Lecture 2 - Immunology & Immunopathology Flashcards
define haematopoiesis?
proliferation and differentiation of pluripotent stem cells into all types of blood cells (WBC, RBC etc.)
where is the common pluripotent stem cell, from which haematopoiesis begins?
bone marrow
where do T cells mature?
T-cell precursor forms in bone marrow, travels in blood to thymus to mature
where do B cells mature?
bone
post maturation, where do T and B cells travel? (general)
transit around in blood, arriving at then travelling through various lymphoid tissues
from what cell do osteoclasts develop from?
monocyte-macrophage lineage
this is why Mauro put osteoclast under macrophage
Provide examples of macrophages & their locations.
- Kupffer cells (liver)
- alveolar macrophages
- spleenic macrophages
- peritoneal macrophages
- microglial cells (CNS)
t/f: pathogenic micro-organisms and their products are diverse in size and complexity
true
provide examples of pathogenic microorganisms and their products?
- proteins (bacterial toxins)
- small particles (viruses)
- large particles (bacteria, fungi, protozoans)
- helminths, mites
List some of the fundamental immune responses against pathogens?
- Neutralization - of viruses/ bacterial toxins, achieved with plasma proteins
- Phagocytosis - ingestion by WBC’s, then digestion
- Cytotoxicity - lysis of infected cells
- Humoral response - substances found in body humor (fluid) such as antibodies
- Lymphocyte action - may be cytotoxic
- Granulomas - containment of infected cells
Comparing innate and adaptive immune responses:
When present?
Innate - present from birth
Adaptive - present post exposure to antigens
Comparing innate and adaptive immune responses:
Onset speed?
Innate - rapid onset (as it’s non-specific)
Adaptive - relatively slower (time required for recognition)
Comparing innate and adaptive immune responses:
Specificity?
innate - non-specific
adaptive - specific to antigen
Comparing innate and adaptive immune responses:
Memory?
innate - no memory
adaptive - memory for antigens (B and T cells)
Comparing innate and adaptive immune responses:
Diversity?
innate - limited diversity
adaptive - high diversity
Comparing innate and adaptive immune responses:
Presence in vertebrates and/ or invertebrates?
innate - present in both invert. & vert.
adaptive - present in vert. only
Humoral immune response:
a. ) whys it so called?
b. ) present in innnate or adaptive?
c. ) mediated by?
- occurs within body humor (fluid)
- innate and adaptive
- mediated by soluble (cell-free) proteins (antibodies) in plasma/ interstitial fluids and mucosal secretions
cellular immune response:
a. ) innate or adaptive?
b. ) effective against?
- innate and adaptive
- mediated by cells of immune system
- particularly effective against intra-cellular pathogens
describe the relationship between humoral and cellular immune responses?
they compliment each-other
expand acronym ‘MAC’?
Membrane attack complex
“The complement system exerts multiple anti-microbial activities”. Explain 4 aspects of this?
- Lyse bacteria by forming MAC.
- Tag pathogens - enhancing recognition and destruction by phagocytes (opsonization)
- Activate inflammatory response by triggering release of histamine from mast cells.
- Enhance clearance of antigen-antibody complexes.
Explain the possible outcome(s) of a naive, but mature B cell upon exposure to an antigen?
Naive mature B cell will differentiate into either a plasma B cell or a memory B cell
Basic role of plasma cell?
Produce & secrete antibodies
Production of certain immunoglobins requires the help of T cells. Which immunoglobins are these?
IgG, IgA, IgE
Production of IgG, IgA, IgE all requires the help of which cell?
T-cell
Which immunoglobin can be produced by B cells independent of T cell help?
IgM
t/f: memory cells express specific antigen on their surface.
FALSE - memory cells express specifc antibody on their surface, however they do not begin to produce such antibody until they have been reactivated by the specific antigen (re-exposure)
when do memory cells produce antibodies to target their specified pathogen?
when reactivated by specific antigen on pathogenic organism (re-exposure)
Long lived memory B cells produce which immunoglobins?
Do these require T cell help for manufacture?
IgG, IgA, IgE, these all require T cell help for manufacture
Short lived memory B cells produce which immunoglobins?
Do these require T cell help for manufacture?
IgM, this does not require T cell help
antibodies are also known as?
immunoglobins
State the function of immunoglobin isotype:
IgD
Primary B cell receptor
State the function of immunoglobin isotype:
IgM
- Primary B cell receptor
- Agglutination
- Complement activation
- Opsonophagocytosis
State the function of immunoglobin isotype:
IgG3
Broad complement cell activation
State the function of immunoglobin isotype:
IgG1
Broad complement cell activation
State the function of immunoglobin isotype:
IgA1
Mucosal antibodies
State the function of immunoglobin isotype:
IgG2
Opsonophagocytosis complex antigens
State the function of immunoglobin isotype:
IgG4
Regulation of antibodies
State the function of immunoglobin isotype:
IgA2
Mucosal antibodies to proteolytic bacteria
State the function of immunoglobin isotype:
IgE
Activation of mast cells and eosinophils
List functional effects of antibodies against pathogenic microbes?
- Neutralization bacteria toxins/ viruses
- Opsonisation of particles for phagocytosis
- Activation complement pathway:
- Activation NK cells leading to antibody dependent cell-mediated cytotoxicity (ADCC)
- Activation of basophils/ mast cells
- Activation eosinophils
Explain the basic process of phagocytosis of particulate antigens
- Chemotaxis and adherence of microbe to phagocyte
- Ingestion of microbe
- Formation of phagosome
- Fusion of phagosome with lysosome, forming phagolysosome
- Microbe digestion by enzymes
- Formation of residual body (undigestable)
- Discharge waste material
define chemotaxis
movement of an organism in response to a chemical stimulus
Phagocytosis may be activated by (one/ 2/ multiple) cell-surface molecules
(choose correct)
multiple
What may the phagocytic cell be - what cell types?
- Neutrophils
- Dendritic cells (conventional, plasmacytoid)
- Macrophages
- Monocytes
Functional effects of activating phagocytic cells:
Neutrophils
What pathogens are included here?
Intracellular killing
bacteria/ fungi
Functional effects of activating phagocytic cells:
Monocytes & Macrophages
What pathogens are included here?
Antigen processing then presentation to B and T lymphocytes
&
Intracellular killing (bacteria, fungi, mycobacteria)
Functional effects of activating phagocytic cells:
Conventional dendritic cells
Antigen processing then presentation to B and T lymphocytes
Functional effects of activating phagocytic cells:
Plasmacytoid dendritic cells
Production of type 1 interferons
“There is great diversity in human immune responses”
Provide evidence to substantiate this statement.
- Humoral or cell mediated?
- Innate or adaptive?
- Many Ig types meaning diverse functions
- Multiple types of CD4+ T cell’s means that T cell function and regulation diverse
- Highly polymorphic genes for class I and class II HLA (MHC) molecules
Explain how the primary and secondary immune response differs? How does this relate to vaccines?
due to memory cells (which have receptors for antigen of pathogen seen previously):
- Stronger response on secondary
- More rapid response on secondary
Vaccines take adv by using antigen which is non-threat (attenuated etc.), however adequate time for antibody production must be given
How does the immune system regulate itself (basic)?
The ability to recognize self and non-self antigens - clearly this doesn’t always work, hence hypersensitivities exist
For the following type of tolerance, state the mechanism and site of action:
central tolerance
deletion editing
thymus, bone marrow
For the following type of tolerance, state the mechanism and site of action:
antigen segregation
physical barrier to self-antigen (it has no access to lymphoid system)
peripheral organs (thyroid etc.)
For the following type of tolerance, state the mechanism and site of action:
Peripheral anergy
Cellular inactivation by weak signalling (without co-stimulus)
secondary lymphoid tissue
For the following type of tolerance, state the mechanism and site of action:
Regulatory cells
supression by cytokines, intercellular signals
secondary lymphoid tissue, sites of inflammation
For the following type of tolerance, state the mechanism and site of action:
cytokine deviation
Differentiation of TH2 cells limiting inflammatory cytokine secretion
secondary lymphoid tissue, sites of inflammation
For the following type of tolerance, state the mechanism and site of action:
clonal deletion
apoptosis post activation
secondary lymphoid tissue, sites of inflammation
what is meant by primary lymphoid tissue?
bone marrow, thymus
what is meant by secondary lymphoid tissue?
lymph nodes, spleen
define apoptosis
programmed cell death
define hypersensitivity/ hypersensitivity diseases
disorders caused by immune responses
