Adaptive immune system

Question 1

What are the differences between innate and adaptive immune system?

Answer 1

• Adaptive can identify exactly which microbe is present by using antibodies rather than using the mannise receptor on the phagocyte
• they have different receptors but limited to toll like n-formyl methionyl receptor and mannose in innate and in adaptive can recognise antigens specfically
• innate receptors are nonclonial but with adaptive they can make billions of receptors

Question 2

What is the T-cell receptor composed of?

Answer 2

Alpha and beta chains, some are conserved and some are variable

Question 3

What occurs at the variable region of the t-cell recptor?

Answer 3

The antigen binding

Question 4

When will the TCR recognise the antigen?

Answer 4

When it is present by an MHC

Question 5

What is a MHC complex?

Answer 5

They are peptide-binding cell surface proteins they starbd for major histocompatibility complex

Question 6

What is a HLC-complex? How many are there ?

Answer 6

The same as a MHC in humans theres 2 types class one and class two

Question 7

Which cells express MHC-class-I?

Answer 7

• on all cells with nucleus
• high expression on lymphocytes
• low expression on non lymphoid cells

Question 8

Which cells express MHC-class-II?

Answer 8

• not on all cells

- high expression on antigen presenting cells (dentritic cells, macrophage, B cells, activated T-cells

Question 9

What is the peptide-binding cleft?

Answer 9

It is where the peptide can bind to the MHC molecule

Question 10

What is CD8?

Answer 10

It is a protein found on cytotoxic T-cells

Question 11

What needs to occur for the antigen to bind to a T-cell?

Answer 11

-MHC class I needs to have CD8 bound

Question 12

What activates cytotoxic T-cells?

Answer 12

MHC class I

Question 13

What is CD4?

Answer 13

Protein found on helper T-cells

Question 14

What are some features of MHC molecule?

Answer 14

• bind 1 peptide at a time
• bind only peptide
• low affinity
• broad specificity
• only stable on Cell surface membrane if bound to peptide(antigen)

Question 15

What do lymph nodes have ?

Answer 15

Lots of B cells and Tcells

Question 16

What cell gets an antigen to the lymph nodes?

Answer 16

Dendritic cells

Question 17

What do dendritic cells do?

Answer 17

• Sit in our tissue They eat up microbes they come across and take them to the lymph node and show the cell to lots of T-cells
• antigens in our blood strem are captured by antigen presenting cells in the spleen

Question 18

What happens when a cell is infected by an intracellular microbe?

Answer 18

• they are capturered by an antigen presenting cell

- antiges are then broken down and presented in association with the MHC molecule of the APC.

Question 19

What is pathway for an antigen in the body? CD4

Answer 19

• endocytosis of the microbe occurs
• the microbe is now in a vesicle in the cell
• fusing with a lysosome forms a phagolysosome where the microbe is broken down into different peptides
• these broken down peptides will bind to a MHC class II molecule
• the complex is then transported to the cell SM where it can now activate CD4+ Tcell

Question 20

What is the pathway for an antigen in the body? CD8?

Answer 20

• occurs when microbe is infecting the cell and makes its way into the cell on its own (not via phagocytosis)
• microbial proteins are made and some of the peptides will bind to MHC class I molecule
• they go to the ER to golgi and transported on the cell surface membrane to be recognised by CD8+ CTL

Question 21

How are antibody diversity reached?

Answer 21

• combination of genes
• combination of heavy and light chains
• somatic hypermutation

Question 22

What increases the most when presence of antigen occurs on graph?

Answer 22

IgG

Question 23

What is IgG?

Answer 23

Type of antibody found in the blood and other body fluid and protects use from bacterial and viral infections. It takes time to form after an infection or immunisation.

Question 24

What is IgM?

Answer 24

Type of antibody mainly found in the blood and lymph fluid. Its the first antibody made to fight an infection

Question 25

Why do we want B- cells that produce high affinity antibodies?

Answer 25

-as they can bind to the dendritic cells and recieve the anti-apoptosis signal and stay on as plasma cells and memory cells using