Diponkar Banerjee

A unique subset of self-specific intraintestinal T cells maintains gut integrity.

Lymphocytes residing in the intestinal epithelium are exclusively T cells and account for one of the largest collection of T cells in the organism. However, their function remains obscure. We and others have shown that the development of intestinal intraepithelial T cells is compromised in mutant mice prone to chronic intestinal inflammation. These results led us to directly assess their role in regulating the development of colitis secondary to transfer of primary splenic TCRαβ+CD4+CD45RBhi T cells into severe combined immunodeficiency (SCID) mice. Here we demonstrate that prior reconstitution of SCID recipients with intraintestinal TCRαβ+CD4−CD8α+β− T cells prevents disease, and does so in an interleukin (IL)-10–dependent fashion. In contrast, reconstitution with either TCRγδ+ or TCRαβ+CD4− CD8α+β+ intestinal T cells did not prevent colitis. TCRαβ+CD4−8α+β− T cells are unique to the intestinal epithelium of both rodents and humans. Previous repertoire analyses of TCRαβ+CD4−CD8α+β− T cells revealed a high proportion of cells expressing high affinity, self-specific TCR within this subset. We demonstrate that monoclonal, self specific TCRαβ+CD4−CD8α+β− cells derived from TCR transgenic mice also prevent the onset of colitis. Thus, intestinal TCRαβ+CD4−CD8α+β− T cells, selected based on their self-reactivity, maintain gut integrity in a IL-10–dependent fashion.

Immunohistochemical localization of metallothionein in cell nucleus and cytoplasm of rat liver and kidney

Abstract Metallothionein (Mt) is a low molecular weight metalloprotein and its synthesis is induced by various divalent metals (Cd, Zn, Hg and Cu). The Intracellular distribution of Mt in hepatic and renal cells from control and CdCl2 injected rats was investigated by immunohistochemical methods. Antiserum to purified rat-liver Mt was prepared in rabbits after partial polymerization of the protein. The unlabelled peroxidase-antiperoxidase method using the specific rabbit anti-rat liver Mt provided a sensitive technique to localize Mt in tissue sections. In control rats, Mt or thionein (metal-free protein) was mainly localized in the cytoplasm of hepatocytes, renal collecting duct epithelium and distal convoluted tubular epithelium. In rats, injected intraperitoneally (i.p.) with CdCl2 (0.6 mg/kg) for 2 weeks, Mt was present mainly in the nuclei which were largely negative in control rats. Repeated injection with CdCl2 for 4–8 weeks resulted in the appearance of Mt in both the nucleus and cytoplasm. Intraluminal staining was also noted in proximal convoluted tubules along with marked vacuolation in the cytoplasm at 6 and 8 weeks. High intensity staining was observed in proximal convoluted tubules and collecting duct epithelium of the kidneys in CdCl2 injected rats. The bile duct epithelium in liver samples, renal glomerular mesangial cells, glomerular visceral epithelial cells and vascular smooth muscle cells showed weak to moderately intense staining. No staining was seen in vascular endothelial cells, fibroblasts or leukocytes. The staining for Mt in this technique was abolished when the antibody was absorbed with rat-liver Mt in vitro or by substitution of the antiserum with normal rabbit serum, demonstrating the specificity of the staining reaction for Mt. The results showed the presence of small amounts of Mt predominantly in the cytoplasm of control rat hepatocytes and renal tubular epithelium and its appearance in both the nucleus and cytoplasm after its synthesis induced by CdCl2 injections.

Changes in the intracellular accumulation and distribution of metallothionein in rat liver and kidney during postnatal development

Metallothionein (MT) bound to zinc and copper was detected in high concentration in fetal and newborn rat livers by a cadmium saturation method. The levels of both hepatic zinc and MT remained high for the first 14 days after birth and decreased to adult levels by 24 days of age. There was a direct linear relationship between hepatic metallothionein and zinc concentrations during the first 31 days after birth. The ratio of MT to zinc levels also decreased with age suggesting a rapid degradation of MT during postnatal development. Immunohistochemical localization of MT by peroxidase-antiperoxidase technique, using a specific antibody to MT, showed intense intranuclear staining for MT in fetal and newborn rat liver which persisted until Day 9. The nuclear MT staining decreased with age; at 11 days it was equal both in nucleus and cytoplasm and at 14 days, MT was localized mainly in the cytoplasm, similar to adult rat liver pattern. The intranuclear localization of MT in neonates could be considered as a typical fetal-neonatal morphological pattern and its subsequent presence in the cytoplasm, an adult pattern.

Immunohistochemical localization of metallothionein in cell nucleus and cytoplasm of fetal human liver and kidney and its changes during development.

&NA; The distribution of metallothionein (MT) during human development was investigated using both immunohistochemical and biochemical methods. The level of MT in the fetal liver was higher than the adult liver levels. Higher levels of zinc (Zn) and copper (Cu) were also detected in the fetal liver compared to the adult liver. Although cadmium (Cd) was present in detectable levels in the human adult liver, none was detected in the human fetal liver. MT was localized in the nucleus and the cytoplasm of human fetal and neonatal hepatocytes, using a specific rabbit antibody raised to rat liver MT. In the adult human liver cells, MT was localized mainly in the cytoplasm. In the fetal and neonatal human kidney, MT was localized mainly in the nucleus and the cytoplasm of the proximal tubular epithelial cells. In the adult kidney, in addition to nuclear‐cytoplasmic localization of MT, intraluminal localization was also observed.

Transferrin Receptors in the Human Gastrointestinal Tract Relationship to Body Iron Stores

Fluorescently labeled antibodies were used to identify transferrin receptors and mucosal transferrin in human gastrointestinal biopsy sections. Transferrin receptors were evident in the villous epithelium and the crypt areas of duodenum, ileum, and colon, predominantly in the basal-lateral area. In 7 subjects with low iron stores, the intensity of duodenal villous staining for receptor, on a scale of 0-4, was 2.1 +/- 0.3 (mean +/- SD). This value was significantly higher than the value in 13 subjects with normal iron stores (1.1 +/- 0.4). In 5 patients with hereditary hemochromatosis, duodenal transferrin receptor staining was not significantly different from that in the subjects with normal iron stores. Transferrin staining was found in the apical cytoplasm of epithelial cells in the duodenum, ileum, and colon, but observer assessment was not sufficiently reproducible to make a quantitative analysis. Our results suggest that iron deficiency is accompanied by an increase in transferrin receptors in duodenal absorptive cells, and the genetic lesion in hemochromatosis does not involve an increase in transferrin receptors in the intestinal mucosa compared with subjects with normal iron stores.

Metallothionein in testicular germ cell tumors and drug resistance: Clinical correlation

Background. Metallothioneins (MT) are endogenous metalloproteins involved in the homeostasis of essential metals and detoxification of toxic metals. Some recent experimental studies suggested tumor resistance to cisdiamminedichloroplatin may be associated with overexpression of MT in the tumor.

Intestinal inflammation observed in IL-2R/IL-2 mutant mice is associated with impaired intestinal T lymphopoiesis

BACKGROUND & AIMS Although interleukin (IL)-2(-/-) and IL-2Ralpha(-/-) mice develop inflammatory bowel disease, IL-2Rbeta(-/-) animals are apparently free of gut pathology. Intraintestinal T lymphopoiesis is reported to be impaired in IL-2Rbeta(-/-) mice; we have determined whether this characteristic correlated with the apparent resistance of this mutant strain to intestinal inflammation. This led us to reassess intraintestinal T lymphopoiesis in these 3 mutant strains. METHODS Intestinal histology and intraintestinal T lymphopoiesis were analyzed in unmanipulated mutant mice and in athymic and euthymic radiation chimeras reconstituted with bone marrow derived from IL-2(-/-), IL-2Ralpha(-/-), and IL-2Rbeta(-/-) donors. RESULTS Intraintestinal T lymphopoiesis was ablated in the 3 mutant strains and was associated with cryptopatch abnormalities. The intestinal mucosa of mice reconstituted with lymphocytes from IL-2Rbeta(-/-) mice exhibited lesions of both the small and large bowel similar to those observed in the early stages of human gluten enteropathy and acute ulcerative colitis, respectively. Analysis of euthymic and athymic bone marrow radiation chimeras indicated that T cells located in the intestinal mucosa of unmanipulated IL-2(-/-), IL-2Ralpha(-/-), and IL-2Rbeta(-/-) mice are of thymic origin. CONCLUSIONS Null mutations at IL-2/IL-2Ralpha and beta loci differentially affect intraintestinal and intrathymic T lymphopoiesis. These conditions are associated with lesions of intestinal inflammation that are mediated by thymus-derived T cells.

Malignant lymphoma complicating lymphocytic interstitial pneumonia: A monoclonal B-cell neoplasm arising in a polyclonal lymphoproliferative disorder

Cell surface-marker analysis and immunohistochemical tests were performed on lymph node cells from a patient with a malignant lymphoma that developed six years after the onset of lymphocytic interstitial pneumonia (LIP). These studies revealed a monoclonal (IgM-κ) B-cell neoplasm. However, immunohistochemical examination of the pulmonary lesion revealed a polyclonal B-cell proliferation. This case study suggests that LIP may be a polyclonal lymphocytic disorder even in patients who subsequently develop a monoclonal B cell neoplasm.

Effect of indomethacin plus ranitidine in advanced melanoma patients on high-dose interleukin-2

Preclinical models of advanced melanoma have shown that chronic indomethacin therapy combined with interleukin 2 (IL-2) can eradicate experimental metastases. A phase II trial was done in patients with advanced melanoma. Indomethacin and ranitidine were begun at least one week before IL-2. Of the objective responses in 3 patients, 2 were achieved on ranitidine and indomethacin alone, before start of IL-2. Indomethacin and ranitidine may be responsible for some responses in melanoma patients previously attributed to IL-2.

Primary gastric T-cell lymphoma of suppressor-cytotoxic (CD8+) phenotype: Discordant expression of T-cell receptor subunit βF1, CD7, and CD3 antigens

Primary gastric T-cell lymphomas are rare neoplasms, and all but one of the previously phenotyped cases have shown a helper-inducer phenotype. The present case is the second reported case of a primary gastric T-cell lymphoma of suppressor-cytotoxic phenotype. The tumor histology was similar to that described in some forms of node-based peripheral T-cell lymphomas. Phenotypic analysis revealed low expression of pan-T marker CD7, reduced expression of CD3, but higher density and frequency of expression of CD8 antigens that could be predicted on the basis of the pan-T markers. Natural killer cell (NK) related markers CD16, HNK-1 and NKH-1 were not expressed by the neoplastic cells. T-cell receptor (TCR) beta subunit expression was detected on fewer cells than would have been predicted on the basis of CD3 and CD8 expression, and TCR delta chain expression was undetectable.