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Overview of the Course
Lecture 1
The Components of the Immune System
Lecture 2
Innate Immunity
Lecture 3
Antigen Recognition by T lymphocytes
Lecture 4
Antigen Presentation by T lymphocytes
Lecture 5
Antigen Recognition by B cell Receptors
Lecture 6
The Humoral Immune Response
Lecture 7
Signaling Through Lymphocyte Receptors
Lecture 8
The Development and Survival of Lymphocytes
Lecture 9
T-cell Mediated Immunity
Lecture 10
Adaptive Immunity to Infection
Lecture 11
Mucosal Immunity
Lecture 12
HIV Infection
Lecture 13
Failures in Host Defense Mechanisms
Lecture 14
Evasion of the Immune System by Pathogens
Lecture 1: The Components of the Immune System
Summary of the
Entire Immunology Unit
 Kill the pathogen and
don’t harm the host
Questions to Consider
 Why do you only get some infections like chicken pox




aka varicella zoster only once?
How do you generate an system able to recognize a
broad array of pathogens with a high level of
sensitivity and specificity using a finite amount of
coding DNA?
Why do subsequent immune responses to a
pathogen occur more rapidly and at higher titers than
previous immune responses?
How does the immune system provide a high degree
of sensitivity and specificity to the broad array of
pathogens without attacking self?
Why are T cells and B cells effective against different
pathogens and how do T cells and B cells see
antigens differently?
David
Smallpox Infection
Immunity
 From the Latin word “immunitas” meaning
exemption from civic duties.
 Historically immunity was the observed
protection from infection by individuals
previously exposed or infected.
 Chinese made children inhale powder from
crusted smallpox lesions.
Eradication of Smallpox by Vaccination
Functional Immunity
Innate
Acquired
Barrier
Skin
Mucosal immunity
Soluble Protein
Complement
Antibodies
Cells
Phagocytes
T and B cells
Mediators
IL-1, TNF
-interferon
Function of Immune System
 Identification- foreign vs. self
 Designation- accentuate foreign origin
 Recruitment- mobilize effectors
 Elimination- clear pathogen
 Prevent Recurrence- prepare for future
Sensitivity and Specificity
of Detection Determines
the Effectiveness of
Immune Surveillance
Design of the Immune System
 Specificity- fine distinctions
 Diversity- broad repertoire
 Memory- accelerate next response
 Demobilization- after clearance
 Distinguish self from non-self- prevent
attack of normal tissues
Mobilization of the Immune System
 Cognitive phase- binding of antigen to
specific cell that recognizes it
 Activation phase- proliferation and
differentiation of antigen-specific cell
 Effector phase- assemble response to
eliminate infection
Targets of the Immune System
CD Nomenclature
 CD = Cluster of Differentiation
 Cells express unique membrane proteins
identified by monoclonal antibodies.
 Cells are identified by the pattern of cellspecific CD markers expressed.
 CD proteins are identified by sequential
numbers.
Hematopoietic Lineage
Histological Appearance
of Lymphocytes
Activation of Lymphocytes
How Does the Immune System
Provide a High Degree of Sensitivity
and Specificity to the Broad Array of
Pathogens Without Attacking Self?
Clonal Selection Hypothesis
Expression of Antigen-specific Membrane Proteins
Clonal Selection
The Antibody Recognizes an
Epitope Within the Antigen
Development of a Secondary Amplified Response
Clonal Expansion
Structure of Antigen Recognition Molecule
Different Antigen Recognition
Molecules Are Used by B Cells and T Cells
Identity of Lymphocytes in the Peripheral Blood
Primary and Secondary Lymphoid Tissues
Lymph Node Organization
Spleen Organization
Anatomical Localization of
B cells and T Cells
B Cells and T cells Recognize
Different Antigenic Contexts
 B Cells use the Immunoglobulin Molecule to recognize 3D
structures of the native molecules.
 T Cells use the T cell receptor to recognize primary structures.
Structure of Immunoglobulin Molecule
Function of Immunoglobulin Molecules
T cells Recognize Peptides
Presented by Cells
Helper T cell
Cytotoxic T cell
Function of Cytotoxic and Helper T Cells
Questions to Consider
 Why do you only get some infections like chicken pox




aka varicella zoster only once?
How do you generate an system able to recognize a
broad array of pathogens with a high level of
sensitivity and specificity using a finite amount of
coding DNA?
Why do subsequent immune responses to a
pathogen occur more rapidly and at higher titers than
previous immune responses?
How does the immune system provide a high degree
of sensitivity and specificity to the broad array of
pathogens without attacking self?
Why are T cells and B cells effective against different
pathogens and how do T cells and B cells see
antigens differently?