MC | IMMUNOLOGY
INTRODUCTION TO IMMUNOLOGY Adaptive Response
Topic Outline: ● Slower specific response to a particular antigen
1. Immune System
a. Immune Response Non-specific Augmentation in Response
2. Antigen Memory of Specific Immune Response
3. Features that determine the
immunogenicity ● quicker and larger response on repeated exposure
4. Innate Immunity to same antigen -> ANAMNESTIC
5. Adaptive Immunity MEMORY
Reference: Innate Immunity
Jawetz’ Medical Microbiology 28th Edition ● first line of defense, (-) immunologic memory
● Nonspecific to invading pathogen, rapidly
mobilized at initial site of infection
Immune System
● Humoral components - soluble molecules
● Evolved as host defense and resistance -> ● Cellular components - blood and tissues
infectious disease & foreign antigens ● Immunologic Responses: Accompanied by
● Consists of proteins, cells and organs inflammation - few hours of stimulation
● Innate: Rapid response mechanism ○ Ex: Pricked during gardening - there will
● It is already present in the body, when there be inflammation
is bacteria that enters the body, there is
already a mechanism to defend our body.
● Has no memory
● Adaptive: Specific, adaptability, intricate
regulatory network and memory
Immune Response
● Response generated against a potential
pathogen (bacteria, virus, fungi infection
etc..
● Consists of 5 parts
Recognition
● able to distinguish between “non-self”
(pathogens) from “self” (host cells) Antigen
● both applicable with adaptive and innate
immunity ● A protein substance induces production of
● involves professional dendritic cells: antibodies
○ Recognition: General pathogen ● Antibody - hero
features or specific antigenic ● Antigen - villain
molecules ● Conventionally divided into:
○ Processing and presentation of ○ Thymus-dependent antigens
Ags to cells of immune system ○ Thymus-independent antigens
○ Initiation of non-specific Immunogens
inflammation
● induce an immune response
Early or Innate (Non-Specific Immune Response) ● most antigens are also immunogens
● on recognition followed by: “All immunogens are antigens but not all antigens are
● Effector phase immunogens.”
○ Innate immunity - neutrophils and
macrophages
○ Adaptive Immunity - Antibodies and Thymus-Dependent Antigens
effector T lymphocytes
● Require T-cells participation to provoke the
production of antibodies
I BELIEVE IN THE PERSON THAT I WANT TO BE 1
, MC | IMMUNOLOGY
○ E.g. mostly proteins
● Produces immunological memory Table 1.2 Factors influencing the immune
response to an antigen, i.e., immunogenicity
Thymus-Independent Antigens 1. Nature of molecule:
○ Protein content
● Require no T-cell cooperation for antibody ○ Size
production ○ Solubility
● Directly stimulate specific B lymphocytes by 2. Dose
virtue of: ○ Low doses provoke small amounts
● Ability to cross-link antigen receptors on the of antibody with high affinity and
B-cell surface restricted specificity
● produce predominantly IgM and IgG2 ○ Moderate doses provoke large
antibodies provoke poor immunological amounts of antibody but mixed
memory affinity and broad specificity
○ High doses provoke tolerance
Features that Determine the Immunogenicity 3. Route of entry
○ ID, IM SC → regional lymph nodes
● Recognition of foreignness ○ IV → spleen
○ Molecules recognized as “self” = not ○ Oral → Peyes’s patches
immunogenic ○ Inhalation → bronchial lymphoid
○ Molecules recognized as foreign tissue
“non-self” = immunogenic 4. Addition of substances with
● Size synergistic effects
○ Potent immunogens = Large, complex ○ E.g. adjuvants
proteins 5. Genetic factors of recipient animal:
○ MW < 10,000 = weakly immunogenic ○ Species differences
○ larger proteins are more immunogenic ○ Individual differences
compared to smaller and simpler
proteins
○ HAPTENS: low molecular weight Superantigen
proteins + linked to carrier CHON =
immunogenic (E.g. Lipids and Amino ● Foreign CHONs not specifically recognized by
Acids) the adaptive system
● Chemical and structural complexity ● Do not require processing
○ AA Heteropolymers > AA ● Bind to MHC molecules outside peptide-
Homopolymers binding cleft at the invariant part of TCR
● Host genetic constitution of the host
○ Differences in MHC alleles - strains of Cytokine Storm
same species respond differently to
same antigen ● Overproduction of cytokines
● Dosage, route, and timing of antigen ● Consequence of massive activation of T-cells
administration = IFN-y
○ higher dosage, inhalation and more ● Activated macrophages produce IL-1, IL-6,
frequent administration are more and
immunogenic in comparison with a ● TNF-a leading to shock and multiple organ
lower dose, oral administration & failure
seldom timing Examples of Antigens
● Staphylococcal enterotoxins
● Concentration of antigen administered
● TSST - Toxic Shock Syndrome Toxin
● Route of administration and timing of
● Group A Streptococcal Pyrogenic Exotoxin A
antigen administration
Adjuvants
● Substances that improve an immune
response combined to a weak Ag
● Important in vaccines against infective
agents and tumors
● A supplement for treatments
○ ex: There is a 35 y/o patient with
stage 3 ovarian cancer, a 25-cm
I BELIEVE IN THE PERSON THAT I WANT TO BE 2
INTRODUCTION TO IMMUNOLOGY Adaptive Response
Topic Outline: ● Slower specific response to a particular antigen
1. Immune System
a. Immune Response Non-specific Augmentation in Response
2. Antigen Memory of Specific Immune Response
3. Features that determine the
immunogenicity ● quicker and larger response on repeated exposure
4. Innate Immunity to same antigen -> ANAMNESTIC
5. Adaptive Immunity MEMORY
Reference: Innate Immunity
Jawetz’ Medical Microbiology 28th Edition ● first line of defense, (-) immunologic memory
● Nonspecific to invading pathogen, rapidly
mobilized at initial site of infection
Immune System
● Humoral components - soluble molecules
● Evolved as host defense and resistance -> ● Cellular components - blood and tissues
infectious disease & foreign antigens ● Immunologic Responses: Accompanied by
● Consists of proteins, cells and organs inflammation - few hours of stimulation
● Innate: Rapid response mechanism ○ Ex: Pricked during gardening - there will
● It is already present in the body, when there be inflammation
is bacteria that enters the body, there is
already a mechanism to defend our body.
● Has no memory
● Adaptive: Specific, adaptability, intricate
regulatory network and memory
Immune Response
● Response generated against a potential
pathogen (bacteria, virus, fungi infection
etc..
● Consists of 5 parts
Recognition
● able to distinguish between “non-self”
(pathogens) from “self” (host cells) Antigen
● both applicable with adaptive and innate
immunity ● A protein substance induces production of
● involves professional dendritic cells: antibodies
○ Recognition: General pathogen ● Antibody - hero
features or specific antigenic ● Antigen - villain
molecules ● Conventionally divided into:
○ Processing and presentation of ○ Thymus-dependent antigens
Ags to cells of immune system ○ Thymus-independent antigens
○ Initiation of non-specific Immunogens
inflammation
● induce an immune response
Early or Innate (Non-Specific Immune Response) ● most antigens are also immunogens
● on recognition followed by: “All immunogens are antigens but not all antigens are
● Effector phase immunogens.”
○ Innate immunity - neutrophils and
macrophages
○ Adaptive Immunity - Antibodies and Thymus-Dependent Antigens
effector T lymphocytes
● Require T-cells participation to provoke the
production of antibodies
I BELIEVE IN THE PERSON THAT I WANT TO BE 1
, MC | IMMUNOLOGY
○ E.g. mostly proteins
● Produces immunological memory Table 1.2 Factors influencing the immune
response to an antigen, i.e., immunogenicity
Thymus-Independent Antigens 1. Nature of molecule:
○ Protein content
● Require no T-cell cooperation for antibody ○ Size
production ○ Solubility
● Directly stimulate specific B lymphocytes by 2. Dose
virtue of: ○ Low doses provoke small amounts
● Ability to cross-link antigen receptors on the of antibody with high affinity and
B-cell surface restricted specificity
● produce predominantly IgM and IgG2 ○ Moderate doses provoke large
antibodies provoke poor immunological amounts of antibody but mixed
memory affinity and broad specificity
○ High doses provoke tolerance
Features that Determine the Immunogenicity 3. Route of entry
○ ID, IM SC → regional lymph nodes
● Recognition of foreignness ○ IV → spleen
○ Molecules recognized as “self” = not ○ Oral → Peyes’s patches
immunogenic ○ Inhalation → bronchial lymphoid
○ Molecules recognized as foreign tissue
“non-self” = immunogenic 4. Addition of substances with
● Size synergistic effects
○ Potent immunogens = Large, complex ○ E.g. adjuvants
proteins 5. Genetic factors of recipient animal:
○ MW < 10,000 = weakly immunogenic ○ Species differences
○ larger proteins are more immunogenic ○ Individual differences
compared to smaller and simpler
proteins
○ HAPTENS: low molecular weight Superantigen
proteins + linked to carrier CHON =
immunogenic (E.g. Lipids and Amino ● Foreign CHONs not specifically recognized by
Acids) the adaptive system
● Chemical and structural complexity ● Do not require processing
○ AA Heteropolymers > AA ● Bind to MHC molecules outside peptide-
Homopolymers binding cleft at the invariant part of TCR
● Host genetic constitution of the host
○ Differences in MHC alleles - strains of Cytokine Storm
same species respond differently to
same antigen ● Overproduction of cytokines
● Dosage, route, and timing of antigen ● Consequence of massive activation of T-cells
administration = IFN-y
○ higher dosage, inhalation and more ● Activated macrophages produce IL-1, IL-6,
frequent administration are more and
immunogenic in comparison with a ● TNF-a leading to shock and multiple organ
lower dose, oral administration & failure
seldom timing Examples of Antigens
● Staphylococcal enterotoxins
● Concentration of antigen administered
● TSST - Toxic Shock Syndrome Toxin
● Route of administration and timing of
● Group A Streptococcal Pyrogenic Exotoxin A
antigen administration
Adjuvants
● Substances that improve an immune
response combined to a weak Ag
● Important in vaccines against infective
agents and tumors
● A supplement for treatments
○ ex: There is a 35 y/o patient with
stage 3 ovarian cancer, a 25-cm
I BELIEVE IN THE PERSON THAT I WANT TO BE 2
