Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells Plasma cells Specialized forms of antibody-producing B-lymphocytes. They synthesize and secrete immunoglobulin. They are found only in lymphoid organs and at sites of immune responses and normally do not circulate in the blood or lymph. Humoral Adaptive Immunity that act in immune responses by recognizing and binding specific antigens. Antibodies undergo processes that improve antigen Antigen Substances that are recognized by the immune system and induce an immune reaction. Vaccination affinity and provide appropriate defense by class switching. The various Ig Ig X-linked Agammaglobulinemia classes are 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 (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity Specificity Specificity is the probability of correctly determining the absence of a condition. Immunoassays, and distribution. General functions include opsonization, neutralization of infectivity of the pathogens, cytotoxicity, and 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. Specific classes have unique defensive mechanisms.
Last updated: 29 Apr, 2022
Immunoglobulin domains:
The heavy chains and light chains are folded up into domain type structures. The light chain has 1
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 domain and 1 constant domain. The heavy chain has 1
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 domain but has different constant domains depending on the
Ig molecule
Ig molecule
Humoral Adaptive Immunity (
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, IgA, and IgD have 3 constant domains, whereas IgM and IgE have 4 constant domains).
Structure of the antibody (regions):
Antibody has a unique
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 region (formed by heavy and light chains) 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 (formed by heavy chains).
Fragments of the
Ig
Ig
X-linked Agammaglobulinemia (determined by location where the enzyme papain splits the
Ig
Ig
X-linked Agammaglobulinemia):
Fab (fragment
antigen
Antigen
Substances that are recognized by the immune system and induce an immune reaction.
Vaccination-binding) 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 (blue) of both heavy and light chains. Fc (fragment crystallizable) contains the remaining part (tail) of the antibody (constant region of the heavy chain only).
Class-switch recombination
Class-switch recombination
Gene rearrangement of the b-lymphocyte which results in a substitution in the type of heavy-chain constant region that is expressed. This allows the effector response to change while the antigen binding specificity (variable region) remains the same. The majority of class switching occurs by a DNA recombination event but it also can take place at the level of RNA processing.
B cells: Types and Functions (CSR):
The heavy chain has different
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 segments:
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 region (V), diversity region (D), joining region (J), and constant (C) region.
The heavy-chain C region determines the
Ig
Ig
X-linked Agammaglobulinemia class/isotype. When antigens are encountered, mature IgM-positive
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 undergo CSR.
Exons
Exons
The parts of a transcript of a split gene remaining after the introns are removed. They are spliced together to become a messenger RNA or other functional RNA.
Post-transcriptional Modifications (RNA Processing) encoding the constant coding
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 segment (CÎĽ) of IgH are excised. Repetitive areas of
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure, switch regions (the black diamonds), are present.
Switch regions guide
enzymes
Enzymes
Enzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules.
Basics of Enzymes (e.g.,
activation-induced cytidine deaminase
Activation-induced cytidine deaminase
B cells: Types and Functions (AICDA)) to where to create
DNA
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
DNA Types and Structure double-stranded breaks (DSBs) and where the VDJ segment and the new constant region are joined by a repair enzyme. The CÎĽ is replaced with a new constant
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 segment (e.g., Cγ, Cε, or Cα). In the image, Cγ1 attaches to the VDJ segment and creates IgG1.
Antibodies that are created have important properties (diversity and specificity Specificity Specificity is the probability of correctly determining the absence of a condition. Immunoassays) that are essential in the immune response.
Unique mechanisms creating antibody diversity Antibody Diversity The phenomenon of immense variability characteristic of antibodies. It enables the immune system to react specifically against the essentially unlimited kinds of antigens it encounters. Antibody diversity is accounted for by three main theories: (1) the germ line theory, which holds that each antibody-producing cell has genes coding for all possible antibody specificities, but expresses only the one stimulated by antigen; (2) the somatic mutation theory, which holds that antibody-producing cells contain only a few genes, which produce antibody diversity by mutation; and (3) the gene rearrangement theory, which holds that antibody diversity is generated by the rearrangement of immunoglobulin variable region gene segments during the differentiation of the antibody-producing cells. B cells: Types and Functions include:
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
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. 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 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.
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 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 cells
Plasma cells
Specialized forms of antibody-producing B-lymphocytes. They synthesize and secrete immunoglobulin. They are found only in lymphoid organs and at sites of immune responses and normally do not circulate in the blood or lymph.
Humoral Adaptive Immunity 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.
Monomers and polymers:
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, IgD, and IgE are monomers (structure illustrated on the leftmost image). IgA becomes a dimer in mucous secretions. IgM forms a pentamer.
Image by Lecturio.The 5 Ig Ig X-linked Agammaglobulinemia classes, their structures, and their characteristics
Image: “Five immunoglobulin classes” by OpenStax College. License: CC BY 3.0