Introduction To The Immune System (Ch. 1) Flashcards
Define extracellular microbes
Able to survive in animals by growing extracellular and being simply immersed in nutrients
Define intracellular microbes
Invade and live and replicate intracellularly within animal cells where they utilize host-cell energy sources
What are the primary fixed elements of the immune system
Bone marrow and thymus
What are the secondary fixed elements
Spleen and lymph nodes
Mucosal immune tissues
What are the mobile elements of the immune system
Immune cells and soluble humoral components
Define active immunity
A subset of adaptive immunity
Is conferred by a host response to a microbe or microbial Ags
Only one that generates immunologic memory
Ex. Vaccine
Define passive immunity
A subset of adaptive immunity
Is conferred by adoptive transfer of antibodies or T-lymphocytes specific for the microbe
Define innate immunity
1st line of defense against infection
Works rapidly
Gives rise to an acute inflammation
No memory
Specific for Ags shared by groups of related microbes and molecules produced by damage host cells
Define adaptive immunity
Take longer to develop
Highly specific
Shows memory with that remembers Ag
Very specific for microbial and nonmicrobial antigens
What is the first phase of immune response
Non-induced innate response
Comprised of skin barrier, pH, saliva
What is the second phase of immune response
Induced innate response
Phagocytosis, inflammatory mechanisms
Cytokine secretion
What is the last phase of the immune response
Induced adaptive response
B cells, T cells, and Helper T cells
What are the two types of phagocytes
Neutrophils and macrophages
What is the most abundant circulating WBC’s
Neutrophils
Where are neutrophils produced
BM
What doe mast cells, basophils, and eosinophils have in common
- Play roles in innate and adaptive immunity
2. Have granules filled with inflammatory and antimicrobial mediators
Mature monocytes enter what and then migrate to where
Enter blood and then migrate to tissues and mature into macrophages
Define tissue-resident macrophages
Hetrogeneous population of immune cells that fulfill tissue-specific and niche-specific functions
Define Dendritic Cells. What is their function? What do they induce?
Cells of innate immunity
Are antigen presenting cells, capture microbe and stimulate T cells to induce adaptive immunity
When T cells are Ag stimulated, they give rise to what
Cellular immunity
B cells give rise to what? Also define this
Humoral immunity - provides soluble molecules (immunglobins)
T cells work in conjunction with what cells
Ag-Presenting cells (DC’s)
What is the purpose of cellular immunity
To kill infected Host cells
Define humoral adaptive immunity. What is this the principle defense mechanism against
Mediated by antibodies in the blood which are produced by B cells
Extracellular microbes
Three main properties of adaptive immunity
Allows immune system to respond to large number of Ags
Increases the ability to combat repeat infections
Increases number of Ag-Specific lymphocytes to keep pace with microbes
Each B cell and T cell has a receptor for what?
A specific Ag that are generated by gene rearrangement from multiple germlines
What happens when Ag is induced into an individual?
Lymphocytes with receptors for this Ag seek out and bind Ag and are triggered to proliferate and differentiate, giving rise to clones of cells specific for the Ag
What do B cells do in humoral adaptive immunity
B cells secrete Abs that prevent infections and eliminate extracellular microbes
What do T Helper cells do in CMI
Recognize Ags on DC’s and secrete cytokines which Activate macrophages to kill microbes or cytoxic lymphocytes to directly kill infected cells
What do cytotoxic T lymphocytes do
Recognize Ags on infected cells and kill these cells
What do regulatory T cells do
Suppress and prevent immune responses
What is the membrane immunoglobin isotype for Naive cells
IgM and IgD
What is the membrane immunoglobin isotype for activated or effector lymphocytes
IgG, IgA, and IgE
What is the membrane immunoglobin isotype for memory lymphocytes
Same as activated
What are the primary antigen-presenting cells in the epidermis
Langerhans cells
Define CD8+ T cells and their function
Live exclusively in the epidermis to rapidly respond to viral infections
Define CD4+ T cells
Reside in dermis and carry out a variety of effector functions
Define lymphnodes and their functions
Encapsulated nodular aggregates of lymphoid tissues located along lymphatic channels in the body
Takes up Ags from tissues, processes them and uses Naive T and B cells to sample them so that the body can create the correct immune response
Blood born Ags are captured and concentrated by what
Local APC’s (DC’s)
What is more rapid, the secondary or the primary response to the Ag?
Secondary
Describe what primary IgA antibodies do
Form together as a dimer, which can enter the lumen of the intestine to neutralize danger.
Why do IgA antibodies form a dimer
Makes them resistant to proteases
What cells bring Ag into Peyer’s patch?
M cells
What are Peyer’s patch?
Localizations of lymphocytes within the intestinal lamina
Define PALS within the spleen
PALS are periartieriolar lymphoid sheaths that have naive T cells which sample Ags to make immune response
What does the innate immune system recognize
Shared structures of classes of microbes
B cells secrete antibodies to block and eliminate what types of microbes
Extracellular
T-helper cells do what three functions by releasing cytokines
- Activate macrophages
- Inflammation
- Activate B Cells
A vaccine is what type of immunity
Active
What type of cell initiates the primary immune response
Naive lymphocytes
Memory lymphocytes initiate what
The secondary response
DC’s capture AG’s and present them for what type of cells
T cells
Macrophages do what
Engulf microbes and initiate some inflammation
What do follicular dendritic cells do
Display antigens to B-cells in humoral immune response
What are the only cells that produce antibodies
B cells
T cells only recognize what type of Ag’s
Peptide based ones
What are the two generative lymph organs
Bone marrow and thymus
What is the effector form of B cells and what do they do
Plasma cells which secrete antibodies
What are the two effector forms of T cells and what do they do
CD4 - secrete cytokines which help with B cells, macrophages, and inflamation
CD8 - kill infected host cells
Where are FDC’s found
In the geminal centers of lymphoid follicles
T cells go to where in spleen
B cells go to where
PALS - T cells
Follicular Zones - B Cells
M cells do what
Bring Ag into laminar propinar to be destroyed in the Preyer Patch
What tells B cells to go to follicles in LN
What tells T cells to go to Profollicular Coretx in LN
CXCR 5 for B cells
CCR7 for T cells
This keeps them separated until they are needed
