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
T/F: Dendritic cells are excellently phagocytic
FALSE;
poorly phagocytic
Where can dendritic cells be found?
Skin (specifically epidermis) and CT
Where can macrophages be found?
Lymphoid organs and CT
Macrophages develop from ______
Monocytes
Macrophages in Skin/CT
Histiocytes
Macrophages in Liver
Kupffer Cells
Macrophages in Lung
Alveolar Macrophages or Dust Cells
Macrophages in Brain
Microglia
Macrophages process and present antigens to what type of cells?
CD4 (T-Helper Cells)
NK cells are also known as
Large Granular Lymphocytes (LGL)
Granules found in NK cells are called
Birbeck Granules
Describe how NK cells mount an immune response
Utilizes performing to crease pores in antigens —> apoptosis
Pattern Recognition Receptors (PRR)
Receptors found on innate immune cells that can recognize microorganisms and trigger and inflammatory response
Pattern Recognition Receptors bind to ______ found on microorganisms (but not on mammalian)
Pathogen Associated Molecular Patterns (PAMPs)
Pattern Recognition Receptors (PRRs) found on immune cell membranes are often referred to as
Toll-Like Receptors
The primary acquired immune response refers to the…
First encounter with the pathogen
After B-cells originate in bone marrow, where does it travel to?
Germinal centers of lymph nodes and lymphoid follicles of spleen
T/F: B-cells account for most circulating blood lymphocytes
FALSE; only 15%
T/F: each B-cell is specific to one antigen
TRUE
B-cell surface glycoproteins (numbers)
19/20, 40
(Higher numbers)
Both CD4 and CD8 cells have CD___ markers
(Number)
CD 3
T-cells make up ___% of circulating lymphocytes — mostly _____ (Th/Tc)
70%
Mostly T-helper cells (2:1)
CD8 T-cells respond to antigen fragments from MHC-____ (I/II)
CD8 — MHC-1
CD4 T-cells respond to antigen fragments from MHC-____ (I/II)
CD4 — MHC II
One of the most important cytokines released by CD4
Interleukin-2
Acts as costimulator for other immune cells
Function of Memory T-cells
Recognize original antigen
Allows for more swift reaction second time around
Humoral Immunity is associated with what type of immune cells?
B-cells
Cell Immunity is associated with what type of immune cells?
T-cells
Another name for Humoral Immunity
AMI — antibody-mediated immunity
“Cell-mediated immunity always involves ____ attacking ____.”
cells attacking cells
____ (B-cells/T-cells) are most effective with extracellular antigens.
B-cells
____ (B-cells/T-cells) are most effective with intracellular antigens.
T-cells
e.g. fungi, parasites, viruses, cancer cells, tissue transplants
Anamnestic
Relating to a Second Immune Response
(Previously encountered antigen)
Explain class-switching
Initially, B-cells produce IgM (and IgD)
But after a secondary infection, Th release cytokines that signal IgM to change its Fc to form IgG, IgA, or IgE
Example of active, naturally acquired specific immunity
After recovery from infection
Example of passive, naturally acquired specific immunity
Placental passage of antibody from mom to fetus
Example of active, artificially acquired specific immunity
Vaccination
Example of passive, artificially acquired specific immunity
Injection of antibodies (aka gamma globulins)
Example of passive, artificially acquired specific immunity
Injection of antibodies (aka gamma globulins)
