Immunology Part I Flashcards
What does TLR3 bind (innate system)?
dsRNA of viruses
What is the first cell to encounter pathogen/infection/resident in tissue?
Resident macrophage
What is the first cell that responds/migrates to infection/pathogen?
Neutrophil
What is innate immunity?
“Built-in” immunity that is non inducible, preexisting ability to recognize and destroy pathogens and associated products.
- Does not require previous exposure to pathogen to work
- Mediated be phagocytosis
- Recognizes common molecular pattern of pathogens known as PAMPs
- CANNOT BE INDUCED TO BE MORE SPECIFIC
In general, myeloid precursors give rise to. . .
. . .innate immune cells!
What are innate immune receptors called?
Pattern Recognition Receptors (PRRs) –> TLRs are a subfamily of this!
Overall goal of complement:
Control inflammation
What happens after TLR3 binds dsRNA?
- NRKB and IRF3 are activated and go the nucleus
- Causes changes in gene transcription that lead to the release of IFN-beta
- IFN-beta is a potent ANTI-VIRAL response
What are the three main functions of complement?
- Lysis
- Chemotaxis
- Opsonization
What are cytokines?
Secreted molecules involved in cell-to-cell signaling
What are chemokines?
A large family of cytokines that can attract cells into inflamed tissue and play a role in leukocyte homing. - “direct traffic of immune cells”
What are the six major categories of cytokines?
- Interferons (IFNs)
- Type I (alpha and beta)
- Type II (gamma) - Interleukins (ILs)
- Colony Stimulating Factors (CSFs)
- Chemokine
- Tumor Necrosis Factors (TNFs)
- Transforming Growth Factors (TGFs)
What are Interferons?
Generally, they are cytokines that are important in limiting the spread of viral infections.
-They induce a state of antiviral resistance in uninfected cells
What are Type I Interferons?
IFN alpha & IFN beta - Produced by cells that have become infected with virus
What are Type II Interferons?
IFN gamma - released by activated Th1 cells!
What are Interleukins?
Large group of cytokines produced mainly by T cells (also macrophages, dendritic cells, and epithelial cells, etc.).
–Variety of functions including causing neighboring cells to divide and differentiate.
What are Colony Stimulating Factors (CSF)?
- Primarily involved in directing the division and differentiation of bone marrow stem cells and precursors of blood leukocytes.
- Controls how many and what kind of leukocyte is to be produced
What is a chemokine?
Chemotactic cytokine used to direct the movement of leukocytes around the body
What is Tumor Necrosis Factor (TNFs)?
Particularly important in mediating inflammation and cytotoxic reactions
What are Transforming Growth Factors (TGFs)?
Important in regulating cell division and tissue repair.
What are important properties of Adaptive Immunity?
- It has “memory”. The secondary adaptive immune response is faster and stronger than the first.
- It shows “tolerance”. In ability to make an immune response toward self-antigens.
What are Antigen Presenting Cells (APCs)?
Bridge cells
-They link the innate and adaptive immune systems by taking up and processing antigens so they can be recognized by T cells.
[Dendritic cells, B cells, Macrophages]
What provides the “bridge back” to help phagocytes work better at cleaning infection?
Antibodies!
What is the difference between active and passive immunity?
Active - memory response - outcome of exposure to antigens through infection and usually results in protective immunity conferred by antibodies and T cells.
Passive - Immunoglobulin transfusion or breast milk. No exposure to antigen, response developed immediately but cannot be maintained.
What does the Lymphoid progenitor side need to form from a Pluripotent Stem Cell?
IL-3
What does the Myeloid progenitor need to form from a Pluripotent Stem Cell?
IL-3 & GM-CSF (Granulocyte-Monocyte Colony Stimulating Factor)
What does a Natural Killer Cell do?
Looks to see if MHC is missing on cells, and then kills the cell if MHC is missing
What are the characteristics associated with SCID?
Severe Combined Immunodeficiency Disorder
- Low gamma globulin fraction
- Combined B and T cell immunodeficiencies (don’t make any B or T cells)
- Recurrent infection with a wide range of pathogens
- ADA deficiency that leads to no Pro-B or Pro-T cells being formed
- Immune system protection from mother in womb and until 6 months of age - so usually not discovered until later than 9 months
What cell marker do all leukocyte groups have?
CD45+ (on all T cells!!)
What are PMNs?
Polymorphonuclear neutrophils
- Most numerous of the polymorphonuclear granulocytes
- Constitute the majority of leukocytes (white blood cells) int he blood stream (around 60-70% in adults)
What are the primary actions of eosinophils and basophils?
Function as phagocytes and involve granule release (exocytosis)
What is required for a CFU-GEMM (myeloid lineage) to form CFU-GM?
IL-3 and GM-CSF
What is required for CFU-GM to make monocytes?
M-CSF, GM-CSF, IL-3
What is required for CFU-GM to make neutrophils?
G-CSF, GM-CSF, IL-3
What is required for Monocytes to make macrophages?
GM-CSF, M-CSF
What is required for monocytes to make DC?
GM-CSF, IL-4
What is required for CFU-Eo to make eosinophils?
IL-5, IL-3, GM-CSF
What promotes the growth of megakaryocytic?
Thrombopoietin (TP)
What should you know about Monocytes?
- Large relative to lymphocyte
- Horseshoe shaped nucleus
- Primary azurophilic (blue-staining granules)
- Lysosomes contain peroxidase
- Actively phagocytose microorganisms
- Long-lived (months to years)
What should you know about polymorphonuclear granulocytes?
- Short-lived (2-3 days)
- Adhesion is mediated by receptors on granulocytes and ligands on endothelial cells and promoted by chemo-attractants like IL-8
- Main role in phagocytosis and destruction of pathogens
- 95% of circulating granulocytes are neutrophils
What two types of granules do neutrophils have?
- Primary (azurophilic) granules - lysosomes containing acid hydrolases, myeloperoxidase, and mermaids (lysozyme), antimicrobial proteins: defensins, cathelicidins, bacterial permeability including protein
- Secondary granules (specific to neutrophils): lactoferrin and lysozyme
