H antigen can refer to one of various types of
antigens having diverse biological functions. H antigen is located on the
19th chromosome in humans, and has a variety of functions and definitions as follows:
* Also known as substance H, H antigen is a precursor to each of the
ABO blood group antigens, apparently present in all people except those with the Bombay Blood phenotype
(see
hh blood group
hh, or the Bombay blood group, is a rare blood type. This blood phenotype was first discovered in Bombay by Dr. Y. M. Bhende in 1952. It is mostly found in the Indian sub-continent (India, Bangladesh, Pakistan) and parts of Iran.
Problems with ...
)
*
Histocompatibility
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 uni ...
antigen, a major factor in
graft rejection. Even when
Major Histocompatibility Complex
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 calle ...
genotype is perfectly matched, can cause slow rejection of a graft.
** major H antigens "encode molecules that present foreign
peptides
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
A p ...
to
T cells"
** minor H antigens "present polymorphic self peptides to T cells".
Includes, e.g. the
H-Y antigen
* a bacterial
flagellar
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have fro ...
antigen
References
Medical tests
Bacterial proteins
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