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Advanced Biology. Chapter 22 Nonspecific Body Defenses and Immunity. Nonspecific – Innate Specific – Adaptive. Intact skin and mucosa. Phagocytes Other cells (inflammatory). Specific Defense B Cells and T Cells. Functional System No Organs Trillions of Cells. Resistance to Disease. - PowerPoint PPT PresentationTRANSCRIPT
Advanced BiologyAdvanced Biology
Chapter 22Chapter 22Nonspecific Body Nonspecific Body
Defenses and ImmunityDefenses and Immunity
Nonspecific – InnateNonspecific – Innate
Specific – AdaptiveSpecific – Adaptive
Intact skin and Intact skin and mucosamucosa
PhagocytesPhagocytesOther cells Other cells (inflammatory)(inflammatory)
Specific DefenseSpecific DefenseB Cells and T CellsB Cells and T Cells
Functional SystemFunctional SystemNo OrgansNo OrgansTrillions of CellsTrillions of Cells
Resistance to DiseaseResistance to Disease
NonspecificNonspecific
SpecificSpecific
Keratin provides a Keratin provides a barrier – resistant to barrier – resistant to weak acids/bases and weak acids/bases and bacterial toxinsbacterial toxins
Acidic – pH 3-5, Acidic – pH 3-5, inhibits bacterial inhibits bacterial growth; sebum growth; sebum contains chemicals contains chemicals toxic to bacteriatoxic to bacteria
Stomach – Stomach – concentrated HCl and concentrated HCl and protein digesting protein digesting enzymesenzymes
Saliva and lacrimal Saliva and lacrimal fluid contains fluid contains lysozyme which lysozyme which destroys bacteriadestroys bacteria
Sticky mucus traps Sticky mucus traps microorganismsmicroorganisms
MACROPHAGESMACROPHAGESDerived from Derived from monocytesmonocytes
Free MAC wander all Free MAC wander all overover
Kupffer cells -liverKupffer cells -liverAlveolar cells – LungsAlveolar cells – LungsPermanent residentsPermanent residents
WBC that can WBC that can phagocytizephagocytize
Neutrophils release Neutrophils release defensins – kills defensins – kills everything around it, everything around it, including itselfincluding itself
WBCWBCDefend against Defend against parasitic worms by parasitic worms by surrounding it and surrounding it and discharging enzymesdischarging enzymes
Some bacteria can Some bacteria can replicate inside MACs, replicate inside MACs, MACs are stimulated to MACs are stimulated to release other release other chemicals (Nitric oxide)chemicals (Nitric oxide)
Police the bodyPolice the bodyChecks markers – Checks markers – releases cytolytic releases cytolytic chemicalschemicals
Prevent Spread of Prevent Spread of damaging agentsdamaging agents
Dispose of cell debrisDispose of cell debris
Set stage for repairSet stage for repair
Enhance the body’s Enhance the body’s nonspecific defenses by nonspecific defenses by attacking microorganisms attacking microorganisms or hinder their ability to or hinder their ability to reproducereproduce
Classical – Binding of Classical – Binding of antibodiesantibodies
Alternative – Certain Alternative – Certain protein factors are protein factors are initiatedinitiated
Convergence on C3, Convergence on C3, Splitting it, C3a, C3b. Splitting it, C3a, C3b. Initiates events that Initiates events that cause lysis, promotes cause lysis, promotes phagocytosis and phagocytosis and enhances inflammationenhances inflammation
Message to tell other Message to tell other cells there is a viruscells there is a virus
Those cells synthesize Those cells synthesize “PKR” which interferes “PKR” which interferes with viral replicationwith viral replication
PyrogensPyrogensPyro – firePyro – fire
Causes liver/spleen Causes liver/spleen to retain zinc/ironto retain zinc/iron
Helps speed up Helps speed up metabolic rate of metabolic rate of cellscells
Can denature Can denature bacterial enzymesbacterial enzymes
Advanced BiologyAdvanced Biology
Chapter 22Chapter 22
Specific Body Specific Body Defenses: ImmunityDefenses: Immunity
Immune ResponseImmune Response
GoodGood
To mount an immune To mount an immune response is expensive. response is expensive.
Lots of energy is Lots of energy is required. Being specific, required. Being specific, energy is only expended energy is only expended
when necessary.when necessary.
Study of ImmunityStudy of Immunity
Antigen-SpecificAntigen-SpecificSystemicSystemicMemoryMemory
Humoral (Antibody-Humoral (Antibody-mediated)mediated)
Cellular (Cell-Cellular (Cell-mediated)mediated)
IntrudersIntrudersNot selfNot self
Immunogenicity – Immunogenicity – stimulate the stimulate the proliferation of specific proliferation of specific lymphocytes and lymphocytes and antibody productionantibody production
Reactivity – Ability to Reactivity – Ability to react with react with lymphocytes or lymphocytes or antibodiesantibodies
Part of antigen that is Part of antigen that is immunogenicimmunogenic
Binds to itBinds to it
Self-antigenSelf-antigenMajor Major Histocompatibility Histocompatibility Complex (MHC)Complex (MHC)
Class I MHC – All body Class I MHC – All body cellscells
Class II MHC – Immune Class II MHC – Immune Response CellsResponse Cells
Antigen Presenting Antigen Presenting Cells (APC)Cells (APC)
B Lymphocytes B Lymphocytes (Humoral)(Humoral)
T Lymphocytes (Cell T Lymphocytes (Cell mediated)mediated)
To be able to To be able to recognize a specific recognize a specific antigenantigen
Eliminates themEliminates them
Before meeting antigenBefore meeting antigen It is in your genesIt is in your genesAn antigen only An antigen only determines which B or T determines which B or T cell will proliferate and cell will proliferate and attackattack
Engulfs antigen, Engulfs antigen, shows it to a T cellshows it to a T cell
Advanced BiologyAdvanced Biology
Chapter 22Chapter 22
Humoral Immune Humoral Immune ResponseResponse
Not a game show Not a game show
11stst Encounter b/w Encounter b/w immunocompetent immunocompetent lymphocyte and lymphocyte and invading antigeninvading antigen
3 to 6 Days3 to 6 DaysTakes time for B cells Takes time for B cells to differentiateto differentiate
2ndry much faster, 2ndry much faster, more prolonged and more prolonged and more effective. 2-3 more effective. 2-3 day responseday response
See pg 775See pg 775
The capacity to The capacity to produce a powerful produce a powerful 2ndry humoral 2ndry humoral responseresponse
When B cells When B cells encounter antigens encounter antigens and produce and produce antibodies against antibodies against themthem
Naturally acquired: Naturally acquired: During bacterial & During bacterial & viral infectionsviral infections
Artificially acquired: Artificially acquired: Through vaccineThrough vaccine
Dead or attenuated Dead or attenuated (living but weakened) (living but weakened) pathogenspathogens
Spare us from most of Spare us from most of the symptomsthe symptoms
Provide functional Provide functional antigenic antigenic determinatesdeterminates
No memory is No memory is establishedestablished
Fetus to motherFetus to mother
ImmunoglobulinsImmunoglobulins
IgD – Attaches to B IgD – Attaches to B cells, activates B cellscells, activates B cells
IgM – Large, pentamer IgM – Large, pentamer shape. Antigen receptive, shape. Antigen receptive, 11stst Ig released during Ig released during primary response. Fixes primary response. Fixes and activates complementand activates complement
IgG – Most abundant – 75-IgG – Most abundant – 75-85%. Crosses placenta, 85%. Crosses placenta, protects against bacteria, protects against bacteria, viruses and toxins. Fixes viruses and toxins. Fixes complement.complement.
IgA – Dimer (2), found IgA – Dimer (2), found in body secretions, in body secretions, helps prevent helps prevent attachment of attachment of pathogens to epithelial pathogens to epithelial cellscells
IgE – Stem region is IgE – Stem region is bound to mast cells bound to mast cells and basophils and basophils (allergies)(allergies)
Antigen-Antibody Antigen-Antibody complexescomplexes
ComplementComplement
Neutralization – Neutralization – blocks specific sites blocks specific sites on viruses and on viruses and bacteriabacteria
Agglutination – Agglutination – Clumping of cellsClumping of cells
Precipitation – not rain.Precipitation – not rain.Antigen molecules, not Antigen molecules, not cells, are clumped cells, are clumped together.together.
See page 780.See page 780.
Advanced BiologyAdvanced Biology
Chapter 22Chapter 22
Cell-Mediated Cell-Mediated Immune ResponseImmune Response
Microorganisms that Microorganisms that slip inside body cellsslip inside body cells
Trying to avoid Trying to avoid immune systemimmune system
CD4 = T4, Helper TsCD4 = T4, Helper TsCD8 = T8, Cytotoxic CD8 = T8, Cytotoxic TsTs
Through processed Through processed parts on an APCparts on an APC
Provide means for Provide means for signaling to immune signaling to immune
system cells that system cells that infectious microorganisms infectious microorganisms
are hiding in body cellsare hiding in body cells
Step 1: Antigen BindingStep 1: Antigen BindingT cell antigen receptors, T cell antigen receptors, TCRs, bind to an TCRs, bind to an antigen-MHC protein antigen-MHC protein complexcomplex
Helper Ts bind to MHC Helper Ts bind to MHC II – w/help of APCII – w/help of APC
Cytotoxic Ts bind to Cytotoxic Ts bind to MHC I – needs no APCMHC I – needs no APC
Step 2: CostimulationStep 2: Costimulation If bound to right costimulator If bound to right costimulator
(protein, chemicals), (protein, chemicals), stimulation (proliferation) stimulation (proliferation)
occurs. W/O right match, T occurs. W/O right match, T cell activity is stoppedcell activity is stopped
Mediators involved in Mediators involved in cellular immunitycellular immunity
Lymphokines – Lymphokines – released by activated released by activated T cellsT cells
Monokines – secreted Monokines – secreted by MACsby MACs
Interleukin 1 & 2 – IL 1 Interleukin 1 & 2 – IL 1 released by MACs tells released by MACs tells T cells to liberate IL 2, T cells to liberate IL 2, which encourages T which encourages T cells to divide more cells to divide more rapidly.rapidly.
Tumor Necrosis Tumor Necrosis Factor (TNF) – Factor (TNF) – enhances nonspecific enhances nonspecific cell killingcell killing
Perforin/lymphotoxin Perforin/lymphotoxin are cell toxins that T are cell toxins that T cells can release. cells can release. Lethal Hit.Lethal Hit.
Gamma Interferon – Gamma Interferon – enhance killing power enhance killing power of MACsof MACs
Regulatory cellsRegulatory cellsInteract with B cellsInteract with B cells
Major function is to Major function is to chemically or directly chemically or directly stimulate proliferation of stimulate proliferation of other T cells and B cells other T cells and B cells that have already that have already become bound to antigenbecome bound to antigen
W/O helper Ts, there W/O helper Ts, there is no immune is no immune response!!response!!
Killer T cellsKiller T cellsThey can directly They can directly attack and kill other attack and kill other cellscells
Main target is virus infected Main target is virus infected cells, also tissue cells that cells, also tissue cells that
have been infected, have been infected, parasites, cancer cells, parasites, cancer cells,
foreign cells introduced by foreign cells introduced by blood transfusions or organ blood transfusions or organ
transplantstransplants
Help stop immune Help stop immune response after response after antigen has been antigen has been destroyeddestroyed
Promote allergic Promote allergic reactionsreactions