Lecture 16 Cellular Cooperation and Antigen Recognition
Lecture 16 Cellular Cooperation and Antigen Recognition
Cellular Cooperation antigen Plasma Cells Antigen presentation to T and B cells by APC T cells elaborate cytokines to Antibody secretion by Antigen presenting cell facilitate B cell proliferation plasma cells and maturation
Cellular Cooperation TH B antigen Antibody secretion by plasma cells Plasma Cells Antigen presenting cell Antigen presentation to T and B cells by APC T cells elaborate cytokines to facilitate B cell proliferation and maturation
Antigen Presenting Cells Must be capable of processing antigen from extracellular and intracellular pathogens Must present processed antigen on MHC class I&II molecules Must express co-stimulatory molecules (cytokines)
Antigen Presenting Cells ◼ Must be capable of processing antigen from extracellular and intracellular pathogens ◼ Must present processed antigen on MHC class I & II molecules ◼ Must express co-stimulatory molecules (cytokines)
Types of Professional Antigen Presenting Cells Macrophages/monocytes Dendritic cells (e.g..,Langerhan's cells) B cells
Types of Professional Antigen Presenting Cells ◼ Macrophages/monocytes ◼ Dendritic cells (e.g.., Langerhan’s cells) ◼ B cells
Macrophages Dendritic cells B cells Properties of Professional Antigen- Presenting +++Phagocylosis by Antigen-specific Cells Antigen Phagocytosis uptake tissue dendritic cels. reoeptor (lg) +++ ++Viral infection ++++ MHC Inducble by bacteria and cytokines Constitutive Constitutive. expression Increases on activation -b+++ +++ +++0++++ Co-stimulator Constitutive;by mature Inducble Inducble delivery 一o+++ np089828oo -0++ ++十+ Antigen Particulate antigens. Peptides Soluble antigens. presented Intracellular and Viral antigens Toxins. extraoellular pathogens (allergens?) Viruses Lymphold tissue Lymphoid tissue. Location Connective tissue Connedtive tissue Lymphoid tissue. Body cavities Epithelia Peripheral blood @1997 Current Biology Ltd./Garland Publishing,Inc
Properties of Professional AntigenPresenting Cells
Cellular Cooperation and Antigen Recognition APC Extracellular Class ll CD4+Helper T Antigen MHC- Lymphocyte associated antigen
Cellular Cooperation and Antigen Recognition APC Extracellular Antigen CD4+ Helper T Lymphocyte Class II MHCassociated antigen +
The Role of Adjuvants Depot effect antigen persists for long period resistance to rapid degradation Macrophage activation production of non-specific enhancing factors Non-specific T cell signal provides "second"signal to B cell normally provided by T cell
The Role of Adjuvants ◼ Depot effect ◼ antigen persists for long period ◼ resistance to rapid degradation ◼ Macrophage activation ◼ production of non-specific enhancing factors ◼ Non-specific T cell signal ◼ provides "second" signal to B cell normally provided by T cell
Types of Adjuvants Freund's Complete Adjuvant (Water-in-oil emulsion) mineral oil ·emulsifying agent microbial preparation (eg.heat-killed extract of Mycobacterium tuberculosis) aqueous phase containing antigen Aluminum Hydroxide Gel Microbial Adjuvants ■C.pavn BCG Peptides and Synthetic Polymers
Types of Adjuvants ◼ Freund's Complete Adjuvant (Water-in-oil emulsion) ◼ mineral oil ◼ emulsifying agent ◼ microbial preparation (eg. heat-killed extract of Mycobacterium tuberculosis) ◼ aqueous phase containing antigen ◼ Aluminum Hydroxide Gel ◼ Microbial Adjuvants ◼ C. parvum ◼ BCG ◼ Peptides and Synthetic Polymers
Effector Mechanisms Mechanisms that are used by the immune system to eliminate pathogens(or other substances)from the body Cellular effector mechanisms ■Activated T cells 。Natural killer cells Humoral effector mechanisms (antibody) Neutralization Opsonization Complement activation Antibody-dependent cell-mediated cytotoxicity (ADCC)
Effector Mechanisms ◼ Mechanisms that are used by the immune system to eliminate pathogens (or other substances) from the body ◼ Cellular effector mechanisms ◼ Activated T cells ◼ Natural killer cells ◼ Humoral effector mechanisms (antibody) ◼ Neutralization ◼ Opsonization ◼ Complement activation ◼ Antibody-dependent cell-mediated cytotoxicity (ADCC)
Effector Activity Against Pathogens Cell-mediated immunity Humoral immunity Mycobacterium tuberculosis Clostridium tetani Vaccinia virus Typical Influenza virus Mycobacteriumn leprae Staphylocoocus aureus pathogens Rabies virus Leishmania donovani Streptoooocus pneumoniae Listeria Pneumocystis carini Polio virus Pneumocystis carini Location Cytosol Macrophage vesides Extracellular fluid Effector Tcell CylotoxicCD8Toell TH1 cell TH1/T2cel Antigen Peptide:MHC dassI Peptide:MHC dass ll Peptide MHC dass ll recognition on infected oell oninfected macrophage on specific Bcell Effector action Killing of infected cell Activation of Activation of specific infected macrophages Bcell to make antibody 1997 Current Biology Ltd./Garland Publishing,Inc
Effector Activity Against Pathogens