Defence Cells Flashcards
what is periodontitis?
destruction of soft and hard tissues which support the teeth
what microbial dysbiosis?
the build up of dental plaque
what type of inflammatory disease is periodontitis?
chronic inflammation
what increases as oral cavity moves from health to aggressive periodontits?
immune and inflammatory cells in the periodontium
name the innate cell subsets
monocytes/macrophages, mast cells, neutrophils, eosinophils and basophils, natural killer cells, dendritic cells
what is the relationship between monocytes and macrophages?
in the blood they circulate as MONOCYTES but once they migrate into tissues they differentiate into MACROPHAGES
what are monocytes/macrophages
early responders to infection or tissue damage
what do monocytes/macrophages do?
phagocytose and present antigen
what are mast cells?
granulocytes, early responders to infection or tissue damage
what do mast cells do?
migrate from blood and differentiate in tissues
what is the immune response role of mast cells?
protect against pathogens and are best known for role in allergy
what are neutrophils?
phagocytic granulocytes and the MOST IMPORTANT cells in innate immune responses
what do neutrophils do?
circulate in blood and move into tissue when required
what are basophils and eosinophils?
granulocytes
what do basophils and eosinophils do?
play a major role in defence against parasites as larger than neutrophils so can ingest larger threats, they also contribute to allergy
what are granules?
degradative enzymes and antimicrobials
collectively, what are neutrophils, macrophages, mast cells, eosinophils and basophils known as?
myeloid cells
what are defence cells derived from?
common precursoe in bone marrow?
what do all the defence cells do?
differentiate into myeloid and lymphoid cells
what are dendritic cells derived from?
myeloid and lymphoid lineage
give an example of a dendritic cell
langerhans cell
what is the main role of dendritic cells?
antigen presentation
what do dendritic cells do?
move from tissues to lymph nodes passing on information and activate T cells and B cells
what do immature dendritic cells do?
take up and process antigen in the epidermis and then migrate to lymph nodes while differentiating along the way
what do mature dendritic cells do?
prime naive T cells and can transfer antigen to other dendritic cells resident in the lymph node
what are natural killer cells?
large cells with granules
what do natural killer cells do?
recognise and kill abnormal cells/tumours/viral infected cells
what are natural killer cells important for?
holding back virus infections until adaptive immunity kicks in
what are innate lymphoid cells?
non-cytotoxic members of the natural killer cell famile
what is the origin of innate lymphoid cells?
lymphoid
what do innate lymphoid cells do?
link innate and adaptive immune immunity and produce effectors (cytokines) similar to T cell subsets
where are T cells derived from and where do they mature?
they are derived from the bone marrow and mature in the thymus
where are T cells?
they circulate in the blood and the lymph and are found in large numbers in lymphoid organs
what do T cells give rise to?
cellular immunity
what do T cells do?
protect against intracellular microbes and help B cell responses
what is T cell repertoire?
T cell receptors can respond to numerous antigens
why are there T cell checkpoints?
to ensure T cells only respond to foreign pathogens and not self peptides
what do T helper cells (CD4+) do?
help support other immune cells to fight threats
what do cytotoxic (CD8+) cells do?
destroy our own cells which have become infected
what do regulatory T cells (Tregs) do?
regulate or suppress other cells in the immune system
what are the 3 different types of T cells?
T helper cells (CD4+), cytotoxic T cells (CD8+) and regulatory T cells (Tregs)
how do CD8+ (cytotoxic) cells breakdown self infected cells?
it produces granzymes and perforins. the perforins form pores in the plasma membrane and the granzymes enter the cell and break down the proteins which lyses the cell
how many signals are required to activate T cells?
3
what are the CD4+ T cells (subsets) ?
TH1, TH2, TH17, TFH and Treg cells
what do TH1 cells do?
support macrophages to destroy intracellular microbes
what do TH2 cells do?
produce cytokines which recruit and activate mast cells, eosinophils and promote barrier immunity at mucosal surfaces
what do TH17 cells do?
secrete IL-17 family cytokines that induce local non-professional immune cells to release cytokines and chemokines
what do TFH cells do?
induce specific B cell responses (promote opsonising antibody response)
what happens when a naive T cell encounters a presented antigen?
it undergoes expansion and differentiation into effector cells of which some become memory T cells
what do B cells do?
communicate with T cells and produce antibodies
what does clonal expansion lead to?
generation of two subsets
what do plasma cells do?
produce antibodies
why are memory B cells important?
they mount a quicker antibody response to any subsequent infections
what induces B cell proliferation?
interaction between T cell and B cell cytokine signals released from T helper cell
what does B cell proliferation do?
generates s pool of plasma cells which produce antibody and generates memory B cells
what does plasma cells produce?
initially IgM but later switches to IgG
name the phagocytic immune cells
neutrophils, macrophages, tissue dendritic cells and mast cells
name the antigen presenting cells
macrophages, dendritic cells and B cells
what cells fight parasite infection?
eosinophils and basophils
what cells are involved in allergic responses?
basophils and mast cells
what cells are innate and adaptive inbetweeners?
dendritic cells, natural killer cells and innate lymphoid cells
what are the cells of the adaptive immune response?
T and B lymphocytes
what do B cells produce?
antibodies
what is the overall function of T cells?
to direct and control the magnitude of immune reactions
