IFN-α-based treatment of patients with chronic HCV show increased levels of cells with myeloid-derived suppressor cell phenotype and of IDO and NOS

INTRODUCTION

Hepatitis C virus (HCV) infection causes chronic hepatitis, which is often associated with suppressed anti-HCV immune responses. We have recently reported accumulation of myeloid-derived suppressor cells (MDSCs) and suppressed immunity in cancer patients.

AIM

The main aim of this study was to determine whether chronic HCV patients harbor high of MDSCs in general and in nonresponders to IFN-based therapy in particular as well as to analyze the immune suppressive molecules.

METHODS

Peripheral blood samples withdrawn from 154 patients with chronic HCV infection and were categorized into responders and nonresponders based on viral titer upon IFN-α treatment.

RESULTS

The relative and absolute numbers of MDSCs defined as Lin^-/HLA-DR^-/CD33⁺/CD11b⁺ increased in all HCV patients, where they were higher in nonresponders than in responders. Additionally, the levels of MDSCs after 4-6 months of treatment in responders were lower than during the course of treatment. The responders also showed higher levels of IL-2 coincided with increased numbers of dendritic cells (DCs), CD4⁺ and CD8⁺ T cells. The levels of total NOS and IDO were also higher in nonresponders as compared to responders and healthy controls, while the expression levels of CD3ζ was lower in responders as compared to nonresponders and healthy volunteers.

CONCLUSION

Chronic HCV patients harbor high numbers of MDSCs, which are higher in nonresponders than in responders. The higher numbers of MDSCs associated with increases in the suppressing factors.

Abstract B13: In vitro animal cancer model for assessment of sulfated polysaccharides extract of Ulva lactuca as colon cancer therapeutic and chemopreventive agents

Purpose: Sulfated polysaccharides extract of Ulva lactuca (ULSP) was in vitro assessed as probable chemopreventive and therapeutic agents for colon cancer (CC) comparing with currently used chemotherapy (5-fluorouracil “5-FU” and mitomycin-C “MMC”) using our newly developed in vitro transformed cancerous rat colon epithelial cells.

Methods: The present study used an in vitro animal CC model as it resembles human multistage of chromosomal instability type of CC that is located mainly at distal colon. Hence, this model was used for evaluating ULSP by the detection of cytotoxicity against normal and cancerous colon cells and antimetastatic potency. Besides, ULSP efficacy as CC chemopreventive agent was assessed through the detection of CC progression markers; loss of heterozygosity of deleted in colorectal cancer (DCC) and p53, aldehyde dehydrogenase (ALDH) 1B1 expression, activities of ornithine decarboxylase (ODC), cyclooxygenase-2 (COX-2) and alkaline phosphatase (ALP), cellular redox state (Eh), doubling time, and mucin level.

Results: The apoptosis-dependent anticancer activity of ULSP (4.9 µg/ml) was revealed at all stages of cancerous distal colon epithelial cells by the formation of apoptotic bodies and DNA fragmentation (above 43%) without affecting normal colon epithelial cells. Also, its inhibitory effect on the invasion of cancerous epithelial and Caco-2 cells (above 49%) was stronger than that of 5-FU+MMC (about 11%). Cells were treated with ULSP before exposure to CC inducers and they showed normal tumor suppressor genes (DCC and p53), normal expression of ALDH1B1, and normal activity of ODC (0.03±0.0004 U/μg) and null activity of COX-2. In addition, their normal pattern of proliferations (doubling time 3 days and Eh 252.7±2.12 mV) and differentiation was confirmed by the maintenance of ALP activity (0.46±0.01 mU/μg) and the secretion of mucin (29.2±0.2 μg/ml) compared to normal and cancerous colon epithelial cells.

Conclusion: Our innovative in vitro model of colon cancer have proved that ULSP could have induced apoptosis at all stages of cancerous colon cells, inhibited cancerous cells to metastasize and blocked CC progression without effect on normal epithelial cells comparable to chemotherapy.

Citation Format: Marwa Abu-Serie, Maha El Demellawy, Mohamed El-Sayed, Fatma El-Rashidy. In vitro animal cancer model for assessment of sulfated polysaccharides extract of Ulva lactuca as colon cancer therapeutic and chemopreventive agents. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr B13.

Influence of interleukin-2 and interferon-gamma in murine schistosomiasis

Schistosoma mansoni-infected mice were administered at the time of parasite residency in the lung with recombinant murine interleukin (IL)-2 or interferon-gamma (IFN-gamma), to evaluate the impact of cytokines in host responses to primary schistosomiasis. S. mansoni lung-stage schistosomula did not affect plasma lipids levels in BALB/c, while elicited significant (p<0.05) increase in free fatty acids (FA) and decrease in cholesterol plasma levels in C57BL/6 and CD1 mice, and stimulated expression of mRNA for Th2 cytokines in BALB/c and Th1 cytokines in C57BL/6 and CD1 mice. Production of specific antibodies was negligible in the 3 strains. Interleukin-2 treatment elicited significant (p<0.001) decrease in triglycerides (TG) in CD1, and decrease in TG and cholesterol plasma levels and down-regulation of TNF-alpha mRNA expression in C57BL/6 mice. Induction of type 2 cytokines and/or IFN-gamma mRNA expression did not lead to increase in percentage of specific antibody responders in any mouse strain. Exogenous IL-2-related reduction in cholesterol plasma levels and TNF-alpha mRNA expression in C57BL/6 mice was associated with significant (p<0.05) decrease in adult worm recovery and egg count. Treatment with IFN-gamma elicited significant (p<0.05) free FA plasma levels increase in BALB/c and C57BL/6 and decrease in CD1 mice. Expression of type 2 cytokines mRNA was stimulated in BALB/c and CD1 mice, yet was not accompanied with increase in humoral responses. Exogenous IFN-gamma-related reduction in free FA plasma levels and IFN-gamma mRNA response, and up-regulation of TNF-alpha mRNA expression in CD1 mice were associated with significant increase in adult worm burden and egg load. The data were discussed in an attempt to define host factors predictive of resistance to schistosome infection.

Impact of interleukin-1 and interleukin-6 in murine primary schistosomiasis

BACKGROUND

Immunization with schistosome antigens invariably elicits a plethora of cytokines and, hence, it is reasonable to assume that these cytokines influence host responses to challenge lung-stage larvae and, consequently, the adult worm burden, and may be responsible for the erratic data generally observed in protection studies against schistosome infection.

METHODS

Schistosoma mansoni-infected mice were administered with recombinant interleukin (IL)-1beta or IL-6 to evaluate the impact of cytokines in host responses to lung-stage schistosomula, and subsequent effects on adult worm parameters. Plasma lipid levels were assayed by colorimetric enzymatic tests and antibody responses by ELISA. Cytokine profile in peripheral blood mononuclear cells was evaluated by RT-PCR.

RESULTS

S. mansoni infection elicited, at the time of parasite residency in the lung, significant increase in free fatty acids (FA) and decrease in cholesterol plasma levels in C57BL/6 and CD1 mice, and stimulation of mRNA expression for cytokines of T helper type (Th) 2 in BALB/c, Th1 in C57BL/6, and Th1/Th2 in CD1 mice. However, no specific antibody production was evident in any mouse strain. In BALB/c mice, exogenous IL-1beta-related plasma free FA level significant increase, stimulation of expression of IL-1 and IL-12 mRNA, and considerable increase in percent of specific antibody-producing mice were associated with significant reduction in adult worm burden and egg load. In contrast, exogenous IL-1beta elicited decrease in free FA plasma levels, and down-regulation of cytokines' mRNA expression in C57BL/6 and CD1 mice, changes associated with aggravation of the worm burden. Likewise, exogenous IL-6 failed to stimulate increase in plasma free FA levels or percent of antibody-producing mice except in BALB/c mice, effects that were protective for the host in BALB/c and for the parasite in C57BL/6 and CD1 mice.

CONCLUSION

These findings were discussed in relation to the erratic data of protection experiments with schistosome subunit antigens in different mouse strains.