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Flashcards in 2 Hour Surprise Complement Lecture Deck (52):
1

Immunization

Ag stimulus that stimulus specific adaptive immune response that can be recalled during subsequent infections
Passive - Ab/antiserum only
Active - intro Ag that induces adaptive immune response

2

Herd immunity

Immunity acquired when a critical number of individuals in a population are vaccinated

3

Considerations for immunization schedule

Timing of exposure
Immunological maturity of child
Passively transferred Ab that may interfere with immune response of vaccine
Interference

4

Passively transferred maternal IgG is completely degraded

At 9 months of age

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Criteria for effective vaccine (only indicated item)

Must induce protective T cells
Some pathogens, particularly intracellular, are more effectively dealt with by cell-mediated responses
Also need T cells to activate B cells for Ab production

6

Inactivated vaccines contain

Killed/ inactivated viruses
Subunits or components
Toxoid
Conjugated Ag

7

Adjuvants

Increase vaccine efficacy
Bacterial components or media that prolongs exposure or induces mild inflammation to attract phagocytes (increases chance that Ag will be picked up and presented)

8

Conjugate vaccines

Capsular polysaccharides from pathogenic bacteria elicit a t independent response
Must conjugate the vaccines by linking to a polysaccharide to Ag or toxoid to form an immunogen (t-dependent Ag)

HiB vaccine

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Immunological tolerance

Unresponsiveness of adaptive immune system to Ag as a result of inactivation or death of Ag-specific lymphocytes, induced by exposure to the Ag

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Factors that promote immune tolerance

Soluble, aggregate free, simple small molecules
Improper processing
Oral/IV presentation
Age (too young or too old)
Dose (too large or small)

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Characteristics that promote adaptive immune response

Large, aggregated complex molecules
Proper processing
Subcutaneous or IM exposure
Intermediate dose
not young af or old af

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Functions of complement

Triggering, amplification of inflammation
Attraction of phagocytes by chemotaxis
Clearance of immune complexes
Cellular activation
Direct microbial killing
Development of humoral response

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Classical pathway is activated by

Ab-Ag complex stimulates C1 binding
Either IgG or IgM (must bind multiple globular domains of C1q in order to activate)

14

Alternative pathway activated by

Spontaneous lysis of C3

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Lectin pathway initiated by

MBL binding lectin and recruiting MASP1 + MASP2

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C1qrs can be inhibited by

C1 inhibitor
Binds C1r and C1s to prevent cleave of C4 and C2

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C3 convertase classical pathway consists of

C4b2a

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C5 convertase classical pathway consists of

C4b2a3b

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Inserts into membrane and forms small pore

C4b67

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Recruits 10-16 copies of C9

C8

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Host cells protect themselves from spontaneous lysis of C3 by expressing high levels of what on their cell surface

Sialic acid

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Factor D

Cleaves factor B --> Bb and Ba

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Binds C3bBb and C3bBb3b and prevents increases half-life

Properdin

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Alternative C3 convertase

C3bBb

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Alternative C5 convertase

C3bBb3b

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Binds N-acetylglucosamine on bacterial cell wall to induce autocleavage of MASP1 and MASP2

Ficolin

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Deficiency resulting in: High degree of SLE from failure to clear circulatory immune complexes - deposits on endothelial cells and activates alternative complement, local inflammation

C2 deficiency

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Deficiencies in Factor H and Factor I mimic

C3 deficiencies - unregulated C3b generation exhausts C3 from serum

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Deficiency results in increased susceptibility to Neisseria gonorrhoeae and N. meningitidis

MAC deficiencies (C5-C9)

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Factor I

Cleaves C3b and C4b
Cofactors: Factor H, MCP, C4BP, CR1
SERINE PROTEASE

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Factor H

Binds C3b and displaces Bb
Also serves as a cofactor for Factor I cleavage of C3b

32

C4BP

C4 binding protein - binds C3b and displaces C2
Cofactor for Factor I cleavage of C4b

33

DAF functions in a similar capacity as what two RCAs?

Factor H (alternative pathway)
C4BP (classical pathway)

34

MCP

Also known as CD46
Cofactor for Factor I cleavage of C3b and C4b

35

DAF

Displaces C2b from C4b (classical)
Displaces Bb from C3b (alternative)
Aka inactivates the C3 convertases

36

CD59

Blocks C9 binding and prevents formation of MAC

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Vibronectin

S protein - prevents C5b67 from penetrating (heh) membrane

38

Hereditary Angioneurotic Edema

C1 inhibitor deficiency
Swelling attacks from physical trauma/emotional stress
Affects extremities, face, GI tract
Treat with androgens (increase transcription of C1 inhibitors)

39

Paroxysmal nocturnal hemoglobinuria

Deficient DAF
Hemolytic disorder with spontaneous episodes of RBC lysis, leukocytes, platelets sensitive to complement
Treat with EPO

40

Type III Hypersensitivity

Little Ab and excess Ag will lead to small immune complexes that are not cleared from circulation because they do not fix complement --> local inflammation --> basophils degranulation, platelet aggregation --> increase vascular permeability --> complex deposition --> attract neutrophils who further mess it up
==> increased Bp and vascular turbulence

41

Biological functions of complement

Opsonization (C3b, and a little C4b)
Waste management (C3b binds CR1 of RBCs to transport Immune complexes to spleen/liver)
Cell lysis (mac)
Inflammatory mediators (anaphylatoxins C3a, C5a, C5b67)

42

Prokinin

Also known as C2b - cleaved by plasmin to yield kinin --> edema

43

Epstein Barr virus abuses complement to gain entry into cells by

Using CR2 as a receptor for attachment

44

Measles utilizes the complement system to infect cells by

Using MCP (CD46) as a receptor

45

West Nile hijacks complement machinery by

Coating viral particles in C3b to gain entry into cells by CR3

46

Neisseria meningitidis escapes complement degradation by

Expressing protein on its cell surface that block the formation of convertases

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CH50 assay tests for

Test ability of patients blood to perform Complement mediated hemolysis

48

Classical deficiency

Increases risk of developing immune complex diseases like SLE

49

MBL deficiency

Increases risk of infection by yeast sacchromyces cerevisiae and encapsulated bacteria

50

Alternative pathway deficiency

Decreases opsonization activity and increases risk of infection by encapsulated bacteria

51

C3 deficiency

Leads to
Defective opsonization
Defective leukocyte chemotaxis
Decreased bactericidal killing activity (no MAC)
Also indicated in immune complex disease

52

MAC deficiency

Increased risk of infection to N. meningitidis