Treatment-associated severe thrombocytopenia affects survival rate in esophageal cancer patients undergoing concurrent chemoradiotherapy.

BACKGROUND: Esophageal cancer is commonly treated with surgery, concurrent chemoradiotherapy (CCRT), or a combination of both. The correlation between the hematological parameters during CCRT and early survival of esophageal cancer has not been fully evaluated. MATERIALS AND METHODS: We analyzed the records of 65 esophageal cancer patients treated by CCRT between 2007 and 2010 retrospectively. The association between CCRT-associated myelosuppression, demographic variables, and survival rates were analyzed by univariate and multivariate analysis. RESULTS: The univariate analysis showed that tumor extent of T3-4, a higher stage of tumor, a lower albumin level, grade 3 or higher anemia and thrombocytopenia, and interruptions in treatment affected survival rates. Further, the multivariate analysis revealed that stage IV (P = 0.030) is an independently negative prognostic factor for a one-year survival rate. Stage IV (P = 0.035), tumor extent of T3-4 (P = 0.002), and grade 3-4 thrombocytopenia (P = 0.015) are independently negative prognostic factors for a two-year survival rate. CONCLUSIONS: Severe decrease in platelet count during CCRT independently affects survival of esophageal cancer patients in addition to stage of the tumor.

Ginkgo biloba extract enhances noncontact erection in rats: the role of dopamine in the paraventricular nucleus and the mesolimbic system.

Penile erection is essential for successful copulation in males. Dopaminergic projections from the paraventricular nucleus (PVN) to the ventral tegmental area (VTA) and from the VTA to the nucleus accumbens (NAc) are thought to exert a facilitatory effect on penile erection. Our previous study showed that treatment with an extract of Ginkgo biloba leaves (EGb 761) enhances noncontact erection (NCE) in male rats. However, the relationship between NCE and dopaminergic activity in the PVN, VTA, and NAc remains unknown. The present study examined the relationship between NCE and central dopaminergic activity following EGb 761 treatment. We report here that, in comparison with the controls, there was a significant increase in the number of NCEs in rats after treatment with 50 mg/kg of EGb 761 for 14 days. EGb 761-treated rats also showed more NCEs than the same group before EGb 761 treatment. A significant increase in the expression of catecholaminergic neurons in the PVN and the VTA was seen by means of tyrosine hydroxylase immunohistochemistry, and tissue levels of dopamine and 3,4-dihydroxyphenylacetic acid in the NAc were also markedly increased in the EGb 761-treated animals. However, the norepinephrine tissue levels in the PVN and the NAc in the EGb 761-treated group were not significantly different from those in the controls. Together, these results suggest that administration of EGb 761 increases dopaminergic activity in the PVN and the mesolimbic system to facilitate NCE in male rats.

Long-term survival after surgery for stage III-IV maxillary sinus carcinoma.

OBJECTIVES: How to optimally treat maxillary sinus carcinoma is subject to debate. This study assessed how clinical features and treatment modalities corresponded with long-term survival. METHODS: Sixty-five patients at our institution were diagnosed with maxillary sinus carcinoma from 1982 to 2003. The median follow-up time was 92.9 months. We evaluated the prognostic value of age, gender, symptoms at presentation, histological classification, tumour stage, and treatment modality with regard to overall survival. RESULTS: The five-year survival rate was 52%. Age (p = 0.03), TNM stage (p = 0.04), T classification (p = 0.04), nodal involvement (p = 0.03), and surgery (p = 0.04) were significant prognostic factors for overall survival. There was a significant difference in the overall survival rate and months of survival between patients who underwent surgery and those who had nonsurgical treatment (p = 0.04). In patients with T3 disease, patients who received en bloc surgery had a higher overall survival than patients who received piecemeal surgery (p = 0.045). Multivariate analysis revealed that T classification was the most powerful prognostic factor for overall survival (p = 0.026), followed by nodal involvement (p = 0.036). Surgery was a marginally significant prognostic factor (p = 0.066). CONCLUSIONS: Although multivariate analysis showed that T classification and nodal involvement corresponded more with survival than did surgery, we conclude that adequate surgical removal should be an integral component of multimodal treatment.

Signal transduction pathways of nitric oxide release in primary microglial culture challenged with gram-positive bacterial constituent, lipoteichoic acid.

Between one-third and one-half of all cases of sepsis are known to be caused by gram-positive microorganisms through the cell wall component, e.g. lipoteichoic acid (LTA). Gram-positive bacteria are also known to induce encephalomyelitis and meningeal inflammation, and enhance the production of nitric oxide (NO) via expression of inducible nitric oxide synthase (iNOS) in murine tissue macrophages. It remains to be explored if LTA could activate microglia considered to be resident brain macrophages. We report here that LTA derived from gram-positive bacteria (Staphylococcus aureus) significantly induces NO release and iNOS expression in primary microglia. LTA-induced NO accumulation was detected at 2 h in microglial culture and was significantly attenuated by pretreatment with anti-CD14, complement receptor type 3 (CR3) or scavenger receptor (SR) antibodies. LTA activated mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase, p38 MAPK or c-Jun N-terminal kinase in cultured microglia. LTA-elicited microglial NO production was also drastically suppressed by SB203580 (p38 MAPK inhibitor) or pyrrolidine dithiocarbamate (an inhibitor of nuclear factor kappaB), indicating that p38 MAPK and nuclear factor kappaB were involved in microglial NO release after LTA challenge. These results suggest that gram-positive bacterial product such as LTA can activate microglia to release NO via the signal transduction pathway involving multiple LTA receptors (e.g. CD14, CR3 or SR), p38 MAPK and nuclear factor kappaB. The in vivo study further confirmed that administered intracerebrally LTA induced considerable noticeable iNOS, phospho-IkappaB and phospho-p38 MAPK expression in microglia/macrophages.

Production of multiple cytokines and induction of cachexia in athymic nude mice by a new anaplastic thyroid carcinoma cell line.

An anaplastic thyroid cancer cell line, Thena, was recently established in our laboratory following radical thyroidectomy of a patient with anaplastic thyroid cancer. Microscopically, Thena cells were spindle-shaped or small round cells. Thena cells were reactive with cytokeratin AE1/AE3 antibodies, epithelial membrane antigen, interleukin (IL)-6, epithelial growth factor receptor, transforming growth factor (TGF)-alpha, vascular endothelial growth factor, and vimentin. Thena cells secreted high levels of IL-6, leukemia inhibitor factor (LIF), tumor necrosis factor (TNF)-alpha, and TGF-beta1 in the culture supernatants, as determined by enzyme-linked immunosorbent assay. When subcutaneously injected with Thena cells, athymic nude mice developed tumor masses in the skin within 2 weeks. Furthermore, Thena cells induced cachexia in these tumor-bearing mice. High levels of human IL-6, LIF and TGF-beta1 were detected in the mouse sera. To our knowledge, the Thena cell line is the first thyroid cancer cell line reported to induce cachexia in nude mice. This cachectic animal model is worthy of further study to explore the treatment of thyroid cancer-induced cachexia.

Gender discrepancy observed between chemotherapy-induced emesis and hiccups.

The aim of this paper was to describe striking gender differences observed between emesis and hiccups in patients receiving cisplatin-based chemotherapy (CT) and one of two dexamethasone-containing anti-emetic regimens. Four hundred patients were evaluated in a crossover study with two arms. Patients in arm A received three doses of ondansetron 8 mg i.v. at 4-h intervals plus dexamethasone 20 mg i.v. from the start of CT, followed by dexamethasone 5 mg i.v. every 12 h, until CT was complete, after which dexamethasone was discontinued. For patients in arm B the treatment was the same as in arm A except that the three doses of ondansetron 8 mg i.v. were given at 24-h intervals. There were 363 patients in arm A and 358 patients in arm B. Vomiting/nausea/hiccups were observed in 30.3%/41.6%/23.7% of patients in arm A and 28.8%/39.1%/23.7% of patients in arm B, respectively. Comparison showed that the rates for complete control of vomiting and nausea on days 1 through 6 were significantly lower in women (P<0.0001 and =0.0004 in arm A and P<0.0001 and <0.0001 in arm B, respectively). Men had a significantly higher incidence of hiccups (P<0.0001 in both arms), but no apparent associations with age, cisplatin dose, tumor type, and the presence of vomiting and nausea during CT were found. Hiccups usually began 24 h after cisplatin administration and persisted for some days. Women had significantly higher rates of vomiting and nausea. The cause of the gender discrepancy is unknown.

Dietary iron induces rapid changes in rat intestinal divalent metal transporter expression.

The divalent metal transporter (DMT1, also known as NRAMP2 or DCT1) is the likely target for regulation of intestinal iron absorption by iron stores. We investigated changes in intestinal DMT1 expression after a bolus of dietary iron in iron-deficient Belgrade rats homozygous for the DMT1 G185R mutation (b/b) and phenotypically normal heterozygous littermates (+/b). Immunofluorescent staining with anti-DMT1 antisera showed that DMT1 was located in the brush-border membrane. Duodenal DMT1 mRNA and protein levels were six- and twofold higher, respectively, in b/b rats than in +/b rats. At 1.5 h after dietary iron intake in +/b and b/b rats, DMT1 was internalized into cytoplasmic vesicles. At 1.5 and 3 h after iron intake in +/b and b/b rats, there was a rapid decrease of DMT1 mRNA and a transient increase of DMT1 protein. The decrease of DMT1 mRNA was specific, because ferritin mRNA was unchanged. After iron intake, an increase in ferritin protein and decrease in iron-regulatory protein binding activity occurred, reflecting elevated intracellular iron pools. Thus intestinal DMT1 rapidly responds to dietary iron in both +/b and b/b rats. The internalization of DMT1 may be an acute regulatory mechanism to limit iron uptake. In addition, the results suggest that in the Belgrade rat DMT1 with the G185R mutation is not an absolute block to iron.

Regulation of E-selectin expression in postischemic intestinal microvasculature.

Monolayers of cultured endothelial cells exposed to hypoxia-reoxygenation exhibit a transcription-dependent increase in E-selectin expression and E-selectin-dependent neutrophil-endothelial cell adhesion. The overall objectives of this study were 1) to determine whether ischemia-reperfusion (I/R) promotes upregulation of E-selectin in vivo; 2) if so, to define the mediators of this response; and 3) to assess the contribution of E-selectin to I/R-induced neutrophil recruitment. The dual-radiolabeled monoclonal antibody (MAb) technique was used to measure E-selectin expression in the intestinal vasculature. Ischemia was induced by complete occlusion (30-60 min) of the superior mesenteric artery followed by 3-24 h of reperfusion. Increasing durations of ischemia elicited progressively increasing (2- to 5-fold) levels of E-selectin expression, with the peak response noted after 45 min of ischemia and 5 h of reperfusion. Subsequent experiments revealed that I/R-induced increase in E-selectin expression (at 5 h) is significantly blunted in transgenic mice that overexpress Cu,Zn-superoxide dismutase or by treatment of wild-type mice with either a blocking antibody against tumor necrosis factor (TNF)-alpha or an inhibitor of nuclear factor-kappaB (NF-kappaB) activation (PS341). Administration of an E-selectin-specific MAb dramatically reduced I/R-induced recruitment of neutrophils in the intestine. These findings suggest that superoxide and TNF-alpha mediate gut I/R-induced E-selectin expression via an NF-kappaB-dependent mechanism; this upregulation of E-selectin contributes significantly to I/R-induced neutrophil recruitment.

Rapid activation of NF-kappaB and AP-1 and target gene expression in postischemic rat intestine.

BACKGROUND & AIMS: The molecular mechanisms underlying intestinal mucosal damage-repair processes induced by ischemia-reperfusion (IR) remain unknown. We determined nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) activities and the expression of potential target genes relevant to damage-repair events. METHODS: Rat jejunal segment was subjected to ischemia for 30 minutes followed by reperfusion for defined times. NF-kappaB and AP-1 activities; mucosal p105, p50, and inhibitor kappaB-alpha (IkappaB-alpha) levels; and c-fos, neurotensin, and ferritin H expression were determined by electrophoretic mobility shift assay and Western and Northern analyses, respectively. RESULTS: NF-kappaB and AP-1 activities were significantly elevated from 1 to 12 hours after reperfusion. The activated NF-kappaB in the nuclear extract consisted of solely p50 homodimers. Activation of p50 was associated with a decrease of p105, generation of p50, and increased phosphorylation and degradation of IkappaB-alpha. The activated AP-1 contained c-fos but not c-jun, fosB, and Fra-1. Reperfusion induced a transient elevation of c-fos, prolonged increase of neurotensin, and early reduction followed by recovery of ferritin H messenger RNA. CONCLUSIONS: The intestine shows organ-specific responses to IR, characterized by prolonged NF-kappaB and AP-1 activation involving NF-kappaB p50 dimers and excluding AP-1 c-jun protein. Degradation of the IkappaB-gamma component of p105 and partial reduction IkappaB-alpha selectively activate p50/p50 dimers. Temporal patterns of target gene expression reflect functional relevance to mucosal damage-repair processes after IR.

Glucocorticoids and dietary iron regulate postnatal intestinal heavy and light ferritin expression in rats.

To cope with increasing dietary iron exposure, the intestinal epithelium of weaning rats must control intracellular labile iron pools. Intestinal expression of heavy (H) and light (L) ferritin subunits during early weaning and after cortisone administration and/or iron feeding was investigated. Changes in H and L ferritin gene expression were determined by nuclear runoff transcriptional assay, Northern blot analysis, and metabolic labeling of protein synthesis. H ferritin mRNA levels did not change between days 12 and 15, doubled on day 18, and tripled on day 24. L ferritin mRNA was reduced by 50% on days 18 and 24. The protein level of the H and L subunits paralleled the change in mRNAs. Cortisone treatment on day 12 induced a precocious increase of H and decrease of L mRNA expression on day 15. Nuclear runoff assays showed that cortisone did not change H and reduced L ferritin gene transcription. The increased level of H mRNA by cortisone was not translated, unless the rats were fed an iron-fortified diet, which reduced iron regulatory protein activity and stimulated a three- to sixfold increase of ferritin synthesis. Thus changes in intestinal H and L ferritin expression in weaning rats are modulated by glucocorticoids and iron; the former stabilizes H mRNA and suppresses L ferritin gene transcription, and the latter derepresses translation of ferritin mRNA.

Expression of intestinal brush-border membrane hydrolases and ferritin after segmental ischemia-reperfusion in rats.

Jejunal expression of three brush-border membrane (BBM) enzymes, intestinal alkaline phosphatase (IAP), lactose-phlorizin hydrolase (LPH), and sucrase-isomaltase (SI), and a cytosolic protein, ferritin (Ft), was investigated after transient segmental ischemia-reperfusion (I/R). I/R reduced mucosal IAP, LPH, and SI mRNAs to 36%, 11%, and 38% of normal jejunal levels after 3 h of reperfusion and to 22%, 8%, and 51% of normal jejunal levels after 6 h of reperfusion, respectively. Intriguingly, in the internal control jejunum IAP and LPH mRNAs also decreased significantly. LPH and SI mRNA rapidly recovered to levels significantly higher than those of normal jejunum at 12 h, whereas IAP mRNA levels did not recover until 48 h. Enzyme activity paralleled changes in mRNA levels in the ischemic reperfused jejunum. Electrophoretic mobility shift assays showed that I/R significantly increased SI footprinting 1 (SIF1) binding activity. The mobility of one of the DNA-protein complexes was further retarded in the presence of anti-Cdx-2 antibody, suggesting that either Cdx-2 or a related protein was interacting with the SIF1 sequences. Similar to BBM enzymes, cytosolic Ft mRNA and protein were significantly decreased at 3 and 6 h after I/R. By 12 h, Ft mRNA, but not Ft protein, had increased to higher than normal levels. We conclude that a rapid recovery of BBM mRNAs and enzymes occurs in regenerating mucosa after upper villus damage. The increase of SIF1 binding protein activity after I/R may enhance SI, and perhaps LPH, gene transcription. The expression of Ft is regulated at both pretranslational and translational levels.

IL-3-mediated enhancement of particulate antigen presentation by macrophages.

Mice were exposed to interleukin- (IL-) 3 in vivo by injection of tumor cells transfected with the IL-3 gene. At 10 days post tumor injection, bone marrow cells were recovered, pulsed with particulate antigen in the form of ovalbumin (Ova)-coated magnetic beads, and tested for their ability to present antigen via class I to an Ova/class I-restricted T cell hybridoma. Cells from IL-3-stimulated mice exhibited a marked increase in antigen presentation compared with cells from mice injected with control non-cytokine-secreting tumor cells. These cells were markedly more efficient at presenting particulate Ova antigen than in presenting soluble Ova. Based on adherence, radiation resistance, and surface markers, the cells presenting antigen appear to be in the macrophage cell lineage. These cells are susceptible to lysis by antigen-specific cytotoxic T lymphocytes, which may contribute to limiting the effectiveness of antitumor responses.

IL-3 enhances both presentation of exogenous particulate antigen in association with class I major histocompatibility antigen and generation of primary tumor-specific cytolytic T lymphocytes.

Recent studies have reported that APC can present particulate exogenous Ag in the context of class I MHC to CD8+ CTL, and our laboratory demonstrated that IL-3 could enhance CTL generation to exogenous Ag. In this paper, we wished to determine whether presentation of particulate Ag could be enhanced by IL-3. A T cell hybridoma, B3Z86/90.14 (B3Z) restricted to Ova/Kb, was used as an indicator for presentation of particulate Ag with class I MHC. When activated, this hybridoma expresses lacZ, allowing a simple colorimetric measurement of Ag-specific T cell stimulation. We demonstrated that bone marrow cells stimulated by IL-3 in vivo and in vitro exhibited significantly increased presentation of exogenous OVA linked to beads. Lysate from OVA-transfected line 1 murine lung adenocarcinoma cells (line 1/OVA) was also presented by IL-3-stimulated bone marrow cells, suggesting that these APC can process tumor fragments or debris. Studies using TAP1/2-deficient mice and Ag presentation inhibitors indicate that this exogenous Ag presentation is mediated via the conventional class I MHC pathway. Adoptive transfer of IL-3-stimulated bone marrow cells pulsed with lysate from line 1/OVA tumor cells into naive recipient mice led to the generation of a potent CTL response. These observations indicate that use of such cells may provide a new avenue for development of tumor vaccines.

Mother-to-infant transmission of GB virus C/hepatitis G virus: the role of high-titered maternal viremia and mode of delivery.

To study mother-to-infant transmission of GB virus C/hepatitis G virus (GBV-C/HGV), blood samples of infants born to carrier mothers were collected beginning 3 months after birth and were tested for GBV-C/HGV RNA until 1 year of age. Of 2046 mothers, 2.1% were positive for GBV-C/HGV RNA, and 25 of their infants were followed for a median of 12 months. Thirteen infants (52%) were viremic, and infection became persistent in all. Maternal GBV-C/HGV RNA levels of this group were >10(7) copies/mL. Nucleotide sequence comparison in 5 viremic mother-infant pairs revealed a homology of 93%-98.2%, and none delivered by elective cesarean section. In comparison, of the 12 uninfected infants' mothers, 10 had lower GBV-C/HGV RNA levels (mean, 5 x 10(4) copies/mL), and the remaining 2 high-titered mothers had elective cesarean section. Thus, high-titered maternal viremia and mode of delivery are closely associated with the mother-to-infant transmission of GBV-C/HGV to infants, and the infection usually becomes persistent.

Expression of B7-1 by Pam 212 squamous cell carcinoma enhances tumor cell interactions with dendritic epidermal cells but does not affect in vivo tumor growth.

Direct antigen presentation of tumor-associated antigens by tumor cells to T lymphocytes may induce clonal anergy as a mechanism of escape from immune surveillance. B7-1 is a costimulatory molecule for the activation of both CD4+ and CD8+ T lymphocytes that prevents the induction of clonal anergy. Thus, the transfer of B7-1 genes into tumor cells can induce protective immunity and lead to tumor rejection of some tumors in model systems of in vivo tumor growth; however, there is no information on whether stable expression of B7-1 can affect the in vivo growth of squamous cell carcinoma, a common skin cancer. Here, we study how the stable cell surface expression of high levels of B7-1 by Pam 212, a murine squamous cell carcinoma, affects tumor cell-lymphocyte interactions (lymphocyte proliferation and cytotoxicity). Consistent with its costimulatory role, we demonstrate that B7-1 can efficiently induce dendritic epidermal T-cell proliferation in three different dendritic epidermal T-cell cell lines. In addition, B7-1 enhances dendritic epidermal T-cell cytolytic activity against Pam 212 cells in an in vitro 51Cr-release assay, which was blocked by CTLA-4/Ig fusion protein. In contrast to dendritic epidermal T cells, the expression of B7-1 does not alter Pam 212 interactions with either cytotoxic T-lymphocytes, natural killer, or lymphokine-activated killer cells. B7-1 expression by Pam 212 cells did not alter its ability to grow tumors in vivo, as their rate of tumor growth was the same as vector-transfected Pam 212 cells, which were B7-1 negative. Our studies indicate that B7-1 gene transfer into Pam 212 does not alter its tumorigenicity, because it does not alter tumor cell-lymphocyte interactions with cytotoxic T lymphocytes, natural killer cells, and lymphokine-activated killer cells. Further studies of B7-1 modified Pam 212 and dendritic epidermal T cells will clarify whether T-cell receptor-gamma/delta-bearing T lymphocytes can play a role in immunotherapy of Pam 212 squamous cell carcinoma.

Expression of human prostate-specific antigen (PSA) in a mouse tumor cell line reduces tumorigenicity and elicits PSA-specific cytotoxic T lymphocytes.

Human prostate-specific antigen (PSA) has a highly restricted tissue distribution. Its expression is essentially limited to the epithelial cells of the prostate gland. Moreover, it continues to be synthesized by prostate carcinoma cells. This makes PSA an attractive candidate for use as a target antigen in the immunotherapy of prostate cancer. As a first step in characterizing the specific immune response to PSA and its potential use as a tumor-rejection antigen, we have incorporated PSA into a well-established mouse tumor model. Line 1, a mouse lung carcinoma, and P815, a mouse mastocytoma, have been transfected with the cDNA for human PSA. Immunization with a PSA-expressing tumor cell line demonstrated a memory response to PSA which protected against subsequent challenge with PSA-expressing, but not wild-type, tumors. Tumor-infiltrating lymphocytes could be isolated from PSA-expressing tumors grown in naive hosts and were specifically cytotoxic against a syngeneic cell line that expressed PSA. Immunization with tumor cells resulted in the generation of primary and memory cytotoxic T lymphocytes (CTL) specific for PSA. The isolation of PSA-specific CTL clones from immunized animals further demonstrated that PSA can serve as a target antigen for antitumor CTL. The immunogenicity studies carried out in this mouse tumor model provide a rationale for the design of methods to elicit PSA-specific cell-mediated immunity in humans.

Interleukin 3 enhances cytotoxic T lymphocyte development and class I major histocompatibility complex "re-presentation" of exogenous antigen by tumor-infiltrating antigen-presenting cells.

We show that interleukin 3 (IL-3) enhances the generation of tumor-specific cytotoxic T lymphocytes (CTLs) through the stimulation of host antigen-presenting cells (APCs). The BALB/c (H-2d) spontaneous lung carcinoma line 1 was modified by gene transfection to express ovalbumin as a nominal "tumor antigen" and to secrete IL-3, a cytokine enhancing myeloid development. IL-3-transfected tumor cells are less tumorigenic than the parental cell line, and tumor-infiltrating lymphocytes isolated from these tumors contain increased numbers of tumor-specific CTLs. By using B3Z86/90.14 (B3Z), a unique T-cell hybridoma system restricted to ovalbumin/H-2b and implanting the tumors in (BALB/c x C57BL/6)F1 (H-2d/b) mice, we demonstrate that the IL-3-transfected tumors contain an increased number of a rare population of host cells that can process and "re-present" tumor antigen to CTLs. Electron microscopy allowed direct visualization of these host APCs, and these studies, along with surface marker phenotyping, indicate that these APCs are macrophage-like. The identification of these cells and their enhancement by IL-3 offers a new opportunity for tumor immunotherapy.

Rat intestinal and hepatic ferritin subunit expression during development and after dietary iron feeding.

Ferritin consists of 24 heavy (H) and light (L) subunits in varying proportions in different tissues and plays a significant role in iron metabolism. We studied rat ferritin subunit expression in the duodenum and liver during early life, when a cycle of iron depletion and repletion occurs. In both tissues, ferritin contents decreased to low levels from day 3 to day 12. The ferritin on day 3 had an H/L mRNA ration of 0.9 and an H/L subunit ratio of 0.6. The decrease of tissue ferritin levels, but not mRNA, on day 12 suggests translational repression consistent with iron depletion. In the duodenum, a twofold increase in both H and mRNA and subunit protein occurred on day 18. The subsequent increase of H mRNA was accompanied by a 50% decrease in L mRNA, resulting in the increase of H/L mRNA and subunit ratios to 7.9 and 9, respectively, by day 32. In contrast, liver H/L mRNA and subunit ratios were similar throughout development. The possibility that dietary iron regulates duodenal ferritin subunit expression was investigated. When day 12 rats were fed 6 ml of a milk formula containing 56 microgram/ml iron for 18 h, dietary iron increased the duodenal levels of L mRNA but not H mRNA. In contrast, hepatic H and L mRNA levels did not change. Dietary iron promoted greater increases in ferritin protein than mRNA in both tissues. Thus a shift from L-rich to H-rich ferritin isoforms occurs in the duodenum but not in the liver during neonatal development. This change is regulated at the pretranslational level and is independent of dietary iron.

Analysis of the effect of cytokines (interleukins 2, 3, 4, and 6, granulocyte-monocyte colony-stimulating factor, and interferon-gamma) on generation of primary cytotoxic T lymphocytes against a weakly immunogenic tumor.

We have investigated the role of cytokines (IL-2, IL-3, IL-4, IL-6, IFN-gamma, and GM-CSF) in the generation of primary cytotoxic T lymphocytes (CTL), within a single tumor system. The murine carcinoma line 1 was transfected with expression vectors with cDNA for these cytokines. Line 1 expresses low levels of class I MHC molecules, but can be induced with dimethyl sulfoxide or IFN-gamma to express high levels of class I. Class I low line 1 cells are not susceptible to CTL lysis, while class I high line 1 are lysed by CTL, which allows us to assay for CTL activity. To isolate primary CTL, tumor-infiltrating lymphocytes were isolated from cytokine-expressing or control tumors, growing in vivo. Most cytokines stimulated nonspecific killers, but IL-2 and IL-3 stimulated primary CTL. While IFN-gamma alone did not generate primary CTL, coexpression of IFN-gamma with IL-2 resulted in CTL generation. This is the first comparison of the effects of a series of cytokines on primary CTL development, and has important implications for vaccine development and immunotherapy.

B7-1 enhances natural killer cell-mediated cytotoxicity and inhibits tumor growth of a poorly immunogenic murine carcinoma.

The B7-1 molecule expressed on antigen presenting cells is an important costimulatory molecule for T cell activation. It has been demonstrated that murine B7-1 can enhance host immunity and lead to tumor rejection via its costimulatory function. Here, we investigate how transfection of B7-1 into line 1, a poorly immunogenic murine lung carcinoma, affects the generation and function of different immune effector cells. Line 1 cells expressing B7-1 form tumors that grow at a slower rate than the parental line 1. Our studies have shown that tumor infiltrating lymphocytes present within the B7-1 expressing tumors are primarily composed of nonspecific killer cells with no specific cytotoxic T cells present. To determine if increased nonspecific killer cells could inhibit the tumor growth of line 1 in the presence of B7-1, we examined the cytotoxicity of natural killer (NK) cells and lymphokine-activated killer (LAK) cells on the B7-1-transfected line 1 and the parental line 1. We found that B7-1 augments the NK- but not LAK-mediated killing against line 1 as measured in an in vitro 51Cr-release cytotoxicity assay. This enhancement could be blocked by CTLA-4 Ig. In vivo depletion of NK cells led to growth of the B7-1-transfected line 1 at the same rate as the parental line 1. These results suggest that in addition to its costimulatory role for T cell activation B7-1 could be an accessory molecule that intensifies NK-mediated cytotoxicity. This novel finding may provide a mechanism for the effect of B7-1 on tumors of low immunogenicity.