Untitled - D Ank Unlimited

memory 489 mercury and immunity
disorders (e.g., diabetes mellitus). Clinically, it is a principal
cause of nephrotic syndrome in adults. The subepithelial
immune deposits are shown by immunofluorescence to contain
both immunoglobulins and complement. Proteinuria
persists in 70 to 90% of cases, and half of the patients
develop renal insufficiency over a period of years. A less
severe course appears in 10 to 30% of cases.
memory
The capacity of the adaptive immune system to respond
more rapidly, more effectively, and with greater magnitude
to a second (or subsequent) exposure to an immunogen
compared to its response to the primary exposure. Refer to
immunological memory.
memory B cells
Long-lived antigen-specific B cells generated during exposure
of naïve B lymphocytes to antigen in a primary immune
response. Subsequent exposure to the antigen for which they
are specific leads to reactivation and differentiation into
plasma cells as a secondary or subsequent immune response.
memory cells
Immunocompetent T and B lymphocytes generated during
a primary immune response. They have the ability to
mount an accentuated response to antigen, compared with
that of virgin immunocompetent cells, because of their
previous exposure to the antigen through immunization or
infection. Activated memory cells yield effector cells more
rapidly and with less costimulation than naïve lymphocytes.
Homing and chemokine receptors of memory cells direct
them to sites where they were first exposed to antigen.
Memory cells are responsible for immunological memory
and protective immunity.
memory lymphocytes
Lymphocytes of the B or T type that respond rapidly with an
enhanced memory or recall response to second or subsequent
exposure to an antigen to which they were primed previously.
Antigen stimulation of naïve lymphocytes leads to the production
of memory B and T cells that persist in a functionally
dormant state years following antigen elimination.
memory response
Refer to immunological memory.
memory T cells
Long-lived antigen-specific T lymphocytes that are activated
in secondary and subsequent immune responses to antigen
and respond in an immediate and exaggerated manner to
induce a heightened immune response to a specific antigen.
meningococcal D (Groups A,C,Y, and W-135)polysaccharide
diphtheria toxoid conjugate vaccine
Bactericidal anticapsular meningococcal antibodies are
associated with protection from invasive meningococci.
Meningococcal polysaccharide diphtheria toxoid conjugate
vaccine induces synthesis of bactericidal antibodies specific
for the capsular polysaccharides of serogroups A, C, Y, and
W-135. Immunogenicity and clinical efficacy of serogroups
A and C meningococcal vaccines are well established. The
serogroup A polysaccharide induces antibodies in children
as young as 3 months of age, although a response comparable
with that among adults is not achieved until 3 to 5 years
of age; the serogroup C component is weakly immunogenic
in recipients who are younger than 18 to 24 months of age.
The serogroups A and C vaccines have clinical efficacies of
85 to 100% in older children and adults and are used to control
epidemics. Serogroups Y and W-135 polysaccharides
are safe and immunogenic in adults and in children above
2 years of age. In the first 3 years following a single dose
of vaccine, the measurable levels of antibodies against
groups A and C polysaccharides decrease significantly. This
decrease in antibody occurs more rapidly in infants and
younger children than in adults. Vaccine-induced clinical
protection probably persists in school children and adults
for at least 3 years.
meningococcal vaccine
An immunizing preparation that contains bacterial
polysaccharides from certain types of meningococci.
Meningococcal polysaccharide vaccines A, C, Y, and
W-135 are available for preventing diseases induced by
those serogroups. There is no vaccine for meningococcal
serogroup B.
H
H
C C
H H
OH
2-mercaptoethanol agglutination test
A simple test to determine whether an agglutinating
antibody is of the immunoglobulin M (IgM) class. If treatment
of an antibody preparation such as a serum sample
with 2-mercaptoethanol can abolish the ability of the
serum to agglutinate cells, then agglutination was due to
IgM antibody. Agglutination induced by IgG antibody is
unaffected by 2-mercaptoethanol treatment and is just as
effective after the treatment as it was before. Dithiothreitol
(DTT) produces the same effect as 2-mercaptoethanol in
this test.
6-mercaptopurine (6-MP)
A powerful immunosuppressive drug used prior to the
introduction of cyclosporine in organ transplantation. It
is also an effective chemotherapeutic agent for the treatment
of acute leukemia of childhood and other neoplastic
conditions. 6-MP is a purine analog in which a thiol group
replaces the 6-hydroxyl group. Hypoxanthine–guanine
phosphoribosyl transferase (HGPRT) transforms 6-MP to
6-thioinosine-5′-phosphate. This reaction product blocks
various critical purine metabolic reactions. 6-MP is also
incorporated into DNA as thioguanine.
mercury and immunity
Mercury does not have any known physiologic function in
humans. This highly toxic metal affects enzyme function
and calcium ion channels. It is especially toxic for the
kidneys and the central nervous system and may affect
SH
2-Mercaptoethanol agglutination test.
N
SH
N
Structure of 6-mercaptopurine (6-MP).
N
N
H
M