Chapter 21 (P&A II)
Terms in this set (43)
What is the innate immune system? (Examples)
1st LOD: Surface barriers (Skin and mucous membranes)
2nd LOD: Internal defenses (Phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever)
What is the adaptive immune system? (Examples)
3rd LOD: Humoral immunity (B Cells)
Cellular immunity (T Cells
Examples and functions of protective chemicals of the innate immune system
- Phagocytes - Natural killer (NK) cells
- Antimicrobial proteins (interferons and complement proteins)
- Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals)
Examples of phagocytes
• Macrophages are chief phagocytic cells. They wander through tissue spaces looking for antigens.
• Neutrophils most abundant but die fighting
- Become phagocytic on exposure to infectious material
Mechanism and function of phagocytosis (21.2)
Beneficial effects of inflammation
• Triggered whenever body tissues injured
• Prevents spread of damaging agents
• Disposes of cell debris and pathogens
• Alerts adaptive immune system
• Sets the stage for repair
Examples of inflammatory chemicals (21.1)
histamine, complement, kininsm prostaglandins
Four cardinal signs of inflammation
Mechanism of inflammation (21.3)
Role of toll like receptors
Recognize Pathogen Associated Molecular Patterns (PAMPs)
of microrganisms as bacteria, viruses, parasites, fungi.
Examples of toll like receptors and their ligands or PAMPs (Slide #30, 31)
-Peptidoglycan of Gram + binds to TLR2
-Lipopolysaccharide of Gram - binds to TLR4
-Flagellin of bacteria binds to TLR5
-dsRNA of viruses binds to TLR3
-ssRNA of viruses binds to TLR7
-CpG DNA of batceria binds to TLR9
What does Toll like Receptors binding to their ligand cause? (slide# 33,34)
The binding of the Toll Like Receptors to their ligands will activate a cascade of proteins.
At the end of the cascade, transcription factors are activated. They will transcribe genes and form new proteins called cytokines and chemokines that cause inflammation.
Homeostatic imbalance 21.1
Function of interferons
-Attack microorganisms directly
-Hinder microorganisms' ability to reproduce
Viral-infected cells secrete IFNs (e.g., IFN alpha and beta) to "warn" neighboring cells
IFNs enter neighboring cells produce proteins that block viral reproduction and degrade viral RNA
IFN alpha and beta also activate NK cells
Since IFNs activate NK cells and macrophages, indirectly fight cancer
Artificial IFNs used to treat hepatitis C, genital warts, multiple sclerosis, hairy cell leukemia
Briefly, what is the complement? (interferons)
-Unleashes inflammatory chemicals that amplify all aspects of inflammatory response
-Kills bacteria and certain other cell types by cell lysis
-Enhances both innate and adaptive defenses
What are its functions (Fig 21.6: Opsonization and enhancement of inflammation (interferons)
What is opsonization? (slide#59)
Coats pathogen surfaces, which
Function of NK cells (slide #60)
-Nonphagocytic large granular lymphocytes
-Attack cells that lack "self" cell-surface receptors
Induce apoptosis in cancer cells and virus-infected cells
-Secrete potent chemicals that enhance inflammatory response
Function of fever
Systemic response to invading microorganisms
Leukocytes and macrophages exposed to foreign substances secrete pyrogens
Pyrogens act on body's thermostat in hypothalamus, raising body temperature
Function and main components of Adaptive Immune System.
-Protects against infectious agents and abnormal body cells
-Amplifies inflammatory response
-Must be primed by initial exposure to specific foreign substance
Priming takes time
Explain the three important aspects of Adaptive Immune System (pag 773).
Specific - recognizes and targets specific antigens
Systemic - not restricted to initial site
memory - stronger attacks to "known" antigens
Humoral immunity versus cellular immunity (What are they? What cells.are responsible for each of them?)
Antibodies, produced by lymphocytes, circulating freely in body fluids
Bind temporarily to target cell
Mark for destruction by phagocytes or complement
Lymphocytes act against target cell
Directly - by killing infected cells
Indirectly - by releasing chemicals that enhance inflammatory response; or activating other lymphocytes or macrophages
Definition of self antigen and nonself antigen.
Protein molecules (self-antigens) on surface of cells not antigenic to self but antigenic to others in transfusions or grafts
Most are large, complex molecules not normally found in body (nonself)
MHC Class I and MHC Class II.
Lymphocyte development, maturation and inactivation (Fig. 21.8).
Explain Immunocompetence and self tolerance.
Function of positive selection and negative selection.
What is an Antigen Presenting Cell?
Antigen Presenting Cells cleave the antigen and expose a portion of it on their surface, associate with an MHC class I or II molecule.
Examples of antigen presenting cells.
Dendritic Cells, macrophages, B lymphocytes
Where and how does an Antigent presenting cell encounter a T cell? How do T cells get activated?. (t-cells)
Describe the 3 signals necessary for T cells activation.
1) Binding of TCR with the Ag
associated to MHC molecule
and of CD4 (or CD8) with
2) Binding of CD28 on T cell with
B7.2 on APC
3) Biding of cytokine produced by
APC on its receptor on T cells
Which is the main event of synthesis of T and B cell receptor?
Can you briefly describe the antigen binding site of T and B cells receptor?
About the first signal, where does binding of Antigen to MHC Class I or Class II occur.
How does the third signal influence the type of activated CD4 T cell (you do not need to learn names of the factors, but please understand how they influence T cell activation)?.
What do CD8 T cells, and CD4 (Th1 T cells, Th2 T cells, Th17, Treg) T cells do once they are activated?
Be sure to have understood the function of CD8 T cells and CD4 T cells.
Activation of B cells (where? how?)
B cell activated when antigens bind to its surface receptors and cross-link them
Structure of B cells receptors (shape, heavy chains, light chains, Ag binding sites).
List the different Isotypes of antibodies: what is their function (Tab 21.4)?
Types of Antibodies released after primary and secondary response to a pathogen.
Primary (Antibodies to A)
secondary (Antibodies to B)
Definition of pathogen.
a bacterium, virus, or other microorganism that can cause disease.
Explain and give examples of Active and passive, Naturally acquired or Artificially acquired.
Naturally acquired—antibodies delivered to fetus via placenta or to infant through milk
Artificially acquired—injection of serum, such as gamma globulin
Protection immediate but ends when antibodies naturally degrade in bod
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