Untitled - D Ank Unlimited

K antigens
Surface epitopes of Gram-negative microorganisms. They
are either proteins (fimbriae) or acid polysaccharides found
on the surfaces of Klebsiella and Escherichia coli microorganisms.
K antigens are exterior to somatic O antigens.
They are labile to heat and crossreact with the capsules
of other microorganisms such as Hemophilus influenzae,
Streptococcus pneumoniae, and Neisseria meningitidis. K
antigens may be linked to virulent strains of microorganisms
that induce urinary tract infections. Anti-K antibodies
are only weakly protective.
Fc receptor
K cell
IgG
Schematic representation of a K (NK) cell.
K (killer) cell
Name originally given to null cells that were first recognized
as non-B non-T lymphocytes. They were described to
have lymphocyte-like morphology but functional characteristics
different from those of B and T cells. Killer cells are
now called natural killer (NK) cells. One type of immune
response in which they are involved is antibody-dependent
cell-mediated cytotoxicity (ADCC) in which they kill target
cells coated with immunoglobulin G (IgG) antibodies. A K
cell is an Fc-bearing killer cell that has an effector function
in mediating antibody-dependent, cell-mediated cytotoxicity.
An IgG antibody molecule binds through its Fc region
to the Fc receptor of the K cell. Following contact with a
target cell bearing antigenic determinants on its surface for
which the Fab regions of the antibody molecule attached to
the K cell are specific, the lymphocyte-like K cell releases
lymphokines that destroy the target. This represents a type
of immune effector function in which cells and antibody
participate. Other cells that mediate antibody-dependent
cell-mediated cytotoxicity include cytotoxic T cells, neutrophils,
and macrophages.
K region
The K region and the D region relate to major histocompatibility
complex (MHC) class I segments in the murine genome.
K562 cells
A chronic myelogenous leukemia cell line that serves as
a target cell in a 51 Cr release assay of natural killer (NK)
cells. Following incubation of NK cells with 51 Cr-labeled
target K562 cells, the amount of chromium released into the
supernatant is measured and the cytotoxicity is determined
by use of a formula.
K
K562 Target cell
NK cells
Schematic representation of a K562 target cell bound to natural killer
(NK) cells.
NK cells
K562 Target cell
K562 target cell (large arrow) bound to natural killer (NK) cells (small
arrows).
Kabat, Elvin Abraham (1914–)
American immunochemist; with Tiselius, he was the first to
separate immunoglobulins electrophoretically. He also demonstrated
that γ globulins can be distinguished as 7S or 19S.
Other contributions include research on antibodies to carbohydrates,
antibody combining sites, and the discovery of immunoglobulin
chain variable regions. He received the National
Medal of Science. (Refer to Experimental Immunochemistry
[with Mayer], 1948; Blood Group Substances: Their
Chemistry and Immunochemistry, 1956; Structural Concepts
in Immunology and Immunochemistry, 1968.)
Kabat Wu plot
Refer to Wu Kabat plot.
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