Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Immunology > Respiratory Immunology 2 > Flashcards

Respiratory Immunology 2 Flashcards

(52 cards)

Start Studying
1
Q

Stages of response to an infection?

A 
Adherence to epithelium
Local infection and epithelium penetration
Local infection of tissues
Lymphatic spread
Adaptive immunity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Timescale of the acquired immune response?

A

After 96 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Organs involved with the adaptive immune response?

A 
Thymus - in anterior mediastinum and where T cells mature
Bone marrow
Tonsils - specialised lymph nodes
Spleen
Appendix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Generation of T-lymphocytes?

A

Arise from haematopoetic stem cells in bone marrow
Form LYMPHOID PROGENITORS and then PRE T-CELLS
Pre T-cells exported to thymus where they undergo selection (only 10% cells survive)
Mature T-lymphocytes enter circulation and reside in lymph nodes and secondary lymphoid follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many distinct T cell clones are there?

A

Each individual possesses 107-109 distinct T cell clones and each is ready to use when the right antigen comes along

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T-lymphocyte functions?

A

Defense against INTRACELLULAR PATHOGENS and VIRUSES

Immunoregulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Classification of T-lymphocytes?

A

Two main groups which have different functions and different expression of cell surface proteins:
CD4
CD8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Functions and mechanism of CD4+ T lymphocytes?

A

Recognise peptides presented on HLA class II molecules

Immunoregulatory functions:
Provide COSTIMULATORY signals - for ACTIVATION OF CD8+ T lymphocytes and NAIVE B CELLS and also INFLUENCE PHAGOCYTE FUNCTION
Produce cytokines

Regulate other lymphocytes and phagocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does HIV do?

A

Knocks out CD4+ cells and thus affects CD8+ and B cells as well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are CD8+ cells and mechanism of recognition?

A

Specialised CYTOTOXIC cells that recognise peptides in association with HLA class I (HLA-A, HLA-B, HLA-C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Functions of CD8+ cells?

A

Important in defense against VIRAL INFECTIONS and TUMOURS

Kill cell directly via production of pore-forming molecules (PERFORIN); can also trigger apoptosis of the target and can secrete cytokines, like IFNγ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

B lymphocyte generation and locations?

A

Arise from haematopoietic stem cells in bone marrow (do not have to go to thymus like T cells)
Mature B lymphocytes found mainly in BONE MARROW, LYMPHOID TISSUE and SPLEEN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Functions of B lymphocytes?

A 
Antibody production
Antigen presentation (showing pathogen to other immune system components)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Normal B lymphocyte development?

A

Stem cells form lymphoid progenitors which then form pro B and pre B cells
These can be used to form IgM B cells
IgM B cells get signals, and can mature into different immunoglobulins producing B cells:
IgG
IgE
IgA
IgM plasma cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Activation of T lymphocytes and what this involves?

A

Encounters with antigen in lymph node

Provided with appropriate signals from CD4+ cells - stimulated B cells rapidly proliferate

Undergo complex genetic rearrangements - B cells become more specific

Further differentiation produces:
Long-lived memory cells
Plasma cells which produce antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Antibody functions?

A

Important in defense against BACTERIA

Identify pathogens
Recruit other components of immune response to remove pathogens, like complement, phagocytes, NK cells
Neutralisation of toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Defects of the adaptive immune response?

A

Defects of haematopoietic stem cells - Recticular dysgenesis
Failure of lymphocyte precursors - Severe Combined Immunodeficiency
Failure of thymus development - DiGeorge Syndrome

Defective T lymphocyte activation and effector function:
Failure of HLA molecule expression - Bare Lymphocyte Syndromes
Failure of signalling, cytokine production and effector functions - gIFN and/or IL12 deficiency
Failure of normal apoptosis - Autoimmune Lymphoproliferative Syndromes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Recticular dysgenesis?

A 
Failure of production of:
Neutrophils
Lymphocytes
Monocyte/macrophages
Platelets 
Fatal unless corrected with bone marrow transplant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thymus in recricular dysgenesis?

A

Small thymus as these children have no lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is severe combined immunodeficiency?

A

AKA SCID
Failure of lymphocyte production (defect in lymphocyte precursors)
Adults can get this

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Clinical phenotype of SCID?

Study These Flashcards
A

Unwell by 3 months of age
Failure to thrive
Infections of ALL TYPES (common infections being more severe than usual, unusual and opportunistic infections and vaccine associated disease -live)
Unusual skin disease - Graft vs Host disease (maternal lymphocytes not killed by child’s so they colonise “empty” bone marrow and attack baby’s own cells causing severe eczema like problem)
Family history of early infant death

22
Q

Why is the baby usually well in SCID until 3 months?

Study These Flashcards
A

Maternal IgG protects the neonate (via placenta and breast milk)

23
Q

SCID causes?

Study These Flashcards
A

Over 20 possible pathways, e.g:

Deficiency of cytokine receptors, signalling molecules, metabolic defects and defective receptor rearrangements

24
Q

Describe the commonest form of SCID?

Study These Flashcards
A

X-linked SCID - mutation of component of IL2 receptor (drives lymphocyte proliferation); shared by many other cytokine receptors and results in inability to respond to cytokines:
Failure of T and NK cell development
Production of immature B cells

25
Clinical phenotype of X-linked SCID?
Very low/absent T cells (as IL2 is important for T cell development) Normal/increased B cells but are immature Poorly developed lymphoid tissue and thymus
26
SCID treatment?
Prphylactic treatment with antibiotics/anitfungals and no vaccines Antibody replacement with iv immunoglobulin Definitive treatment with a stem cell transplant from HLA identical sibling, if possible
27
SCID gene therapy?
Lymphoid cells are dysfunction so stem cells can be treated ex vivo to express missing component (IL2 receptors) RISK OF CANCER
28
What is DiGeorge syndrome and cause?
Developmental defect of the 3rd/4th pharyngeal pouch (strange from mid-face to below the aortic arch), due to deletion of chromosome 22q11 (key gene probably TBX1)
29
Appearance and clinical features of child with DiGeorge syndrome?
T cell lymphoenia (low levels) - FAILURE OF THYMIC DEVELOPMENT results in immunodeficiency of T cells as there is no place for T cells to mature Developmental delay Psychiatric disorders - OCD, schizophrenia Low set ears that are abnormally folded High forehead Cleft palate Small mouth and jaw Hypocalcaemia - do not have parathyroids which are important for calcium metabolism and they will suffer from seizures Oesophageal atresia - oesophagus ends in a blind-ended pouch instead of connecting to stomach Complex congenital heart disease
30
Infections in people with DiGeorge Syndrome?
RECURRENT VIRAL INFECTIONS - CD8 T cells essential in killing if viral infected T cells RECURRENT BACTERIAL INFECTIONS - CD4 T cells help B cells make antibody FREQUENT FUNGAL INFECTIONS - T cells essential for fungal defense
31
Lab investigation for DiGeorge syndrome?
Absent/decrease no . of T cells, due to defective T cell activation response Normal/increased B cells that produce low IgA, IgG and IgE; so, poor antibody response to specific pathogens Normal NK cell numbers
32
Managing DiGeorge syndrome?
Correct metabolic/cardiac abnormalities Prophylactic antibiotics Early, aggressive infection treatment Patient may require immunoglobulin replacement
33
DiGeorge Syndrome with increasing age?
T cell function improves with age as T cells may have found another place to mature
34
Disorders of T cell effector functions?
Cytokine production Cytotoxicity T-B cell communication
35
Describe defense against intracellular organisms
E.g: mycobacteria IL12-gIFN network activated: Infected macrophages stimulated to produce IL12 Induces T cells to secrete gIFN gIFN feeds back to macrophages and neutrophils Stimulates TNF production Activates NADPH oxidase
36
What results in defective cytokine production in T cell effector function?
IL12 IL12 receptor gIFN gIFN receptor
37
Infections in people who have defective cytokine production?
TB Atypical mycobacteria BCG infection after immunisation Deep fungal infections, e.g: Aspergillus
38
Clinical features of T cell deficiencies?
``` Recurrent infections: Viral Fungal Bacterial Intracellular pathogens, e.g: mycobacteria ``` Opportunistic infections Malignancies at young age Autoimmune disease
39
First line investigations for T cell deficiencies?
Total wbc count (normally higher in children than in adults) and differential Serum immunoglobulins (surrogate marker of functional T cells) and protein electrophoresis Quantification of lymphocyte sub-populations
40
Second line investigations for T cell deficiencies?
Functional tests of T cell activation and proliferation - useful is signalling/activation defects are suspected Additional tests of lymphocyte lineage HIV TEST IS ESSENTIAL
41
Clinical presentation of antibody deficiencies?
RECURRENT BACTERIAL INFECTIONS (viral less common) ANTIBODY MEDIATED AUTOIMMUNE DISEASE: Idiopathic thrombocytopaenia - low platelet levels Autoimmune haemolytic anaemia - autoantibodies attack rbcs
42
B cell maturation defects?
Failure of lymphocyte precursore - severe combined immune deficiency Failure of B cell maturation - Bruton's X-linked hypogammaglobulinaemia Failure of IgA production - Selective IgA deficiency Failure of IgG production: Common variable immune deficiency Selective antibody deficiency
43
What is Bruton's X-linked hypogammaglobulinaemia?
Failure to produce mature B cells: No circulating B cells No plasma cells No circulating antibody after first 6 months
44
Describe selective IgA deficiency
2/3rd individuals asymptomatic 1/3rd have recurrent respiratory tract infections Genetic component but cause is unknown
45
What is common variable immune deficiency?
Heterogenous group of disorders of which the cause and disease mechanism are unknown
46
Common variable immune deficiency and consequences?
Cause and mechanism unknown: Low IgG, IgA, IgE Recurrent bacterial infections - often severe end-organ damage, e.g: bronchiectasis, persistent sinusitis, recurrent GI infection Often associated with autoimmune disease Granulomatous disease
47
First line investigations for B cell deficiencies?
Total wbc count and differential Serum immunoglobuline Serum and urine electrophoresis
48
Second line investigations for B cell deficiencies?
Quantification of B and T lymphocytes Specific antibody responses to known pathogens: Measure IgG antibodies against tetanus, Haemophilus influenzae B and S. pneumoniae If specific antibody levels low, immunise with appropriate KILLED VACCINE and repeat antibody measurement 6-8 weeks later Failure to mount a response indicates a significant defect in antibody production
49
Managing B cell deficiencies?
Aggressive infection treatment Immunoglobulin replacement - derived from polled plasma of 1000s of donors and contain IgG antibodies to a wide variety of common organisms; usually administered via iv every 3-4 weeks to maintain IgG levels within normal range and so is life long Stem cell transplantation in some situations
50
Summary of selective IgA deficiency diagnosis?
``` Serum immunoglobulins: IgM - normal IgG - often increased IgA - none IgE - normal ``` Lymphocyte subpopulations: B cells - normal T cells -normal
51
Summary of common variable immune deficiency diagnosis?
``` Serum immunoglobulins: IgM - normal but decreased IgG - decreased IgA - decreased IgE - decreased ``` Lymphocyte subpopulations: B cells - variable T cells - variable Other investigations: Failure to produce specific antibodies after test immunisation
52
Summary of specific antibody deficiency diagnosis?
``` Serum immunoglobulins: IgM - normal IgG - normal IgA - normal but decreased IgE - normal ``` Lymphocyte subpopulations: B cells - normal T cells - normal Other investigations: Failure to produce specific antibodies after test immunisation

Immunology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions