12 Antibacterial Immunity

Question 1

High Affinity Receptors (phagocyte recognizes microbe) include:

Answer 1

1. Mannose Receptor- binds mannose on microbial cell wall -> phagocytosis
2. Scavenger Receptor- binds microbes in non-mannose specific manner
3. Mac-1 Integrin- binds microbes opsonized with complement proteins

Question 2

Occurs when microbe is coated/bound by IgG to target it for phagocytosis

Answer 2

Opsonization

Question 3

Activated macrophages and neutrophils will convert molecular oxygen into ROS (process is called _____).
ROS (reactive oxygen species) and RNI (reactive nitrogen intermediates) are used to kill phagocytosed microbes.

Answer 3

Respiratory burst

Question 4

Found in serum. Serves as an opsonin and enhances phagocytosis. Serves as a chemokine and recruits/activates leukocytes. Forms the membrane attack complex (MAC) and mediates lysis of microbe.

Answer 4

Complement

Question 5

___ cells can neutralize microbes and microbial toxins by _____

Answer 5

B

Antibodies

Question 6

____ cells are T cells that make inflammatory cytokines. Promote intracellular immunity (cell mediated)

____ cells are T cells make B cell promoting cytokines. Promote extracellular immunity (antibody mediated)

Answer 6

Th1 (1->i->inflammatory/intracellular)

Th2

Question 7

Which Th response is more important during extracellular defense?

Answer 7

Th2

Question 8

Mechanisms of immune evasion by extracellular bacteria:

Answer 8

1. Antigenic variation
2. Inhibition of complement activation (many bacteria)
3. Resistance to phagocytosis (e.g. Pneumococcus)
4. Scavenging of ROS (e.g. Catalase-positive staphylococci)