19 - Specific (Aquired) Immune Response

Question 1

Define antigen

Answer 1

A molecule that induces a specific immune response

Question 2

Define epitope (antigenic determinant)

Answer 2

The subregion of an antigen which is recognised by a specific immune antigen receptor (Antigens may possess multiple epitopes which may be unique or repeating)

Question 3

Clarify the difference between Cell mediated and humoral immunity…

Answer 3

Humoral immunity is transferred with serum and is directed against free antigens. It is mediated by antibodies from B lymphocytes Cell mediated immunity is transferred by cells and directed against cell associated antigens (such as those attached to intracellular pathogens). It is mediated by T lymphocytes.

Question 4

Large globular glycoproteins in serum bind to…

Answer 4

Epitopes on antigens (which may neutralise toxins and prevent adherence, or act as an adapter to interact with innate defences)

Question 5

in Cell mediated specific immunity T cells recognise epitopes from…

Answer 5

Antigen fragments presented by MHC cells

Question 6

In cell-mediated specific immunity, cytotoxic T cells kill…

Answer 6

Virus infected cells

Question 7

What do T helper cells help B cells to do?

Answer 7

Make antibodies

Question 8

List the 5 types of T cell…

Answer 8

• T helper cells (TH1 and TH2)
• Cytotoxic T cells (CTL)
• T regulatory cells (Treg)
• Memory cells (of both TH and CTL)
• Natural Killer T cells

Question 9

In practice, the immune response often involves…

Answer 9

Both humoral and cell mediated responses working together

Question 10

In addition to helping B cells make antibodies and activating macrophages, what other important role do T helper cells play?

Answer 10

Release of cytokines

Question 11

The specific immune response may ( increase / decrease ) inflammation produced by the innate immune responses.

Answer 11

The specific immune response may increase inflammation produced by the innate immune responses.

Question 12

Highlight aspects of the specific immune response that may result in increased inflammation.

(Hint: Antibodies and T cells)

Answer 12

• Antibodies
  
  • IgE -> mast cell degranulation releases histamine
  • IgM, IgG -> classical complement pathway
• T cells
  
  • Release inflammatory cytokines (e.g. TNF-α)

Question 13

Lymphocytes derive from the common lymphoid progentator cells.

They can be grouped into two based on size…

Answer 13

Large and small (normal) lymphocytes

Question 14

Large lymphocytes (other than their greater size) can be distinguished from small lymphocytes by their…

Answer 14

Abundant and slightly granular cytoplasm

Question 15

Haematopoesis

Initial differentiation from the pluripotent stem cells occurs where?

Answer 15

Bone marrow

Question 16

Further differentiation occurs in reponse to an antigen. This is called…

Answer 16

Antigen-driven clonal selection

Question 17

Antigens induce the formation of both effector and…

Answer 17

Memory lymphocytes

Question 18

The secondary response is:

a) Slower and with fewer antibodies
b) Faster but with fewer antibodies
c) Slower but with greater antibodies
d) Faster and with greater antibodies

Answer 18

The secondary response is:

a) Slower and with fewer antibodies
b) Faster but with fewer antibodies
c) Slower but with greater antibodies

d) Faster and with greater antibodies

Question 19

Secondary response requires the presence of which types of B and T cell?

Answer 19

Memory B and T cells

Question 20

Lymphocyte antigen receptors

The structure of B-cell receptors (BCR) is…

Answer 20

a surface anchored Ig (antibody)

(BCR is also known as sIG, as in surface IG)

Question 21

Lymphocyte antigen receptors

T cell receptors (TCR) are similar to the single arm of an antibody. They bind to…

Answer 21

Antigen MHC complexes

Question 22

Describe the process leading to antibody production (4)…

Answer 22

1. BCR of each B cell is specific to one antigen
2. Contact with matching antigen activates
3. B cell divides and differentiates into plasma cells
4. Plasma cells secrete antibodies (of same specificity of the original receptor)

Question 23

The primary (central) lymphoid tissues are (2)…

Answer 23

Bone marrow and the foetal liver

Question 24

The secondary (peripheral) lymphoid tissues are (5)…

Answer 24

• Lymph nodes
• Spleen
• MALTs
• Blood
• Lymphatic vessels

Question 25

The spleen can be divided into 2 main regions…

Answer 25

White pulp and red pulp

Question 26

The white pulp of the spleen functions similarly to…

Answer 26

Lymph node nodules

(contains mostly lymphocytes)

Question 27

Red pulp in the spleen has which purpose (and therefore contains mostly which two cell types)?

Answer 27

Red pulp phagocytisoses old RBCs, therefore it contains mostly RBCs and macrophages

Question 28

MALT can be found in which two regions of the body?

Answer 28

Intestinal and respiratory tracts

(known as GALT and BALT respectively)

Question 29

Mucosa Associated Lymphoid Tissues (MALTs) comprise of…

Answer 29

Non-encapsulated submucosal lymphoid nodules and diffuse lymphocytic infiltrates

(located in the submucosa)

Question 30

What are the two arms of the immune system?

Answer 30

Innate and Adaptive

Question 31

What are the two arms of the adaptive immune system?

Answer 31

Cell-mediated and Humoral

Question 32

Where is the spleen located?

Answer 32

Upper left abdomen

Question 33

What is the name of the lymphoid tissue along the small intestine?

Answer 33

Gut-Associated Lymphoid Tissue (GALT)

Question 34

Are there any specific risks for patients post splenectomy?

(Splenectomy = surgical removal of the spleen)

Answer 34

Higher risk in children (equivalent to asplenia)

Lower risk in adults who have already aquired immunity against various pathogens, however protective vaccinations still advised (esp. against S. pneumoniae)

Asplenia = absence of normal spleen function