Lecture 5 Flashcards
Immunocompetent
able to distinguish self (tolerance) and non self (activation)
Where are WBC produced?
Bone marrow
Where are set up the immune response?
Immune response is set up in primary and secondary lymphoid organs
Primary lymphoid organs
BM: fabrication. Thymus: T cell differentiation
Secondary lymphoid organs
Tonsils, spleen, lymph nodes
Lymphatic velles
recirculation between secondary lymphoid organs and tissues
Innative vs Adaptive immune response
Innate: 0-12 hours. Skin. Epithetlial barriers, phagocytes, dendritic cells, NK cells
Adaptive: 12 hours -5 days. Humoral (B lymphocytes -> antibodies). Cellular (T lymphocytes -> effector T cells)
Epidermis cells
CD8+ T cells, langerhans cells
Dermis cells
Dermal DC, CD4+ T cell, ILC, macrophage,
How does the epithelia protect?
- physical barrier (hermetic)
- chemical
antimicrobial products (lysozym)
acid pH - Immune cells patrolling
Mastocytes
- Tissue-resident cells
- Detection of non self agents in tissue
- Activated by receptors recognizing general motifs on pathogens PRR (Pattern Recognition Receptors)
- Instigate inflammation
- Receptor of IgE (allergies)
Macrophages
- Detection of non self agents in tissue
- Activated by unspecific receptors : PRR
- phagocytosis : « eat & digest » pathogenes, dead cells
- long survival
- pro-inflammatory cytokine secretion => recruitment of other immune cells
Neutrophiles
- 1st recruited cells from blood to the inflammed tissue
- Most abundant immune cells in blood but short lifetime (few hours)
- Detection of non self agents in tissue
- Activated by unspecific receptors : PRR
- phagocytosis : « eat & digest » pathogens, dead cells
Monocytes
- monocytes exit from the blood
- Join injured tissue
- Differentiate into macrophages
- same properties as resident macrophages
Natural Killer cells
- Cytotoxic lymphocytes : perforine, granzyme
- kill infected or cancerous cells
- Produce pro-inflammatory cytokines
Dendritic cells
Ubiquitanous & polyvalent
- Antigen capture
- phagocytosis
- Antigen presentating cells (APC)
- Initiate adaptive immune response by activating T cells
Dendritic cells are the bridge between
innate & adaptive parts
Cytokines
- molecular signal for intercellular communication
- Secreted by activated cells
- Recognized by a specific receptor
- autocrine or paracrine stimulation
- Various cellular responses (survival/apoptosis, proliferation, differentiation, mobility, cytokine secretion…)
Pro-inflammatory cytokines
Pro-inflammatory: IL1b, TNFa, IL8, IL6 Fever, CRP synthesis by liver, vasodilation, leukocyte diapedesis and activation
Anti-inflammatory cytokines
Anti-inflammatory: IL10, TGFb inflammation resolution
Activation cascade of inflammation
3 functions - activation of phagocytosis (PMN and macrophages)
- osmotic lysis of pathogenic microbes (massive entrance of water)
- stimulation of inflammation (anaphylotoxines produced during activation cascade)
5 cardinal signs of inflammation
“heat, Redness, Swelling, Pain, Loss of function”
Three phases of inflammation
Initial: vascular activation of primary effectors, recruitment of circulatory inflammatory cells (redness, heat, pain, swlling)
Amplification: Mobilisation of other immune cells, pus formation. Chemotaxis of lipid mediators, Cytokines, Chimiokines, anaphylatoxines
Repair: re-epithelialization, reconstruction fo matrix, neovascularization
Lipoxin, resolvins, protectins & maresins are ___ factors
anti-inflammatory. DECREASE neutrophil, INCREASE monocytes, INCREASE macrophages. Eliminate apoptotic neutrophils
B cells activate after ____, they are synthesized in the ____
non self antigen encounter
lymph nodes
Immunoglobulines = antibodies
Y-shape
- Hypervariable domains -> Antigen binding - Constant domains -> activation of cells and complement
T cells recognize peptides
- Antigen degradation by an APC
- Presentation of Antigen by a specific molecule MHC (Major Histocompatibility complex)
2 types of T cells
- CD8+ -> cytotoxic T cells -> CMH I
- CD4+ -> Helper T cells -> CMH II
Actived CD8+ T cells
=>
multiplication
Activated CD4 T cells
=>
- cytokine production
- Expression of co-activation molecules
