BIOCHAP7D

Question 1

Immunological memory:

Answer 1

ability of the immune system to quickly and aggressively combat a previously encountered pathogen due to the presence of T and B memory cells.

Question 2

B memory cell:

Answer 2

differentiated B lymphocyte that is responsible for providing long lasting immunological memory of an antigen

Question 3

T memory cell:

Answer 3

differentiated T lymphocyte that is responsible for providing long-lasting immunological memory

Question 4

2 unique features that separates it from the second line of defense

Answer 4

specificity > response to each distinct pathogen in unique manner

immunological memory > allow body to respond to future re-infections by previously encountered pathogen efficiently

Question 5

Antigen presentation

Answer 5

initiation of adaptive immune response, involves selection of a type of T lymphocytes called T helper cells

Question 6

Antigen presentation
Process:

Answer 6

1. After an antigen-presenting cell engulfs and digests a pathogen, they display the pathogenic antigen on their MHC Class II markers.
2. travel to the lymphatic system to lymph nodes to present foreign antigens on their surface using MHC Class II proteins.
3. These interact with complementary T cell receptors on the surface of T helper cells
4. T helper cell becomes activated and ‘ initiates the adaptive immune response through either the humoral or cell-mediated immune response.

Question 7

Humoral Immunity

Answer 7

• neutralization and destruction of extracellular pathogens via the production and secretion of antibodies
  -B lymphocytes are key mediators. Travel around the body in bloodstream and reside in high numbers within lymph nodes

Question 8

Stages of the humoral immune response

Answer 8

1. pathogen with an antigen that is complementary to the shape of the antigen-binding site on the receptor of a B cell interacts with said B cell)

A T helper cell selected through antigen presentation will recognize the selected B cell and secrete a number of different cytokines. causes B cell to undergo clonal expansion through multiple copies produced

T helper cell also stimulates the selected b cell via cytokines to undergo differentiation.

After differentiating, they secrete antibodies into the blood in order to defend against the selected pathogen.

Question 9

Antibodies

Answer 9

released by plasma cells are proteins with a quaternary structure.

Composed of four polypeptide chains arranged in a ‘Y’ shape. The two heavy chains are joined by a disulphide bond.

Question 10

Cell - mediated immunity

Answer 10

destruction of infected abnormal cells via clonal selection of cytotoxic T cells which asses MHC Class 1 marker of infected cells.

if cell has been infected MHC present antigens that can be detected by cytotoxic T cells

Question 10

IgA

IgD

IgE

IgG

IgM

Answer 10

found in mucus,breast milk and saliva

important for activation of immune cells

protects againts woms, resp for allergic reactions

common antibody, able to cross placenta to feotus

first type of antibody produced by plasma cells in response ot an infection

Question 11

Stages of the Cell - mediated immunity

Answer 11

1. antigen presenting cells come upon naive T cell with T cell receptor. initiating clonal selection and the naive T cell undergoes clonal differentiation
2. clones of selected T cell differentiates into effector and T memory cells. majority of selected T cells differentiate into cytotoxic T cells that leaves lymph nodes and travel throughout the body
3. due to clonal selection, cytotoxic T cells that arrive at site of infection have specific T cell receptors for antigen. once cytotoxic T cells has found abnormal cell, perforin is secreted to the cell to induce apoptosis