Immunology Flashcards
1
Q
Type 1 Hypersensitivity
- What are the humoral components?
- What are the cellular components?
A
- IgE
- Basophils and Mast Cells
2
Q
Type 2 Hypersensitivity
- What are the humoral components?
- What are the cellular components?
A
- IgG, IgM, complement activation
- NK cells, eosinophils, macrophages, neutrophils
3
Q
Type 3 Hypersensitivity
- What are the humoral components?
- What are the cellular components?
A
- Ag-Ab Complex Deposition, complement activation
- Neutrophils
4
Q
Type 4 Hypersensitivity
- What are the humoral components?
- What are the cellular components?
A
- NONE
- T-cells & Macrophages
5
Q
What are examples of Type 1 Hypersensitivity?
A
Anaphylaxis
Allergies
6
Q
What are examples of Type 2 Hypersensitivity Reactions?
A
Autoimmune Hemolytic Anemia
Goodpasture Syndrome
(glomerulonephritic + hemoptysis)
7
Q
What are examples of Type 3 Hypersentivity Reactions?
A
Serum Sickness (joint pain + pruritic rash)
Poststreptococcal Glomerulonephritis
Polyarteritis Nodosa
(vasculitis with fibrinoid necrosis)
8
Q
What are examples of Type 4 Hypersensitivity reactions?
A
Contact Dermatitis (poison ivy, nickel allergy)
Graft vs. Host Disease
(maculopapular rash, jaundice, diarreha, hepasplenomegaly)
Tuburculin Skin Test (PPD)
9
Q
How does serum sickness present?
A
- Pruritic skin rash
- arthralgia (joint pain)
- Decreased C3 & C4
- fever
10
Q
What activates macrophages?
What cell secretes it?
A
Interferon-gamma and LPS
secreted by Th1 cells
11
Q
What do macrophages secrete to recruit other macrophages and monocytes?
A
TNF-alpha
12
Q
What cell is responsible for killing cells with decreased or absent MHC class I?
A
Natural Killer Cells
13
Q
What are the common causes of SCID?
A
- Defective IL-2R gamma chain
- Adenosine Deaminase Deficiency
- MHC Class II Deficiency
14
Q
How does SCID present?
A
-chronic diarrhea
-failure to thrive
-thrush
-recurrent infections
(due to Decreased T-Cells and B-cells)
15
Q
Which 4 key mediators attract and activate neutrophils?
A
1. LTB4
2. C5a
3. IL-8
4. bacterial products
16
Q
Chronic Granulomatous Disease
- Pathogenesis
- What are u at increased risk for?
- What test is used to detect it?
A
1. NADPH Oxidase deficiency
(decreased oxidative burst in neutrophils)
- Infection via Catalase Positive organisms
- Nitroblue Test: failure to turn blue
DHR Flow Cymmetry: decreased fluorescenst green
17
Q
Toxic Shock Syndrome Toxin
(superantigens)
What cells are activated?
A
T lymphocytes
(very large amount get activated by the superantigen)
Macrophages
18
Q
Which cell belongs to the surface marker:
- CD4
- CD8
- CD14
- CD20
A
1. CD4 = T-helper cell
2. CD8 = T-killer cell
3. CD14 = Macrophage
4. CD20 = B-cells
19
Q
Anaphylaxis
- What are the 2 main cells involved?
- Degranulation of these cells releases what?
A
- Mast Cells and Basophils
- Histamine and Trypsin
(Note: Trypsin is often used as a marker for mast cell activation)
20
Q
What triggers the release of histamine (and trypsin) from mast cells or basophils?
A
Binding of IgE to the mast cell via the IgE receptor (FCΣR1) results in cross-linking of multiple bound IgE molecules resulting in aggregation of FCΣR1 receptors which causes degranulation
21
Q
What substance is most likely to be released following a bee-sting in an allergic child?
A
Histamine
22
Q
What region of the Antibody is A+B?
What attaches there?
A
The hypervariable region of the FAB
(antigen binding fragment)
It is where the antigen binds
(only 1 antigenic specificy expressed per B cell)
23
Q
What region of the Antibody is E?
What attaches there?
A
The Fc (phagocytic) Region
The Fc receptors bind macrophages, neutrophils and B-cells
24
Q
What region of the Antibody is D?
What attaches there?
A
The Compliment Binding region
It is where the compliment (C1) binds
25
What region of the **_Antibody_** is C?
What attaches there?
The **Disulfide bonds** that hold the 2 heavy chains together
Nothing attaches there
26
What are the 2 main cells activated in **Tuberculosis**?
**_Macrophages_** and **_CD4+ T-cells_**
(since Tb replicates within the **phagosome**, it will be displayed on **MHC class II**)
27
**_alpha and Beta (Type 1) Interferons_**
1. Which cells secrete them ?
2. What is their function?
1. They are secreted by cells is response to **_viral infections_**
2.
They **_downregulate protein synthesis_** in infected cells
**_increase MHC class I_** expression in all cells
28
**_gamma (Type 2) Interferon_**
1. Which cells secrete them ?
2. What is their function?
1. They are secreted by **T-cells** and **NK cells**
2.
Promotes **Th1 differentiation**
Increases **expression of MHC Class II** on APCs
Activates and improves **macrophage killing** ability
29
**_Calcineurin_**
1. What does it do?
2. How does it do it?
3. Which drugs inhibit it?
1. It promotes growth and differentiation of **_T-cells_**
2. It **phoshorylates NFAT** which then **binds IL-2** and promotes growth+differentiation of T-cells
3. **_Cyclosporine_** and **_Tacrolimus_**
(immunosuppresants)
30
**_Bcl-2_**
1. What is it?
2. What it is associated with?
**1. Apoptosis inhibitor**
2. Follicular lymphomas t(14;18) translocation
31
**_p53_**
1. What is it?
2. How does it work?
1. **Tumor supressor**
2. It causes **cell cycle arrest** and **apoptosis**
32
**_Neurofibromin_**
1. What is it?
2. How does it work?
1. Tumor supressor
2. It **supresses Ras**
(a cell proliferation activator)
33
What **enzyme** is activated in both pathways of **apoptosis**?
## Footnote
**Caspases**
34
**_Metalloproteinases_**
1. What is it?
2. What is their function?
1. Zinc containing enzyme that **degrades ECM components**
(degrades collagen, fibronectin, laminin)
2. **Wound Healing**
35
What is the main function of **_IL-1_**?
Fever
Acute Inflammation
"**_Hot_** T-Bone stEAK"
36
What is the main function of **IL-2**?
Stimulates growth of all **T-cells**
Stimulates growth of **NK cells**
"Hot **_T_**-Bone stEAK"
37
What is the main function of **_IL-3_**?
Stimulates growth of and differentiation of **bone marrow** stem cells
"Hot T-**_Bone_** stEAK"
38
What is the main function of **IL-4**?
Promotes **IgE class switching**
Promotes **Th2 differentiation**
Promotes **B-cell growth**
"Hot T-Bone st**_E_**AK"
39
What is the main function of **_IL-5_**?
Promotes **IgA class switching**
Stimulates growth/proliferation of **Eosinophils**
Promotes **B Cell Growth**
"Hot T-Bone stE**_A_**K"
40
What is the main function of **_IL-6_**?
Stimulates **a**_k_**ute-phase protein production**
**Causes Fever**
41
What is the main function of **_IL-8_**?
**Chemotaxis for neutrophils**
42
What is the main function of **_IL-10_**?
**Attenuates the inflammatory response**
"**TGF-_B_** and **IL-10** **_B_**oth at**_TEN_**uate the immune response"
43
What is the main function of **_IL-12_**?
Induces differentiation of T cells in **_Th1 cells_**
Activates **NK cells**
44
What is a major result of **impaired interferon signalling?**
Increased likelihood of **mycobacterial** infection
45
What are the most common ways that **_Toxic Shock Syndrome_** occurs?
How does it present?
Prolonged **tampon** use
Prolonged **nasal packing**
Presents as **fever**, **hypotension**, **end-organ failure**, **diffuse eythematous rash**
46
What is the difference between a **superantigen** and a normal antigen?
Superantigens bind to the **invariant region** of MHC-II _without_ being processed
(this results in massive T-cell activation and cytokine release)
NOTE: antigents are normally processed in the lysosome before being presented
47
What is the difference between the **_structure_** of **MHC-I** and **MHC-2?**
_MHC-I:_
**- Heavy chain (alpha 1,2,3)**
**- Beta-2 Microglobullin**
_MHC-II_
**Alpha chain (alpha 1,2)**
**- Beta chain (beta 1,2)**
48
Which cells express:
## Footnote
**1. MHC Class I**
**2. MHC Class II**
1. **All** nucleated cells
2. **APCs** only (dendritic cells, B-cells, macrophages)
49
**_X-Linked (Bruton) Agammaglobulinemia_**
1. What causes it?
2. What does it result in?
3. What does it increase risk for?
1. BTK mutation (x-linked recessive)
2. No B-cells
3.
- pyogenic bacteria infections
- Giardia infections
- enteroviruses
50
Which surface markers (CD??) will be _absent_ in a patient with X-linked (Bruton) Agammaglobulinemia?
**CD19**
**CD20**
**CD21**
(B-cell surface markers)
51
**_Poliovirus_**
What is the diffrence between the **Live Attenuated Oral (Sabin) Vaccine** and the **Inactivated IntraMuscular (salk) vaccine**?
Where is this difference seen the most?
The **live attenuated oral (sabin) vaccine produces a much stronger mucosal IgA response** since it actually goes through the digestive system
The difference in IgA response is seen mainly at the **intestinal and oropharyngeal mucosa** since the oral live vaccine directly stimulates these areas.
52
**_Wiskott-Aldrich Syndrome_**
What mutation causes it?
What does it result in?
How does it classically present?
1. **WASp** gene mutation
2. **B+T-cell disorder:** defective Ag presentation
**3. Thrombocytopenia, Eczema, Recurrent pyogenic infections**
**"WATER":**
**_W_**iscott **_A_**ldrich: **_T_**hrombocytopenia **_E_**czema, **_R_**ecurrent pyogenic infections
53
Which antibody subtype can cross the placenta?
(Ig?)
**IgG**
54
Which **_antibody_** is seen in the following blood type:
1. Type A
2. Type B
3. Type AB
4. Type O
1. Anti-B (**IgM**)
2. Anti-A (**IgM**)
3. None
**4. Anti-A + Anti-B (IgG)**
(NOTE: IgG can cross placenta)
55
**_ABO Hemolytic Disease of the Newborn_**
How come **fetal hemolysis** can occur in **mothers of Type O** blood but not the others?
Mothers of **type O contain** **_IgG_** antibodies to type A and type B blood, so if their child is born type A or B the antibodies can cross the placenta.
Other blood types result in IgM antibodies which cannot cross the palcenta (Only IgG can cross placenta)
56
Why is the **H. Influenzae Tybe B vaccine** given **conjugated to a carrier protein**?
Since the conjugated elicits a B-cell and **T-cell**
It will also allow for **immunogenicty in infancy.**
(A nonconjugated polysaccharide vaccine will only elicit a B-cell response)
57
Which cells and cell products are primarily responsible in formation of **_granulomas_**?
Macrophages secrete **_IL-12_**, which stimulates **_Th1_** differentiation
Th1 cells secrete **_IL-2_** which increases Th1 proliferation and **I****_FN-Y_** which activates macrophages
58
Which cytokines result in **reduced inflammation**?
**TGF-B** and **IL-10**
"TGF-_B_ and IL-_10_ **_B_**oth at**_TEN_**uate inflammation"
59
**_Hyperacute Transplant Rejection_**
1. Time of onset
2. Etiology
1. minutes to hours
2. Recipient has **preformed antibodies** to the graft (organ)
60
**_Acute Transplant Rejection_**
1. Time of onset
2. Etiology
1. \<6 months
2. **Exposure to donor antigens induces humoral/cellular response**
61
**_Chronic Transplant Rejection_**
1. Time of onset
2. Etiology
1. \>6 months
2. Chronic low-grade immune response
62
How does **_Hyperacute Transplant rejection_** present?
Can it be reversed?
**Thrombosis of graft vessels** which causes **ischemia/necrosis**
No it cannot be reversed, graft must be removed
63
How does **_Chronic Transplant rejection_** present?
**_Vasuclar wall thickeninig, intersitial fibrosis and parenchyma atrophy_**
Heart: accelerated **atherosclerosis**
Kidney: **fibrosis**
Liver: **vanishing bile duct syndrome**
Lungs: **Brochiolitis obliterans**
64
How does **_Acute Transplant rejection_** present?
Can it be reversed?
**Vasucilitis of graft vessels** with a **dense intersitial lymphocitic infiltrate**
Yes, can be reversed with immunosupressants
65
**_The Candida Antigen Skin Test_**
1. What is it testing?
2. What type of hypersensitivity is it?
1. It asses the activity of **T-cell mediated immunity** via the recruitment of **CD4, CD8** T-cells and **macrophages**
**2. Type IV sensitivity (T-cell)**
66
**_Eosinophils_**
1. Against what type of organism to they play a role in defence?
2. What is their role?
1. Against **parasites**
2. They get stimulated by **antibodies** bound to the parasitic organism and destroy the parasite via **antibody-dependant-cell-mediated cytotoxicity**
67
**_Chediak-Higashi Syndrome_**
1. What is it?
2. How does it classically present?
1. A disorder of neutrophil **phagasome-lysosome fusion**
(autosomal recessive)
2.
- **immunodeficiency** (defective neutrophils)
- **albinism**
- **neurological defects**
68
What type of vaccine is the **_tetanus vaccine_**?
How does it work?
**Inactivated toxoid vaccine**
It triggers the production of **antitoxin antibodies**
(active immunity)
69
What tests can be used to detect **_Chronic Granulomatous Disease?_**
**_1. Nitroblue Tetrazolium (NBT) Testing_**
Properly functioning neutrophils will produce reactive oxygen species that will turn the NBT from yellow to **blue**
**_2. Dihydrorhodamine (DHR) Flow Cymmetry_**
Asseses the production of superoxide radicals by measuring the conversion of DHR to Rhodamine (a **fluorescent green** compound)
70
**_Rh Hemolytic Disease of the Newborn_**
1. What is the mother and child bloodtype?
2. Does it occur after the first pregancy?
3. How does it occur?
1. **Rh- mother** & **Rh+ fetus**
2. No it does not occur in the 1st pregnancy, only **subsequent pregnancies**
3. Mother is exposed to fetal blood during delivery where she forms **_anti-D (Rh) IgG_**. In subsequent pregnancies the Abs can cross the placenta and cause hemolysis of RBCs
71
How does **_Rh hemolytic disease of the newborn_** present?
**Jaundice** shortly after birth
**Kernicterus** (bilirubin deposits in basl ganglia - often fatal)
**Hydrops Fetalis / Generalized Edema**
**+ Direct Coombs Test** (RBCs coated with antibodies)
72
**_PD-1 Receptor_**
**(Programmed Cell Death Protein-1)**
1. When its bound by its ligand what occurs?
2. What cells upregulate this ligand?
1. It downregulates the immune response by **inhibiting cytotoxic T-cells**
2. **Cancer cells**
(therefore _antibodies_ against PD-1 and its ligand can be used for cancer therapy)
73
**_Poststeptococcal Glomerulonephritis_**
1. How does it present
2. What type of hypersensitivity reaction is it?
3. What causes it?
1. it is a **_nephritic_** syndrome **(hematuria, edema, HTN)** caused by **immune complex deposition** along the glomerular basement membrane
2. **_Type III_ hypersentivity** (antibody-antigen complex)
3. It occurs 2-4 weeks after a streptococcal infection (impetigo, cellulitis, pharyngitis)
74
Which part of the Lymph Node are the arrows pointing at?
What cellular process is undergone there?
**_Germinal Centers_**
## Footnote
**Isotype Switching**
75
In a patient with Small Intestine Bacterial Overgrowth which vitamins would we expect to see elevated? Decreased?
## Footnote
**_Elevated: Vitamin K , Folate_**
Decreased: A, D, E, B12
76
What are the 2 most important **_opsonins_** for phagocytosis?
**_IgG_** & **_C3b_**
77
In **_SLE_** what autoantibodies are present?
1. Antinuclear Antibodies (non-specific)
2. Anti-double-stranded DNA antibodies (specific)
3. **Anti-smith Antibodies** (Specific)
78
**_C1 Esterase Inhibitor Deficiency_**
1. What does it cause?
2. Labs
3. What medication is contraindicated in these patients?
**1. Hereditary _Angioedema_**
(swelling of the skin, most common in face, lips, tongue)
**2. Overactive _C1_, decreased _C4_, increased _bradykinin_**
**3. ACE Inhibitors**
(since they can cause angioedema due to inc. bradykinin)
79
The inflammatory response to **_Septic Shock_** is mediated by what **cytokines**?
**TNF-alpha**
**IL-1**
**IL-6**
80
A patient presents with jaundice, hepatosplenomegaly, rash and diarrhea 1 months after getting a liver transplant.
1. Most likely diagnosis
2. Pathogenesis
1. Graft vs Host Disease
2.
T-cells from the transplanted organ reject host cells
(results in severe organ dysfunction)
81
Hepatitis B Vaccine
1. What type is it?
2. What is it made of?
3. How does it prevent infection?
1. Subunit Vaccine
2. HBsAg
(which then generates antibodies)
3. Antibodies bind to viral envelope inhibiting viral entry
82
A patients who has been diagnosed with celiac disease and 3 previous episodes of pneumonia develops anaphylaxis in response to a blood transfusion, what is the most likely diagnosis?
**_Selective IgA Deficency_**
Clinical Features
- **_A_**symptomatic (usually)
- **_A_**irway + GI infections
- **_A_**utoimmune Diseases
- **A**naphylaxis during blood transfusion
83
A patient has painful and deformed hands and fingers which improve as the day goes on.
1. What is the most likely diagnosis?
2. This patients serum is most likely to contain antibodies against what?
1. **Rheumatoid Arthritis**
2. IgM antibodies **against Fc portion** of human IgG
