The Immune System
GENERAL FEATURES:
1. Main function is to distinguish self from non-self : tolerance
2. Important functional elements of the immune system include several cell types, tissues, serum proteins, and small
peptides such as cytokines.
3. Composed of different organs and cells (well organized structure)
a. organs
▪ Primary Lymphoid: BM, thymus- provide microenvironments for the development and maturation of
lymphocytes
▪ Secondary Lymphoid: spleen, LN, MALT- traps antigen from defined tissues or vascular spaces; sites where
Mature lymphocytes can interact effectively with that trapped antigen.
b. cells
▪ Phagocytic cells
▪ Inflammatory cells
▪ APCs
▪ Lymphocytes
4. Integrated defense
a. Primary Line of defense- physical barriers, physiologic
b. Secondary line of defense- phagocytosis, inflammation, lysis
c. Tertiary line of defense- production of Abs and effector molecules
5. Innate and adaptive immune system collaborate to increase efficiency of response
a. innate- Primary and secondary line of defense
b. adaptive- Adaptive immunity is capable of recognizing and selectively eliminating specific foreign microorganisms and
molecules (i.e., foreign antigens). Unlike innate immune responses, adaptive immune responses are not the
same in all members of a species but are reactions to specific antigenic challenges
Comparison of Innate and Adaptive immune response:
Immunology/Immune System/rjlp/kdgo Page 1
, Definition of terms:
• Phylogeny- evolution of a species or group, especially in reference to lines of descent and relationships among broad
groups of organisms.
• Ontogeny- (also ontogenesis or morphogenesis) is the origination and development of an organism, usually from the
time of fertilization of the egg to the organism's mature form. Yet, the term can be used to refer to the study of the
entirety of an organism's lifespan.
Phylogeny of the Immune System
Note:
- It took more than 400 million years of evolution for our immune system to develop into the highly complex and
adaptable defense mechanism that it is today.
- IS reaches its highest development in the “warm blooded” animals (mammals, birds)
- Immune mechanisms: a. non specific b. specific
- Both specific and cellular immune response are present in all vertebrates.
- All jawed vertebrates possess a primary lymphoid organ called THYMUS, and specialized secondary lymphoid organ called
LYMPH NODES AND SPLEEN.
- Nonimmunoglobulin agglutinins and lysins are known to exist. These humoral substances function to sequester foreign
materials and are sometimes referred to as “protoimmunoglobulins”
- Abs and certain CHONS of the classical complement pathway are not found in invertebrates
Immunology/Immune System/rjlp/kdgo Page 2
GENERAL FEATURES:
1. Main function is to distinguish self from non-self : tolerance
2. Important functional elements of the immune system include several cell types, tissues, serum proteins, and small
peptides such as cytokines.
3. Composed of different organs and cells (well organized structure)
a. organs
▪ Primary Lymphoid: BM, thymus- provide microenvironments for the development and maturation of
lymphocytes
▪ Secondary Lymphoid: spleen, LN, MALT- traps antigen from defined tissues or vascular spaces; sites where
Mature lymphocytes can interact effectively with that trapped antigen.
b. cells
▪ Phagocytic cells
▪ Inflammatory cells
▪ APCs
▪ Lymphocytes
4. Integrated defense
a. Primary Line of defense- physical barriers, physiologic
b. Secondary line of defense- phagocytosis, inflammation, lysis
c. Tertiary line of defense- production of Abs and effector molecules
5. Innate and adaptive immune system collaborate to increase efficiency of response
a. innate- Primary and secondary line of defense
b. adaptive- Adaptive immunity is capable of recognizing and selectively eliminating specific foreign microorganisms and
molecules (i.e., foreign antigens). Unlike innate immune responses, adaptive immune responses are not the
same in all members of a species but are reactions to specific antigenic challenges
Comparison of Innate and Adaptive immune response:
Immunology/Immune System/rjlp/kdgo Page 1
, Definition of terms:
• Phylogeny- evolution of a species or group, especially in reference to lines of descent and relationships among broad
groups of organisms.
• Ontogeny- (also ontogenesis or morphogenesis) is the origination and development of an organism, usually from the
time of fertilization of the egg to the organism's mature form. Yet, the term can be used to refer to the study of the
entirety of an organism's lifespan.
Phylogeny of the Immune System
Note:
- It took more than 400 million years of evolution for our immune system to develop into the highly complex and
adaptable defense mechanism that it is today.
- IS reaches its highest development in the “warm blooded” animals (mammals, birds)
- Immune mechanisms: a. non specific b. specific
- Both specific and cellular immune response are present in all vertebrates.
- All jawed vertebrates possess a primary lymphoid organ called THYMUS, and specialized secondary lymphoid organ called
LYMPH NODES AND SPLEEN.
- Nonimmunoglobulin agglutinins and lysins are known to exist. These humoral substances function to sequester foreign
materials and are sometimes referred to as “protoimmunoglobulins”
- Abs and certain CHONS of the classical complement pathway are not found in invertebrates
Immunology/Immune System/rjlp/kdgo Page 2
