Defence Cells Flashcards
What is chronic disease?
Chronic disease is caused by a malfunctioning immune system, defence cells might contribute to this malfunctioning
What is periodontal disease?
A chronic inflammatory disease
What is PD characterised by?
Inflammation of the gums, destruction of the alveolar bone and periodontal ligament
What is the initiating factor of PD?
Dental plaque
Does removal of plaque resolve PD?
No, as immune malfunction/dysregulation plays a role in PD too
What would be seen in a tissue cross section of an adult with PD?
Apical migration of epithelial tissue (towards tooth apex, tip of root), formation of a periodontal pocket (around tooth)
Why are cells recruited to epithelial tissues in PD?
In response to biofilm present on tooth surface
Where do majority of defence cells originate from?
Bone marrow
Where do blood cells originate from?
Haematopoietic stem cells
What do haematopoietic stem cells give rise to?
Lymphoid and myeloid
What are the myeloid cells?
Macrophage Eosinophil Basophil Neutrophil Mast cell Dendritic cell (can also be lymphoid)
What are the lymphoid cells?
B cells
T cells
NKC (natural killer cells)
What category of WBC are neutrophils?
Granulocytes
What do neutrophils do?
Circulate in blood and move into tissue when needed
Bring about phagocytosis
Activate bactericidal mechanisms
What do neutrophils contain?
Granules which have degradative enzymes and antimicrobial substances
How are macrophages formed?
Monocytes circulate in blood are precursors
They migrate into tissues and differentiate into macrophages
What cells are early responders to infection or tissue damage?
Macrophages, mast cells
What do macrophages do?
Phagocytosis
Activate bactericidal mechanisms
Antigen presentation
Which cells have a major role in immune responses?
Macrophages
What catagory of WBC are mast cells?
Granulocytes
What do mast cells do?
Migrate from blood and differentiate in tissues
Protect against pathogens- particularly parasitic worms
How do mast cells function?
By releasing granules containing histamine and active agents
What immune reaction are mast cells involved in?
Allergy
What category of WBC are eosinophils?
Granulocytes
What do eosinophils contain?
Granules containing degradative enzymes and antimicrobials
What is the defensive role of eosinophils?
Defence against parasites, larger than neutrophils so can ingest larger threats
What is the function of eosinophils?
Killing antibody coated parasites
Are eosinophils involved in allergy?
Yes
What category of WBC are basophils?
Granulocytes
What is the function of basophils?
To promote allergic responses
Augmentation of anti-parasitic immunity
What is the function of dendritic cells?
Antigen presentation
What do dendritic cells form a bridge between?
Innate and adaptive immune responses
How do dendritic cells appear?
As long, fingerlike processes
What do dendritic cells do?
Migrate from blood to tissue
Phagacytose organisms
Can ingest extracellular fluid- macropinocytosis
Degrade pathogens
What is the major function of dendritic cells?
To present the antigen directly to T cells
Where do t cells mature?
Thymus
What do t cells give rise to?
Cellular immunity
How do T cells recognise peptides presented by antigen presenting cells?
Through T cell receptor TCR
What are the two types of T cell?
CD4+ or CD8+
How are CD molecules named?
According to cluster differentiation (CD!!) glycoprotein on cell surface
What are CD molecules involved in?
Antigen presentation
What are MHC’s?
Major histocompatability complexes, class I or II. They are the ‘flag pole’ that attaches antigen to surface of cell for presentation, which is then recognised by various receptors on T or B cells.
what do T cell CD8+ cells interact with?
MHC class I
What do T cell CD4+ cells interact with?
MHC class II
What are CD8+ cells?
Cytotoxic
Destroy infected self cells
What are CD4+ cells?
Play a central role in immune protection
Numerous subsets which modulate immune response depending on pathogenic threat
How do CD4+ cells come about?
Start life as naive T cell
3 signals for activation of T cells
3rd signal determines fate of naive T cell
What are the CD4+ subsets?
TH1 TH2 TH17 TFH THreg
What does TH1 do?
Supportes macrophages to destroy intracellular microbes
What does TH2 do?
Produces cytokines which activate mast cells and eosinophils
Promote barrier immunity at mucosal surfaces
What does TH17 do?
Secrete IL-17 family cytokines, specific role in supporting immune cell function
What does TFH do?
Induce specific B cell response, antibody responses
What does THreg do?
Switches T cell response off to prevent autoimmunity
Where do B cells mature?
In bone marrow
What does diversity in B cell receptor mean?
That B cells can respond to numerous antigens
What do B cells do?
When activated they turn into plasma cells, which are the cells that produce antibodies. So B cells produce antibodies
What are T and B cells mainly involved in?
Adaptive immunity- memory and specificity
What are natural killer cells?
Considered part of innate immunity
What is natural killer cell function?
Involved in destruction of virus infected cells, can recognise and kill abnormal cells
