Summary Immunotechnology
Reader: Introduction to the immune system
Immunology: the study of our protection from foreign macromolecules or invading organisms and
our responses to them
The immune system is composed of two major subdivisions:
the innate or nonspecific immune system
o first line of defence
o constitutively present and ready
o not antigen specific
the adaptive or specific immune system
o secondary line of defence
o requires time to react
o reacts very specific to a certain antigen
o protects against re-exposure because of immunological memory
reacts faster and stronger on a subsequent exposure
Each of the major subdivisions of the immune system has both cellular and humoral components
Cellular
o occurs inside infected cells
o is mediated by T lymphocytes
o The pathogen's antigens are expressed on the cell surface or on an antigen-
presenting cell
o Helper T cells release cytokines that help activated T cells bind to the infected cells’
MHC-antigen complex and differentiate the T cell into a cytotoxic T cell
Humoral
o Antibody-mediated
o With assistance from helper T cells, B cells will differentiate into plasma B cells that
can produce antibodies against a specific antigen
o Deals with antigens from pathogens that are freely circulating, or outside the
infected cells
o Antibodies produced by the B cells will bind to antigens, neutralizing them, or
causing lysis or phagocytosis
Anatomical barriers: barriers like the skin, mucus or high acidity that prevent pathogens from
entering the body in the first place
All cells of the immune system have their origin in the bone marrow and they include:
Myeloid cells (neutrophils, basophils, eosinophils, macrophages, dendritic cells)
o Give rise to:
Erythrocytes
Platelets
Neutrophils
Monocytes/macrophages
Dendritic cells
Lymphoid cells (B lymphocytes, T lymphocytes,
natural killer cells)
o Give rise to:
NK cells
T cells
B cells
1
Reader: Introduction to the immune system
Immunology: the study of our protection from foreign macromolecules or invading organisms and
our responses to them
The immune system is composed of two major subdivisions:
the innate or nonspecific immune system
o first line of defence
o constitutively present and ready
o not antigen specific
the adaptive or specific immune system
o secondary line of defence
o requires time to react
o reacts very specific to a certain antigen
o protects against re-exposure because of immunological memory
reacts faster and stronger on a subsequent exposure
Each of the major subdivisions of the immune system has both cellular and humoral components
Cellular
o occurs inside infected cells
o is mediated by T lymphocytes
o The pathogen's antigens are expressed on the cell surface or on an antigen-
presenting cell
o Helper T cells release cytokines that help activated T cells bind to the infected cells’
MHC-antigen complex and differentiate the T cell into a cytotoxic T cell
Humoral
o Antibody-mediated
o With assistance from helper T cells, B cells will differentiate into plasma B cells that
can produce antibodies against a specific antigen
o Deals with antigens from pathogens that are freely circulating, or outside the
infected cells
o Antibodies produced by the B cells will bind to antigens, neutralizing them, or
causing lysis or phagocytosis
Anatomical barriers: barriers like the skin, mucus or high acidity that prevent pathogens from
entering the body in the first place
All cells of the immune system have their origin in the bone marrow and they include:
Myeloid cells (neutrophils, basophils, eosinophils, macrophages, dendritic cells)
o Give rise to:
Erythrocytes
Platelets
Neutrophils
Monocytes/macrophages
Dendritic cells
Lymphoid cells (B lymphocytes, T lymphocytes,
natural killer cells)
o Give rise to:
NK cells
T cells
B cells
1
