19 - Specific (Aquired) Immune Response Flashcards
Define antigen
A molecule that induces a specific immune response
Define epitope (antigenic determinant)
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)
Clarify the difference between Cell mediated and humoral immunity…
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.
Large globular glycoproteins in serum bind to…
Epitopes on antigens (which may neutralise toxins and prevent adherence, or act as an adapter to interact with innate defences)
in Cell mediated specific immunity T cells recognise epitopes from…
Antigen fragments presented by MHC cells
In cell-mediated specific immunity, cytotoxic T cells kill…
Virus infected cells
What do T helper cells help B cells to do?
Make antibodies
List the 5 types of T cell…
- 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
In practice, the immune response often involves…
Both humoral and cell mediated responses working together
In addition to helping B cells make antibodies and activating macrophages, what other important role do T helper cells play?
Release of cytokines
The specific immune response may ( increase / decrease ) inflammation produced by the innate immune responses.
The specific immune response may increase inflammation produced by the innate immune responses.
Highlight aspects of the specific immune response that may result in increased inflammation.
(Hint: Antibodies and T cells)
-
Antibodies
- IgE -> mast cell degranulation releases histamine
- IgM, IgG -> classical complement pathway
-
T cells
- Release inflammatory cytokines (e.g. TNF-α)
Lymphocytes derive from the common lymphoid progentator cells.
They can be grouped into two based on size…
Large and small (normal) lymphocytes
Large lymphocytes (other than their greater size) can be distinguished from small lymphocytes by their…
Abundant and slightly granular cytoplasm
Haematopoesis
Initial differentiation from the pluripotent stem cells occurs where?
Bone marrow
Further differentiation occurs in reponse to an antigen. This is called…
Antigen-driven clonal selection
Antigens induce the formation of both effector and…
Memory lymphocytes
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
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
Secondary response requires the presence of which types of B and T cell?
Memory B and T cells
Lymphocyte antigen receptors
The structure of B-cell receptors (BCR) is…
a surface anchored Ig (antibody)
(BCR is also known as sIG, as in surface IG)
Lymphocyte antigen receptors
T cell receptors (TCR) are similar to the single arm of an antibody. They bind to…
Antigen MHC complexes
Describe the process leading to antibody production (4)…
- BCR of each B cell is specific to one antigen
- Contact with matching antigen activates
- B cell divides and differentiates into plasma cells
- Plasma cells secrete antibodies (of same specificity of the original receptor)
The primary (central) lymphoid tissues are (2)…
Bone marrow and the foetal liver
The secondary (peripheral) lymphoid tissues are (5)…
- Lymph nodes
- Spleen
- MALTs
- Blood
- Lymphatic vessels
The spleen can be divided into 2 main regions…
White pulp and red pulp
The white pulp of the spleen functions similarly to…
Lymph node nodules
(contains mostly lymphocytes)
Red pulp in the spleen has which purpose (and therefore contains mostly which two cell types)?
Red pulp phagocytisoses old RBCs, therefore it contains mostly RBCs and macrophages
MALT can be found in which two regions of the body?
Intestinal and respiratory tracts
(known as GALT and BALT respectively)
Mucosa Associated Lymphoid Tissues (MALTs) comprise of…
Non-encapsulated submucosal lymphoid nodules and diffuse lymphocytic infiltrates
(located in the submucosa)
What are the two arms of the immune system?
Innate and Adaptive
What are the two arms of the adaptive immune system?
Cell-mediated and Humoral
Where is the spleen located?
Upper left abdomen
What is the name of the lymphoid tissue along the small intestine?
Gut-Associated Lymphoid Tissue (GALT)
Are there any specific risks for patients post splenectomy?
(Splenectomy = surgical removal of the spleen)
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
