Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

USMLE Step 1 Prep > First Aid: Immunology > Flashcards

First Aid: Immunology Flashcards

You may prefer our related Brainscape-certified flashcards:
USMLE® Step 1 flashcards
1
Q

What are the functions of lymph nodes?

What causes lymph nodes to swell?

A

Nonspecific filtration by macrophages, storage of B and T cells, immune response activation

Paracortex enlarges in extreme cell response e.g. viral infection

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

What are contained within the follicle, medulla and paracortex of lymph nodes?

A

Follicle - B-cell localization and proliferation
Medulla - Medullary cords w/ closely packed lymphocytes and plasma cells and Medullary sinuses w/ macrophages
Paracortex - T-cells and high endothelial venules through which T/B cells enter blood

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

Where are the following cell types found within the spleen? Macrophages, RBCs, T cells, B cells, antigen presenting cells (APCs)

A

T cells - periarterial lymphatic sheath of white pulp
B cells - follicles of white pulp (germinal centers)
Macrophages and RBCs - in Red pulp
APCs- Marginal zone between red/white pulp (specialized Bcells also here)

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

What are asplenic patients at risk for (name specifically)?

A

decreased C3b opsonization by macrophages –> increased susceptibility to encapsulated organisms

SHiNE SKiS: Strep pneumo, H. flu type b, N. meningitidis, E. coli, Salmonella spp., Klebsiella pneumo, Strep-group b

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

What are the components of the thymus and what do they contain? Where do T and B cells mature?

A

T cells = Thymus
B cells = Bone marrow
both are produced in bone marrow

Cortex is dense with immature T cells and medulla is pale with mature T cells and Hassall corpuscles

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

What are the components of the thymus and what do they contain? Where do T and B cells mature?

A

T cells = Thymus
B cells = Bone marrow
both are produced in bone marrow

Cortex is dense with immature T cells and medulla is pale with mature T cells and Hassall corpuscles

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

What are key features in pathogen recognition within the innate immunity?

A

Toll-like receptors (TLRs): recognize pathogen-associated molecular patterns (PAMPs)

e.g. LPS (g- bacteria), flagellin (bacteria, ssRNA (viruses)

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

Where do the various MHC receptors bind, how are they encoded, and which cells express these?

A

MHC I - encoded by HLA -A,B, & C; binds TCR and CD8; expressed on all nucleated cells (not RBCs)

MHCII - encoded by HLA-DR, DP, DQ; binds TCR and CD4; only on APCs

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

Where do the various MHC receptors bind, how are they encoded, and which cells express these?

A

MHC I - encoded by HLA -A,B, & C; binds TCR and CD8; expressed on all nucleated cells (not RBCs)

MHCII - encoded by HLA-DR, DP, DQ; binds TCR and CD4; only on APCs

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

Match the HLA subtypes with associated diseases:

A3, B27, DQ2/DQ8, DR2, DR3, DR4, DR5

A

A3 - hemochromatosis
B27 - PAIR (Psoriatic arthritis, Ankylosing spondyltiis, arthritis of Inflammatory bowel disease, Reactive arthritis)
DQ2/DQ8 - Celiac disease
DR2 - MS, ha fever, SLE, goodpasture syndrome
DR3 - DMT1, SLE, graves disease
DR4 - Rheumatoid arthritis, DMT1
DR5 - Pernicious anemia –> VB12 def., Hashimoto thyroiditis

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

How do Natural killer cells destroy cells and what factors enhance their activity?

A

Induced to kill when exposed to nonspecific activation signal on target cell and/or absence of MHC I on target cell surface

Use perforin and granzymes to induce apoptosis of virally infected cells and tumor cells.

Also kills via antibody-dependent cell mediated cytotoxicity

Enhanced by IL2, IL12, IFN-beta, IFN-alpha

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

What are two methods by which T-cells can differentiate and where does this occur?

A

Positive selection (thymic cortex) - T cells expressing TCRs capable of binding surface self MHC molecules survive

Negative selection (medulla) - T cells expressing TCRs with HIGH affinity for self antigens undergo apoptosis

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

What are two methods by which T-cells can differentiate and where does this occur?

A

Positive selection (thymic cortex) - T cells expressing TCRs capable of binding surface self MHC molecules survive

Negative selection (medulla) - T cells expressing TCRs with HIGH affinity for self antigens undergo apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are two very important interactions that need to occur to activate a T cell to secrete cytokines?

A
  1. phagocytosed antigen is presented by APC onto MHC class II receptor and recognized by TCR on CD4+
  2. B7 on APC binds CD28 on CD4+ T cells activating them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does B-Cell activation and class switching occur?

A
  1. Antigen bound and endocytosed by B-cell (begins secreting IgM)
  2. Active B cell presents antigen to CD4+ Th cell and CD40 on Bcell binds CD40 ligand on Tcell
  3. Th cell secretes cytokines that determine Ig class switch of B cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the differences between Th1 helper cell and Th2 helper cell?

A

Th1 - secretes IFN-gamma to activate macrophages and IL2 to activate CD8+

Th2 - secretes IL 4, 5, 6, 13 –> recruits eosinophils and promotes IgE production

17
Q

How do cytotoxic T cells function? What protein structure allows this to occur?

A

Kill virus infected, neoplastic and donor graft cells by inducing apoptosis (perforin and granzyme method)

CD8 binds MHC 1 on virus infected cells

18
Q

A culture of cells are identified with lymphocytic origin. They produce CD3, CD4, CD25 and FOXP3 cell surface markers. What are these cells and their function?

A

Regulatory T cells - maintain specific immune tolerance by suppressing CD4 and CD8 T cell effector functions.

Produce anti-inflammatory cytokines (IL10 and TGF beta)

aka dampen the immune response

19
Q

A culture of cells are identified with lymphocytic origin. They produce CD3, CD4, CD25 and FOXP3 cell surface markers. What are these cells and their function?

A

Regulatory T cells - maintain specific immune tolerance by suppressing CD4 and CD8 T cell effector functions.

Produce anti-inflammatory cytokines (IL10 and TGF beta)

aka dampen the immune response

20
Q

What are the unique properties of the Fab and Fc portions of the antibodies?

A

Fab - light and heavy chain portion + unique antigen binding fragment

Fc - heavy chain portion only
C = Constant, Carboxyl terminal, Complement binding, Carbohydrate side chain, Determines isotype (IgM, IgA etc.)

21
Q

What are three main roles of antibodies?

A
  1. Promote phagocytosis
  2. Prevent bacterial adherence
  3. Activate complement cascade –> enhance opsonization and lysis
22
Q

What are three main roles of antibodies?

A
  1. Promote phagocytosis
  2. Prevent bacterial adherence
  3. Activate complement cascade –> enhance opsonization and lysis
23
Q

What are the default immunoglobulins expressed by mature B lymphocytes and what could they become? how does that occur?

A

IgM and IgD on surface by default

Isotype class switching can occur in germinal center of lymph nodes –> become Plasma cells secreting IgA, IgE, IgG

CD40 ligand and cytokines mediate this switch

24
Q

What is the role of IgG?

A

Most abundant in SERUM, and main Ab in delayed antigen response; fixes complement; crosses placenta (passive infant immunity); Opsonizes bacteria; neutralizes bacterial toxins and viruses

25
Q

What is the role of IgA?

A

Prevents attachment of bacteria and viruses to mucous membranes; monomer in serum, dimer when secreted; released in secretions (tears, saliva, mucus, breast milk)

most abundant overall

26
Q

What is the role of IgM?

A

Immediate response to an antigen. Fixes complement (does not cross placenta). Monomer on B cells, pentamer when secreted

27
Q

What are the roles of IgD and IgE?

A

IgD - unclear function (on B cells and in serum)

IgE - Binds mast cells and basophils; cross links when exposed to allergen –> immediate type I hypersensitivity rxn via histamine release; immunity to worms via eosinophils. lowest concentration in serum

28
Q

What are the roles of IgD and IgE?

A

IgD - unclear function (on B cells and in serum)

IgE - Binds mast cells and basophils; cross links when exposed to allergen –> immediate type I hypersensitivity rxn via histamine release; immunity to worms via eosinophils. lowest concentration in serum

29
Q

Why do some vaccines require boosters? (e.g. pneumococcal vaccine)

A

Thymus independent antigens are produced because they lack a peptide component (e.g. LPS from g- bacteria). Cannot be presented by MHC to T cells so weakly immunogenic.

30
Q

Name the positive (upregulated acute phase reactants):

What cytokines induce their release?

A

Serum amyloid A, C-reactive protein, Ferritin, Fibrinogen, Hepcidin

Induced by IL6, IL1, TNF alpha, and IFN gamma

31
Q

How is the classic complement pathway mediated? What is the final product of complement cascade?

A

IgG or IgM

Membrane attack complex (MAC)

32
Q

What disorder may cause complement mediated lysis of RBCs?

A

GPI anchor deficiency (DAF) –> paroxysmal nocturnal hemoglobinuria

33
Q

What is the purpose of IL 10, IL 12, TNF-alpha and interferon-gamma?

A

IL 10 - MODULATES inflammatory response (inhibits action of active T cells and Th1)

IL 12 - induce differentiation of T cells into Th1, activate NK cells, B cells may secrete

TNFa- Mediates septic shock, activates endothelium, causes leukocyte recruitment, vascular leak

IFNg - Antiviral and antitumor properties; activates NK cells to kill virus infected cells, increases MHC expression and antigen presentation in all cells

34
Q

What are CD 15, 16 and 19 cell surface markers specific for?

A

CD15 - granulocytes and Reed Sternberg cells (used to dx Hodgkins dz)

CD16 - low affinity Fc receptor on NK cells, neutrophils and macrophages

CD 19 - B cells

35
Q

Two major cytokines that dampen the inflammatory immune response:

A

IL 10 and TGF beta

36
Q

Two major cytokines that dampen the inflammatory immune response:

A

IL 10 and TGF beta

37
Q

Describe the 4 hypersensitivity reactions in simple form:

A

ACID

I. Anaphylactic and Atopic
II. Cytotoxic (antibody mediated)
III. Immune complex
IV. Delayed (cell mediated)

USMLE Step 1 Prep (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions