Dietary supplementation with lactic acid bacteria attenuates the development of atopic-dermatitis-like skin lesions in NC/Nga mice in a strain-dependent manner.

BACKGROUND: Dietary supplementation with lactic acid bacteria (LAB) is a potential approach to the prevention and manipulation of allergic diseases such as atopic dermatitis (AD). However, the influence of different bacterial strains and their immunomodulating capacities is still largely unknown. METHODS: AD-like skin lesions were induced by sensitization to and repeated challenges with picrylchloride in the Th2-skewed NC/Nga mouse strain. The effects of LAB supplementation were assessed over time by monitoring clinical scores and plasma IgE levels. In some cases, mast cell infiltration, cutaneous hypersensitivity responses and cytokine mRNA expression in auricles were also examined. Additionally, cytokine production in vitro and cytokine mRNA accumulation in major lymphoid tissues were measured, comparing Lactobacillus paracasei KW3110 with L. rhamnosus GG (LGG). RESULTS: Supplementation with KW3110 significantly reduced the development of AD-like skin lesions, accompanied by less mast cell infiltration and lower plasma IgE levels. KW3110 also suppressed immediate hypersensitivity reactions and IL-4 mRNA expression in the auricles. These preventive effects sustained when supplementation was terminated; moreover, inhibitory effects were also observed even when supplementation was initiated after the onset of symptoms. In accordance with its effects on IL-12 and IL-4 production in vitro, KW3110 prevented the emergence of clinical symptoms more effectively than LGG in vivo. CONCLUSIONS: Supplementation with KW3110 significantly attenuated the onset and exacerbation of AD-like symptoms in NC/Nga mice. The effects were more prominent than those obtained with LGG, suggesting the importance of differences between LAB strains and their immunomodulating capacity.

Optimization of liver biopsy RNA sampling and use of reference RNA for cDNA microarray analysis.

In this study, we used the rat liver as a model system to optimize the conditions for extracting RNA from liver biopsies for use in cDNA microarrays. We found that a 5-mm biopsy with a 16-gauge needle and storage in RNA later at 4 degrees C were optimal conditions for RNA extraction. The most important factor for the quantity and quality of RNA extraction was the sample diameter. Using the optimized sampling conditions and a cDNA microarray, we compared the expression of genes in the normal and the fibrotic tissues of the LEC rat liver, a model of liver tumorigenesis, with SD rat liver RNA as a reference. We found 29 genes that were up-regulated and 33 genes that were down-regulated in the fibrotic part of the liver. Furthermore, with the help of the reference RNA, we were able to classify the expression profiles into five groups without complex mathematical analyses; without the reference RNA, the genes could be classified into only two groups. Finally, we found that osteopontin was expressed at a very high level in the fibrotic portion of the LEC rat liver. This cDNA microarray result was validated by immunohistochemistry, which showed an elevated expression of osteopontin in the region of cholangiocarcinoma and a lack of expression in normal tissues. With optimized conditions, we should be able to apply the microarray system for routine practice.

Expansion of human T-cell leukemia virus type 1 (HTLV-1) reservoir in orally infected rats: inverse correlation with HTLV-1-specific cellular immune response.

Adult T-cell leukemia (ATL) occurs in a small population of human T-cell leukemia virus type 1 (HTLV-1)-infected individuals. Although the critical risk factor for ATL development is not clear, it has been noted that ATL is incidentally associated with mother-to-child infection, elevated proviral loads, and weakness in HTLV-1-specific T-cell immune responses. In the present study, using a rat system, we investigated the relationships among the following conditions: primary HTLV-1 infection, a persistent HTLV-1 load, and host HTLV-1-specific immunity. We found that the persistent HTLV-1 load in orally infected rats was significantly greater than that in intraperitoneally infected rats. Even after inoculation with only 50 infected cells, a persistent viral load built up to considerable levels in some orally infected rats but not in intraperitoneally infected rats. In contrast, HTLV-1-specific cellular immune responses were markedly impaired in orally infected rats. As a result, a persistent viral load was inversely correlated with levels of virus-specific T-cell responses in these rats. Otherwise very weak HTLV-1-specific cellular immune responses in orally infected rats were markedly augmented after subcutaneous reimmunization with infected syngeneic rat cells. These findings suggest that HTLV-1-specific immune unresponsiveness associated with oral HTLV-1 infection may be a potential risk factor for development of ATL, allowing expansion of the infected cell reservoir in vivo, but could be overcome with immunological strategies.