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Questions and Answers
The ability of a host to resist infection or disease is referred to as ______
The ability of a host to resist infection or disease is referred to as ______
immunity
Innate immunity is also known as ______ immunity.
Innate immunity is also known as ______ immunity.
nonspecific
An antigen can have several ______ that bind to a specific antibody.
An antigen can have several ______ that bind to a specific antibody.
epitopes
Antibodies are ______ that upon binding can inactivate or neutralize an antigen.
Antibodies are ______ that upon binding can inactivate or neutralize an antigen.
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Serum antibodies are referred to as ______.
Serum antibodies are referred to as ______.
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B cells differentiate into ______ secreting plasma cells and memory cells upon activation with an antigen.
B cells differentiate into ______ secreting plasma cells and memory cells upon activation with an antigen.
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Lymphocytes are the major cells of the ______ immune system.
Lymphocytes are the major cells of the ______ immune system.
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There are two major types of lymphocytes: B cells and ______ cells.
There are two major types of lymphocytes: B cells and ______ cells.
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Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by ______ cells.
Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by ______ cells.
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Each B cell expresses on its surface approximately identical ______ molecules.
Each B cell expresses on its surface approximately identical ______ molecules.
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Antibodies have two identical ______ chains and two identical light chains.
Antibodies have two identical ______ chains and two identical light chains.
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The Ab combining site for antigen is made up of amino acid residues contributed by both the ______ and L chains.
The Ab combining site for antigen is made up of amino acid residues contributed by both the ______ and L chains.
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Most classes of Abs have two combining sites for ______.
Most classes of Abs have two combining sites for ______.
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After a B cell differentiates into a ______ cell, the secreted form of Ig is made.
After a B cell differentiates into a ______ cell, the secreted form of Ig is made.
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T lymphocytes destined to become T cells originate in the ______ but mature in the thymus gland.
T lymphocytes destined to become T cells originate in the ______ but mature in the thymus gland.
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A type of T cell called a ______ cell is required to help B cells respond to most antigens.
A type of T cell called a ______ cell is required to help B cells respond to most antigens.
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T cells recognize ______ fragments of molecules derived from a protein antigen.
T cells recognize ______ fragments of molecules derived from a protein antigen.
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MHC class I molecules present fragments of ______ antigens generated in the cytoplasm of the cell.
MHC class I molecules present fragments of ______ antigens generated in the cytoplasm of the cell.
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The mechanism by which a CTL distinguishes a healthy cell from an infected cell is through the ______ peptide.
The mechanism by which a CTL distinguishes a healthy cell from an infected cell is through the ______ peptide.
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MHC Class I molecules present ______ peptides to CD8 T cells.
MHC Class I molecules present ______ peptides to CD8 T cells.
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T cell receptors interact with the ______ peptide as well as the MHC molecule presenting it.
T cell receptors interact with the ______ peptide as well as the MHC molecule presenting it.
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The CD4 molecule is a cell-surface receptor for the ______ Immunodeficiency Virus.
The CD4 molecule is a cell-surface receptor for the ______ Immunodeficiency Virus.
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Helper T cells express ______ molecules on their surface.
Helper T cells express ______ molecules on their surface.
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In an ELISA, the enzyme ______ phosphatase is commonly used to give a colorimetric reaction with its substrate.
In an ELISA, the enzyme ______ phosphatase is commonly used to give a colorimetric reaction with its substrate.
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The secondary antibody in an ELISA is covalently bound to the enzyme ______.
The secondary antibody in an ELISA is covalently bound to the enzyme ______.
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The indicator o-phenylenediamine changes from ______ to yellow-brown when oxidized.
The indicator o-phenylenediamine changes from ______ to yellow-brown when oxidized.
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The ______ molecule is used as a blocking agent in an ELISA to prevent non-specific binding of the antibody.
The ______ molecule is used as a blocking agent in an ELISA to prevent non-specific binding of the antibody.
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The antiserum in an ELISA contains ______ specific for the antigen OVA.
The antiserum in an ELISA contains ______ specific for the antigen OVA.
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In mammalian hosts, this defense system can be divided into two fundamentally different, yet complementary, components called innate and adaptive ______.
In mammalian hosts, this defense system can be divided into two fundamentally different, yet complementary, components called innate and adaptive ______.
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Innate immunity occurs rapidly and acts as a first line of ______.
Innate immunity occurs rapidly and acts as a first line of ______.
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Adaptive immunity is acquired by the host in response to the presence of a foreign substance called a(n) ______.
Adaptive immunity is acquired by the host in response to the presence of a foreign substance called a(n) ______.
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Antibodies reside in the host's _______, and serum antibodies are referred to as immunoglobulins.
Antibodies reside in the host's _______, and serum antibodies are referred to as immunoglobulins.
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Adaptive Immunity has ______, responding faster and more effectively upon repeated exposure to foreign agents such as bacteria, viruses and toxins.
Adaptive Immunity has ______, responding faster and more effectively upon repeated exposure to foreign agents such as bacteria, viruses and toxins.
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Antibodies can directly neutralize a pathogen e.g., a virus, by preventing it from infecting cells or they can mediate the binding of other molecules such as ______ to the microbial surface causing lysis.
Antibodies can directly neutralize a pathogen e.g., a virus, by preventing it from infecting cells or they can mediate the binding of other molecules such as ______ to the microbial surface causing lysis.
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B cells are produced and mature in the ______ marrow.
B cells are produced and mature in the ______ marrow.
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Antibodies are proteins that can directly neutralize a pathogen e.g., a virus, by preventing it from infecting cells or they can mediate the binding of other molecules such as complement to the microbial surface causing ______.
Antibodies are proteins that can directly neutralize a pathogen e.g., a virus, by preventing it from infecting cells or they can mediate the binding of other molecules such as complement to the microbial surface causing ______.
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Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by phagocytic ______
Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by phagocytic ______
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Each B cell expresses on its surface approximately ______ identical g1 molecules
Each B cell expresses on its surface approximately ______ identical g1 molecules
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Abs contain two identical heavy (H) ______ and two identical light (L) chains
Abs contain two identical heavy (H) ______ and two identical light (L) chains
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After a B cell differentiates into a ______ cell, the secreted form of Ig is made
After a B cell differentiates into a ______ cell, the secreted form of Ig is made
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T lymphocytes destined to become T cells originate in the ______ but mature in the thymus gland
T lymphocytes destined to become T cells originate in the ______ but mature in the thymus gland
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A type of T cell called a'Thelper ______ is required to help B cells respond to most antigens
A type of T cell called a'Thelper ______ is required to help B cells respond to most antigens
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T cells recognize short proteolytically digested ______ of molecules derived from a protein antigen
T cells recognize short proteolytically digested ______ of molecules derived from a protein antigen
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MHC class I molecules present fragments of ______ antigens generated in the cytoplasm of the cell
MHC class I molecules present fragments of ______ antigens generated in the cytoplasm of the cell
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Only certain cells called professional ______ presenting cells express MHC class II molecules and process extracellular antigens
Only certain cells called professional ______ presenting cells express MHC class II molecules and process extracellular antigens
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The Ab combining site for antigen is made up of amino acid residues contributed by both the H and ______ chains
The Ab combining site for antigen is made up of amino acid residues contributed by both the H and ______ chains
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Typical ______________ Antigen-Presenting Cell
Typical ______________ Antigen-Presenting Cell
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Different antigen processing pathways lead to the presentation of peptides on MHC class ______________ versus class II molecules
Different antigen processing pathways lead to the presentation of peptides on MHC class ______________ versus class II molecules
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TCell Receptors are similar in structure to surface ______________ but only have one pair of chains
TCell Receptors are similar in structure to surface ______________ but only have one pair of chains
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The CD4 molecule is a cell-surface receptor for the Human ______________ Virus
The CD4 molecule is a cell-surface receptor for the Human ______________ Virus
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Cluster of Differentiation (CD) molecules function as ______________ and co-receptors and play an important role in intercellular communication
Cluster of Differentiation (CD) molecules function as ______________ and co-receptors and play an important role in intercellular communication
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Helper T cells (TH) express CD4 molecules on their surface, while Cytotoxic T cells (CTLs) express CD______________ molecules
Helper T cells (TH) express CD4 molecules on their surface, while Cytotoxic T cells (CTLs) express CD______________ molecules
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For the first step of an ELISA, the antigen is non-specifically adsorbed to a ______________ well microtiter plate
For the first step of an ELISA, the antigen is non-specifically adsorbed to a ______________ well microtiter plate
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To detect bound Abs, secondary Abs made in another species are used that recognize the Abs being tested, and are covalently bound to an enzyme that gives a ______________ reaction with its substrate
To detect bound Abs, secondary Abs made in another species are used that recognize the Abs being tested, and are covalently bound to an enzyme that gives a ______________ reaction with its substrate
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HRP uses the substrate hydrogen peroxide to oxidize an indicator called o-______________diamine
HRP uses the substrate hydrogen peroxide to oxidize an indicator called o-______________diamine
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Horse serum is commonly used as a ______________ agent in an ELISA to prevent non-specific binding of the antibody
Horse serum is commonly used as a ______________ agent in an ELISA to prevent non-specific binding of the antibody
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Study Notes
Immunity and Adaptive Immunity
- Immunity refers to the ability of a host to resist infection or disease
- There are two components of immunity: innate and adaptive
- Innate immunity is non-specific, acts as a first line of defense, and provides basic mechanisms to defend the host against foreign substances or agents of disease
- Adaptive immunity is acquired in response to the presence of a foreign substance called an antigen
- Antigens include microbial proteins, polysaccharides, and lipids
- Antigens have epitopes, which are regions or sites that bind to specific antibodies
Antibodies and Immunoglobulins
- Antibodies are proteins that upon binding can inactivate or neutralize an antigen
- Antibodies can directly neutralize a pathogen, or they can mediate the binding of other molecules such as complement to the microbial surface, causing lysis
- Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by phagocytic cells, a process called opsonization
- Immunoglobulins are serum antibodies that are referred to as Ig
B Lymphocytes
- B cells are produced and mature in the bone marrow
- Upon activation with a specific antigen, B cells differentiate into antibody-secreting plasma cells and memory cells
- Each B cell expresses on its surface approximately 10^5 identical Ig molecules that differ from the secreted Ab in that they contain a transmembrane segment
- The Ab combining site for antigen is made up of amino acid residues contributed by both the H and L chains
T Lymphocytes
- Lymphocytes destined to become T lymphocytes or T cells also originate in the bone marrow but mature in the thymus gland
- T cells can remain in the thymus, circulate in the blood, or reside in lymphoid organs such as the lymph nodes and spleen
- Distinct sub-classes of T cells perform different functions
- A type of T cell called a T helper cell (T,) is required to help B cells respond to most antigens
- T, cells also produce soluble proteins called cytokines that affect B cell differentiation and the activation of other cells
- The other sub-class of T lymphocytes is the cytotoxic T cell (CTL), which can directly kill cells that have been infected with an organism
Antigen Recognition by B and T Lymphocytes
- B cells recognize intact pathogenic organisms, and the antibodies produced generally bind surface molecules of the pathogens in their native conformation
- T cells recognize short, proteolytically digested fragments of molecules derived from a protein antigen, presented on the surface of cells in association with major histocompatibility complex (MHC) molecules
Antigen Processing and Presentation
- Antigens are degraded in cells by mechanisms referred to as "antigen processing"
- Antigens taken up from outside the cell are phagocytosed by macrophages and degraded in phagolysosomes
- The resulting fragments of the antigen are then presented at the surface in association with MHC class II molecules for recognition by T, cells
- Only certain cells called professional antigen-presenting cells (B cells, macrophages, and dendritic cells) express MHC class II molecules and process extracellular antigens taken up from outside the cell for T, cell recognition
T Cell Receptors
- Both T, cells and CTLs express on their surface approximately 10^5 identical receptors that are specific for a particular peptide-MHC molecule complex
- These receptors, called "TCRs or T cell receptors," interact with the antigenic peptide as well as the MHC molecule presenting it
- TCRs are similar in structure to surface Ig but only have one pair of chains (aß) and thus, only one combining site for the antigenic peptide-MHC molecule complex
Immunity and Adaptive Immunity
- Immunity refers to the ability of a host to resist infection or disease
- There are two components of immunity: innate and adaptive
- Innate immunity is non-specific, acts as a first line of defense, and provides basic mechanisms to defend the host against foreign substances or agents of disease
- Adaptive immunity is acquired in response to the presence of a foreign substance called an antigen
- Antigens include microbial proteins, polysaccharides, and lipids
- Antigens have epitopes, which are regions or sites that bind to specific antibodies
Antibodies and Immunoglobulins
- Antibodies are proteins that upon binding can inactivate or neutralize an antigen
- Antibodies can directly neutralize a pathogen, or they can mediate the binding of other molecules such as complement to the microbial surface, causing lysis
- Antibodies can also coat bacteria and parasites to make them more readily recognized and engulfed by phagocytic cells, a process called opsonization
- Immunoglobulins are serum antibodies that are referred to as Ig
B Lymphocytes
- B cells are produced and mature in the bone marrow
- Upon activation with a specific antigen, B cells differentiate into antibody-secreting plasma cells and memory cells
- Each B cell expresses on its surface approximately 10^5 identical Ig molecules that differ from the secreted Ab in that they contain a transmembrane segment
- The Ab combining site for antigen is made up of amino acid residues contributed by both the H and L chains
T Lymphocytes
- Lymphocytes destined to become T lymphocytes or T cells also originate in the bone marrow but mature in the thymus gland
- T cells can remain in the thymus, circulate in the blood, or reside in lymphoid organs such as the lymph nodes and spleen
- Distinct sub-classes of T cells perform different functions
- A type of T cell called a T helper cell (T,) is required to help B cells respond to most antigens
- T, cells also produce soluble proteins called cytokines that affect B cell differentiation and the activation of other cells
- The other sub-class of T lymphocytes is the cytotoxic T cell (CTL), which can directly kill cells that have been infected with an organism
Antigen Recognition by B and T Lymphocytes
- B cells recognize intact pathogenic organisms, and the antibodies produced generally bind surface molecules of the pathogens in their native conformation
- T cells recognize short, proteolytically digested fragments of molecules derived from a protein antigen, presented on the surface of cells in association with major histocompatibility complex (MHC) molecules
Antigen Processing and Presentation
- Antigens are degraded in cells by mechanisms referred to as "antigen processing"
- Antigens taken up from outside the cell are phagocytosed by macrophages and degraded in phagolysosomes
- The resulting fragments of the antigen are then presented at the surface in association with MHC class II molecules for recognition by T, cells
- Only certain cells called professional antigen-presenting cells (B cells, macrophages, and dendritic cells) express MHC class II molecules and process extracellular antigens taken up from outside the cell for T, cell recognition
T Cell Receptors
- Both T, cells and CTLs express on their surface approximately 10^5 identical receptors that are specific for a particular peptide-MHC molecule complex
- These receptors, called "TCRs or T cell receptors," interact with the antigenic peptide as well as the MHC molecule presenting it
- TCRs are similar in structure to surface Ig but only have one pair of chains (aß) and thus, only one combining site for the antigenic peptide-MHC molecule complex
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Description
Learn about immunity, its types, and how B and T lymphocytes recognize antigens in the human body. Explore the differences between innate and adaptive immunity.
