Immunogenetics

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Immunogenetics or immungenetics is the branch of Medical Immunology and Medical Genetics that explores the relationship between the immune system and genetics.

Contents

Autoimmune diseases, such as type 1 diabetes, are complex genetic traits which result from defects in the immune system. Identification of genes defining the immune defects may identify new target genes for therapeutic approaches. Alternatively, genetic variations can also help to define the immunological pathway leading to disease.

Origin

The term immunogenetics is based on the two words immunology and genetics, and is defined as "a sub discipline of genetics which deals with the genetic basis of the immune response (immunity)" according to MeSH. [1]

Genetics (based on Greek γενεά geneá "descent" and γένεσις génesis "origin") [2] is the science researching the transfer of characteristics from one generation to the next. The genes of an organism (strands of DNA) and the transfer of genes from the parent to the child generation of an organism in the scope of possible variations are the basis of genetics.

Immunology deals with the biological and biochemical basis for the body's defense against germs (such as bacteria, viruses, and fungi), as well as against foreign agents such as biological toxins and environmental pollutants, and failures and malfunctions of these defense mechanisms. Apart from these external effects on the organism, there are also defense reactions regarding the body's own cells, e.g. in the scope of the bodily reactions on cancer and the lacking reaction of a body on healthy cells in the scope of immune-mediated disease. Hence, immunology is a sub-category of biology. Its origin is usually attributed to Edward Jenner, who discovered in 1796 that cowpox, or vaccinia, induced protection against human smallpox.

The term immunogenetics comprises all processes of an organism, which are, on the one hand, controlled and influenced by the genes of the organism, and are, on the other hand, significant with regard to the immunological defense reactions of the organism.

History

The history of immunology and the medical study of the immune system dates back to the 19th century. The first Nobel Prize in the field of immunogenetics was awarded to Baruj Benacerraf, Jean Dausset and George Davis Snell in 1980 for discovering genetically determined cellular surface structures, which control immunological reactions. [3]

Current research fields

Since 1972, [4] numerous H&I (histocompatibility and immunogenetics) organizations have been founded specializing in research activities on a large number of different questions in immunogenetics. Both the acceleration of and the decreasing costs for the sequencing of the genes have resulted in more intensive research of both academic and commercial working groups. Current research topics particularly deal with forecasts on the course of diseases and therapy recommendations due to genetic dispositions and how these dispositions can be affected by agents (gene therapy).

A special focus is often laid on the forecast regarding and therapy of genetically based autoimmune diseases, which include all diseases caused by an extreme reaction of the immune system against the body's own tissue. By mistake, the immune system recognizes the body's own tissue as a foreign object which is to be fought. This can result in serious inflammatory reactions which may permanently damage the respective organs. Autoimmune diseases, the outbreak and/or course of which can be visible in the individual genome of the organism, include multiple sclerosis, diabetes type I, rheumatoid arthritis and Crohn's disease. As for multiple sclerosis, an article in the journal Nature dated May 2010 [5] showed that this autoimmune disease is not caused by a genetic variation but the course and the treatability are considerably influenced by genetic dispositions. This research was based on analyzing three monovular pairs of twins, of which one twin has contracted multiple sclerosis whereas the other one has not.

See also

Related Research Articles

<span class="mw-page-title-main">Antigen</span> Molecule triggering an immune response (antibody production) in the host

In immunology, an antigen (Ag) is a molecule, moiety, foreign particulate matter, or an allergen, such as pollen, that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response.

<span class="mw-page-title-main">Immune system</span> Biological system protecting an organism against disease

The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue. Many species have two major subsystems of the immune system. The innate immune system provides a preconfigured response to broad groups of situations and stimuli. The adaptive immune system provides a tailored response to each stimulus by learning to recognize molecules it has previously encountered. Both use molecules and cells to perform their functions.

<span class="mw-page-title-main">Immunology</span> Branch of medicine studying the immune system

Immunology is a branch of biology and medicine that covers the study of immune systems in all organisms.

<span class="mw-page-title-main">Autoimmunity</span> Immune response against an organisms own healthy cells

In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, Henoch–Schönlein purpura, systemic lupus erythematosus, Sjögren syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis, ankylosing spondylitis, polymyositis, dermatomyositis, and multiple sclerosis. Autoimmune diseases are very often treated with steroids.

Histocompatibility, or tissue compatibility, is the property of having the same, or sufficiently similar, alleles of a set of genes called human leukocyte antigens (HLA), or major histocompatibility complex (MHC). Each individual expresses many unique HLA proteins on the surface of their cells, which signal to the immune system whether a cell is part of the self or an invading organism. T cells recognize foreign HLA molecules and trigger an immune response to destroy the foreign cells. Histocompatibility testing is most relevant for topics related to whole organ, tissue, or stem cell transplants, where the similarity or difference between the donor's HLA alleles and the recipient's triggers the immune system to reject the transplant. The wide variety of potential HLA alleles lead to unique combinations in individuals and make matching difficult.

<span class="mw-page-title-main">Major histocompatibility complex</span> Cell surface proteins, part of the acquired immune system

The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules.

Biology is the study of life and its processes. Biologists study all aspects of living things, including all of the many life forms on earth and the processes in them that enable life. These basic processes include the harnessing of energy, the synthesis and duplication of the materials that make up the body, the reproduction of the organism and many other functions. Biology, along with chemistry and physics is one of the major disciplines of natural science.

Immunotherapy or biological therapy is the treatment of disease by activating or suppressing the immune system. Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies, while immunotherapies that reduce or suppress are classified as suppression immunotherapies. Immunotherapy is under preliminary research for its potential to treat various forms of cancer.

<span class="mw-page-title-main">Human leukocyte antigen</span> Genes on human chromosome 6

The human leukocyte antigen (HLA) system or complex of genes on chromosome 6 in humans which encode cell-surface proteins responsible for regulation of the immune system. The HLA system is also known as the human version of the major histocompatibility complex (MHC) found in many animals.

In medicine, the hygiene hypothesis states that early childhood exposure to particular microorganisms protects against allergies by properly tuning the immune system. In particular, a lack of such exposure is thought to lead to poor immune tolerance. The time period for exposure begins before birth and ends at school age.

<span class="mw-page-title-main">Baruj Benacerraf</span> Venezuelan-American- Moroccan immunologist

Baruj Benacerraf was a Venezuelan-American immunologist, who shared the 1980 Nobel Prize in Physiology or Medicine for the "discovery of the major histocompatibility complex genes which encode cell surface protein molecules important for the immune system's distinction between self and non-self." His colleagues and shared recipients were Jean Dausset and George Davis Snell.

<span class="mw-page-title-main">Cytotoxic T-lymphocyte associated protein 4</span> Mammalian protein found in humans

Cytotoxic T-lymphocyte associated protein 4, (CTLA-4) also known as CD152, is a protein receptor that functions as an immune checkpoint and downregulates immune responses. CTLA-4 is constitutively expressed in regulatory T cells but only upregulated in conventional T cells after activation – a phenomenon which is particularly notable in cancers. It acts as an "off" switch when bound to CD80 or CD86 on the surface of antigen-presenting cells. It is encoded by the gene CTLA4 in humans.

<span class="mw-page-title-main">Helminthic therapy</span> Deliberate infestation with parasitic worms

Helminthic therapy, an experimental type of immunotherapy, is the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the eggs of a helminth. Helminths are parasitic worms such as hookworms, whipworms, and threadworms that have evolved to live within a host organism on which they rely for nutrients. These worms are members of two phyla: nematodes, which are primarily used in human helminthic therapy, and flat worms (trematodes).

Immune tolerance, also known as immunological tolerance or immunotolerance, refers to the immune system's state of unresponsiveness to substances or tissues that would otherwise trigger an immune response. It arises from prior exposure to a specific antigen and contrasts the immune system's conventional role in eliminating foreign antigens. Depending on the site of induction, tolerance is categorized as either central tolerance, occurring in the thymus and bone marrow, or peripheral tolerance, taking place in other tissues and lymph nodes. Although the mechanisms establishing central and peripheral tolerance differ, their outcomes are analogous, ensuring immune system modulation.

Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function normally. To be considered a primary immunodeficiency (PID), the immune deficiency must be inborn, not caused by secondary factors such as other disease, drug treatment, or environmental exposure to toxins. Most primary immunodeficiencies are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 430 recognized inborn errors of immunity (IEIs) as of 2019, the vast majority of which are PIDs, most are very rare. About 1 in 500 people in the United States are born with a primary immunodeficiency. Immune deficiencies can result in persistent or recurring infections, auto-inflammatory disorders, tumors, and disorders of various organs. There are currently limited treatments available for these conditions; most are specific to a particular type of PID. Research is currently evaluating the use of stem cell transplants (HSCT) and experimental gene therapies as avenues for treatment in limited subsets of PIDs.

Public health genomics is the use of genomics information to benefit public health. This is visualized as more effective preventive care and disease treatments with better specificity, tailored to the genetic makeup of each patient. According to the Centers for Disease Control and Prevention (U.S.), Public Health genomics is an emerging field of study that assesses the impact of genes and their interaction with behavior, diet and the environment on the population's health.

<span class="mw-page-title-main">HLA-DQB1</span> Protein-coding gene in the species Homo sapiens

Major histocompatibility complex, class II, DQ beta 1, also known as HLA-DQB1, is a human gene and also denotes the genetic locus that contains this gene. The protein encoded by this gene is one of two proteins that are required to form the DQ heterodimer, a cell surface receptor essential to the function of the immune system.

<span class="mw-page-title-main">Autoimmune disease</span> Disorders of adaptive immune system

An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that there are more than 80 recognized autoimmune diseases, with recent scientific evidence suggesting the existence of potentially more than 100 distinct conditions. Nearly any body part can be involved.

<span class="mw-page-title-main">Kamala Balakrishnan</span> Indian military officer and immunologist (1930–2018)

Kamala Balakrishnan was an Indian military officer and immunologist. She was a lieutenant colonel in the Indian Armed Forces, president of the American Society of Histocompatibility and Immunogenetics (ASHI), and director of the Transplantation Immunology Division at the Paul Hoxworth Blood Center in Cincinnati, Ohio.

RCCX is a complex, multiallelic, and tandem copy number variation (CNV) human DNA locus on chromosome 6p21.3, a cluster located in the major histocompatibility complex (MHC) class III region. CNVs are segments of DNA that vary in copy number compared to a reference genome and play a significant role in human phenotypic variation and disease development. The RCCX cluster consists of one or more modules each having a series of genes close to each other: serine/threonine kinase 19 (STK19), complement 4 (C4), steroid 21-hydroxylase (CYP21), and tenascin-X (TNX).

References

  1. ↑ "Immunogenetics - MeSH - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2020-04-07.
  2. ↑ "genetic | Origin and meaning of genetic by Online Etymology Dictionary". www.etymonline.com. Retrieved 2020-04-07.
  3. ↑ "The Nobel Prize in Physiology or Medicine 1980". NobelPrize.org. Retrieved 2020-04-07.
  4. ↑ "ASHI History - American Society for Histocompatibility and Immunogenetics". www.ashi-hla.org. Retrieved 2020-04-07.
  5. ↑ "Neil Miller on "Genome, epigenome and RNA sequences of monozygotic twins discordant for multiple sclerosis"". 2010-07-06. doi:10.4016/19108.01.{{cite journal}}: Cite journal requires |journal= (help)
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