major histocompatibility complex
C2Technical/scientific (immunology, genetics, medicine)
Definition
Meaning
A set of cell surface proteins essential for the acquired immune system to recognize foreign molecules in vertebrates, which determines tissue compatibility and influences transplant rejection.
A large genomic region or gene family found in most vertebrates containing genes critical for immune system function, including antigen presentation. In humans, it's known as the human leukocyte antigen (HLA) system.
Linguistics
Semantic Notes
Always used as a singular noun phrase ('the MHC'), though it refers to a complex of genes/proteins. Implies both a genetic locus and its phenotypic expression. Often abbreviated to MHC after first use.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences; both use 'MHC'. Minor spelling preferences follow general patterns (e.g., 'haematopoietic' vs 'hematopoietic' in related text).
Connotations
Identical technical meaning in both varieties.
Frequency
Exclusively used in technical biomedical contexts in both regions. Laypeople would not typically encounter the term.
Vocabulary
Collocations
Grammar
Valency Patterns
The MHC presents [antigen] to [immune cell].MHC genes are located on [chromosome 6 in humans].Polymorphism in the MHC affects [disease susceptibility].Donor and recipient must be matched for MHC.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “MHC mismatch (a situation where donor and recipient MHC profiles differ, leading to transplant rejection)”
- “MHC restriction (the requirement for T cells to recognize antigen only when presented by a self-MHC molecule)”
Usage
Context Usage
Business
Not used.
Academic
Central term in immunology, genetics, and transplantation medicine papers. Example: 'The extraordinary polymorphism of the MHC is driven by pathogen-mediated selection.'
Everyday
Virtually never used. Might appear in simplified health articles about organ donation.
Technical
Precise term in laboratory, clinical, and research settings. Example: 'Flow cytometry was used to assess MHC class II expression on antigen-presenting cells.'
Examples
By Part of Speech
verb
British English
- The gene products are MHC-encoded.
- The peptide is MHC-restricted.
American English
- The protein is MHC-encoded.
- The response is MHC-restricted.
adjective
British English
- MHC-dependent response
- MHC-matched donor
American English
- MHC-dependent response
- MHC-matched donor
Examples
By CEFR Level
- Doctors check for MHC compatibility before an organ transplant to reduce rejection risk.
- The incredible diversity of the major histocompatibility complex within a population is a key defence against evolving pathogens.
- T-cell receptors recognise antigens only when they are presented by the body's own MHC molecules, a phenomenon known as MHC restriction.
Learning
Memory Aids
Mnemonic
Major HistoCompatibility Complex: Mind How Cells present antigens. (MHC)
Conceptual Metaphor
THE CELL'S IDENTIFICATION BADGE or THE IMMUNE SYSTEM'S RECOGNITION MANUAL.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not translate 'major' as 'главный' in isolation; it's part of the fixed name 'major histocompatibility complex' (основной комплекс гистосовместимости).
- Avoid confusing 'histocompatibility' with 'histology' (гистология).
Common Mistakes
- Saying 'an MHC' (it's 'the MHC').
- Using 'MHC' as a countable plural ('MHCs' is rare; prefer 'MHC molecules' or 'MHC genes').
- Confusing 'MHC' with other immune complexes like the 'complement system'.
Practice
Quiz
What is the primary function of the Major Histocompatibility Complex (MHC)?
FAQ
Frequently Asked Questions
In humans, yes. HLA (Human Leukocyte Antigen) is the name for the human MHC. The term MHC is used for the genetic region across all vertebrates, while HLA refers specifically to its human manifestation.
The MHC proteins on donor cells are recognised as foreign by the recipient's immune system if they are not closely matched, triggering transplant rejection. Therefore, MHC matching is crucial for transplant success.
These are two main types of MHC molecules. Class I molecules are found on almost all nucleated cells and present intracellular peptides (e.g., from viruses) to cytotoxic T cells. Class II molecules are found on professional antigen-presenting cells and present extracellular peptides to helper T cells.
It literally means 'tissue compatibility' (from Greek 'histos' for tissue). It refers to the property of having sufficiently similar tissues to allow grafting or transplantation without a destructive immune reaction.