major histocompatibility complex

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Related to major histocompatibility complex: human leukocyte antigen


1. the sum, combination, or collection of various things or related factors, like or unlike; e.g., a complex of symptoms (see syndrome).
2. a group of interrelated ideas, mainly unconscious, that have a common emotional tone and strongly influence a person's attitudes and behavior.
3. that portion of an electrocardiographic tracing which represents the systole of an atrium or ventricle.
AIDS-related complex (ARC) a complex of signs and symptoms occurring in HIV infection including fever, weight loss, prolonged diarrhea, minor opportunistic infections, lymphadenopathy, and changes in cells of the immune system.
antigen-antibody complex here the complex formed by the noncovalent binding of an antibody and antigen. Complexes of antibodies belonging to certain immunoglobulin classes may activate complement. Called also immune complex.
anti-inhibitor coagulant complex (AICC) a concentrated fraction from pooled human plasma, which includes various coagulation factors. It is administered intravenously as an antihemorrhagic in hemophilic patients with inhibitors to coagulation factor VIII.
atrial complex the P wave of the electrocardiogram, representing electrical activity of the atria. See also ventricular complex.
castration complex in psychoanalytic theory, unconscious thoughts and motives stemming from fear of loss of the genitals as punishment for forbidden sexual desires.
Electra complex libidinous fixation of a daughter toward her father. This term is rarely used, since oedipus complex is generally applied to both sexes.
factor IX complex a sterile, freeze-dried powder consisting of partially purified coagulation factor IX fraction, as well as concentrated factor II, VII, and X fractions, of venous plasma from healthy human donors. It is used in the prophylaxis and treatment of bleeding in patients with hemophilia B, replacement of factor VII in patients deficient in that factor, and treatment of anticoagulant-induced hemorrhage. Administered intravenously.
Ghon complex primary complex (def. 1).
Golgi complex golgi apparatus.
HLA complex the human major histocompatibility complex, which contains the hla antigens.
immune complex antigen-antibody complex.
inclusion complex one in which molecules of one type are enclosed within cavities in the crystalline lattice of another substance.
inferiority complex unconscious feelings of inadequacy, producing shyness or timidity or, as a compensation, exaggerated agressiveness and expression of superiority; based on Alfred Adler's concept that everyone is born with a feeling of inferiority stemming from real or imagined physical or psychological deficiency, with the manner in which the inferiority is handled determining behavior.
interpolated premature ventricular complex a premature ventricular complex that does not interfere with the conduction of the next sinus beat, i.e., it lacks the usual following compensatory pause.
major histocompatibility complex (MHC) the chromosomal region containing genes that control the histocompatibility antigens; in humans it controls the hla antigens.
membrane attack complex (MAC) C5b,6,7,8,9, the five-molecule complex that is the cytolytic agent of the complement system.
Oedipus complex see oedipus complex.
primary complex
1. the combination of a parenchymal pulmonary lesion (Ghon focus) and a corresponding lymph node focus, occurring in primary tuberculosis, usually in children. Similar lesions may also be associated with other mycobacterial infections and with fungal infections.
2. the primary cutaneous lesion at the site of infection in the skin, e.g., chancre in syphilis and tuberculous chancre.
QRS complex a group of waves seen on an electrocardiogram, representing ventricular depolarization. Called also QRS wave. It actually consists of three distinct waves created by the passage of the cardiac electrical impulse through the ventricles and occurs at the beginning of each ventricular contraction. In a normal surface electrocardiogram the R wave is the upward deflection; the first downward deflection represents a Q wave and the final downward deflection is the S wave. The Q and S waves may be extremely weak and sometimes are absent.

One abnormality of the QRS complex is increased voltage resulting from enlargement of heart muscle, which produces increased quantities of electric current. A low-voltage QRS complex may result from toxic conditions of the heart, most commonly from fluid in the pericardium. Pleural effusion and emphysema also can cause a decrease in the voltage of the QRS complex.
VATER complex an association of congenital anomalies consisting of vertebral defects, imperforate anus, tracheoesophageal fistula, and radial and renal dysplasia.
ventricular complex the Q, R, S, and T waves of the electrocardiogram, representing ventricular electrical activity. See also atrial complex.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ma·jor his·to·com·pat·i·bil·i·ty com·plex (MHC),

a group of linked loci, collectively termed H-2 complex in the mouse and HLA complex in humans, which codes for cell-surface histocompatibility antigens and is the principal determinant of tissue type and transplant compatibility.
See also: human leukocyte antigens.
Farlex Partner Medical Dictionary © Farlex 2012

major histocompatibility complex

n. Abbr. MHC
A group of genes that code for cell-surface histocompatibility antigens and are the principal determinants of tissue type and transplant compatibility.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

major histocompatibility complex

The genetic loci that encode the histocompatibility antigens—cell surface proteins which bind peptide fragments of foreign proteins, present them to T cells and trigger a specific immune response.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

ma·jor his·to·com·pat·i·bil·i·ty com·plex

(MHC) (mā'jŏr his'tō-kǒm-pat'i-bil'i-tē kom'pleks)
A group of linked loci, collectively termed H-2 complex in mice and HLA complex in humans, which codes for cell-surface histocompatibility antigens and is the principal determinant of tissue type and transplant compatibility.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

major histocompatibility complex (MHC)

Cell surface protein markers, coded for by a large cluster of genes on chromosome 6, that control the activities of cells of the immune system. The MHC molecules indicates the tissue type and are important in organ donation. They have, however, wider functions in the immune system. Infected cells used their MHC sites to signal the fact to helper T cells and cytotoxic T cells so that they can be attacked. There are two classes of MHC. Class I MHC molecules are present on virtually all body cells other than red blood cells; class II MHC molecules occur on antigen-presenting cells such as MACROPHAGES and B cells. Cytotoxic T cells (CD8) bind to MHC class I, while helper T cells (CD4) bind to MHC class II. MHC variations have been used extensively in human population studies.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

ma·jor his·to·com·pat·i·bil·i·ty com·plex

(MHC) (mā'jŏr his'tō-kǒm-pat'i-bil'i-tē kom'pleks)
A group of linked loci, collectively termed HLA complex in humans, which codes for cell-surface histocompatibility antigens and is the principal determinant of tissue type and transplant compatibility.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
Shi et al., "Expression and regulation of major histocompatibility complex on neural stem cells and their lineages," Stem Cells and Development, vol.
In all higher species, these signature proteins are referred to as the major histocompatibility complex, or MHC.
Boffins in Chicago have been studying a cute little cluster of genes they call the Major Histocompatibility Complex.
Macrophages have a specialized set of molecules, called MHC-II (which stands for class II major histocompatibility complex).
After several medical evaluations, physicians discovered Lawrence had an immune deficiency disease called Major Histocompatibility Complex Class II deficiency.
The nature of selection on the major histocompatibility complex. Crit.
Unlike alpha beta T cells, gamma delta TCRs do not require expression of cell surface proteins (major histocompatibility complex molecules) for target recognition, and their ability to recognize novel targets under stress or metabolic conditions offer an attractive approach to develop potentially effective cell therapies in solid tumors.
Trogarzo binds primarily to the second extracellular domain of the CD4+ T receptor, away from major histocompatibility complex II molecule binding sites.
The swine major histocompatibility complex, known as the swine leukocyte antigen (SLA), is a gene-dense region containing many important immune-related genes [3,4].
Secondly, CMV expresses proteins that interfere with and suppress the receptor binding of inflammatory cytokines such as interferons, which would normally lead to upregulation of genes that encode major histocompatibility complex (MHC) class 1 molecules and various cytokines, resulting in CMV identification and destruction.
It also involves in forming major histocompatibility complex (MHC class I or MHC I) or like heterodimers, covering from antigen presentation to immune homeostasis.

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