52. Human blood groups, alloantigens, the ABO/ H/ system. Flashcards
Alloantigen - an antigen that is part of an animals self-recognition system. Alloantigens are the products of polymorphic genes. ex. blood group antigens, present in some members of the same species, not common to all members of species
Alloantigen - an antigen that is part of an animals self-recognition system. Alloantigens are the products of polymorphic genes. ex. blood group antigens, present in some members of the same species, not common to all members of species
The ABO system - 4 main phenotypes (A, B, AB, O). The ABO gene is located on the long arm of chromosome 9.
The ABO system - 4 main phenotypes (A, B, AB, O). The ABO gene is located on the long arm of chromosome 9.
Blood Group Antigens of RBCs Antibodies in serum Genotypes
A A Anti-B AA or AO
B B Anti-A BB or BO
AB A + B Neither AB
O Neither Anti-A and Anti-B OO
Blood Group Antigens of RBCs Antibodies in serum Genotypes
A A Anti-B AA or AO
B B Anti-A BB or BO
AB A + B Neither AB
O Neither Anti-A and Anti-B OO
The A + B alleles each encode a glycosyltransferase that catalyses the final step in the synthesis of the A + B antigen respectively. The O allele encodes an inactive glycosyltransferase that leaves the ABO antigen precursor (the H antigen) unmodified.
The A + B alleles each encode a glycosyltransferase that catalyses the final step in the synthesis of the A + B antigen respectively. The O allele encodes an inactive glycosyltransferase that leaves the ABO antigen precursor (the H antigen) unmodified.
IgG and IgM are naturally occurring antibodies. Anti -A is found in the serum of people with blood groups O and B. Anti-B is found in the serum of people with blood groups O and A.
The ABO locus encodes specific glycotransferases that synthesise A + B antigens on RBCs.
IgG and IgM are naturally occurring antibodies. Anti -A is found in the serum of people with blood groups O and B. Anti-B is found in the serum of people with blood groups O and A.
The ABO locus encodes specific glycotransferases that synthesise A + B antigens on RBCs.
For A/B antigen synthesis to occur, the H antigen must be present. (the O allele differs from the A allele by deletion of guanine at position 261 - this deletion causes a frameshift)
For A/B antigen synthesis to occur, the H antigen must be present. (the O allele differs from the A allele by deletion of guanine at position 261 - this deletion causes a frameshift)
The H locus - individuals who are homozygous for null alleles at this locus do not produce H antigens - as a result they cannot produce A + B antigens. Therefore their serum contains anti-A and anti-B, in addition to potent anti-M. This rare phenotype of H-deficient RBCs is called Bombay phenotype
The H locus - individuals who are homozygous for null alleles at this locus do not produce H antigens - as a result they cannot produce A + B antigens. Therefore their serum contains anti-A and anti-B, in addition to potent anti-M. This rare phenotype of H-deficient RBCs is called Bombay phenotype
The Rh blood group system consists of 50 defined blood-group antigens, among which the 5 antigens D, C, c, E and e are most important
The se locus: encodes for a specific fucosyltransferase that is expressed in the epithelia of secretory tissues ex. salivary glands
The Rh blood group system consists of 50 defined blood-group antigens, among which the 5 antigens D, C, c, E and e are most important
The se locus: encodes for a specific fucosyltransferase that is expressed in the epithelia of secretory tissues ex. salivary glands
In RBCs the enzymes that synthesise the H antigen is encoded by the H-locus
In saliva, the enzymes that synthesise the H antigens are encoded by Se locus
In RBCs the enzymes that synthesise the H antigen is encoded by the H-locus
In saliva, the enzymes that synthesise the H antigens are encoded by Se locus
