Adaptive Immune System

Question 1

Response time of the adaptive immune system

Answer 1

Days to weeks

Question 2

Adaptive Immunity

Answer 2

Memory, specificity and tolerance

Question 3

Maturation of lymphocytes

Answer 3

B cells: BM then lymph nodes

T cells: BM then thymus

Question 4

Spleen

Answer 4

Lymphoid follicles- B cells, follicular dendritic cells
Macrophages and plasma cells
Filters blood traps microbes and immune complexes

Question 5

Mucosa-associated lymphoid tissue (GALT)

Answer 5

Waldeyer’s ring
Peyers patches in small intestine
Appendix
Lymphoid follicles in large intestine and rectum

Question 6

B-cell maturation and differentiation

Answer 6

Intentional gene recombination produces variety in individual BCR’s

B-cell to mature B-cell which expresses receptors with specific variable portion on surface of Ig specific to particular antigen.

Can become a plasma cell

Can be influenced by Th Cell

Question 7

B cell receptor

Answer 7

which detects antigen is antibody (immunoglobulin, Ig). Antibodies are
also secreted. A cell secretes antibody specific to only one antigen

Question 8

Subclasses of antibody

Answer 8

IgG, IgA, IgM, IgD, IgE

Question 9

Structure of antibodies

Answer 9

heavy and 2 light chains

both with variable & constant regions

Question 10

Functions of antibodies

Answer 10

Antigen presentation

Activation of complement

Opsonisation for phagocytosis

Free antigen neutralisation

Question 11

Major Histocompatibility Complex 1

Answer 11

Occurs on all nucleated cells

Binds to CD8+ T cells

Question 12

MHC II

Answer 12

Occurs on antigen presenting cells

Dendritic cells, macrophages, B cells
Binds to CD4+ T cells

Question 13

Antibody Mediated Immunity

Answer 13

Initial exposure

Primary immune response (IgM)

Secondary exposure

IgA and IgG release

Question 14

T cell Maturation

Answer 14

T cell to CD8+/CD4+ T cell, if it strongly binds to MHC there is apoptosis to avoid developing autoreactivity.

If weak goes on to develop T cells with T Cell receptor for specific antigens

Question 15

Th1 (CD4+)

Answer 15

Activates macrophages, NK, CTL

Secrete: IL-2, IFN-gamma, TNF - alpha

Question 16

Th2

Answer 16

Activate B cells to produce antibodies

Secrete: IL-4, IL-5, IL-6, IL-10, IL-13

Question 17

Th17

Answer 17

Protect mucosal surfaces from microbes
Secrete: IL-17
Activates PMNs and monocytes

Question 18

T regulatory cells

Answer 18

exert a controlling and regulatory influence on immune responses

Question 19

cytotoxic T cells (CD8+)

Answer 19

secrete IFN and can kill cells infected by intracellular microbes eg viruses and some bacteria, and tumour cells.

Question 20

CD4+ T cells

Answer 20

Th0 (naive T helper cell) binds to MHCII and can become memory T helper cell (Specific T cell receptor) or effector T helper cell (release cytokines which activate Eosinophils, macrophages, NK cells, CD8+, B cells)

Question 21

CD8+ T cells (perforin and granzyme mediated apoptosis)

Answer 21

Cell expresses MHCI which activates CD8+ T cells resulting in the release of perforin and granzyme. Perforin creates a pore in the cell membrane and the granzyme enteres the cell which triggers apoptosis.

Question 22

CD8+ T cells (fas-mediated apoptosis)

Answer 22

Nucleated cells infected with some viruses upregulate fas expression (CD95)

When fas antigens present with MHC I molecules to CD8+, this causes the CD8+ cell to express a fasL receptor on their cell membrane

Binding of fas with fasL causes target cell apoptosis

Question 23

Lymphoid Tissues Primary

Answer 23

(thymus, bone marrow) where T and B respectively mature

Question 24

Lymphoid Tissue Secondary

Answer 24

(lymph nodes, spleen, tonsils, adenoids, intestine/Peyer’s patches) where
lymphocyte responses to foreign antigen are initiated