Immune System Flashcards
Bacteria
Individual prokaryotic cells that replicate rapidly and easily infect the body ALSO Can produce toxins that cause cell necrosis
Viruses
Enter cell and hijack the cell to make viral proteins and assemble new viral particles
- contain DNA, RNA, few proteins, and antiviral coat
Parasite
Individual eukaryotic organisms that live inside a human
Interferons
- Cytokines released by lymphocytes, fibroblasts, and macrophages
- cause virally infected cells to make anti-viral proteins and slow proteins synthesis of infected cell
- Types: Alpha, Beta, gamma
Phagocytic cells
Engulf pathogens and clean up tissue debris
Complement
Circulating proteins assist antibodies
Macrophages
- Engulf pathogens and lyse them
- Bind to pathogen and wait for other cells’ help
- Release toxic chemicals that destroy pathogens and cytokines
- present antigen to CD4 cells
Cytokines
Small signaling molecules
- Types: IL-1 and mast cells stimulator
IL-1 cytokine
Substance that produces fever when released into blood
Mast cell stimulator cytokine
Initiates inflammation and pain
Mast cells
Release histamine (substance that increases capillary permeability and increase blood flow), heparin (thins blood at the area which will isolate injury), and cytokines (calls other cells to area)
Natural killer cells
Monitor body for abnormal cells which are infected or cancerous
NK cell activation
1 - NK cells recognizes abnormal surface markers
2 - Golgi begins to manufacture perforins and secretes large numbers of vesicles
3 - perforins interact with target cells surface and poke holes in it which will cause it to lyse
Alpha interferons
Attract and stimulate natural killer cells
Beta interferons
Secreted by fibroblast and slow inflammation
Gamma interferons
Secreted by T & NK cells which stimulate macrophages
Complement functions
- creates pores to help in destruction of target cell membranes
- induces mast cells to release histamine and stimulate inflammation
- attract phagocytic cells enhance phagocytosis
MHC proteins
- Types: MHC class I and II
- MHC I: Found on surface of all nucleated-cells and display what is made inside of cell to CD8 T cells (and destroys nonself cells)
- MHC II: Found on professional antigen-presenting cells (APC) and B cells. APC presents antigens to CD4 T cells when MHC II presents the antigen found outside of APC.
CD8 T cells
- Seek and destroy abnormal and affected tissues directly
- when it recognizes an antigen, it will destroy using perforin, lymphotoxin, and induce apoptosis
Perforin
A protein released by natural killer cells and destroys targeted cells by creating pores in their membrane
CD4 T cells
Activation is initiated by binding to antigens presented on MHC II via B cells or macrophages
Activated CD4 cells
- Stimulate clonal expansion and maturation of CD8 cells (IL-2)
- attract macrophages NK cells
- promote B cell activation and antibody production
CD4 activated by B cells
1) B cell binds to antigen
2) B cell brings antigen and presents to CD4 using MHC class II
3) CD4 is activated if recognizes antigen as non self
4) CD4 stimulates B cell to release cytokines which promote B cell division (ONLY if B cell and CD4 agree it is non self)
5) B cells stimulated by cytokine will divide and form plasma cells
6) Plasma cells release antibody
7) Antibody binds to same antigen
8) Memory B cells remember antigen
Antibody function
1) Binds to toxin to neutralize them
2) antibody and antigen agglutination
3) complement activation if antibody changes shape—which expose complement binding sites
4) Attract phagocytic cells
5) Antigen coated by Antibody via opsonization
6) Bind to bacteria so bacteria won’t bind to body cells
IgG antibody
Resistance against viruses bacteria and bacterial toxins
IgE
Attaches to basophils and mast cells which stimulate release of histamine
IgD
Play a role in activation of B cells
IgM
the first antibodies secreted
IgA
Mostly secreted and mucus tears saliva and usually are a first line defense role
Primary and Secondary antibody response
P1) Exposure to antigen
P2) IgM is secreted by plasma B cells
P3) IgG rises slowly
S4) Memory B cells differentiate into plasma cells and secrete Ig in massive quantities
Bacterial infection
1) Neutrophils and NK cells migrate to affected area and destroy bacteria
2) CD4 cells are activated when macrophages present antigen
3) B cells produce antibody after exposure to soluble toxins
Viral infection
1) CD8 cells are activated when in contact with infected cells
2) B cells are activated later
Immune system disorders
- Immunodeficiency: SCID
- Autoimmune disorder: rheumatoid arthritis, Type 1 diabetes, some sclerosis
- Human immunodeficiency virus: Virus that takes out CD4 cells
- Allergies
- Leukemia/lymphomas: WBC cancer in bone marrow, peripheral lymphatic organs
