Innate Immunity Foundations
What are PAMPs recognized by?
Pattern Recognition Receptors (PRRs)
What does an epitope refer to?
The specific antigenic determinant recognized by antibodies
What is the purpose of selective media?
Allows some microbes to grow while inhibiting others
What structure does β-lactam antibiotics target?
Peptidoglycan/cell wall synthesis
Define incidence
New cases per time period
What does competitive exclusion by microbiota mean?
Normal microbiota outcompete pathogens for space & nutrients.
Which cells create memory after antigen exposure?
Memory B cells and memory T cells
What does MTM agar isolate?
Neisseria gonorrhoeae
Which drug inhibits DNA gyrase?
Quinolones (e.g., ciprofloxacin)
What is herd immunity?
Protection of population when enough individuals are immune
Which leukocytes perform extravasation during inflammation?
Neutrophils & macrophages
What is the difference between active vs. passive immunity?
Active creates memory; passive gives immediate but short-term protection.
What does MIC testing measure?
Minimum inhibitory concentration of an antibiotic
Which antibiotic class targets the 50S ribosomal subunit?
Macrolides (erythromycin)
Distinguish direct vs. indirect transmission
Direct = person to person; indirect = vectors/fomites
Which cytokine class triggers fever (pyrogenic)?
IL-1 and other pyrogens
What must B cells present via MHC II to activate T helper cells?
Processed antigen peptides
In immunofluorescence, what distinguishes direct vs. indirect?
Direct uses labeled primary Ab; indirect uses labeled secondary Ab.
Name one mechanism of antibiotic resistance
Efflux pumps; target modification; enzyme inactivation; reduced permeability.
What type of epidemic shows a slow rise and fall?
Host-to-host epidemic
Name two pathogen strategies to escape phagocytosis
Capsules; survival inside phagolysosome; leukocidins
Explain clonal selection
Only the antigen-reactive B cell clone is selected to proliferate into plasma and memory cells
Explain how nucleic acid hybridization identifies pathogens.
Probe binds complementary pathogen DNA -> reporter allows visualization
Why are gram-negative bacteria sometimes intrinsically resistant?
Outer membrane reduces drug permeability
Why do pathogens become less virulent over time in host–pathogen coevolution?
Killing host too fast reduces transmission, selecting for milder strains