Cells of the Immune System Flashcards
Natural killer cells (NK) and cytotoxic-T-cells are ______________.
Lymphocytes
_________-T-cells are central to all types of immunity.
Helper
Follicular dendritic cells are ___________ ____________ cells.
Antigen presentation
_____________ are antigen presenters, but also capable of phagocytosis.
Macrophages
Treg cells prevent ____________, and produce cytokines.
Autoimmunity
___-cells produce antibodies.
B
What is a mature B-cell called?
Plasma cell
Mast cells and basophils contain _____________, and are prevalent in allergic reactions.
Histamine
_____________ engage in phagocytosis, for destruction of bacteria, and are very important.
Neutrophils
Eosinophils are also capable of phagocytosis, and are important in ______________ infections.
Parasitic
Myeloid stem cells are every cell type except ____________.
Lymphocytes
True or false: NK cells are adaptive.
False
______________ account for 20-40% of WBC population in the peripheral blood, and 99% of cells in the lymph.
Lymphocytes
T-cells, B-cells, and NK cells are small, motile, _____-___________ cells.
Non-phagocytic
T- and B-cells that are not activated by antigen are known as __________ ______, or small lymphocytes.
Resting cells
Upon activation, T- and B-cells undergo _______ ___________, and differentiates into effector or memory cells.
Clonal expansion
T-cells originate in the bone marrow, but mature in the __________.
Thymus
___-__________ cells secrete cytokines, which activate B-cells, other T-cells, macrophages, and other cells that are participants in an immune response.
T-helper
____-___________ cells do not secrete many cytokines, and instead exhibit cell killing or cytotoxic activity; in particular, they display this behaviour towards tumour and graft cells.
T-cytotoxic
The ratio of TH to TC is ~_____ in normal, human peripheral blood.
2:1
T-cells possess a receptor on their surface called a T-cell receptor (TCR), that binds the T-cell to an ___________.
Antigen
T-cells recognise antigen only in the context of _________ ______________ ____________ molecules.
Major histocompatibility complex
Name three cells upon which T-cells will bind, in the presence of antigen.
Virus-infected cells
Cancer cells
Antigen-presenting cells
___________ _____________ results in T-cell proliferation and differentiation into memory T-cells and various effector T-cells.
Antigen recognition
_____________ T-cells suppress the function of other cells, and are important for regulation and self-tolerance.
Regulatory
____________ ________ ___-cells suppress or activate innate and adaptive immune responses, and are important in preventing the development of autoimmunity.
Natural killer T
Where do B-cells mature?
Bone marrow
____________ molecules found on the surface of B cells act as antigen-binding sites.
Antibody
True or false: each B-cell specifically recognises one antigen type.
True
True or false: B-cell interactions require MHC molecules.
False
An activated B-cell undergoes clonal expansion, ____________, and differentiation into a mature B-cell (then termed a plasma cell).
Proliferation
Plasma cells secrete antibodies, and can secrete 2,000 antibody molecules per second, with major effector molecules of ______________ ______________.
Humoral immunity
NK cells comprise 5-15% of blood ____________ cells.
Mononuclear
NK cells are identified in blood by the expression of ______, and by the presence of cytoplasmic granules.
CD56
True or false: NK cells have no immunologic specificity or memory.
True
NK cells display cytotoxic killing activity against a wide range of tumour cells, and cells infected with __________.
Viruses
What cell does a macrophage develop from?
Monocyte
Monocytes and macrophages have horseshoe-shaped nuclei, containing _____________ granules.
Azurophilic
What type of enzymes do monocytes have?
Ruffled
Monocytes and macrophages contain well-developed Golgi complexes, and many _____________ ____________, containing peroxidase and several acid hydrolases.
Intracytoplasmic lysosomes
Macrophages may be fixed (taking up residence in particular tissues), or free (or wandering), moving by ___________ _____________ throughout the tissues.
Amoeboid movement
Where are Kupffer cells found?
Liver
Where are osteoclasts found?
Bone
Where are microglial cells found?
Brain
List five highly-toxic mediators found in macrophages.
Hydrogen peroxide
Free oxygen radicals
Peroxidase
Lysosyme
Hydrolytic enzymes
List three functions of monocytes.
Active phagocytosis
Antigen presentation, and subsequent activation of T-cells
Secretion of cytokines, such as interleukin, α interferon, tumour necrosis markers, and interleukin-6, during inflammation
Dendritic cells are derived from either the ____________ or mononuclear phagocyte lineages.
Lymphoid
True or false: dendritic cells are mostly resident in tissues.
True
Langerhans cells of the ___________ are monocyte-derived.
Epidermis
Interstitial cells are found in _____________ organs.
Lymphoid
Interdigitating cells are found in specific areas of the spleen, ___________, and lymph nodes.
Thymus
Veiled cells are found in _________.
Lymph
What is the most important function of dendritic cells?
To present antigens to T-cells
________________ granulocytes are classified on the basis of how their granules stain with acidic and basic dyes.
Polymorphonuclear
List six features of neutrophils.
Last between seven to ten hours in the blood, and between three and four days in the tissues
Spherical, 12-15µm in diameter
Nucleus is segmented into three to five lobes
Cytoplasm contains primary and secondary granules, which do not stain intensely, and are rich in microbicidal agents, such as defensins and cathelicidins
1x10^11 cells are released from bone marrow per day
Phagocytic, and important in fighting infection
Define extravasation.
The movement of neutrophils from the bloodstream into a site of infection
Describe some features of eosinophils.
Motile cells, with bi-lobed nuclei
Granules (containing toxic agents) stain strongly with eosin
Comprise 2-5% of leucocytes in a non-allergic state
Specialised role in immunity to parasitic worms, although also capable of phagocytosis
Bone-marrow derived
Found mainly in peripheral tissues, such as the linings of GI and respiratory tracts
Play a significant role in allergic reactions
Describe features and functions of basophils.
Less than 0.2% of leucocytes in circulation
Non-phagocytic granulocytes
Peripheral blood form of mast cells
Cytoplasm is rich in granules, which stain with basic dyes
Release pharmacologically-active substances, such as histamine, in allergic responses
_______ _______ cells (MMC) depend on T-cells for proliferation.
Mucosal mast
Name another type of mast cell.
Connective tissue mast cells
