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lood group antigens 110 BLR-1/MDR-15
blood group antigens
Erythrocyte surface molecules that may be detected with
antibodies from other individuals such as ABO blood group
antigens. Various blood group antigen systems including Rh
(Rhesus) may be typed in routine blood banking procedures.
Other blood group antigen systems may be revealed
through cross matching.
blood grouping
The classification of erythrocytes based on their surface
isoantigens. Among the well-known human blood groups
are the ABO, Rh, and MNS systems.
TABelle I
betreffend das blut sechs anscheinend gesunder männer
Sera
Dr. St. – + + + + –
Dr. Plecn. – + + – –
Dr. Sturl. – + – – + –
Dr. Erdh. – + – – + –
Zar. – – + + – –
Landst. – + + + + –
Blutköperchen
von:
Dr. St. Dr. Plecn. Dr. Sturl. Dr. Erdb. Zar. Landst.
Table illustrating ABO blood groups. (From Wien. klin. Wschr., 14, 1132–
1134, 1901.)
TABelle II
betreffend das blut von sechs anscheinend gesunder
puerperae
Sera
Seil – – + – – +
Linsm. + – + + + +
Lust. + – – + + –
Mittelb. – – + – – +
Tomsch. – – + – – +
Graupn. + – – + + –
Blutköperchen
von:
Seil. Linsm. Lust. Mittelb. Tomsch. Graupn.
ABO blood group antigens and antibodies.
Capillary
Capillary
basement
membrane
Antigen
Endothelial
cell
Peri-capillary space
Pericyte Macrophage
Lymphocyte
Epithelial
cell barrier
Interconnecting
epithelial cells
Thymocytes
of cortex
Three levels of lymphocyte protection that form the blood–thymus barrier:
capillary wall, macrophages in pericapillary space, and a wall of
epithelial cells.
blood–thymus barrier
Protects thymocytes from contact with antigen.
Lymphocytes reaching the thymus are prevented from
contact with antigen by a physical barrier. The first level is
represented by the capillary wall endothelial cells inside the
pericytes outside of the lumen. Potential antigenic molecules
that escape the first level of control are taken over
by macrophages present in the pericapillary space. Further
protection is provided by a third level, represented by the
mesh of interconnecting epithelial cells that enclose the
thymocyte population. The effects of thymus and thymic
hormones on the differentiation of T cells is demonstrable
in animals congenitally lacking thymus glands (nu/nu
animals), in neonatal or adult thymectomized animals,
and in subjects with immunodeficiencies involving T cell
function. Differentiation is associated with surface markers
whose presence or disappearance characterizes the different
stages of cell differentiation. Extensive proliferation of the
subcapsular thymocytes occurs. The largest proportion of
these cells die, but remaining cells continue to differentiate.
The differentiating cells become smaller in size and move
through interstices in the thymic medulla. The fully developed
thymocytes pass through the walls of the postcapillary
venules to reach the systemic circulation and seed in the
peripheral lymphoid organs. Some of them recirculate but
do not return to the thymus.
Bloom syndrome (BS)
A very rare clinical entity characterized by a strikingly
small but well-proportioned body size. It is the consequence
of either homozygosity or compound heterozygosity of a
mutation of BLM, a gene that encodes a phylogenetically,
highly conserved nuclear protein. It has been suggested that
this condition should be grouped with the genetically determined
immunodeficiencies. Respiratory tract infections
occur much more commonly in patients with BS than in the
general population; if not treated promptly, these infections
become life threatening, yet 37% of BS patients manifest
no increased tendency to infection of any kind. The disease
is characterized by diminished numbers of T lymphocytes,
decreased antibody levels, and increased susceptibility
to respiratory infections, tumors, and radiation injury.
Mutations in a DNA helicase cause the disorder. Genomic
instability is a characteristic of this rare autosomal recessive
primary immunodeficiency that is attributable to
mutation of the BLM gene associated with the homologous
recombination pathway of DNA repair.
blot
The transfer of DNA, RNA, or protein molecules from an
electrophoretic gel to a nitrocellulose or nylon membrane
by osmosis or vacuum, followed by immersion of the
membrane in a solution containing a complementary (i.e.,
mirror-image) molecule corresponding to the one on the
membrane. This is known as a hybridization blot.
BLR-1/MDR-15
Burkitt’s lymphoma receptor-1/monocyte-derived receptor-15
(BLR-1/MDR-15) is a member of the G proteincoupled
receptor family, the chemokine receptor branch of
the rhodopsin family. It is expressed on B cells and memory
T cells, chronic B lymphoid leukemia and non-Hodgkin
lymphoma cells, peripheral blood monocytes, and lymphocytes.
It is expressed in tonsils and secondary lymphoid
organs and in selected other tissues. Most Burkitt’s