56 research outputs found
Differential expression of 9-O-acetylated sialoglycoconjugates on leukemic blasts: a potential tool for long-term monitoring of children with acute lymphoblastic leukemia
Earlier studies have demonstrated overexpression of 9-O-acetylated sialoglycoconjugates (9-O-AcSGs) on lymphoblasts, concomitant with high titers of anti-9-O-AcSG antibodies in childhood acute lymphoblastic leukemia (ALL). Our aim was to evaluate the correlation between expression of different 9-O-AcSGs during chemotherapeutic treatment. Accordingly, expression of 9-O-AcSGs on lymphoblasts of ALL patients (n = 70) were longitudinally monitored for 6 years (1997-2002), using Achatinin-H, a 9-O-acetylated sialic acid (9-O-AcSA) binding lectin with preferential affinity for 9-O-AcSGs with terminal 9-O-AcSAα2→6GalNAc. Western blot analysis of patients (n = 30) showed that 3 ALL-specific 9-O-AcSGs (90, 120 and 135 kDa) were induced at presentation; all these bands disappeared after treatment in patients (n = 22) who had disease-free survival. The 90 kDa band persisted in 8 patients who subsequently relapsed with reexpression of the 120 kDa band. FACS analysis revealed that at presentation (n = 70) 90.1 ± 5.0% cells expressed 9-O-AcSGs, which decreased progressively with chemotherapy, remained <5% during clinical remission and reappeared in relapse (80 ± 10%, n = 18). Early clearance of 9-O-AcSG+ cells, during 4-8 weeks of treatment showed a good correlation with low risk of relapse. Sensitivity of detection of 9-O-AcSG+ cells was 0.1%. Numbers of both high- and low-affinity binding sites were maximum at presentation, decreased with treatment and increased again in clinical relapse. We propose that close monitoring of 90 and 120 kDa 9-O-AcSGs may serve as a reliable index for long-term management of childhood ALL and merits therapeutic consideration
Gastric adenocarcinoma in a patient re-infected with H. pylori after regression of MALT lymphoma with successful anti-H. pylori therapy and gastric resection: a case report
BACKGROUND: Helicobacter pylori (H. pylori) has been etiologically linked with primary gastric lymphoma (PGL) and gastric carcinoma (GC). There are a few reports of occurrence of both diseases in the same patient with H. pylori infection. CASE PRESENTATION: We report a patient with PGL in whom the tumor regressed after surgical resection combined with eradication of H. pylori infection. However, he developed GC on follow up; this was temporally associated with recrudescence / re-infection of H. pylori. This is perhaps first report of such occurrence. CONCLUSIONS: Possible cause and effect relationship between H. pylori infection and both PGL and GC is discussed. This case also documents a unique problem in management of PGL in tropical countries where re-infection with H. pylori is supposed to be high
Interaction of Leishmania parasites with dendritic cells and its functional consequences
Interaction between dendritic cells (DC) and T cells is essential for the generation of cell mediated immunity and
thus DC play a critical role in the initiation of immune responses against Leishmania parasites. Although macrophages
(Mf) are the major targets of all species of Leishmania, a number of studies demonstrated the infection of DC by
Leishmania. DC specific intracellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN), has been reported to be
the receptor for Leishmania amastigotes. The functional consequences in DC after Leishmania infections appear to
depend on species of Leishmania. Some species of Leishmania enhance the surface expression of co-stimulatory
molecules and CD40-ligand-induced IL-12 production in DC. On the other hand other species down-regulate costimulatory
molecules and inhibit IL-12 production. The intrinsic differences among Leishmania species with regard to
alteration of cell surface molecules and IL-12 production in DC may contribute to the healing and non-healing forms
of the disease
Present Status of Antileishmanial Vaccines
The term leishmaniasis refers collectively to various clinical syndromes that are caused by obligate intracellular protozoa of
the genus Leishmania. Approximately 350 million people in 8 countries are estimated to be threatened by the disease [1]. The
World Health Organization estimated that there are 12 million cases of all forms of leishmaniasis worldwide, with over 500,000
new cases of visceral disease occurring each year [1]. Most of the drugs commonly used to treat different forms of leishmaniasis
are toxic and have unacceptable side effects. Moreover, cases of drug resistant leishmaniasis are on the rise. Due to nonexistence
of effective vaccine to date, improved immunoprophylactic approaches still remain desirable to combat leishmaniasis.
Antileishmanial vaccines developed around the globe are discussed
Introduction of Bacterial Components in Postadsorbed Plasma During Adsorption With Staphylococcus aureus
In ritro plasma adsorption over either protein A-positive Staphylococcus aureus Cowan I (SAC) or
protein A-negative S. aureus Wood 46 (SAW) led to leaching of bacterial biomolecules in the
postadsorbed plasma. Presence of bacterial moieties was demonstrated in the postadsorbed plasma by
more than one method: (1) using radiolabeled bacteria for adsorption with plasma and detecting
radioactivity in the postadsorbed plasma, (2) gel filtration of pre- and post-adsorbed plasmas over
Sephadex C-200 column and detecting additional peak(s) in the postadsorbed plasma, and (3)
immunoelectrophoretic analysis of pre- and postadsorbed plasmas and their column fractions against
rabbit anti-SAC antisera and demonstrating new precipitin bands in postadsorbed plasmas. Using an
extracorporeal plasma adsorption procedure in mongrel dogs, with radiolabeled SAC as the adsorbent,
we have demonstrated the presence of radioactivity in both the adsorbed and filtered (0.2 wm) blood
entering into the body, and the adsorbed blood that passed out of the body to reenter into the
extracorporeal circuit. These data suggest that components of S. aureus origin enter into the host
circulation during both in virro and ex vivo plasma adsorption, although the exact nature of those
extracted staphylococcal components remains unknown. This observation is of much significance since
it can possibly help elucidate the mechanism of tumor regression observed following perfusion of
plasma over SAC or SAW, followed by its reinfusion to the host
Leishmania donovani Parasites Interact with g/dþ Human Peripheral Blood T Cells and Induce Susceptibility to NK Cell-Mediated Lysis
We recently reported that Leishmania donovani infect the human T-cell line in vitro. To examine whether
primary human T cells could be infected by this parasite, a direct interaction of the peripheral blood T cells
with L. donovani was examined. The percentage of g/dþ T cells was markedly increased when in vitro
generated normal human T-cell blasts were cultured with L. donovani amastigotes. About 30% of the g/dþ T
cells in the parasite exposed T-cell blasts expressed parasite antigens intracellularly without detectable
intracellular parasites. Parasite exposed T-cell blasts had a reduced surface expression of HLA-DR and were
lysed by the sorted CD56þ cells. In contrast, neither L. donovani amastigotes nor T-cell blasts exposed to heat
killed amastigotes and/or were sensitive to the NK cell-mediated lysis. Of interest is that about 10% CD3þ
peripheral blood T cells in two out of three Indian Kala-azar patients tested expressed intracellular L. donovani
antigen
Innate Immune Defense in Visceral Leishmaniasis: Cytokine Mediated Protective role by Allogeneic Effector Cell
Antileishmanial role of mouse splenic natural killer (NK) cell was studied in allogeneic condition. In vitro
data indicates that NK cells of allogeneic (C57BL/6, H2b) non-leishmania exposed mouse have strong
antileishmanial effect against Leishmania donovani infected BALB/c (H2d) macrophages. Physical contact
between the effector (NK cell) and the target cells (infected macrophages) is essential in this system
since; cell free supernatant generated after coculturing of effector cells with infected target cells fails to
elicit any antileishmanial effect. Although NK cells from allogeneic mouse are strongly attached to the
infected macrophages but unable to kill it in such interaction. The antileishmanial effect of allogeneic
NK cells is mediated by TNF-� and not by IFN-�. In vivo cellular therapy of established infection with NK
cells from non-leishmania exposed allogeneic mouse significantly reduces the total parasite burden in
the spleen of infected anima
IL-4 Alone without the Involvement of GM-CSF Transforms Human Peripheral Blood Monocytes to a CD1adim, CD83+ Myeloid Dendritic Cell Subset
Myeloid dendritic cells (DCs) are conventionally generated
by culturing human peripheral blood monocytes in the
presence of GM-CSF and IL-4. Here we report that IL-4
alone, in the absence of detectable endogenous GM-CSF,
transforms human peripheral blood monocytes to a
CD1adim DC subset that could be matured to CD83+
DCs. Absence of endogenous GM-CSF in IL-4-DC was
demonstrated by RT-PCR and flow cytometry. With the
exception of CD1a expression, surface marker, morphology
and phagocytic activity of these DCs (IL-4-DC) were
similar to myeloid DCs (GM-IL-4-DC) conventionally
generated in the presence of GM-CSF and IL-4.
Conventional GM-IL-4-DC produced less IL-12 compared with IL-4-DC after stimulation with anti-CD40 monoclonal
antibody, or LPS plus IFN-g, although the difference was
more prominent when LPS plus IFN-g was used as the
stimulus. The GM-IL-4-DC also induced less frequent IFN-
g+ T cells in a mixed leukocyte reaction (MLR) than that of
IL-4-DC. Yields of IL-4-DCs were marginally lower than
that of GM-IL-4-DCs. Our data indicate that peripheral
blood monocytes can be transformed to CD1a-deficient
myeloid DCs solely by IL-4, and these IL-4-DCs are likely
to induce a stronger Th1 response than conventional GMIL-
4-DC
Leishmania donovani Parasites Interact with g/dþ Human Peripheral Blood T Cells and Induce Susceptibility to NK Cell-Mediated Lysis
We recently reported that Leishmania donovani infect the human T-cell line in vitro. To examine whether
primary human T cells could be infected by this parasite, a direct interaction of the peripheral blood T cells
with L. donovani was examined. The percentage of g/dþ T cells was markedly increased when in vitro
generated normal human T-cell blasts were cultured with L. donovani amastigotes. About 30% of the g/dþ T
cells in the parasite exposed T-cell blasts expressed parasite antigens intracellularly without detectable
intracellular parasites. Parasite exposed T-cell blasts had a reduced surface expression of HLA-DR and were
lysed by the sorted CD56þ cells. In contrast, neither L. donovani amastigotes nor T-cell blasts exposed to heat
killed amastigotes and/or were sensitive to the NK cell-mediated lysis. Of interest is that about 10% CD3þ
peripheral blood T cells in two out of three Indian Kala-azar patients tested expressed intracellular L. donovani
antigens
Successful Therapy of Lethal Murine Visceral Leishmaniasis with Cystatin Involves Up-Regulation of Nitric Oxide and a Favorable T Cell Response1
The virulence of Leishmania donovani in mammals depends at least in part on cysteine proteases because they play a key role in
CD41 T cell differentiation. A 6-fold increase in NO production was observed with 0.5 mM chicken cystatin, a natural cysteine
protease inhibitor, in IFN-g-activated macrophages. In a 45-day BALB/c mouse model of visceral leishmaniasis, complete elimination
of spleen parasite burden was achieved by cystatin in synergistic activation with a suboptimal dose of IFN-g. In contrast
to the case with promastigotes, cystatin and IFN-ginhibited the growth of amastigotes in macrophages. Although in vitro cystatin
treatment of macrophages did not induce any NO generation, significantly enhanced amounts of NO were generated by macrophages
of cystatin-treated animals. Their splenocytes secreted soluble factors required for the induction of NO biosynthesis, and
the increased NO production was paralleled by a concomitant increase in antileishmanial activity. Moreover, splenocyte supernatants
treated with anti-IFN-g or anti-TNF-a Abs suppressed inducible NO generation, whereas i.v. administration of these
anticytokine Abs along with combined therapy reversed protection against infection. mRNA expression and flow cytometric
analysis of infected spleen cells suggested that cystatin and IFN-g treatment, in addition to greatly reducing parasite numbers, resulted in reduced levels of IL-4 but increased levels of IL-12 and inducible NO synthase. Not only was this treatment curative when administered 15 days postinfection, but it also imparted resistance to reinfection. These studies provide a promising alternative
for protection against leishmaniasis with a switch of CD41 differentiation from Th2 to Th1, indicative of long-term
resistance. The Journal of Immunology, 2001, 166: 4020–4028
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