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Biomedical subjects

D Nandi

Publications and source records attributed to D Nandi.

28 records · Page 2Linked to original sources
PubMed1995

The genetics of proteasomes and antigen processing.

The T cell arm of the immune system of higher vertebrates is specific for antigenic peptides bound to cell surface major histocompatibility complex (MHC) molecules. These peptides are derived from two distinct pathways of antigen processing. The class I, or endogenous pathway, utilizes proteasomes and the ubiquitin system for protein degradation, with subsequent transport of the resulting peptides into the lumen of the endoplasmic reticulum by a specific peptide transporter, called TAP. The expression of distinct proteasome subsets is regulated by the cytokine gamma interferon (IFN-gamma). The class II, or exogenous pathway, utilizes the endosomal and lysosomal pathways for protein degradation, and a number of immune-specific accessory molecules including the class-II associated Invariant chain (Ii) and MHC-encoded HLA-DM (H2-DM in mouse) molecules.

Animals↗
PubMed1994

CD28-mediated costimulation is necessary for optimal proliferation of murine NK cells.

CD28, a cell surface molecule expressed on all murine T cells, plays a critical role in T cell activation. We show here that NK-1.1+ cells, a subpopulation of SCID splenocytes, and IL-2-activated NK cells express CD28, although at lower levels than alpha beta T cells. Optimal proliferation of highly purified asialo GM1+ NK cells from the SCID spleen was observed in response to stimulation with IL-2 and PMA, together with anti-CD28 or L-B7+ cells. Thus, in addition to IL-2, murine NK cells require CD28-mediated costimulatory signals for optimal proliferation. IL-2-activated NK cells produced enhanced levels of IFN-gamma and TNF in response to stimulation with anti-CD28 and PMA. On the other hand, we were unable to demonstrate that CD28 signaling had any effect on NK-mediated cytotoxicity. We conclude that the CD28 costimulatory pathway is functional in NK cells and plays an important role in their proliferation and cytokine production.

Animals↗
PubMed1993

Intrathymic differentiation of V gamma 3 T cells.

Whereas there is considerable information on the phenotypic and functional maturation of T cell receptor (TCR) alpha/beta thymocytes, comparatively little is known of the maturational processes that affect development of TCR-gamma/delta thymocytes. One class of gamma/delta T cells, those bearing the V gamma 3 gene product, are generated only during the early fetal stages of thymic development, and then migrate to the skin. Here we examine the intrathymic differentiation of these V gamma 3+ cells. The earliest V gamma 3 cells to appear in the thymus expressed low levels of TCR (V gamma 3low) and high levels of heat stable antigen (HSA). Over the next few days, V gamma 3+ thymocytes appeared which expressed high levels of TCR (V gamma 3high) and very low levels of HSA. The antigens CD5, CD45RB, and MEL14 were also differentially expressed on V gamma 3low versus V gamma 3high thymocytes, but the shift in expression was the opposite as compared with immature and mature TCR-alpha/beta thymocytes. Transfer experiments of sorted V gamma 3low/HSAhigh thymocytes to SCID thymic lobes showed that these cells were indeed the precursors of V gamma 3high/HSAlow thymocytes. The phenotype of the V gamma 3high thymocytes was similar to that of the postthymic V gamma 3+ cells found in the skin of adult mice. The differentiation of V gamma 3low in V gamma 3high thymocytes was also observed in fetal thymic organ culture. Addition of cyclosporin A (CsA) to these cultures had little effect on the appearance of V gamma 3low/HSAhigh cells, but blocked the appearance of V gamma 3high/HSAlow cells. These results show that, like alpha/beta T cells, V gamma 3+ thymocytes differentiate from TCRlow precursors to cells with a mature phenotype and that CsA inhibits this transition.

Animals↗
PubMed1992

Effect of pregnancy associated hypertension on immunoglobulin levels in newborns.

In a prospective study of 124 neonates born to mothers with normal pregnancy and pregnancy associated hypertension (PAH), serum IgG, IgA and IgM were estimated by single radial immunodiffusion technique. Significantly low levels of IgG were found in mothers having PAH, as compared to normal pregnancy (p less than 0.001), whereas IgA and IgM showed no difference in the two groups. There was no statistical difference in maternal and cord blood IgG in either the control or study group. IgG was significantly higher (p less than 0.001) in cord blood of babies born by vaginal route as compared to forceps (via vaginal route) or cesarean section. IgA and IgM levels did not vary with mode of delivery.

Adult↗
PubMed1991

Phenotypic analysis and gamma delta-T cell receptor repertoire of murine T cells associated with the vaginal epithelium.

T cells expressing alpha beta- and gamma delta-TCR are associated with the murine vaginal epithelium. A combination of phenotypic analysis of cell surface Ag and molecular analysis of the gamma- and delta-genes was used to demonstrate that vaginal gamma delta-T cells have several features that distinguish them from gamma delta-T cells present in other tissues. Three color flow cytofluorometric analysis demonstrated that freshly isolated vaginal gamma delta-T cells are CD4-CD8- and their expression of Thy-1 is strain dependent. Furthermore, specific differences in CD5, CD28, and p55IL-2 receptor expression were found between alpha beta- and gamma delta-T cells isolated from vaginal tissue. The vaginal gamma delta-T cells are predominantly CD45+, pgp-1+, HSA-, Ly-6C-, and MEL-14-. Both alpha beta- and gamma delta-T cells were absent in vaginal tissue from nude mice, although Thy-1-positive cells are present. It was also demonstrated that V gamma 4 and V delta 1 are the only gamma- and delta-genes that are expressed by vaginal cells. Sequence analysis of their junctions revealed that they express the V gamma 4 and V delta 1 sequences also found in fetal thymocytes. Furthermore, the V delta 1 sequence is identical in the vaginal cells and the gamma delta-T cells from the epidermal epithelium. We conclude that the vagina, like the skin, is a site where gamma delta-T cells with an invariant TCR exist.

Animals↗
PubMed1991

Gamma delta T cells in murine epithelia: origin, repertoire, and function.

The earliest TCR+ cells to appear during fetal development express products of the gamma and delta loci, and emerge as successive waves of cells bearing different V gamma gene products. These appear to emigrate and seed different epithelia. The TCR repertoire of the first two of these waves, V gamma 3 and V gamma 4, respectively, is extremely restricted. Whether the repertoire of these cells is restricted by selective processes or is shaped by developmental restrictions on rearrangements remains to be determined. These cells may function in surveillance for signals of trauma by recognizing self products induced by cellular stress.

Animals↗
PubMedDate not supplied

Effect of human chorionic gonadotrophin coadministration on the activities of ovarian Delta5-3beta-hydroxysteroid dehydrogenase, and 17beta-hydroxysteroid dehydrogenase, and ovarian and uterine histology in lithium chloride-treated albino rats.

Lithium chloride, a compound with clinical use in bipolar disorder, produces adverse effects on ovarian function in amphibian and rodent models. This study examined the effect of human chorionic gonadotrophin coadministration on ovarian steroidogenic and gametogenic activities in lithium chloride-treated rats. Relative ovarian and uterine weights, ovarian Delta(5)-3beta-hydroxysteroid dehydrogenase and 17beta-hydroxysteroid dehydrogenase activities, folliculogenesis, uterine diameter, endometrial and myometrial thickness, and uterine luminal epithelial height were decreased significantly after lithium chloride treatment for 28 days at 1.6 mg/kg/day, the human therapeutic dose. These parameters were unchanged from the control level when subcutaneous (s.c.) human chorionic gonadotrophin (hCG) at 25 microg/kg/day was coadministered with the lithium chloride. The duration of the oestrous cycle was increased in lithium chloride-treated rat with longer metestrous and diestrous phases. Administration of hCG with lithium chloride prevented these estrous cycle alterations. We conclude that hCG can protect ovarian steroidogenic and gametogenic function after lithium chloride treatment.

17-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Characterization of neutrophils and T lymphocytes associated with the murine vaginal epithelium.

The murine vaginal epithelium was investigated as a site for the presence of leukocytes, using monoclonal antibodies to various cell surface antigens in conjunction with multiparameter flow cytometry. Two types of CD45+ leukocytes were found with distinct expression of Mac-1 and CD3. The Mac-1+ cells are neutrophils, as evidenced by their multilobed nuclei. Previously, we have shown that alpha beta T cells, gamma delta T cells, and a novel population of Thy-1+CD3- cells are associated with the vaginal epithelium. In addition, a small number of MHC class II+ cells were detected. B cells, macrophages, and natural killer cells were not detected and do not contribute to the cellular immunity of the vagina. It is known that the lumen of the murine vagina is lined with stratified squamous epithelium, which undergoes marked changes during the estrous cycle. The cellular number and composition of dissociated epithelial associated Mac-1+ cells, alpha beta T cells, gamma delta T cells, and Thy-1+CD3- cells did not change significantly during the estrous cycle or under the influence of the ovarian hormones 17 beta-estradiol and progesterone. In summary, this study characterizes the leukocytes involved in mucosal immunity of the murine vagina.

Animals↗
PubMedDate not supplied

Hydropneumothorax secondary to hydatid lung disease.

A case of pulmonary hydatid disease which ruptured to produce a hydropneumothorax is reported. Radiologically the patient presented with an oval opacity which enlarged with an appearance of air crescent. Diagnosis was established by cytological examination of aspirated pleural fluid and an histopathological examination of tissue found in the drainage tube. The patient was managed conservatively with intercostal drainage, albendazole therapy and other supportive measures.

Echinococcosis, Pulmonary↗