6. immunology refresher

Question 1

explain the process of immunological memory

Answer 1

1. primary immune response is when the immune system encounters a pathogen for the first time and initiates primary response (naive B cells activated and produce antibodies, primarily IgM followed by IgG –> IgG concentration gradually increases reaching peak after a few weeks and memory B cell specific to the pathogen are generated)
2. memory B cells form and remain in the body for extended periods ready to respond quickly upon re-exposure. IgG levels decline after primary peake but does not return to baseline
3. secondary immune response occurs upon re-exposure to the same pathgoen. memory B cells are rapidly activated and differentiate into plasma cells that produce large amounts of IgG, resulting in a rapid and significant increase in IgG levels much higher and faster than in primary response

Question 2

what do neutrophils do

Answer 2

engulf and digest pathogens

Question 3

what do macrophages do

Answer 3

engulf pathogens, present antigens, and activate other immune cells

Question 4

what do dendritic cells do

Answer 4

capture and present antigens to activate adaptive immune responses

Question 5

what is the function of natural killer cells

Answer 5

to detect and destroy virus infected cells

Question 6

what is the function of the complement system

Answer 6

• complement proteins enhance the ability of antibodies and phagocytic cells to clear pathogens
• promotes inflammation

Question 7

what is the function of the inflammatory response

Answer 7

• release histamine and other chemicals to increase blood flow and attract immune cells
• promotes phagocytosis and tissue repair

Question 8

what are cytokines

Answer 8

signalling molecules that regulate immune responses

Question 9

what do T helper cells do

Answer 9

coordinate immune responses, activate B cells and cytotoxic T cells

Question 10

what do cytotoxic T cells do

Answer 10

destroy infected or abnormal cells

Question 11

what do plasma cells do

Answer 11

produce antibodies that bond to and neutralize pathogens

Question 12

what do memory B cells do

Answer 12

remember pathogens for faster response upon re-exposure

Question 13

what do antibodies do

Answer 13

• bind to pathogens
• facilitate destruction or neutralization

Question 14

what does opsonisation do

Answer 14

enhance phagocytosis by marking pathogens for engulfment

Question 15

major histocompatability complex 1 does:

Answer 15

presents intra cellular antigens to cytotoxic T cells

Question 16

major histocompatability complex 2 does:

Answer 16

presents extra cellular antigens to helper T cells

Question 17

what do regulatory T cells do

Answer 17

suppress immune responses to prevent excessive reactions or autoimmune responses

Question 18

what do cytokines do

Answer 18

• mediate communication between immune cells
• regulate inflammation, immune cell activation and differentiation

Question 19

what are the roles of MHC in antigen presentation

Answer 19

MHC molecules bind to antigen fragments and transport them to the cell surface. T cells recognize these antigen-MHC complexes, leading to the activation of T cell responses. Antigen presentation is crucial for the coordination of adaptive immune responses. It allows the immune system to distinguish between self and non-self, facilitating targeted responses against specific pathogens.

Question 20

what are the MHC molecules and what do they do

Answer 20

• MHC molecules are cell surface proteins that present antigens to T cells. There are two main classes:
• MHC I: Found on the surface of all nucleated cells. Presents antigens derived from intracellular pathogens (viruses, intracellular bacteria) to cytotoxic T cells.
• MHC II: Expressed on the surface of professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. Presents antigens from extracellular sources to helper T cells.