Mechanisms of Immunity Flashcards Preview

MSS-IHL Final Exam > Mechanisms of Immunity > Flashcards

Flashcards in Mechanisms of Immunity Deck (25):
1

categories of pathogens?

extracellular bacteria
intracellular bacteria
fungi
viruses
parasites

2

two extremes of pathology?

bacteria that result in single toxin or attach to surface epithelial (needs antibody neutralization)

bacteria that are not toxic and cause disease by invasion of tissues (needs mediated immunity)

3

extracellular bacteria

replicate outside host cells

4

innate response to extracellular bacteria?

epithelial barrier, flora
alternative C'
phagocytes (macs and neutros)
pro-inflammatory cytokines

PAMP recognition
C3 - alternative C' > C5a C3a

may lead to clotting and fibrin formation

5

adaptive immune response to extracellular bacteria?

antibody production and activation CD4+

helper T cells produce cytokines for B cell response, macrophage activation, and inflammation

6

opsonization?

extracellular bacteria

antibody and complement

7

SIRS

systemic inflammatory response syndrome

8

what can lead to endotoxic shock?

LPS

9

what are the results of TNF and IL-1

cause endothelial cells to express cell adhesion molecules and thromboplastin

promote adhesion of cells and fibrin deposition

enhanced by PAF

10

how do gram + bacteria induce shock?

massive release of cytokines (storm) by superantigens

11

how to block shock?

TNF neutralizing antibody

thromboplastin antibodies

PAF and NO inhibitors

not useful clinically (only modeled experimentally)

12

how do bacteria evade complement?

-outer capsule with no complement binding
-outer surface so phagocytes can't access bound C3b
-surface structures that divert the MAC away
-membrane enzymes can degrade complement
-outer membrane can resist insertion of MAC
-secrete decoy proteins that cause complement to be deposited on them and not on bacterium

13

how do bacteria and fungi evade phagocyte killing?

-repellent or toxins that inhibit chemotaxis
-capsules that inhibit phagocyte attachment
-once phagocytosed, release factors blocking killing
-catalase - breaks down H2O2
-resistant outer coats
-lipoarbinomannan - block ability of macrophages to respond to IFN-gamma
-impair antigen presenting function
-escape phagosome and multiple in cytoplasm
-organism can kill phagocyte via necrosis or apoptosis

14

neisseria gonorrhoeae

bacteria
-IgA protease
-blebs membrane to soak up antibody
-LPS is sialylated
-phase variation - alternative set of surface molecules
-genes for pilus under go recombination

15

rickettsia

intracellular bacteria

16

innate immune response to intracellular bacteria?

phagocytes, NK cells, IL-12, IFN-gamma

17

adaptive immune response to intracellular bacteria?

T cells activate phagocytes to eliminate the microbes

18

cytokines and intracellular bacteria

IL-12 knockout reduce ability to control bacterial growth

IFN-gamma knockout cannot control growth

19

innate immunity can control what?

bacterial growth and spread

but elimination requires CD4 and CD8 response

20

cross presentation

dendritic cells can display virally infected cells to CTLs and T helper cells

21

granuloma

collection of macrophages that fuse to form multinucleated giant cell

22

haemophilus influenza type B (HiB)

encapsulated Gram - rod bacteria
vaccine available

23

innate viral immunity?

IFNs and NK cells

24

adaptive viral immunity?

antibodies, CTLs, CD8, phagocytosis

25

antiviral state

IFNs (interferons)
-protect against viral infections and promote cell-mediated immunity

-inhibit viral replication

increase class I HLA
promote Th1 development
promote lymphocytes migration and sequestering in lymph nodes