Lecture 1 Flashcards
What are extracellular microbes?
able to survive in animals by growing extracellular being simple immersed in nutrients
What are intracellular microbes?
invade and live and replicative intracellular within animal cells where they utilizing host cell energy sources
What can all microbes do?
grow, reproduce and infect humans
What is immunity?
set of cooperative defense mechanisms which provide protection from various infectious diseases
What are antigens (Ags)?
substances that induce an immune response
What can be an Ags?
proteins
carbohydrates
lipids
nucleic acids
What is an antibody (Ab)?
protein produced by the immune system when it detects antigens
What is an epitope?
a portion of Ag molecule to which antibody binds
All immunogens are ______, but not all _____ are immunogens.
Ags, Ags
What are immunogens?
Ags which can stimulate an immune response
What are happens?
small Ags that can bind to Abs but can’t initiate immune response
Describe innate immunity
First line of defense: works rapidly
give rise to acute inflammation
has some specificity for Ag
no memory
Describe adaptive immunity
takes longer to develop
highly specific
shows memory
What are the components of innate immunity?
antimicrobial peptides complement acute phase proteins cytokines chemokines phagocytes
What are antimicrobial peptides?
small peptides which target pathogenic microorganisms ranging from viruses to parasites
What is a complement?
system of plasma proteins that enhances the ability of Abs and phagocytic cells to clear pathogens from an organism
What are acute phase proteins (APPs)?
large group of blood proteins whose plasma concentrations change in response to tissue injury, acute infections, burns, or inflammation
What are cytokines?
cell signaling molecules that aid in cell to cell communication in immune responses
What are phagocytes?
immune cells that have the ability to ingest and digest microbes
What are the cellular and chemical barriers in adaptive immunity?
lymphocytes in epithelia; antibodies secreted at epithelial surfaces
what are blood proteins in adaptive immunity?
antibodies, cytokines
What are the cells in adaptive immunity?
B and T lymphocytes
What is the specificity in innate immunity?
for molecules (Ags) shared by groups of related microbes and molecules produced by damaged host cells
What is the specificity in adaptive immunity?
for microbial and nonmicroblal antigens
How is the diversity in innate immunity?
limited; germline encoded
How is the diversity in adaptive immunity?
very large; receptors are produced by somatic recombination of gene segments
Is there memory in innate immunity? adaptive?
innate: no
adaptive: yes
Is there reactivity to self in innate immunity? adaptive?
none in both
What are the functions of cytokines?
regulate growth and differentiation of immune cells
activate the effector functions of lymphocytes and phagocytes
Each cytokine acts via a _______ receptor expressed on target cells
specific signaling
What are chemokines?
a subfamily of cytokines secreted by immune cells to induce chemotaxis (movement) in nearby cells
Does innate immunity exist before or after infection?
before
What is the primary function of phagocytes?
ingest and destroy microbes and get rid of damaged tissues (scavenger function)
What are the steps in function responses of phagocytes?
- recruitment of cells to the sites of infection
- recognition of and activation by microbes
- ingestion of the microbes by the process of phagocytes
- destruction of ingested microbes
Neutrophils are produced in the _____ and arise from ____ that also give rise to mononuclear phagocytes
bone marrow; precursors
The production of neutrophils are stimulated by cytokine called ______
granulocyte colony stimulating factor (G-CSF)
An adult human produces more than ____ neutrophils a day
1 x 10^11
What drives production of of macrophages in the bone marrow?
monocyte/macrophage colony stimulating factor (M-CSF)
dendritic cells are cells of _____ immunity
innate
What are the two categories of dendritic cells?
myeloid DCs (mDCs) and plasmacytoid DCs (pCDs)
macs are derived from ______
monocytes
Where are mast cells common at?
sites in the body that are exposed to the external environment
Why are mast cells in close proximity to blood vessels?
they can regulate vascular permeability and effector cell recruitment
What are the two types of lymphocytes?
B cells and T cells
Where does the development and maturation of T cells occur?
in the thymus
When a mature T cell is Ag stimulated, it gives rise to ______
cellular immunity
Where does the development and maturation of B cells occur?
bone marrow
What type of immunity does B cells give rise to?
humoral
What does humoral immunity produce?
immunoglobulins
what is humoral adaptive immunity?
principal defense mechanism against extracellular microbes and their toxins
What is the function of cell mediated immunity?
killing of infected host cells to eliminate reservoirs of infection
In _____ immunity, B lymphocytes secrete Abs that prevent infections and climate extracellular microbes
humoral
In _____ immunity, T helper cells active macrophages to kill phagocytize microbes, or cytotoxic T lymphocytes to directly destroy infected cells
cell mediated
What is active immunity?
conferred by a host response to a microbe or microbial Ags
What is passive immunity?
conferred by adoptive transfer of antibodies or T lymphocytes specific for the microbe
only ____ immune responses generate immunological memory
active
what do B lymphocytes do?
recognize soluble Ags and develop into Ab secreting cells
What do T helper lymphocytes do?
recognize Ags on the surfaces of Ag presenting cells and secret cytokines, which stimulate different mechanisms of immunity and inflammation
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 response
