Lymphoid organs and immune cells L19 Flashcards Preview

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Flashcards in Lymphoid organs and immune cells L19 Deck (21)

what is innate immunity

always present (ready to attack); many pathogenic microbes have evolved to resist innate immunity


what is adaptive immunity

stimulated by exposure to microbe, more potent


what are lymphocytes

cells of the adaptive immunity, recognise antigens and develop into cells that perform defence functions


what re antigen presenting cells

cells that capture antigens and display them to lymphocytes, interphase between innate and adaptive immunity


what are effector cells

leukocytes (white blood cells) that eliminate microbes, may be lymphocytes but are often leuockotes (e.g. phagocytes, innate immune cells)


how are lymphoid organs classified

2 groups, primary and secondary


what is the primary lymphoid organs roles

provides an appropriate microenvironment for the development and maturation of lymphocytes, bone marrow and thymus


what is the secondary lymphoid rogans role

traps antigens, generally from nearby tissues/fluid and are sites where lymphocytes can effectively interact with antigens (lymph node, spleen etc.)


helper T lymphocytes can produce ______ to have what effects

cytokines to activation macrophages, inflammation edna citation of T and B lymphocytes


what is the role of the B lymphocytes

secretion of antibodies and this causes neutralisation of microbes, complement activation and pahgocytosis


what is the role of the cytotoxic T lymphocyte and the natural killer cell

killing of the infected cell


what are the subsets of the native T cell and what is each role of them

Th1 (recognition of intracellular microbes (bacteria and viruses), involved in autoimmunity and DTH), Th2 (recognition of extracellular microbes (parasites and bacteria), involved in allergy and asthma), Th17 (protection against extracellular bacteria (bacteria, fungi), involved in autoimmunity) Treg (involved in immunosuppression), Tfh (T follicular helper cell, trigger and maintain germinal center/important for B cell function, role in auto-immunity pathogenesis


What are needed to initiate immune responses and how

APC, co-localize with T cells and display HLA molecules that interact with T cell receptors (class 1 and class 2)


conseuqnce of mutations in AIRE

human disease, autoimmune polyendocrinopathy with candidiasis and ectodermal dysplasia, also called autoimmune polyendocrine syndrome.


naive T cells can be primed by what

dendritic cells


what are the functions of antigen-presenting cells

capture antigens and take them to correct place, display antigens in a form that can be recognised by specific lymphocytes (T cells are MHC- associated peptides and B cells are native antigens), Provide secondary signals for T cell activation


what are dendritic cells found

at sites of microbe entry


what are the receptors on dendritic cells

TLR and tohers


what are the 4 subsets of dendritic cells

classical (role in presentation), plasmacytoid (source of type 1 IFN), immature (in tissues, role in presentation of self antigen and maintain of tolerance ), mature (activated by TLR and other signals, role in T cell activation)


what could be the four outcomes from B cell activation and antibody production

antibody secretion, isotope switching, affinity maturation, memory B cell


what are the two B cell subsets

T dependent (isotope switched, high affinity antibodies, long lived plasma cells, follicular B cells) T independent (mainly IgM, short-lived plasma cells, marginal zone B cells and B1 B cells)

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