Revision

Question 1

What are the 2 types of Immunity

Answer 1

Adaptive
Innate

Question 2

2 types of adaptive immunity

Answer 2

T cell (mediated)
B cell (humoral)

Question 3

2 types of innate immunity

Answer 3

Bloodborne
Physical barriers

Question 4

Which blood cells are involved in innate immunity

Answer 4

Neutrophils
Macrophages
Basophils
Eosinophils
Natural Killer Cells

Question 5

What is the purpose of the complement system

Answer 5

enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism
It promotes inflammation and attacks the pathogen’s cell membrane

Question 6

What part of the immune system is the complement system in

Answer 6

Part of the innate immune system but can be bought into action by antibodies generated by the adaptive immune system

Question 7

Where are complement proteins synthesized e.g. C3, C5

Answer 7

liver- they circulate in the blood as inactive precursors

Question 8

What is the end result of the complement cascade (3)

Answer 8

1. Stimulation of phagocytes to clear foreign and damaged material
2. Inflammation which attracts additional phagocytes (self-amplification)
3. Activation of cell-killing membrane attack complex

Question 9

Role of neutrophils

Answer 9

Engulf and destroy

Question 10

Role of Monocytes/macrophages

Answer 10

Engulf and destroy

Question 11

Role of eosinophils

Answer 11

fight parasitic infections

Question 12

Role of basophils

Answer 12

Release histamine

Question 13

Role of Lymphocytes

Answer 13

Attack Specific pathogens

Question 14

Role of plasma cell

Answer 14

produce antibodies

Question 15

Describe humoral adaptive response to a pathogen

Answer 15

• After being exposed to a pathogen, in the humoral adaptive immune response, antigen presenting cells pick up the pathogens antigens.
• They internally process this antigen and present it on a MHC-2 receptor on their cell membrane which is able to bind to a T helper 2 cell.
• This cell then processes this antigen and releases cytokines such as IL-4 and IL-5, (which activate B cells that have receptors specific for the same antigen. The activated B cell undergoes clonal expansion, dividing to produce a large population of identical B cells.) to cause a naïve B cell to differentiate and undergo class switching to obtain B cell receptors that are specific to the antigen from the pathogen.
• This specific antigen related B cell is then going to further differentiate to either plasma cells (release specific antibodies) or recruited as B memory cells incase the pathogen is exposed again

Question 16

Describe cell mediated immune response

Answer 16

Does not involve antibodies, involves activation of cytotoxic T lymphocytes and the release of cytokines in response to those particular antigens
Used to destroy damages or virally infected body cells
Cytotoxic T cells bind to an MHC class 1 receptor on an apoptotic cell as it is expressing this pathogenic antigen
The connection with the CD8+ cell and the apoptotic cell releases cytokines that bring about the destruction of the cell
Could also have T helper 1 cells which recognise antigens on pathogens and stimulate cytotoxic T lymphocytes to kill pathogen

Question 17

What is a dendritic cells

Answer 17

Antigen presenting cell
Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system.

Question 18

What are CD8+ cells

Answer 18

CD8+ cells are primarily responsible for recognizing and destroying infected or abnormal cells, such as virus-infected cells or cancer cells. They do this by recognizing and binding to specific proteins, called antigens, that are present on the surface of these cells. Once a CD8+ cell has bound to an antigen, it can release toxic substances, such as perforin and granzymes, that cause the targeted cell to undergo apoptosis, or programmed cell death.

CD8+ cells are activated when they encounter antigen-presenting cells, such as dendritic cells or macrophages, which have captured and processed antigens from invading pathogens or abnormal cells. Once activated, CD8+ cells undergo clonal expansion, which allows them to produce large numbers of identical T cells that are specific for the same antigen. These can then destroy more infected cells due to releasing toxic substances. Some of these activated CD8+ cells also differentiate into long-lived memory T cells, which can quickly respond to future encounters with the same antigen.

Question 19

Role of IgG

Answer 19

Common Ig found in serum and colostrum

Question 20

Role of IgA

Answer 20

Common Ig found at mucosal surfaces

Question 21

Role of IgM

Answer 21

Common B cell receptor Ig

Question 22

Role of IgE

Answer 22

Common Ig for allergic response

Question 23

Role of IgD

Answer 23

Unknown specific role, thought to be B cell function

Question 24

Roles of antibodies

Answer 24

1. neutralization of microbes and toxins
2. Opsonisation and phagocytosis of microbs
3. Antibody-dependent cellular cytotoxicity
4. Complement activation -> lysis of microbes, phagocytosis of microbes opsonised with complement fractions, inflammation