Glossary 2 Flashcards
histocompatability
flexible stretch of amino acids between two domains, Cg1 and’CyQ of an lgG molecule, that allows the antigen-binding sites mobility relative to one another
Human anti-mouse lg antibody (HAMA):
antibody produced by an immune response in humans to determinants on mouse lg, which limits the therapeutic usefulness of mouse monoclonal antibodies
Humanized antibodies:
monoclonal antibodies made by using mouse cells and subsequently manipulated by recombinant DNA technology to produce a molecule most of which is derived from human sequences, with only antigen-binding loops of the mouse molecule
lmmunofluorescence:
a technique in which fluorescently labelled antibodies are used to determine the location of the corresponding antigen in a tissue section or in cells
lmmunogenic:
able to induce an adaptive immune response. Many antigens are recognised by lymphocytes of the adaptive immune system fail to elicit immune responses in the absence of adjuvants that promote adaptive immune responses, often by activating cells of the innate immunity
lmmunoglobulin (lg):
a class of proteins produced by B lymphocytes of the immune system and that recognise and binds to foreign antigens. Also called an antibody.
lmmunoreceptor tyrosine-based activation motif (ITAM):
a sequence in the cytoplasmic domains of inhibitory immunoreceptors that, upon phosphorylation on tyrosine recruits signalling inhibitors
lmmunotherapy:
(of illergies) a treatment for atopic diseases in which the allergen responsible for the condition is injected repeatedly.
lnducible nitric oxide synthase (INOS):
one of the three isoforms of NOS, the enzyme that makes nitric oxide, and that is synthesised by phagocytic cells as part of the microbicidal response
lnflammation:
coordinated response to infection or tissue injury recognised since ancient Roman times and characterised by heat, pain, redndss and swelling
lnflammatory cytokines:
cytokines that are released by phagocytes of the innate immune system on the presence of microorganisms, or by activated lymphoid cells, and that act on blood vessels and cells of the immune system to induce or amplify immune responses
Innate immunity:
immune responses mediated by cells and molecules recognizing conserved features of microorganisms and activated immediately on encounter with them
lnterleukin cytokine:
participating in immune responses and originally thought always to be produced by leukocytes. Many cytokines have been given a systematic name of interleukin x, wehre x is a number from one to at least 29. lt is now clear that often the range of ac;tion of interleukins extends to non-hematopoietic lineage lines
kupffer cells
macrophages in the live
langerhans cells
immature dendritic cells in the epidermal layer of the skim
lectin
protein that binds specifically to particular polysaccharides or other carbohydrate structures. There are four major structural groups: C-type lectins, ptype lectins, ltype lectins and galectin-like lectins
lectin pathways
complement activation pathway through which mannose-binding lectin and ficolins stimulate the complement cascade
light chain
the immunoglobulin light chains are the smaller of the two kinds of chains in the immunoglobulin molecule. Each has a variable region contributing to the antigen-binding site, and a constant region containing a cysteine by which it makes a disulfide bond with the constant region of the heavy chain
LPS
major component of the outer membrane of Gram-negative bacteria and an important recognition element for innate immunity
lymph
Lymph: fluid drained from the tissues flowing through lymphatic vessels
lymphatic vessels
system of vessels draining fluid (lymph) from the tissues and in which dendritic cells and antigens are delivered to lymph nodes
lymph nodes
secondary lymphoid organs distributed widely in the body but especially in the groin, the axilla and the neck, and along the small intestine
macrophages
phagocytic cells resident in tissues th’at detect microorganisms by means of receptors recognising conserved components and ingest and destroy them, and function in tissue repair and maintenance
MHC
cluster of genes encoding the classical and many non- classical MHC molecules and other structurally unrelated molecules, many with important functions in immunity
Mannose-binding lectin
a collectin family member that recognises terminal sugars with equatorial hydroxyls in the C3 and C4 positions, such as mannose and fructose. Also called mannose-binding protein (MBP)
M cells
specialised epithelial cells in the small intestine that collect antigen at Peyer’s patches
memory celsl
Iong-lived lymphocytes that differentiate during the clonal expansion of antigen-specific lymphocytes during a primary immune response and provide a rapidly activated effector pool on subsequent challenge with the same antigen
Metacyclic promastigotes:
infectious forms of Leishmania that represent terminally differentiated promastigotes released from the intestinal epithelia and that migrate to the sandfly proboscis; metacyclic forms are covered with the lengthened form of surface lipophosphoglycan molecules that renders parasites more resistant to complement and macrophage oxidant killing
MHC class I
cell surface glycoproteins most of which are encoded in the major histocompatibility complex and most of which bind peptide fragments of cytoplasmic and secreted proteins and display them on the cell surface. AN important function of these cells is to signal the presence of viral infection to CD8 T cells
MHC class II
cell surface glycoproteins encoded in the major histocompatibility complex and most of which bind peptide fragments of proteins derived from internalised molecules, including those of extracellular pathogens, and display them for recognition bu CD4 cells
monoclonal antibodies
antibodies produced by a single clone of cells and therefore with a single specificity
monocytes
circulating precursors of macrophages and some dendritic cells
NK cells
cytotoxic lymphocytes lacking antigen-specific receptors but with invariant receptors that detect infected cells and some tumour cells and actiriate their destruction
Neuraminidase
influenza homotetrameric sialidase expressed on the virion that cleaves terminal sialic acid residues from host glycoconjugates to allow the release of infectious progeny virus
neutralising antibodies
antibodies that can directly block infection by viruses or attachment by bacteria or toxins, without need of complement or Fc receptors
neutrophils
phagocytic cells that circulate in the blood and deteet microorganisms by means of receptors that recognise conserved components
opsonin
any soluble molecule that-recognises and coats microorganisms and thereby stimulates internalisation of the microorganism by phagocytes
opsonized
bound by soluble recognition elements of the innate or adaptive immune system, such as antibody, iC3b and collectins, that are recognised by phagocytic receptors
paracrine
produced by one cell and acting on a nearby cell. ls thought to be the main mode of action of cytokines, although they can act in an autocrine fashion or systemically in an endocrine fashion
pathogenicity island
Pathogenicity islands: DNA encoding contiguous virulence genes and found in pathogenic bacteria
pentraxin
any of a small family of pentameric serum proteins that participate in innate immunity by binding to membranes of microbes and apoptotic cells and activating the classical pathway of complement.
peptidoglycan
ridgid polymer of repeating disaccharides cross-linked by short peptides that is a major structural element of most types of bacterial cell walls
Peter’s patches
organised regions of secondary lymphoid tissue in the wall of the small intestine
phage display
a technique for isolating proteins with specific binding characteristics whereby the desired protein is expressed on the surface of a bacteriophage. This allows phage to be selected for binding to a tissue culture dish coated with the ligand
phagocytic cells
cells that recognise and ingest molecules and particles including microorganisms and destroy them
phagocytic receptor
cell surface motecule of phagocytes that binds microbes, viruses or apoptotic cells, either directly or through opsonins, and induces phagocytosis
phagocytosis
receptor-mediated internalisation of cells or other particles larger than 1 pm in diameter
phagolysosome
phagosome that has fused with lysosomes
phagosome
vesicle generated by invagination and fusion of the plasma membrane of a phagocyte around a particle bound to phagocytic receptors
plasma cell
erminally differentiated B lineage cells secreting large quantities of antibody
polyclonal antibodies
heterogeneous antibodies against an antigen that are obtained by immunising an individual
Polymeric Ig receptor
receptor mediating transcytosis of immunoglobulin A across epithelial cells to mucosal surfaces
primary lymphoid tissue
bone marrow and thymus, where lymphocytes differentiate and mature
Proinflammatory cytokines:
cytokines that act on endothelial cells to induce inflammation. Also known as inflammatory cytokines
Reactive nitrogen intermediates
highly reactive and toxic compounds generated from L-arginine by inducible nitric oxide synthase (|NOS)
reactive oxygen intermediates
highly reactive and toxic compounds generated rom molecular oxygen by NADPH oxidase, superoxidde dismutase andlor myeloperoxidase
secondary lymphoid tissues
tissues in which lymphocytes are brought together when antigen and adaptive immune responses are initiated
secondary component
a chain of secreted lgA that is derived from the polymeric Lg receptor and remains bound to polymeric lgA after proteolytic cleavage of the transport receptor
Src- family tyrosine kinases
a family of eight memebrane-linked intracellular protein kinases first discovered as the product of a viral oncogene causing sarcoma in chickens. Src kinases participate in lmmune cell function primarily via ITAM and lTlM receptor signalling
surfactant
any of a number of lung proteins of diverse functions. The collectins surfactant protein A (SP-A) and surfactant protein D (SP-D) are important molecules of innate immunity
T cell receptor (TCR)
The complex of variable chains whereby T cells recognise antigen and signalling chains whereby antigen recognition is signalled to the cell interior
T helper cell
T lymphocytes that activate other cells of the immune system, including phagocytes, mast cells, basophils, eosinophils and B cells, which when activated differentiate into antibody-producing cells
Thymus
primary lymphoid organ in which T lymphocytes mature
T lymphocytes
lymphocytes that mature in the thymus and different classes of which mediate cytotoxic responses against cells infected with viruses, activate B lymphocytes to produce antibodies, and activate phagocytes to ingest and destroy microorganisms
TLR
family of receptors that have leucing-rieh repeats in their extracellular domains and the TIR domain in their cytoplasmic domains
T2 granuloma
granulomatous response orchestrated by TaZ cells, eosinophils, alternatively activated : macrophages and collagen-secreting mesenchymalcells organised in a dense sphericalstructure around a
central inciting agent, such as a schistosome egg
Type II secretion system
mechanism by which Gram-negative bacteria translocate host-modifying ‘ proteins into the cytoplasrn of the target cells through a syringeJike structure penetrating the host cell
membrane. The type lll secretion gystem is encoded in pathogenicity islands
variable domain
Ig-like domain of the type found in immunoglobulin variable regions. V domains have two more beta strands in the beta sandwich than do C domains. ln antigen receptors, the V domain contains the variable binding site for antigens
Variable region
region of a lymphocyte receptor for antigen that participates in antigen binding and varies between cells of different antigen specificities
Viral set-point
the relatively steady-state level of plasma HIV reached after acute infection becomes controlled by CD8 T cell responses. Although viral and CD4 T cell levels are relatively stable for prolonged periods, these levels reflect dynamic turnover in both compartments
zoonotic infection
an infection that crosses species, from an animal to infect humans
zymosan
cell wall preparation of Saccharomyces cerevisiae composed of B-glucans, mannans, mannoproteins and chitin
