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Flashcards in Immunology of infectious Disease Deck (31):
1

What are the features of Extracellular Bacterial infections?

Multiply outside the host cell
Tissue Destruction
Induce inflammation!
Toxins that kill host cells
Immunity by killing EC bacteria and neurrialize toxin

2

How does the innate immunity deal with EC bacteria?

Phagocytosis= first line of defense
Neutrophils in Blood
Macrophages in tissue
Pahgocytes recognize bacterial structures(polysaccharides, peptides,
Fc Receptors and C3b receptors to bind IgG and C3b
Phagocytes remove bacteria in the lymph nodes and the spleen

3

What are examples ofExtracellular Bacteria?

Staph, strep, Neisseria, E coli, Clostridium

4

What is the first immune cell to arrive at the site of infection?

Neutrophils.

5

What are the most important opsonins?

C3b and IgG

6

WHat is the Fe binding molecule that keeps it from bacteria?

Lactoferrin

7

What activates the Alternative pathway of compliment activation?

Peptidoglycan and LPS
Leads to lysis or opsinization

8

What complement deficiencies lead to Neisseria Infections?

C5-C9 dificiencies

9

What is the effect of Complement on G- and G+ bacteria?

Lyses G- Bacteria
Opsonizes G+ bacteria

10

How does Adaptive immunity attack extracellular bacteria?

IgG opsonizes and enhances Phagocytosis
Toxin specific Ab neutralizes toxins
IgM and IgG activate classical complement => Lyse Bacteria

11

What Immunoglobulin can cross the placenta?

IgG

12

What type of infections is baby vulnerable to at 6 mo old?

S. Pneumo
N meningiditis
H. influenzae B

13

What Bacteria produce M protein? What does it do?

S. Pyogenes and S. Pneumo
Many forms mean that one type of Ab may not work against next infection

14

What is the Ig at Mucosal sites?

IgA
Fixes Comlement

15

What happens to a Pt that is Deficient in IgA?

IgM Ab can compensate
Can be more suceptible to URT infections (mucosa)

16

How do EC bacteria evade immunity?

Polysaccharide capsule
Variation of surface antigen
IgA Protease(Neisseria and Hemophilus)
Interfere with complement activation(S. Pyogenes, S pneumo)
S. Typhi => Type 3 secretion system

17

What are the bad effects of the Immune response?

Septic Shock: HypoTn and DIC
Superantigens

18

What are the disease Causing Ab?

Rheumatic Fever
Post Strep glomerulonephritis

19

What Bacteria are included in Spirochetes?

Treponema Pallidum
Borrelia Burgdorpheri
Leptospira

20

What are features of Spirochete Infections

Cant penetrate unbroken skin
Arthropod vectors
Local Multiplication
Periods of latency

21

How does the immune system fight Spirochete infections?

Neutrophils, Phago
ADAPTIVE better
T pallidum => strong cell mediated and humoral immunity
Th1
Ab => opsonzation + protective immunity after latent syphilis
Classical compliment for Borrelia

22

How does T pallidum evade immunity

lacks virulence factors
Hard to kill

23

How does B Burgdorpheri evade immunity

Coats with amorphous host material => prevents phagocytosis and complement andevades adaptive imm.

24

What are the bad effects of immunity to Spirochetes?

2^ syphilis###

25

How does the innate immune system fight Fungi?

Neutrophils
Phagocytosis

26

How does the adaptive immune system fight Fungi?

Th1 mediated immunity
Crypto = CTL elimination
Intracellular fungus Histo => granulomas
Antibodies to Candida

27

What cells are present in granulomas?

Mycobacteria (inside macrophages)
Multi-nucleated giant cells
epithelioid cell
T cells (outer layer)

28

How does the adaptive immunity fight Parasites?

IgE production
-Mast cells release histamine
-triggers vomiting

29

What is the difference between Th1 and Th2 mediated immune response?

Th1: CTLs, Macrophage-mediated killing and/or IgG
Th2: IgE and infiltration by eosinophils
Cytokines downreg opposing response

30

What are rhe evasion strategies that Parasites use?

Concealment
Coats with host protein
Outer surface inhibits complement, repairs damage
Ez cleaves membrane bound Ab

31

What are rhe bad effects of immunity to parasites?

Malaria increases TNF-a production
Chronic parasite infection = immune complexes = vasculitis and nephritis