Colorectal cancer-derived Foxp3(+) IL-17(+) T cells suppress tumour-specific CD8+ T cells

The pathogenesis of cancer is remained to be further understood. This study aims to investigate the role of tumour-derived Foxhead box P3 (Foxp3)(+) interleukin (IL)-17(+) T cells on suppressing tumour-specific CD8(+) T cells. Colorectal cancer (CRC) tissue was collected from surgically removed cancer tissue of 22 patients with CRC. Foxp3(+) IL-17(+) T cells in cancer tissue were examined by flow cytometry. A set of cell markers and cytokines expressed by Foxp3(+) IL-17(+) T cells were determined by immune staining. By coculture with isolated peripheral CD8(+) T cells, the immune regulatory capacity of Foxp3(+) IL-17(+) T cells was examined. The results showed that a number of Foxp3(+) IL-17(+) T cells were found in CRC tissue (22.8 ± 2.6 cells/mm(2) tissue) that was significantly more than in non-cancer colonic mucosa (5.6 ± 1.04 cells/mm(2) tissue). The Foxp3(+) IL-17(+) cells also CD4(+), CCR6(+), transforming growth factor (TGF)-beta(+) and IL-6(+) . The CD8(+) T cells proliferated markedly after exposure to tumour protein in culture that was suppressed in the presence of CRC-derived Foxp3(+) IL-17(+) T cells; the suppression was attenuated by pretreatment with anti-IL-17 antibody. We conclude that CRC-derived Foxp3(+) IL-17(+) T cells have the ability to suppress tumour-specific CD8(+) T cells. This subset of T cells may be a novel therapeutic target in the treatment of CRC.

An ABA-binding protein with nucleic acid-binding property

Maize cDNA expression library was screened using the antibodies against ABA-binding proteins (ABBP). From 200 000 separated phage plaques, only one cDNA clone coding for a polypeptide was obtained. It shows 60%-65% homology to the genes of nucleic acid-binding proteins in mammalia. However, about 120 cDNA clones coding maize 17s rRNA were unexpectedly obtained. In view of this, the ABBP purified by ABA affinity chromatography and the antibodies derived from the purified ABBP were examined. It is found that rRNA is indeed present in the ABBP. In addition, the obtained antibodies could recognize RNA as well as ABBP. It is suggested that the ABBP have nucleic acid-binding property and can form a complex with rRNA.

Colonic microbiota alters host susceptibility to infectious colitis by modulating inflammation, redox status, and ion transporter gene expression

Individuals vary in their resistance to enteric infections. The role of the intestinal microbiota in altering susceptibility to enteric infection is relatively unknown. Previous studies have identified that C3H/HeOuJ mice suffer 100% mortality during Citrobacter rodentium-induced colitis, whereas C57BL/6 mice recover from infection. The basis for their differences in susceptibility is unclear and has been mainly attributed to differences in host genetics. This study investigated the role of the intestinal microbiota in altering susceptibility to C. rodentium-induced colitis. When the feces of C57BL/6 mice were gavaged into antibiotic treated C3H/HeOuJ mice, the C57BL/6 microflora led to a complete reversal in mortality patterns where 100% of the C3H/HeOuJ mice survived infection. This protection corresponded with reduced colonic pathology and less systemic pathogen load and was associated with increased inflammatory and redox responses with reduced epithelial cell death. C3H/HeOuJ mice are normally susceptible to infection-induced dehydration due to defective expression of colonic ion transporters such as Dra, CA IV, and CA I; expression of these genes was normalized when C3H/HeOuJ mice were colonized with the C57BL/6 microflora. Together, these data reveal that the colonic microbiota play a critical role in protecting against intestinal infection by inducing proinflammatory and prooxidant responses that control pathogen load as well as ion transporter gene expression previously shown to prevent fatal dehydration. Protection of mice from lethal colitis was associated with higher levels of bacteria from Bacteroidetes. This study reveals that the microbiota is sufficient to overcome inherent genetic susceptibility patterns in C3H/HeOuJ mice that cause mortality during C. rodentium infection.