Early Immune Responses Innate Immunity

Question 1

Pathogen

Answer 1

Microorganism that is able to breach host barriers to gain access to a tissue site where it can replicate/establish a latent infection

Extracellular and Intracellular

Question 2

Routes of Infection

Answer 2

External Epithelia: wounds and abrasions, insect bites

Mucosal Surfaces: airway, GI tract, reproductive tract

Question 3

Barriers

Answer 3

Skin

Gut/Lungs: tight junctions, mucous, airflow, low pH, antibacterial peptides, flora

Eyes/nose: tears, nasal cilia, enzymes in tears

Question 4

Barriers to Infection

Answer 4

Primary: structural barriers/antimicrobial factors

Secondary: inflammatory response

Adaptive: adaptive immunity

Question 5

Innate immunity of different pathogens

Answer 5

Extracellular: epithelial defenses, recruitment of phagocytes from blood, opsonization for uptake and killing by phagocytes

Viral pathogens: activation of type 1 interferon, activation of NK cells to lyse the pathogen infected cell

Question 6

defensins

Answer 6

Anti microbial peptides

Directly damage pathogen membranes by inserting into them, creating a pore that leads to osmotic imbalance

Question 7

Commensals

Answer 7

Microbiological barriers

In skin, gut, vaginal tract

Not pathogenic

Vaginal tract: enzymes secreted by commensal bacteria keeps low pH to inhibit growth of pathogens

Question 8

Phagocytes

Answer 8

Macrophages: long lived. present in blood/tissues

Neutrophils: short lived, present in blood, predominant leukocyte in blood

Dendritic cells: traffic antigen to lymph nodes

Question 9

Pattern recognition receptors

Answer 9

Recognize structure of microbes

On phagocytes

Polysaccharides

Cell wall components

dsRNA

Question 10

Opsonins

Answer 10

Recognition Molecules

Plasma proteins that bind to microbes and then to other cellular receptors so they can be recognized

CRP, MBL activate complement

Question 11

Complement system

Answer 11

Important for opsonization of microbes

Can be activated by: innate or Igm, Igg antibodies

C3A=inflammation

C3b= opsonization and phagocytosis

C5=inflammation

Question 12

Toll Like Receptors

Answer 12

Pattern recognition receptor

TLR1,TLR2: Bacterial lipopeptides

TLR2: Bacterial peptidoglycan

TLR4: LPS

TLR5: Bacterial Flagellin

TLR2, TLR6: Bacterial lipopeptides