2nd line Diapedesis

1
2nd line Diapedesis
neutrophil
Figure 15.7
2
2nd line Phagocytosis

• Chemotactic factors
• Virulence factors/ capsules
• Opsonization
• Pseudopodia
• Phagosome
• Phagolysosome
• Exocytosis

3
2nd line A phagocyte and a yeast cell
4
2nd line Extracellular killing by leukocytes

• Attach to parasitic helminths
• Secrete chemicals to weaken/ kill helminth
• Eosinophilia indicative of helminth infection
• Secrete toxins onto virally-infected cells and
  neoplasms
• Distinguish normal, healthy cells from diseased
  cells

5
2nd line Complement System

• Small proteins are
• Activated in presence of
• Activation of innate and acquired immune defenses
• Results in inflammation, lysis of foreign cells
  and

6
2nd line Complement System
7
Characteristics of human interferons
8
2nd line Interferons
9
2nd line Inflammation

• Limits damage but the process can cause harm
• Actue inflammation
• Chronic inflammation
• systemic
  inflammation
• Release of pro-inflammatory cytokines ?
• Lipopolysaccharide (endotoxin)
• Components of Gram-positive cell walls

10
Increased vascular permeability during
inflammation
11
2nd line Inflamation
Bacteria
1
Penetration of the epidermis ? bacteria invade.
Damaged cells release inflammation-promoting
factors (shown in green here).
2
Factors make vessels more permeable. Histamine ?
vasodilation
3
4
Diapedesis
12
2nd line Inflamation
Increasd permeablility ? antimicrobial chemicals
and clotting proteins to seep into damaged tissue
? swelling, pressure on nerve endings, and pain.
Swelling
Heat
5
Nerve ending
6
Blood clot forms.
More phagocytes migrate to the site ? phagocytize
7
Accumulation of damaged tissue andleukocytes ?
pus.
8
Repair of damaged tissue. Blood clot is absorbed
or falls off as a scab.
9
13
Fever

• Important vertebrate defense mechanism
• 37º C (normal) ? 37.8º C (fever)
• special cytokines
• Fever inhibits pathogenic growth
• Temperature rises above optimal pathogen growth
  temperature
• Increased temperature speeds up other host
  defense mechanisms