Review: Cells of the Immune System. Leukocytes – White blood cells Myelocytes –macrophage , neutrophil, eosinophil , basophil Leukocytes – B, T and NK cells. From Larsson and Karlsson (2005). Review: Cells of the Immune System. Larsson and Karlsson (2005). Review: Myelocytes.
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Leukocytes– White blood cells
Myelocytes–macrophage, neutrophil, eosinophil,basophil
Leukocytes – B, T and NK cells
From Larsson and Karlsson (2005)
Larsson and Karlsson (2005)
•Macrophages – phagocytes, antigen presenting cells (APCs), specialized cells different organs, secrete cytokines, produce complement proteins, can produce ROS/RNS.
•Neutrophils – phagoctyes, can produce ROS/RNS, secrete antimicrobial peptides, 1st cell type to migrate from blood to infections, main targets are bacteria and fungi
•Eosinophils– phagocyte, targets parasites
•Basophils – secrete cytokines, involved in allergic response
Natural killer cells
• B cells – naïve B cells: contain antigen binding receptor (or membrane bound antibody), once activated –
memory cells: provides memory of antigen/antibody interaction; plasma cells: secrete soluble antibody
• T cells - contain antigen binding receptor (TCR)
THcells: secretes cytokines that activate B cells, TCcells, macrophages and others.
TCcells: eliminates altered/damaged self cells (particularly those infected by viruses), fights tumors cells, secrete cytotoxins.
Tregcells: helps suppress immune response, plays a role in tolerance.
T reg cell
•Natural killer cells – distinct from T and B cells due to lack of an antigen binding receptor, similar in function to TCcells, macrophage activation, defense against viruses, fight tumor formation, secrete cytotoxins.
Derived from both lymphoid and myeloid precursors
•Dendritic cells – phagoctyes, antigen presenting cells (APCs), can produce ROS, secrete proinflammatory cytokines, secrete antimicrobial peptides.
1°- maturation of lymphocytes
2°- sites where mature lymphocytes interact with antigen.
Level of organization:
collection of cells
Antigen – any substance that binds specifically to an antibody or a T cell receptor (TCR).
Antibody- a protein (immunoglobulin) that recognizes a specific region (component) of an antigen.
Properties of immunogenicity:
Route of entry
Assist/activate complement system
•Humoral immunity – Host defenses that are mediated by antibody present in the plasma, lymph and tissue fluids.
•Cellular immunity – Host defenses that are mediated by antigen-specific T cells and various nonspecific cells of the immune system.
Ricklin and Lambris 2007
Functions of the Complement System
Components of the Complement System:
proteins and glycoproteins
synthesized mainly by liver
5% of serum
circulate as zymogens
Designation of complement components:
letter symbols (factor D)
trivial names (homologous restriction factor)
cleavage products – “a” and “b”
Complement Activation Pathways: