Untitled - D Ank Unlimited

Calmette, Albert (1863–1933) 131 Campylobacter immunity
Endoplasmic reticulum
Cytosol
TAP
transporter
Peptides
Peptides are transported into the endoplasmic reticulum.
Once the peptide binds, MHC class I
folding is complete and calnexin is
released.
Calmette, Albert (1863–1933)
French physician who was subdirector of the Institut
Pasteur in Paris. In a popular book published in 1920 titled
Bacillary Infection and Tuberculosis, he emphasized the
necessity of separating tuberculin reactivity from anaphylaxis.
With Guérin, he perfected the BCG (bacille
Calmette–Guérin) vaccine and also investigated snake
venom and plague serum.
calnexin
An 88-kDa membrane molecule that combines with
newly formed α chains that also interact with nascent
β 2-microglobulin. Calnexin maintains partial folding of
major histocompatibility complex (MHC) class I molecules
in the endoplasmic reticulum. It also interacts with MHC
class II molecules, T cell receptors, and immunoglobulins
that are partially folded.
calreticulin
A calnexin structurally-related soluble protein present in the
endoplasmic reticulum that facilitates proper folding of major
histocompatibility complex (MHC) molecules and other
glycoproteins; a molecular chaperone that binds to MHC class
I and class II, as well as other immunoglobulin-like domains
containing proteins, including antigen receptors for both T
and B cells. Calreticulin resembles calnexin structurally and
functionally.
CAM (cell adhesion molecule)
Cell-selective proteins that promote adhesion of cells to one
another and are calcium-independent. They are believed to
help direct migration of cells during embryogenesis. The
majority of lymphocytes and monocytes express this antigen,
which is not found on other cells. The “humanized” antibodies
specific for this epitope are termed Campath-1H. Refer to
CD52.
campath-1 (CD52) CAMPATH-1M
A rat immunoglobulin M (IgM) monoclonal antibody
against the CD52 antigen. It is able to lyse cells using
human complement, making no other manipulation necessary
to deplete T cells other than to add donor serum.
This antibody has been used to deplete T cells to prevent
MHC class I Calnexin
The folded molecule is exported
to the Golgi apparatus.
Calnexin.
Calnexin is bound to partially folded MHC class I.
Peptide approaches MHC class I.
MHC class I transports the bound
peptide to the surface of the cell.
graft-vs.-host disease. It is a lipid-anchored glycoprotein
with a very small peptide constituent. Anti-CD52 antibodies
are potent lytic agents, killing cells in vitro with human
complement as well as in vivo. These antibodies have been
used for therapy of leukemia, bone marrow transplantation,
organ transplantation, rheumatoid arthritis, vasculitis,
and multiple sclerosis. Campath-1H (human IgG 1) was the
first monoclonal antibody to be humanized. It was formed
by transplanting complementarity-determining regions of
campath-1G into human heavy and light chain genes. Even
though initial binding affinity was decreased, this was corrected
by modifying framework residues. Patients receiving
this humanized antibody developed very low antiglobulin
responses compared with the original rat antibodies. The
CD52 antigen is a glycoprotein with only 12 amino acids. It
is a complex carbohydrate consisting of sialylated polylactosamine
units with fucosylated mannose cores. It is
attached to Asn3 at the C terminus as a glycosylphosphatidylinositol
(GPI) anchor. The campath-1 epitope is comprised
of the C terminal amino acids and part of the GPI
anchor, which means that the antibodies bind near the cell
membrane, facilitating cell lysis. The antigen is expressed
abundantly on all lymphocytes except plasma cells and
also on monocytes, macrophages, and eosinophils. It is not
found on any other tissues except the male reproductive
tract, where it is strongly expressed on epithelial cells lining
the epididymis, vas deferens, and seminal vesicle. The
CD52 antigen is a principal membrane protein of sperm.
Campylobacter immunity
Circulating antibodies develop rapidly in patients with
Campylobacter enteritis. These antibodies fix complement,
are bactericidal, and agglutinate. Following an initial but
short-lived immunoglobulin M (IgM) response, a rapid
IgA response peaks 14 days after onset of symptoms but
declines by the fifth week. IgG antibodies appear by the
tenth day after infection and are present for several months.
Antibodies are believed to limit the infection. Serologic
tests for diagnosis depend on an acid-extractable surface
antigen that consists mainly of flagellin, which is the
C