Pathology 3500 Lecture Notes - Lecture 6: Cell-Mediated Immunity, Adaptive Immune System, Innate Immune System
1 May 2018
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Lecture 006: Immune Response
Innate Immunity
● Exists at birth
● Cellular response
● Does not require prior-recognition events/learning
Adaptive Immunity
● Acquired through exposure to antigens
● antibodies
● Cell mediated
● Has long term memory
● Able to protect us when we are exposed to the pathogen the second time
Inflammation
● Components of the inflammatory process:
○ WBC
■ Important in both the innate and adaptive response
■
○ Plasma proteins in the blood
● The inflammatory reactions goal is to bring these to the site of infection and/or tissue
damage
○ Cytokines and chemical are there to bring these cells (normally circulating in the
bloodstream) to the site of infection (in the tissue)
● Inflammation is induced by chemical mediators produced by damaged host cells
○ Cytokines and other mediators
■ Switch on other inflammatory process
● Immune response has to be controlled and self-limited
○ Has to be balanced!
■ Immune system can cause harm otherwise
● Ex. shock (a negative effect)
○ Other immune response dampen the effects of the cytokines so that you can get
a measured immune response
Innate immune system
● First to respond (rapid)
○ Does not require memory
● Limit infections before adaptive response
● Macrophages and polymorphonuclear neutrophils (PMN)
○ Go immediately to the site of infection
○ Engulfs and kills pathogens
● Also involves complements and acute phases
● If innate immunity cures infection, no adaptive immunity develops
○ Never evokes that system
find more resources at oneclass.com
find more resources at oneclass.com
Adaptive immune system
● Cell-mediated immunity
○ Induced antigen specific responses
● Primary lymphoid organs produce lymphocytes capable of responding to various
antigens
● Lymphocytes circulate in peripheral lymphoid organs
● Locations for Ag-dependent immune response
● Innate: T-cells recognizes viral antigens on infected cells and attacks it
○ Then other parts develop an immune memory to that antigen
○ Recognize that antigen if you are reinfected
■ Stimulate production of antibodies
○ This is the adaptive system
Blood Cell Development
● Starts from a stem cell in the red bone marrow
○ Differentiates into
■ Lymphoid progenitors
■ Myeloid progenitors
Lymphoid progenitors: cells that develop into lymphocytes
Large lymphocytes:
● Natural killers cells
○ Part of the Innate immune
system
○ Can recognize foreign
antigen on YOUR cells
■ Viral infection, etc
○ Attack and kill them
○ Also recognize foreign
tissues
■ Transplant rejections
Small lymphocytes:
● T-lymphocytes
○ Produced in the bone marrow
(like all WBCs)
■ But goes to the
thymus to differentiate
into T-lymphocytes
○ Help in the immune response
■ Interact and switch on macrophages
■ Interact with B-cells, help stimulate the produce of antibodies
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find more resources at oneclass.com
● B-lymphocytes
○ Store the immune memory
■ Long lived
■ Carry receptors on their surface that recognize previously exposed
antigens
○ When it binds to an antigen it differentiates into a plasma cell
● plasma cell
○ Make antibodies for a specific antigen
○ Protects against reinfection
Myeloid progenitors: all the rest of the blood cells
● Megakaryocytes
○ thrombocytes -> platelets
■ Band-aids
■ Blocks bleeding
● Erythrocytes (RBCs)
○ No nuclei
○ Lots of hemoglobin
○ Bind and carry O2 from lungs to tissue
● Myeloblast (progenitor of white cells)
○ Have multiple nuclei (3-4) that join
together
■ Basophil
■ Neutrophil
■ Eosinophil
○ Monocytes (in circulation)
■ Only one nuclei (that looks like
a kidney)
■ Called macrophages when in tissue
● Mast cells
○ Functions the same as basophil
Granulocytes
● 3 multi-nucleated WBCs
● All contain cytoplasmic granules
● Named according to their granule stain
○ Neutrophil (neutral dye - pink)
○ Eosinophil (acidic dye -orange)
○ Basophil (basic dye - blue)
Basophil and Mast cells
● Most important activators of inflammation
○ Because they have preformed granules that contains histamines
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Able to protect us when we are exposed to the pathogen the second time. Important in both the innate and adaptive response. The inflammatory reactions goal is to bring these to the site of infection and/or tissue damage. Cytokines and chemical are there to bring these cells (normally circulating in the bloodstream) to the site of infection (in the tissue) Inflammation is induced by chemical mediators produced by damaged host cells. Immune response has to be controlled and self-limited. Other immune response dampen the effects of the cytokines so that you can get a measured immune response. Go immediately to the site of infection. If innate immunity cures infection, no adaptive immunity develops. Primary lymphoid organs produce lymphocytes capable of responding to various antigens. Innate: t-cells recognizes viral antigens on infected cells and attacks it. Then other parts develop an immune memory to that antigen. Recognize that antigen if you are reinfected.
