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Todayy
“Immunochemistry”
Innate and adaptive
(Chapter 31, Bettelheim et al)(Chapter 31, Bettelheim et al)
Antigeng
Foreign substances that elicit an immune response Foreign substances that elicit an immune response (“immunogens”)
The smallest unit of an antigen capable of binding ith tib d i ll d “ it ” with an antibody is called an epitope
To elicit an immune response the epitope must be brought to the surface of a cell
Innate immunityyExternal Internal
Skin Dendritic cells
Mucous
T
Natural killer cells
M hTears Macrophages
Dendritic cells
Found in skin, mucus membranes the lungs membranes, the lungs, and the spleen
Engulf viruses and b t ibacteria
Dendritic cells
P i f Present antigens of digested viruses and bacteria to cells of bacteria to cells of adaptive immunity (helper T cells)(helper T cells)
“A ti ti “Antigen presenting cells” (APCs)
Macrophagesp gFirst cells in the blood to encounter an antigenencounter an antigen
Attack anything not Attack anything not recognised as “self”
Activity mediated by interferon and NO
Digest and display antigen on their surfaceon their surface
Natural killer cells
Target abnormal cellsTarget abnormal cells
d d bActivity mediated by perforins
Adaptive immunityp yCells Molecules
“Lymphocytes” “Immunoglobulin superfamily”
B cells Antibodies
T cells T cell receptors (TcR)
Major histocompatibilitycomplexes (MHC)
Adaptive immunity characterised by specificity and memory
Cells of adaptive immunityp yT cells B cells
Killer T cells attach to target cells (cf. NK cells of innate immunity) B ll diff i i immunity)
Some T cells remain as
B cells differentiate into antibody (immunoglobulin) producing plasma cellsSome T cells remain as
“memory” cellsp g p
Most plasma cells reside in Helper T cells assist in recognition of antigens
t d b APC
plymph nodes
presented by APCs
Differentiation of cells of adaptiveDifferentiation of cells of adaptive immunityy
Molecules of adaptive immunityp yImmunoglobulin super family
Soluble immunoglobulinsg
Receptors on the surface of T cells (TcR)
M j hi ibiliMajor histocompatibilitycomplexes (MHC)
Alternate splicingp g
Hybridomasy
A checklist of the components ofA checklist of the components of immunityyInnate Adaptive
Barriers (skin, mucous membranes tears) Cells (B cells T cells and membranes, tears)
Cells (dendritic cells
Cells (B cells, T cells and plasma cells)
Cells (dendritic cells, macrophages, natural killer cells)
Immunoglobulins
Protect against “non‐self”Respond to specific antigens
Th f i d d i i i The components of innate and adaptive immunity interact through a variety of signalling pathways
Helper T cells are a mediator of these signalling p g gpathways
Lymphatic systemy p y
Lymphatic systemy p y
Dendritic cells
Found in skin, mucus membranes the lungs membranes, the lungs, and the spleen
Engulf viruses and b t ibacteria
Antigen presentationg p
Dendritic cells
P i f Present antigens of digested viruses and bacteria to cells of bacteria to cells of adaptive immunity (helper T cells)(helper T cells)
“A ti ti “Antigen presenting cells” (APCs)
The T cell receptor (TcR)p ( )
MHC and TcR interaction