Flashcards in Adaptive Immunity Deck (66):
Ensures immune response to a microbe (or nonmicrobial antigen) is targest to that microbe (or antigen)
Very diverse: somatic recombination of gene segments responsible for generating array of antibodies
Increases ability to combat repeat infections by same microbe
Increases number of antigen specific lymphocytes to keep pase with microbes
generates responses that are optimal for defense against different types of microbes
Contraction and homeostasis
Allows immune system to recover from one response so that it can effectively respond to newly encountered antigens
Nonreactivity to self
Prevents injury to the host during responses to foreign antigens
another name for determinants
epitope: the part of the antigen recognized by specific lymphocytes
How do lymphocytes achieve such fine ability to distinguish between antigens?
specificity and variety of cell surface receptors
Total number of antigenic specificities of the lymphocyte....name and number...
lymphocyte repertoire; 107-109 distinct antigenic determinants
Primary and Secondary immune response
Primary: slow, produces antibody
Secondary: faster, larger, qualitatively different from the first
Antibodies produced by primary and secondary responses: how do they differ
secondary typically have a higher affinity for the epitope than the primary antibodies
Memory cells versus primary response cells
memory cells have features that make them more efficient, and they operate more rapidly
humoral and cell mediated immunity are elicited by
different ______ or _____ and at different ______ of _____
classes of microbes or at different stages of infection
Contraction of immune response is called the
return to resting stage, or homeostasis
Why does contraction occur?
Immune responses are launched to eliminate antigens; so the process wanes as the stimulus dies
Tolerance is also called
non-reactivity to self
Nonreactivity to self is maintained via
elimination of reactive lymphoctyes, inactivating them, or suppressing them
Regulation of immune responses
through positive feedback loops = amplify reaction
control mechanisms = prevent inappropriate reactions
T lymphocytes consist of distinct subpopulations. What are they called?
helper T cells and cytotoxic (cytolytic) T lymphocytes
antigenic ____ causes ---> ___ cells to release ____
helper T cells to release cytokines
helper T cells secrete what in reaction to what?
cytokines, antigenic stimulation
cytokines secreted by helper T cells do what?
stimulate proliferation/differentiation of more T Cells, B cells, macrophages, and other leukocytes.
CTLs do what
kill cells that produce foreign antigens such as infected cells, virus infected cells or other intracellular microbes
Regulatory T cells: function
to suppress immune response when its unneeded
This is a small population of T lymphocytes that produce a cell surface protein. What is it, what's its function?
Natural killer cells (NKT)
destroy infected cells (not microbes, but infected cells)
antigen presenting cells
The most specialized APC are the
APCs do what
capture external antigens, transport them to lymphoid organs, present to naive T lymphocytes to initiate immune response
Antigen elimination often requires what kind of cell?
What cells are dubbed "effector cells"
mononuclear phagocytes, activated T lymphocytes, and other leukocytes
how does innate immune system block microbes?
Main barriers of defense include skin, lungs, and gastrointestinal tract, respiratory tract.
Epithelia is important, why?
main "interfaces" between inside and outside the body
Main two mechanisms of innate cellular immunity
2. antiviral defense
Inflammation: how does it work
process of leukocyte recruitment and plasma proteins from the blood, their accumulation in tissues, and activation to destroy microbes
many activities involve cytokines produced by dendritic cells
Main cells involved in inflammation
leukocytes and plasma proteins
Innate immunity is the " ______" stage of immunity
decision making stage
it "evaluates" the invader in the context of intracellular vs extracellular microbes and then provides instructions to adaptive immunity
Cell communication is through
cell-to-cell signaling and cytokines and chemokines
Specific Signaling Receptors detect what?
Functions of cytokines
growth, differentiation, activation of effector functions
chemokines assist in mobility of cells
T cells ---> ___ immunity?
cell-mediated (cellular immunity)
B cells ---? ____ immunity?
involves production of immunoglobulins
a. who mediates it?
b. against what?
c. the function of CI
d. dual function
a. mediated by T-lymphocytes
b. fights intracellular infection
c. destruction of microbes residing in phagocytes, or killing of infected cells to eliminate them
d. assist B cells make effective antibodies
a. who mediates it?
b. against what?
c. the function of HI
a. Mediated by antibodies (Abs) in blood and mucosal secretions, produced by B lymphocyte
b. extracellular microbes
c. production of Abs to recognize, neutralize microbes, or target them for destruction by various effector mechanisms
d. Effector mechanism refers to the recruitment of cells that recognize antigens on microbes and destroy them
tissue damage caused by invasive microbes
Define antigens, and what do they include?
substances which induce an immune response
carbohydrates, proteins, lipids, and nucleic acids
The smallest unit to which an antibody can be made is
6 amino acids or 5-6 sugar residues
Describe the "smallest antigenic determinant"
6 amino acids or 5-6 sugar residues
The FULL name of the structure antibodies bind to
conformational antigenic determinant
conformational antigenic determinant relies on the
folding of the molecules
T cell receptors recognize
linear amino acid sequences
Ags which stimulate an immune response are called
All _______ are antigens but not all _____ are ______
All immunogens are antigens but not all antigens are immunogens
very small molecules that can bind to Abs and TCRs, but can't initiate an immune response
Innate immunity reacts to
products of microbes and injured cells
In humoral immunity ___ cells do what?
secrete antibodies that neutralize infection and eliminate extracellular microbes
In cell mediated immunity
T-helper cells activate macrophages to kill phagocytized microbes, or cytotoxic T lymphocytes directly destroy infected cells
Clonal Selection occurs how?
lymphocytes possessing specific Ag receptors bind to Ag, triggerign proliferation and differentiation, giving rise to clone cells speicific for Ag
Clone cells do what?
act in the presence of specific Ag to neutralize or eliminate Ag
"Ag-specific cells" late in the immune response, is responsible for what?
responsible for the 'memory' involved in adaptive immunity
B lymphocyte ---> 1 ---> 2 ---> outcomes
1. antigen recognition
2. differentiate into antibody secreting plasma cells
3. neutralization of microbe, phagocytosis, complement activation
Helper T Cell ---> 1 --> 2 --> outcomes
1. microbial antigen presented by antigen presenting cell to HTC
2. Helper T lymphocyte releases cytokines
3. cytokines can
a. activate macrophages
c. activation (proliferation and differentiation) of T and B lymphocytes
Cytotoxic T lymphocyte (CTL) --> 1 ---> outcomes
1. infected cell expresses microbial antigen to CTL
2. CTL kills infected cell directly
Regulatory T lymphocyte --> 1 --> outcome
RTL suppresses other lymphocytes to reduce immune activity
the elimination of the antigen is called the