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Chapter 1
Dr. Capers
IRSC
Kindt • Goldsby • Osborne
Kuby IMMUNOLOGY
Sixth Edition
Chapter 1
Overview of the Immune System
Copyright © 2007 by W. H. Freeman and Company

Discipline of immunology grew out of observation
that individuals who recovered from infectious
diseases were protected from disease

15th Century

Chinese and Turks tried to prevent smallpox
 Dried crust from pustules were inhaled or inserted into small
cuts

1718

Lady Montagu had that technique done in her children

1798

Edward Jenner
 Noticed that milkmaids that contracted cowpox were
immune to smallpox
 Innoculated small boy with fluid from cowpox pustule
 He then intentionally infected the boy with smallpox – the
child did not develop smallpox

1881

Louis Pasteur
 Vaccinated sheep with heat-attenuated anthrax
 Then infected sheep with virulent strain of anthrax – they
did not develop anthrax

1977



Last known naturally acquired case of smallpox
Is it still a threat?
In industrialized nations, measles, mumps,
whooping cough, tetanus, polio, and diptheria
are extremely rare or nonexistent
 This is due to vaccines!
 Prevent death, paralysis, deafness, blindness, mental
retardation

1883


Metchnikoff demonstrated that certain white blood
cells were able to phagocytize microorganisms
1901

Von Behring and Kitasato
 Demonstrated that serum (noncellular component of
blood) from animals immunized to diptheria could
transfer that immunity to non-immunized animals


Immune system evolved to protect multicellular
organisms from pathogens
Does this by 2 related activites

Recognition and response

Innate Immunity
 1st line of defense
 Molecular and cellular mechanisms deployed before an
infection
 Distinguishes between self and pathogens but not
specialized to distinguish small differences in the
foreign particles

Adaptive Immunity
 Develops in response to infection
 Adapts to recognize, eliminate, and remember
pathogen


Less specific
1st line of defense
 Barriers that protect host
 Skin
 Acidity of stomach
 Lysozymes in fluids
 Phagocytic cells
 Antimicrobial peptides (interferons, complement)
 Temperature


Highly specific
Characteristic attributes
 Antigenic specificity
 Antibodies can distinguish between 2 proteins that differ
in only 1 amino acid
 Diversity
 Immunologic memory
 Self-nonself recognition

Effective Immune response involves 2 groups
of cells
 Lymphocytes
 B cells
 T cells
 Antigen-presenting cells

B cells


Mature in bone marrow
Antigen binding receptor – Antibody
 Glycoproteins


Glycoproteins
Structure


2 identical polypeptides – heavy chains
2 shorter identical polypeptides – light chains

Antigen coated by antibody is eliminated in
several ways
 Antibody can cross-link several antigens, making it easier
to be ingested by phagocytic cells
 Activate complement system resulting in lysis of
microorganism

T cells


Arise in bone marrow but mature in thymus
2 well define subpopulations of T cells
 T helper cells
 T cytotoxic cells

T cells
 Can only recognize
antigen bound to cell
membrane proteins
called Major
Histocompatibility
Complex (MHC)
 MHC molecules are
expressed by antigenpresenting cells
 B cells
 Macrophages
 Dendritic cells

T cells
 Cytokines secreted by TH cells can activate phagocytic
cells
 TC cells can kill altered self-cells
 Cells infected by viruses
 Tumor cells

Antigen presenting cell associating with T cell


Initial encounter with antigen causes primary
response
Later contact with antigen will result in more
rapid response




Allergies and Asthma
Graft rejection
Autoimmune Disease
Immunodeficiency