Rosa

Question 1

Acute infections

Answer 1

influenza and rotavirus

Question 2

chronic infections

Answer 2

HBV, HCV

Question 3

latent infection

Answer 3

herpesvirus

Question 4

slow infection

Answer 4

HIV

Question 5

types of ab-mediated immunopathology

Answer 5

immune complex disease and ab dependent enhancement

Question 6

Transmembrane receptors

Answer 6

expressed on myeloid cells:
TLRs
- cytoplasmic membrane and endosomal membrane
CLRs

Question 7

cytosolic receptors

Answer 7

RIG-I-like receptors
Nod-like
AIM2-like

Question 8

How can viruses induce immunopathology?

Answer 8

exaggerated acute or chronic inflammation, CTL-mediated, Ab-mediated

Question 9

How are type I interferons induced? function?

Answer 9

induced by PRM recognition of PAMPs

- act as autocrine and paracrine; bridge between innate and adaptive immunity

Question 10

What is Type I IFN?

Answer 10

Type I IFN enhance antigen presenting function of professional APCs and enhance antiviral function (B cells, T cells and NK)

Question 11

What are ISG?

Answer 11

block viral replication cycle, promote viral clearance, induce antiviral state in uninfected cells and apoptosis in infected cells

Question 12

NK cells effector mechanisms

Answer 12

induced by IFNs

• direct cellular cytotoxicity; “missing self” model (down regulation MHC I) and Ab dependent cell mediated cytotoxicity
• production of inflammatory cytokines that promote influx of CD8+ T cells

Question 13

Avoidance of NK cell activation

Answer 13

MHC-1 homologs binding to inhibitory NK receptors -> selective expression of NK inhibitory MHC molecules

Question 14

Antibody mediated effector mechanisms

Answer 14

only effective during virus extracellular stage

• virus neutralization: prevents attachment and entry via secreted Abs
• virus agglutination: easier target for immune cells
• opsonization: clearance by phagocytosis
• activation of complement system: phagocytosis and/or direct lysis of enveloped viruses
• ADCC

Question 15

Immune mechanisms that are targets for viral evasion

Answer 15

antigenic variation, latency, apoptosis interference, miRNAs

Question 16

Antigenic drift vs shift

Answer 16

drift = accumulation of mutations in genes that code for receptor binding sites
shift = genetic recombination of two strains forming different surface antigens
- most recent influenza strain via antigenic shift

Question 17

persistent latent infection

Answer 17

viral genome exists as episome (naked, circular DNA) in host nucleus; no virus produced until reactivation

Question 18

Immune tolerance and diseases associated

Answer 18

unresponsiveness to antigen that is induced by previous exposure to that antigen
- immune reactivity = autoimmune disease, chronic inflammation and pregnancy failure

Question 19

Self tolerance

Answer 19

tolerance to self antigens

• antigen specific; resulting from recognition by individual clones of lymphocytes
• eliminate and inactivate lymphocytes that express high-affinity receptors for self antigens
• induced in immature self reactive lymphocytes in primary lymphoid organs (central tolerance) or mature lymphocytes in secondary tissue (peripheral tolerance)

Question 20

central T cell tolerance

Answer 20

in thymus

• negative selection = deletion
• development of regulatory T cells

Question 21

Peripheral T cell tolerance

Answer 21

1. deletion
2. anergy (functional unresponsiveness
3. suppression by regulatory T cells
4. clonal exhaustion

Question 22

What is a tolerogenic dendritic cell?

Answer 22

missing DAMPs/PAMPs

Question 23

T cell anergy mechanisms

Answer 23

1. block of TCR-induced signal transduction

2. inhibitory receptors; CTLA-4 and PD-1

Question 24

types of inhibitory receptors

Answer 24

CTLA-4
- expressed on regulatory and antigen activated T cells
- binds B7, competitive inhibitor of CD28
PD-1
- expressed on antigen activated T cells
recognize PD-L1 on APCs and many other tissue cells and PD-L2 mainly on APCs

Question 25

reg T cells

Answer 25

maintain self tolerance and immune homeostasis

Question 26

T reg cell mechanisms

Answer 26

suppress activation, proliferation and cytokine production of CD4+ and CD8+ T cells - require intercellular contact independent of TCRs - produce immunosuppressive cytokines - induce tolerogenicity on DCs - suppress B cells and DCs

Question 27

Roles of reg T cells in self-tolerance and autoimmunity

Answer 27

- promote tissue repair - stem cell proliferation and differentiation - control fat metabolism - maintain fetal tolerance - prevent elimination of commensal microbes

Question 28

CD8+ Treg cells function

Answer 28

- block proliferation of naive and effector T cell via direct contacts - secrete Il 10 and TGF beta - induce tolerogenicity on immature DCs

Question 29

immune privilege

Answer 29

anatomical regions that are naturally less subject to immune responses - CNS, eyes, testes

Question 30

mechanisms in immune privilege

Answer 30

``` physical barriers? Fas:FasL immunosuppressive cytokines actions of Treg cells immune deviation: bias from Th1 inflammatory T subset to Th2 subset ```

Question 31

What is a tolerogen?

Answer 31

experimental foreign Ag that binds to Ag receptors of lymphocytes and induces activation

Question 32

Maternal fetal tolerance

Answer 32

- high presence CD4+ nTreg - cytokine microenvironment - non professional APCs lack costimulatory molecules - almost no MCH class I and II - some placental cells express FasL, kill Ag before reach fetus

Question 33

Neonatal tolerance

Answer 33

- IgG and IgA protection - high IL10 and TGF beta - few T cells - reduced Ag presentation capacity - B cells: inefficient maturation and differentiation

Question 34

Oral tolerance microbes

Answer 34

commensal organisms - induce tolerogenic Dcs - promote differentiation of Th0 cells toward Treg - promote homing of Treg - Treg secrete immunosuppressive cytokines Food antigens - absence of DAMPs/PAMPs induce tolerogenic DCs and T cell tolerance

Question 35

orthotropic transplantation

Answer 35

diseased organ removed and transplanted organ placed in same location

Question 36

heterotypic transplantation

Answer 36

transplanted organ placed in different location

Question 37

autologous autograft

Answer 37

from one part of body to another

Question 38

syngeneic isograft

Answer 38

between genetically identical individuals

Question 39

allogeneic allograft

Answer 39

between different members of same species - Ags = alloantigens - Lymphocytes and Abs = alloreactive

Question 40

Xenogeneic xenograft

Answer 40

between members of different species - Ags = xenoantigens - lymphocytes and Abs = xenoreactive

Question 41

allorecognition

Answer 41

refers to recipient immune responses against donor MHC

Question 42

H-2 complex

Answer 42

HLA in mice

Question 43

MHC haplotype

Answer 43

determines which peptides bind and how they bind | - influences how individual responds, susceptibility to certain diseases and transplant success

Question 44

Alloantigens immune responses

Answer 44

humoral or cell mediated

Question 45

Direct alloantigen recognition

Answer 45

recognize intact, unprocessed MHC molecules in graft

Question 46

Indirect alloantigen recognition

Answer 46

only recognize in context of recipient's MHC molecules

Question 47

types of allograft rejection

Answer 47

hyper acute, acute, chronic

Question 48

Hyper acute rejection

Answer 48

thrombotic occlusion, mediated by preexisting antibodies, complement activation and inflammation

Question 49

Acute rejection

Answer 49

injury to graft parenchyma and blood vessels, mediated by alloreactive T cells and antibodies, inflammation caused by cytokines - intravascular thrombosis

Question 50

chronic rejection

Answer 50

distinct pathologic changes, activation alloreactive T cells and secretion IFN gamma