Immunology MS L2 Flashcards
Examples of APCs?
Antigen presenting cells
Dendritic cell, Macrophage which activate T cells which activate B cells to make antibodies
What comes from the myeloid progenitor cell?
Megakaryocyte, erythrocytes, basophil (mast cell in tissue), eosinophil, neutrophil, monocyte (macrophage, dendritic cell) - innate immunity
What comes from Lymphoid progenitor cell?
T cell, B cell (plasma cell), NK cell - adaptive immunity
What are the steps of the inflammatory reponse?
Recognition - PRRs (TLRs) on epithelia, phagocytes
Recruitment - cytokine secretion - attracts leukocytes and plasma components
Resolution - successful acute response eliminates infection - resolution and repair by tissue resident macrophages
What is the role of neutrophils?
- Phagocytosis
- Degranulation - alpha-defensins 1-4, enyzmes, ROS,NO
- NETosis
Structure of neutrophils
Multilobed nucleus
40-75% of WBCs
Short lived (2-6 days)
Function of Eosinophils?
- Anti-parasitic and allergic response
- Degranulation upon recognising antibody bound parasites - MBP (major basic protein), enzymes, cytokines
Structure of Eosinophils
Bi-lobed nucleus
1-6% of WBCs
Short lived (8-12 days)
Function of basophils (and mast cells)?
- Anti-parasitic and allergy response
- Degranulation - histamine, enzymes, cytokines
Basophil structure
Bi or Tri lobed nucleus
< 1% of WBCs
Short- lived / uncertain
Macrophages structure
- Phagocytosis - removes microbes, antigens and dying cells
- Antigen presentation cell - presents antigens to T cells
- Tissue- specific macrophages - look at list
Structure of macrophages
Monocyte in blood differentiates into macrophage in the tissue - seen in tattoos
Process of killing pathogens by phagocytosis?
-Microbes bind to phagocytic receptors
-Phagocyte membrane zips up around microbe
-Microbe ingested in phagosome
-Fusion of phagosome with lysosome
-Killing of microbes by ROS, NO and lysosomal enzymes in phagolysosomes
Carried out by monocytes, macrophages, neutrophils, dendritic cells
What is present in phagocytosed bacteria?
Hydroxyl radical
Hydrogen peroxide
Nitric oxide
Superoxide anion
Inflammatory response and wound healing steps
- Bleeding and hemostasis
- Inflammation
- Proliferation
- Remodeling
Dendritic cells function
- Phagocytic - Antigen presentation cell - present microbial antigen via APC
- Activation of T cells (main func)
How do dendritic cells become competent to stimulate T cells?
- Immature dendritic cell recognizes PAMPs and become activated
- TLR signalling induces CCR7 and enhances processing of pathogen-derived antigens
Process of dendritic cells carrying antigen into the lymph nodes for T cell priming?
- Immature dendritic cells reside in peripheral tissues
- Dendritic cells migrate via lymphatic vessels to regional lymph nodes
- Mature dendritic cells activate naive T cells in lymphoid organs such as lymph nodes
