Flashcards in Immunology- Foundations Deck (83)
-Anything that causes an immune response
-->bacteria, viruses, fungi, parasites, or smaller proteins
Antibody (immunoglobulin or Ig)
-Protein molecule created by our immune system to target an antigen for destruction
-Cell-to-Cell communication proteins that control cell development, differentiation, and movement to a specific part of the body
-Produced by leukocytes
-13 Cytokines that are regulators of immune responses, inflammatory reactions, and hematopoiesis
What are IL's 1 & 6 responsible for?
What does IL-6 cause?
Tumor Necrosis Factor (TNF)
-Mediates septic shock
-Causes tumor necrosis
What are Chemokines?
-Type of cytokine released by infected/injured cells
What do Chemokines initiate?
-An immune response by signaling circulating neutrophils and macrophages
-Warn neighboring cells of the threat
-Block/interfere virus replication
-Alpha, beta, and gamma subtypes
What is the strongest IFN?
-Produced by T cells
-Activates macrophages, natural killer cells and neutrophils
Diffuse inflammation in the system
Type I interferons
-Alpha and Beta forms
-Function: Induce viral resistance in cells
-Can be produced by almost any cell type in the body
Type II Interferons
-Secreted ONLY by natural killer cells and T lymphocytes
-Man Function: Signal the immune system to respond to agents or cancerous growth
Type I interferon disadvantages
-May actually suppress the immune response
-->important when we talk about things like HIV
The immune system
1. Barriers= Skin, coughing
2. Recognition= foreign/mutated cells, recognition of proteins or polypeptides on the surface to recognize foreign cells
3. Destruction=phagocytosis, lysis
Innate Immune system
-"Natural immune system"
-Inflammation, swelling, pus
Adaptive Immune system
-Specific, "humoral", "cell-mediated"
Formation and development of the cells that make up "blood"
-Embryo and fetus: occurs in liver, spleen, thymus
-Birth-Adult: occurs primarily in bone marrow
Where is bone marrow primarily produced in children?
Where is bone marrow primarily produced in adults?
Sternum and pelvis (axial skeleton)
WBC (granulocytes, plasma cells, lymphocytes)
Subset of leukocytes
Describe the components of the skin physical barrier
-Protects against invasion
-Acidic pH of sweat
-FA's and enzymes from pores/follicles
What do tears, saliva and mucus all have that aids in the protection as a physical barrier?
Lysozyme= protects against gram (+) bacteria
Explain the role of Adhesion Molecules
-Membrane proteins that connect cells to other cells or the ECM
-Recruitment of neutrophils to the site of inflammation
What results from chronic inflammation?
Chronic cytokine release and leukocyte infiltration-->release of lysozyme and free radicals---> TISSUE DAMAGE
What is the second line of defense in the innate immune system?
Granulocytes= Basophils, eoisinophils, neutrophils
Explain Basophil's role
-Circulate in bloodstream
-Allergic and helminth response
-Release histamine and heparin
Polymorphoneucolytes= neutrophils, eosinophils, basophils
Explain the role of Eosinophils
-Circulate in bloodstream and present in organs (GI tract and respiratory tract)
-Release H202 and other Oxygen Radicals to kill Microbes
-->Viruses, parasites (helminths)
-->lipid signaling molecules that cause airway smooth muscle contraction
-Active in allergic reactions, asthma
-Stimulate T lymphocytes (adaptive immune system)
-Act as "antigen presenting cells" (APC)
What is the most abundant granulocyte?
Who are the "first responders" of granulocytes?
What would you expect to be elevated in a bacterial or fungal infection?
Neutrophil Extracellular Traps (NETS)
Throw out extracellular fibers that bind bacteria
What does Neutrophils recruit?
Monocytes and macrophages
-->monocytes are the precursors to macrophages
What does Neutrophils release?
Cytokines to recruit monocytes and macrophages
Neutrophils respond to chemokines
What do Mast cells release?
*Causes inflammatory cascade
Where do mast cells mature?
When will mast cells degranulate?
-Encounters antigen or allergen
-Exposed to complement proteins
Which granulocyte causes anaphylaxis?
Mast cells (because there are so many of them)
-HTN and massive organ failure b/c your aren't profusing organs
Myeloid Stem Cells
-Granulocytes (Basophil, Neutrophil, Eoisinophil, mast cell )
-Monocyte: Macrophages and Dendritic cells
Lymphoid Stem Cells
-Natural Killer Cells
-T and B Lymphocytes
Where are monocytes stored in the body?
What are the 3 primary functions of monocytes, macrophages and dendritic cells?
2. Antigen presentation (APC's)
3. Cytokine production
Who is the strongest of the APC's?
-->Antigens are captured by dendritic cells
-->Migrate to nearest lymph node and present antigen to T cells and B cells
Specialized dendritic cells in skin
-may be initial cellular targets in the sexual transmission of HIV
-target, reservoir, and vector of dissemination
What are the 3 stages of readiness in Macrophages?
1. Resting- Cleaning up cellular debris
2. Primed- Activated by injury (cytokines)
3. Hyper-activated-Very initial hyper-inflammatory phase of infection
-Specialized macrophages w/in liver
-Destroy bacteria and old RBC's
What is the result of chronic activation of Kupffer cells?
-Due to toxins, alcohol
-Leads to overproduction of inflammatory cytokines and chronic inflammation
*Result= liver cell damage and cancer
Natural Killer Cells
-Active against viruses and cancerous cells
-Contain granules that contain destructive enzymes
How do NK cells kill their target?
-Release performs and proteases=cause membrane lysis
-Trigger Apoptosis in target cell
Major Histocompatibility Complex (MHC) Proteins
"Human leukocyte antigen"
-Cell surface molecules which help the immune system to determine if a protein is "self" or "not-self"
-Bind antigen to cell surface and display for recognition by T cells
3 key points of MHC proteins
1. Determines organ donation compatibility
2. Autoimmune dz is a malfunction in this recognition system
3. Participates in T and B cell activation
Acute Phase Proteins
-Produced by liver in response to inflammation induced release of IL-1, IL-6, and TNF
-Identify or "mark" pathogens or injured cells for destruction
Acute Phase Proteins
-C-reactive protein (CRP)= non-specific
-Mannose-Binding lectin (MBL)
Complement System (Complement Cascade)
-Enhances the ability of phagocytic cells to destroy pathogens
-Made by liver
-Activated by Antigens
What is the most abundant complement protein in humans?
What are the complement activation pathways?
1. Classical-Requires triggering
2. Alternative- Continuously activated @ low level
3. Lectin Pathway
Functions of Complement
1. Opsonization-Enhancing phagocytosis of antigens by "marking" them for destruction
2. Chemotaxis-Attracting and activating macrophages and neutrophils
-->inducing Mast cells and Basophils to degranulate
3. Lysis- Rupturing pathogen cell-membranes by forming Membrane Attack Complex (MAC)
-Antigen combines w/ an antibody and it's complement, causing the complement factor to become inactive or fixed
Membrane Attack Complex
-C5b forms a complex w/ C6, C7, C8, C9
-Lysis of cell by disrupting osmotic balance
Antibodies: Each only recognize ONE antigen
Adaptive Immunity Functions
-Directly block binding of the invader to cells
-Inactivate viruses and neutralize toxins
What does increased IgM indicate?
-Recent exposure to antigen
What is the initial antibody that is produced?
-Formed late in the primary immune response
-Longest half-life of the Ig's (~23 days)
-Used for passive immunization against rabies and hepatitis
What is the only class that crosses the placenta?
-Prepared from immunized animals
-Each AB can interact/bind w/ multiple sites on antigen
-Produced in lab
-Bind only to one site on an antigen
Where are IgA's primarily found?
External secretions=Barrier System
Hyper-sensitivity reactions IgE
Pt's with hyper IgE profile/syndrome of overproduction of this antibody are prone to massive anaphylaxis reactions
Hyper IgM Syndrome
Produces tons of IgM, never convert to IgG so you don’t have a long lasting immune system AND all of the IgM crowds out the rest of Ig’s
*Considered myloproliferative disorder
Primary Lymphoid Organs
Where immature lymphocytes (B & T ) grow up and proliferate
-Thymus (T cells) in children
Secondary Lymphoid Organs
Where antigens are presented to mature B &T lymphocytes to initiate adaptive immune response
-Tonsils and adenoids (lymphatic tissues)
B- Cells (lymphocytes)
Eliminate Extracellular pathogens
Destroy intracellular pathogens
-Identify and kill cells INFECTED w/ viruses