Chapter 57: Overview of Immunity
FUNCTION OF THE IMMUNE SYSTEM
The main function of the immune system is to prevent or limit infections due to various pathogens by
different lines of defense.
Logic?
Some microbes are eliminated by innate immunity. Those that resist and cross innate lines of defense
attacked by adaptive immunity.
Failure of both types of immunity to defend against microbes leads to disease.
INNATE & ADAPTIVE IMMUNITY
1. Innate Immunity
- Defenses fully encoded in the genes, prior to exposure to any microbes, present at the time of
birth (thus called innate immunity)
- Is nonspecific and includes barriers
- Has no memory
- Can function independently but often amplified by the adaptive immune arm.
FUNCTIONS:
1. Host defense
2. Heal damaged tissue and clear away dead cells in a way that does not harm the body.
3. Activating adaptive immunity
Components of the Innate Arm:
Neutrophils, only kill microbes
Macrophages and Dendritic cells, kill microbes and also communicate with T cells.
, ★ Severe combined immunodeficiency disease (SCID): children who have intact innate immunity
but no adaptive immunity, often suffer from repeated, life-threatening infections. (thus only innate
immunity ain't enough)
Antigens:
Microbial peptide fragments formed when phagocytic cells break down ingested microbes.
Presented on phagocytic cells’ surface to alert the adaptive immune system, specifically T cells.
Antigen Presentation: Processing of microbial products into peptides for Tcell activation.
Inflammatory proteins/signals: Cytokines (proteins that immune cells use to communicate) and
chemokines (proteins that recruit other cells to join in).
FUNCTION OF THE IMMUNE SYSTEM
The main function of the immune system is to prevent or limit infections due to various pathogens by
different lines of defense.
Logic?
Some microbes are eliminated by innate immunity. Those that resist and cross innate lines of defense
attacked by adaptive immunity.
Failure of both types of immunity to defend against microbes leads to disease.
INNATE & ADAPTIVE IMMUNITY
1. Innate Immunity
- Defenses fully encoded in the genes, prior to exposure to any microbes, present at the time of
birth (thus called innate immunity)
- Is nonspecific and includes barriers
- Has no memory
- Can function independently but often amplified by the adaptive immune arm.
FUNCTIONS:
1. Host defense
2. Heal damaged tissue and clear away dead cells in a way that does not harm the body.
3. Activating adaptive immunity
Components of the Innate Arm:
Neutrophils, only kill microbes
Macrophages and Dendritic cells, kill microbes and also communicate with T cells.
, ★ Severe combined immunodeficiency disease (SCID): children who have intact innate immunity
but no adaptive immunity, often suffer from repeated, life-threatening infections. (thus only innate
immunity ain't enough)
Antigens:
Microbial peptide fragments formed when phagocytic cells break down ingested microbes.
Presented on phagocytic cells’ surface to alert the adaptive immune system, specifically T cells.
Antigen Presentation: Processing of microbial products into peptides for Tcell activation.
Inflammatory proteins/signals: Cytokines (proteins that immune cells use to communicate) and
chemokines (proteins that recruit other cells to join in).
