by MHC

Non self: Antigen encoded by the virus

Question 11

The T cell receptor is:

Answer 11

A membrane bound Ig-like molecule on T lymphocytes

Question 12

H2 refers to:

Answer 12

The antigen on mouse cells

Question 13

Humans Class 1:

Answer 13

A, B, C

Question 14

Class 2:

Answer 14

DR, DP, DQ

Question 15

HLA molecules are expressed on most cell and:

Answer 15

Present peptide antigens to T cells. They are highly polymorphic

Question 16

CD4 and CD8 are:

Answer 16

Accessory molecules that physically associate with TcR.

Question 17

CD4:

Answer 17

Helper T cells recognise antigens in MHC class II.

Question 18

CD8:

Answer 18

Cytotoxic T cells that recognise antigens in MHC class I.

Question 19

CD4 and CD8 have ___ that initiate T cell signalling through:

Answer 19

intracellular tyrosine kinases associated with their cytoplasmic tails, through phosphorylation

Question 20

MHC class 1 peptide source, pathogen, T cell, effector function

Answer 20

Intracellular, Viruses, CD8, Cytotoxic

Question 21

MHC class 2 peptide source, pathogen, T cell, effector function

Answer 21

extracellular, bacteria, CD4, Help

Question 22

TcR does not undergoe affinity maturation. True or false?

Answer 22

True

Question 23

TcR only recognises one antigen. T or F?

Answer 23

True

Question 24

Congenic mice are:

Answer 24

Mice that are genetically identical excpet for the locus that controls tissue rejection. This means they only killed virally infected cells from their own strain, CTL is restricted by MHC.

Question 25

The antigen binding surface of the TcR binds to:

Answer 25

the top of MHC, the peptide groove. Thus TcR has affinity towards the combination of MHC

Question 26

Individual expression of MHC

Answer 26

Both maternal and paternal genes 2x3 Class 1 (A, B, C) and 2 x 3 class 2 (DR, DP, DQ). Co dominance for a total of 12 polymorphic molecules expressed on your cells.

Question 27

2 major consequences of polymorphism:

Answer 27

1 Tissue transplantation is difficult except for in twins. This is because no two people share exactly the same MHC profile.

2. MHC polymorphisms are strongly linked to many autoimmune diseases.

Question 28

Cellular immunity is regulated by:

Answer 28

MHC, a set of highly polymorphic genes coding for a group of membrane molecules called HLA in humans.