Innate + Acquired Immunity Flashcards
T/F: Microorganisms are literally everywhere
TRUE; ”ubiquitous”
Resistance
Ability to ward off pathogens that produce disease
T/F: Acquired Immunity is considered “part of the lymphatic system”
TRUE
Susceptibility
Lack of resistance, often caused by opportunistic organisms
T/F: both the innate and the acquired immune system become more efficient with each subsequent exposure to the same organism
FALSE;
Only the Acquired Immune System becomes more efficient; the Innate remains the same
First Line of Defense in the Innate Immune System
Skin and Mucous Membranes
1. Physical Barriers
2. Chemical Protections
3. Presentation of Stasis
Describe the affects of Kartagener’s Syndrome on Innate Immune Response
Dysfunction in bronchitis cilia —> stasis (inability to to move pathogens) —> decreased immune protection in lungs —> increased risk of infection/disease
Example of a defect in a first line defense
How can skin act as a physical barrier to pathogens?
Closely packed keratinized cells keeps pathogens out of + shedding helps remove them
How can mucous membranes act as a physical barrier to pathogens?
Cilia and mucus trap microbes and move it to lymph tissue/organs
Also, tears, urine, and saliva can wash microbes away
Describe some mechanisms of Chemical Protection (as in First Line Immune Response)
- Antimicrobial cationic peptides
- Lysozymes released into tears, salvia, and sweat
- Low pH
Describe some mechanisms of Stasis Prevention (as in First Line Immune Response)
- Peristalsis
- Urine flow
- Coughing
- Vomiting
- Upward movement of bronchial tree secretions
Second Line of Defense in Innate Immune System
- Internal Antimicrobial Proteins
- Fever / Inflammation
- Innate Cells
T/F: complement system can enhance certain allergic reactions
TRUE
Opsonization
“Tagging” an antigen for phagocytosis
The Classical Complement Pathway is also known as the
Antigen-Antibody Complex Mediated Pathway
Describe the Classical Pathway
C1 (complement protein 1) binds to Fc region of IgG or IgM (bound to antigen at its Fab region) —> cascade of cleavages/activations —> forms C3 convertase
Describe the Mannan-Binding Lectin Pathway
MBL binds to mannose residue on antigen —> MBL-Activated Serine Protease (MASP) binds to MBL —> forms C3 convertase
Describe the Alternative Pathway
Bypasses initial stages:
Begins with spontaneous hydrolysis of C3
Factor D cleaves Factor B
C3 and Factor B fragments forms C3 convertase
Note: No antibody participation
Describe the Common Pathway
C3 Convertase cleaves C3 into C3a and C3b
C3a — returns to circulation + recruits other immune cells to site of infection
C3b — opsonization
or forms C5 convertase —> cleaves C5 into C5a and C5b —> C5b binds to C6, C7, C8, and multiple C9’s —> forms Membrane Attack Complex (MAC) —> implants into pathogen —> creates pore —> causes cell lysis
Interferons (IFNs) are produced from cells infected by ______
Viruses
Describe the mechanism by which IFNs provide immune defense
- Virus enters Cell 1
- Cell 1 activates IFN genes
- IFNs are produced and released via exocytosis
- Cell 1 succumbs to viral infection
- But IFNs bind to Cell 2
- Cell 2 activates anti-viral protein
- As replicated viruses attempt to infect Cell 2, they are blocked by the anti-viral proteins
Cytokines
Proteins that act as chemical messengers amongst immune cells
Chemokines
Specific type of cytokines involved in chemotaxis (movement of immune cells in response to cytokines)
Major types of Antigen-Presenting Cells
- Dendritic cells
- Macrophages
- B-cells