Immune system Flashcards
Adaptive immune response
Requires T and B cells and MHC. Previous encounters enhace immune response.
Adjuvant
A substance which makes a vaccine more effective.
Agglurination
Aggregation of antigen and antibodies
What is an allergy mediated by
Mast cells and IgE
Antibody
Protein produced by B cells during adaptive immune response. Activate complement, neutralise toxins or opsonise pathogens.
Antigen
Can be recognised by the immune system
Antigen presenting cells (APC)
White blood cells expressing MHC-II. APC phagocytose antigens from microbes and present these antigens to both CD4 and CD8 T cells.
B cells
Involved in antibody production. Receive help from helper T cells and differentiate into antibody producing cells and memory B cells.
B cell receptor
Membrane bound antibody expressed by mainly naïve B cells. B cell signalling and antigen uptake
CD4 helper Tcell
Required for initiation of cytotoxic T cell responses and stimulates antibody secretion by B cells. Secrete cytokines.
CD8 T cells
Recognise antigenic peptide complexed to MHC-I
Complement
Plasma proteins punch holes in membranes of microbes, opsonize microbes and contribute to inflammation
Clonal selection
B and T cells have diversity of receptors which are ‘clonally’ expressed on different lymphocytes
Cytokines
Soluble proteins released from a variety of cells. Involved in variety of immune functions
Cytotoxic T cells
Differentiated CD8+ Tcells, which kill virally infected cells or tumor cells
Dendritic cells
One of the first cells to encounter and phagocytose antigen. High levels of both MHC-I and MHC-II
Fc-receptors
Receptors that bind antibody. are present on phagocytes
Immunoglobulins
Family of proteins that includes antibodies and T cell receptors
Innate immune response
Rapid immune response mostly mediated by phagocytosis and complement.
Interferons
Class of cytokines hacing activity against viruses and intracellular bacteria
Isotypes
Class of antibody that differ in the constant region of theur heavy chain
Lysozyme
Enzyme present in secretions that breaks down bacterial cell walls
Macrophage
Phagocytic cell involved in the remvoal of microbes and apoptotic cells
MHC-I
Present endogenous antigens derived from the cytoplasm
MHC-II
Presents exogenous antigens derived from the endocytic pathway. Pepetide loading takes place in phagolysosome
Mast cells
Cells present in the tissue that bind IgE and are involved in anti-parasite responses. Mediate allergic responses
Memory cell
Memory T or B cells arise following antigenic stimulation of naïve T or B cells
Natural killer cells
Lymphcytes that destroy cells that lack MHC-I
Neutrophil
Most numerous white blood cell, active phagocytes
Passive immunity
Occurs when antibodies are transferred to another individual to provide an immune response
Pattern recognition receptors
Innate receptors that sense conserved molecular structures of pathogens
Peptides
Fragments of proteins composed of amino acids
Phagolysosome
Acidic vesicle formed following phagocytosis of microbes, degrades proteins to peptides
Plasma cells
Fully differentiate B cells that secrete large amouts of antibody
T cells
Include CD4+ and CD8+T cells. T cell precursors migrate from the bone marrow to the thymus where they complete development
T cell receptors
Expressed by T cells that recognise antigen fragments complexed to MHC molecules
