Humoral adaptive immunity is an integral part of the adaptive immune system Immune system The body's defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs, which mounts a highly specific defense against pathogens but takes a longer time to respond (compared to the innate immune system Immune system The body's defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs). Humoral immunity is the arm Arm The arm, or "upper arm" in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of the immune system Immune system The body's defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs protecting the extracellular fluids of the lymphatics ( lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs), interstitium, and circulatory system ( plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products) from microbial contamination mediated through soluble molecules. The B cells B cells Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions play a major role, producing antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions or immunoglobulins Immunoglobulins Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions. Arising from the bone marrow Bone marrow The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells. Bone Marrow: Composition and Hematopoiesis, B cells B cells Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions originate from the common lymphoid progenitor and undergo stages to assemble the B cell receptor B cell receptor Lymphocytes: Histology. To become fully functional, activation follows, and this can be T cell–dependent (which produces memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment cells) or T cell–independent (producing a short-lived response). When activated, B cells B cells Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions go through processes enhancing antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination affinity, class switching, and differentiation to plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products cells and memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment cells. Plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products cells produce the antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions, while memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment B cells B cells Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation. B cells: Types and Functions respond to reinfection. There are different immunoglobulin isotypes, generally providing immune protection through complement activation Complement Activation The sequential activation of serum complement proteins to create the complement membrane attack complex. Factors initiating complement activation include antigen-antibody complexes, microbial antigens, or cell surface polysaccharides. Systemic Lupus Erythematosus, opsonization, neutralization of toxins or viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology, and induction of cell lysis.
Last updated: 8 Apr, 2022
The immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs provides defense (immunity) against invading pathogens ranging from viruses Viruses Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells. Virology to parasites. The components of the system are interconnected by blood and the lymphatic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment.
2 lines of defense Lines of Defense Inflammation (that overlap):
Innate immunity Innate immunity The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring anti-infective agents, constitutional factors such as body temperature and immediate acting immune cells such as natural killer cells. Innate Immunity: Phagocytes and Antigen Presentation | Adaptive immunity | |
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Genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics | Germline encoded | Gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics rearrangements involved in lymphocyte development |
Immune response | Nonspecific | Highly specific |
Timing of response | Immediate (minutes to hours) | Develops over a longer period of time |
Memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment response | Without memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment response | With memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment response, which responds quickly upon recognition of antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination |
Recognition of pathogen | Pattern recognition receptors Pattern recognition receptors A large family of cell surface receptors that bind conserved molecular structures (pamps) present in pathogens. They play important roles in host defense by mediating cellular responses to pathogens. Innate Immunity: Barriers, Complement, and Cytokines (PRRs) such as TLRs recognize pathogen-associated molecular patterns Pathogen-Associated Molecular Patterns Sepsis and Septic Shock ( PAMPs PAMPs Sepsis and Septic Shock). |
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Responding to microbial invaders is the responsibility of the immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs. Often, the innate immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs has the capability to contain the pathogens, but invaders have evolved means to evade innate immunity Innate immunity The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring anti-infective agents, constitutional factors such as body temperature and immediate acting immune cells such as natural killer cells. Innate Immunity: Phagocytes and Antigen Presentation. The next line of defense is the adaptive immune system Immune system The body’s defense mechanism against foreign organisms or substances and deviant native cells. It includes the humoral immune response and the cell-mediated response and consists of a complex of interrelated cellular, molecular, and genetic components. Primary Lymphatic Organs.
The
B cell receptor
B cell receptor
Lymphocytes: Histology (
BCR
BCR
Lymphocytes: Histology) consists of the
Ig
Ig
X-linked Agammaglobulinemia molecule and the signaling molecule:
Ig
Ig
X-linked Agammaglobulinemia contains 2 identical
heavy chains
Heavy chains
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kda.
Immunoglobulins: Types and Functions and 2 identical
light chains
Light chains
Polypeptide chains, consisting of 211 to 217 amino acid residues and having a molecular weight of approximately 22 kda. There are two major types of light chains, kappa and lambda. Two ig light chains and two ig heavy chains (immunoglobulin heavy chains) make one immunoglobulin molecule.
Immunoglobulins: Types and Functions linked by a disulfide bridge. The membrane-bound
Ig
Ig
X-linked Agammaglobulinemia is anchored to the cell surface.
Steps needed for the B cell to function:
Differentiation stages of the B cell:
In antigen-independent stages, B cell production starts with the hematopoietic stem cell (HSC), which becomes a common lymphoid progenitor (CLP) and then a
pre-pro-B cell
Pre-pro-B cell
Lymphocytes: Histology or B progenitor cell. The next steps include
gene
Gene
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Basic Terms of Genetics rearrangement to assemble the
Ig
Ig
X-linked Agammaglobulinemia molecule. Immunoglobulin
heavy chains
Heavy chains
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kda.
Immunoglobulins: Types and Functions start with rearrangement of diversity and joining segments to form the
pro-B cell
Pro-B cell
Lymphocytes: Histology. In the next step (pre-B cell),
Ig
Ig
X-linked Agammaglobulinemia heavy-chain
recombination
Recombination
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, crossing over; gene conversion; genetic transformation; genetic conjugation; genetic transduction; or mixed infection of viruses.
Virology (
variable
Variable
Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups.
Types of Variables, diversity, joining) is completed and the pre-B cell
receptor
Receptor
Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.
Receptors is formed. Light-chain (kappa (κ) or lambda (λ)) rearrangement occurs, resulting in the expression of a complete
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions antibody molecule by an
immature B cell
Immature B cell
Lymphocytes: Histology. Formation of the
mature B cell
Mature B cell
Lymphocytes: Histology (naive) with both
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions and
IgD
IgD
An immunoglobulin which accounts for less than 1% of plasma immunoglobulin. It is found on the membrane of many circulating B lymphocytes.
Immunoglobulins: Types and Functions follows.
Antigen-dependent stages take place in secondary lymphoid tissues. Once the
mature B cell
Mature B cell
Lymphocytes: Histology produces
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions and
IgD
IgD
An immunoglobulin which accounts for less than 1% of plasma immunoglobulin. It is found on the membrane of many circulating B lymphocytes.
Immunoglobulins: Types and Functions, a class switch can take place to make
IgE
IgE
An immunoglobulin associated with mast cells. Overexpression has been associated with allergic hypersensitivity.
Immunoglobulins: Types and Functions,
IgG
IgG
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.
Hypersensitivity Pneumonitis, and
IgA
IgA
Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory iga is the main immunoglobulin in secretions.
Immunoglobulins: Types and Functions.
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions are activated and become
plasma
Plasma
The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.
Transfusion Products cells or
memory
Memory
Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.
Psychiatric Assessment cells.
B cell activation (T cell dependent):
Circulating
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination interacts with the Bcell
receptor
Receptor
Receptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.
Receptors (
BCR
BCR
Lymphocytes: Histology) of the B cell. The
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination is endocytosed and degraded, and the peptide components are complexed with cell surface MHC II molecules. T follicular helper (Tfh) cells (specialized CD4+ T helper cells) recognize and
bind
BIND
Hyperbilirubinemia of the Newborn the
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination–MHC II complex.
Cytokines
Cytokines
Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.
Adaptive Immune Response are released by the Tfh cells, leading to B cell activation and proliferation. Activated
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions enter the germinal centers, where they continue the process, leading to differentiation.
B cell activation and maturation processes taking place in the germinal center:
On activation, the B cell moves from the mantle zone and enters the germinal center. B cell proliferation (
clonal expansion
Clonal Expansion
Seborrheic Keratosis) takes place, and antibody affinity to the
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination is enhanced through the process of
somatic hypermutation
Somatic hypermutation
A programmed mutation process whereby changes are introduced to the nucleotide sequence of immunoglobulin gene DNA during development.
B cells: Types and Functions. Repeated cycles of proliferation and hypermutation fine-tune the
B cell receptor
B cell receptor
Lymphocytes: Histology. However, not all
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions continue to differentiate, especially if the affinity is weak.
Apoptosis
Apoptosis
A regulated cell death mechanism characterized by distinctive morphologic changes in the nucleus and cytoplasm, including the endonucleolytic cleavage of genomic DNA, at regularly spaced, internucleosomal sites, I.e., DNA fragmentation. It is genetically-programmed and serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
Ischemic Cell Damage follows if the
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination–antibody binding is not optimized. Those with strong affinity survive (
selection
Selection
Lymphocyte activation by a specific antigen thus triggering clonal expansion of lymphocytes already capable of mounting an immune response to the antigen.
B cells: Types and Functions) with the help of survival signals from follicular
dendritic cells
Dendritic cells
Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as skin and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process antigens, and present them to T-cells, thereby stimulating cell-mediated immunity. They are different from the non-hematopoietic follicular dendritic cells, which have a similar morphology and immune system function, but with respect to humoral immunity (antibody production).
Skin: Structure and Functions and
T cells
T cells
Lymphocytes responsible for cell-mediated immunity. Two types have been identified – cytotoxic (t-lymphocytes, cytotoxic) and helper T-lymphocytes (t-lymphocytes, helper-inducer). They are formed when lymphocytes circulate through the thymus gland and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
T cells: Types and Functions. These selected
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions move on to class switching and differentiation into
plasma
Plasma
The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.
Transfusion Products cells or
memory
Memory
Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.
Psychiatric Assessment cells.
Primary and secondary immune response:
In a primary immune response, naive
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions are stimulated by
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination. B cell activation and then differentiation into antibody-secreting cells occur. The
antibodies
Antibodies
Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.
Immunoglobulins: Types and Functions are specific for the eliciting
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination. The production of
IgM
IgM
A class of immunoglobulin bearing mu chains (immunoglobulin mu-chains). Igm can fix complement. The name comes from its high molecular weight and originally being called a macroglobulin.
Immunoglobulins: Types and Functions is followed by
IgG
IgG
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.
Hypersensitivity Pneumonitis. While there is an immune response, the production is low-level. In the secondary immune response, the same
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination stimulates
memory
Memory
Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.
Psychiatric Assessment
B cells
B cells
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
B cells: Types and Functions, leading to the production of greater quantities of specific
antibodies
Antibodies
Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.
Immunoglobulins: Types and Functions that are produced in the primary response. The production and
release
Release
Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane.
Virology of
IgG
IgG
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of igg, for example, igg1, igg2a, and igg2b.
Hypersensitivity Pneumonitis also occur earlier.
Fragments of the immunoglobulin (determined by location where the enzyme papain splits the
Ig
Ig
X-linked Agammaglobulinemia):
The
Fab
Fab
Univalent antigen-binding fragments composed of one entire immunoglobulin light chain and the amino terminal end of one of the immunoglobulin heavy chains from the hinge region, linked to each other by disulfide bonds. Fab contains the immunoglobulin variable regions, which are part of the antigen-binding site, and the first immunoglobulin constant regions. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme papain.
Immunoglobulins: Types and Functions (fragment antigen-binding) region contains the
variable
Variable
Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups.
Types of Variables regions (red) and parts of the
constant region
Constant region
The domains of the immunoglobulin molecules that are invariable in their amino acid sequence within any class or subclass of immunoglobulin. They confer biological as well as structural functions to immunoglobulins. One each on both the light chains and the heavy chains comprises the c-terminus half of the immunoglobulin fab fragment and two or three of them make up the rest of the heavy chains (all of the immunoglobulin Fc fragment).
Immunoglobulins: Types and Functions (blue) of both heavy and
light chains
Light chains
Polypeptide chains, consisting of 211 to 217 amino acid residues and having a molecular weight of approximately 22 kda. There are two major types of light chains, kappa and lambda. Two ig light chains and two ig heavy chains (immunoglobulin heavy chains) make one immunoglobulin molecule.
Immunoglobulins: Types and Functions. The
Fc
Fc
Crystallizable fragments composed of the carboxy-terminal halves of both immunoglobulin heavy chains linked to each other by disulfide bonds. Fc fragments contain the carboxy-terminal parts of the heavy chain constant regions that are responsible for the effector functions of an immunoglobulin (complement fixation, binding to the cell membrane via fc receptors, and placental transport). This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme papain.
Immunoglobulins: Types and Functions (fragment crystallizable) region contains the remaining part (tail) of the antibody (
constant region
Constant region
The domains of the immunoglobulin molecules that are invariable in their amino acid sequence within any class or subclass of immunoglobulin. They confer biological as well as structural functions to immunoglobulins. One each on both the light chains and the heavy chains comprises the c-terminus half of the immunoglobulin fab fragment and two or three of them make up the rest of the heavy chains (all of the immunoglobulin Fc fragment).
Immunoglobulins: Types and Functions of the heavy chain only).
Structure of the antibody (regions):
An antibody has a unique
variable region
Variable region
That region of the immunoglobulin molecule that varies in its amino acid sequence and composition, and comprises the binding site for a specific antigen. It is located at the n-terminus of the fab fragment of the immunoglobulin. It includes hypervariable regions (complementarity determining regions) and framework regions.
Immunoglobulins: Types and Functions (formed by heavy and
light chains
Light chains
Polypeptide chains, consisting of 211 to 217 amino acid residues and having a molecular weight of approximately 22 kda. There are two major types of light chains, kappa and lambda. Two ig light chains and two ig heavy chains (immunoglobulin heavy chains) make one immunoglobulin molecule.
Immunoglobulins: Types and Functions) capable of binding a different
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination and a
constant region
Constant region
The domains of the immunoglobulin molecules that are invariable in their amino acid sequence within any class or subclass of immunoglobulin. They confer biological as well as structural functions to immunoglobulins. One each on both the light chains and the heavy chains comprises the c-terminus half of the immunoglobulin fab fragment and two or three of them make up the rest of the heavy chains (all of the immunoglobulin Fc fragment).
Immunoglobulins: Types and Functions (formed by
heavy chains
Heavy chains
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kda.
Immunoglobulins: Types and Functions).
Protection against infectious Infectious Febrile Infant agents and their products by: