We previously reported that microRNA (miRNA) is present in human breast milk. Recently, other groups have reported that bovine milk also contains miRNA; however, these reports are few. We therefore investigated bovine milk miRNA using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk. The RNA concentration in a colostrum whey fraction was higher than that in a mature milk whey fraction. In total, 102 miRNA were detected in bovine milk by microarray analysis (100 in colostrum and 53 in mature milk; 51 were common to both). Among these miRNA, we selected several immune- and development-related miRNA, including miR-15b, miR-27b, miR-34a, miR-106b, miR-130a, miR-155, and miR-223. These miRNA were detected in bovine milk by quantitative PCR, and each of these miRNA was significantly more highly expressed in colostrum than in mature milk. We also confirmed the presence of some mRNA in bovine milk. Nevertheless, synthesized miRNA spiked in the raw milk whey were degraded, and naturally existing miRNA and mRNA in raw milk were resistant to acidic conditions and RNase treatment. The RNA molecules in milk were stable. We also detected miRNA and mRNA in infant formulas purchased from Japanese markets. It is still unknown whether milk-derived RNA molecules play biological roles in infants; however, if milk-derived RNA do show functions in infants, our data will help guide future studies.

We investigated the possible association between the Kobe earthquake (January 1995) and the sex ratio among live-born infants after the catastrophe. A significant decline in the sex ratio (0.501) of Hyogo Prefecture in October 1995 was observed 9 months after the Kobe earthquake as compared with an expected value of 0.516 in the period from January 1993 to January 1996 (P = 0.04; one-tailed). Simultaneously, a reduction in fertility of approximately 6% was also observed, compared with the month of October 2 years previously. Thus, the acute stress resulting from a great natural catastrophe can be a cause of a low sex ratio at birth 9 months later.

Interleukin-10 (IL-10) is a multifunctional cytokine that can exert suppressive and stimulatory effects on T cells. It was investigated whether IL-10 could serve as an immunostimulant for specific CD8 ؉ cytotoxic T cell (CTL) in vivo after vaccination and, if so, under what conditions. In tumor prevention models, administration of IL-10 before, or soon after, peptide-pulsed primary dendritic cell immunization resulted in immune suppression and enhanced tumor progression. Injection of IL-10, however, just after a booster vaccine significantly enhanced antitumor immunity and vaccine efficacy. Analysis of spleen cells derived from these latter animals 3 weeks after IL-10 treatment revealed that the number of CD8 ؉ CD44 hi CD122 ؉ T cells had increased and that antigen-specific proliferation in vitro was enhanced. Although cytotoxicity assays did not support differences between the various treatment groups, 2 more sensitive assays measuring antigen-specific interferon-␥ production at the single-cell level demonstrated increases in the number of antigen-specific responder T cells in animals in the vaccine/IL-10 treatment group. Thus, IL-10 may maintain the number of antitumor CD8 ؉ T cells. In adoptive transfer studies, the ability of IL-10 to maintain CTL function could be enhanced by the depletion of CD4 ؉ T cells. This suggests that IL-10 mediates contrasting effects on both CD4 ؉ and CD8 IntroductionDendritic cells (DCs) play a key role in the initiation of CD8 ϩ cytotoxic T cell (CTL)-mediated immune responses and have been used successfully in cancer vaccines. 1,2 We have previously reported that CD8 ϩ CTLs can be generated from naive precursors using DC preloaded with leukemia antigens as stimulators. [3][4][5] Leukemic cell-derived DCs have been used to successfully treat patients with chronic myelogenous leukemia. 6 To more effectively treat patients with cancer, vaccines must not only amplify antitumor CTL responses, they must maintain them to preclude disease recurrence. The main predictor of a strong response versus a weak CTL appears to be the size of a proliferative burst. 7,8 However, for the promotion of long-term effector CTL activity, the participation of T-cell growth and antiapoptotic factors, such as interleukin 2 (IL-2), In this study, we have evaluated whether IL-10 plays a dominant role in supporting the maintenance of effector CD8 ϩ T-cell function after initial priming in situ.IL-10, which is produced by a variety of cells including T lymphocytes, B lymphocytes, and monocytes, has been identified as a key immunomodulatory cytokine 15,16 capable of mediating both immunosuppressive and immunostimulant effects. 17 In vitro studies showed that IL-10 inhibits antigen-specific activation and proliferation of human CD4 ϩ T cells, at least in part by downregulating the cytokine production (ie, IL-2 and tumor necrosis factor-␣). 18,19 IL-10 also reduces the expression of CD54 (ICAM-1), CD80, CD86, and major histocompatibility complex (MHC) class II on monocytes and DCs, resulting in incomplete T-ce...

Blood and/or breast milk have been used to assess human exposure to various environmental contaminants. Few studies have been available to compare the concentrations in one matrix with those in another. The goals of this study were to determine the current levels of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in Japanese women, with analysis of the effects of lifestyle and dietary habits on these levels, and to develop a quantitative structure–activity relationship (QSAR) with which to predict the ratio of serum concentration to breast milk concentration. We measured PBDEs and PCBs in 89 paired samples of serum and breast milk collected in four regions of Japan in 2005. The geometric means of the total concentrations of PBDE (13 congeners) in milk and serum were 1.56 and 2.89 ng/g lipid, respectively, whereas those of total PCBs (15 congeners) were 63.9 and 37.5 ng/g lipid, respectively. The major determinant of total PBDE concentration in serum and milk was the geographic area within Japan, whereas nursing duration was the major determinant of PCB concentration. BDE-209 was the most predominant PBDE congener in serum but not in milk. The excretion of BDE 209 in milk was lower than that of BDE 47 and BDE 153. QSAR analysis revealed that two parameters, calculated octanol/water partition and number of hydrogen-bond acceptors, were significant descriptors. During the first weeks of lactation, the predicted partitioning of PBDE and PCB congeners from serum to milk agreed with the observed values. However, the prediction became weaker after 10 weeks of nursing.

Human milk contains sphingomyelin (SM) as a major component of the phospholipid fraction. Galactosylceramide (cerebroside), a metabolite of sphingolipids, increases along with CNS myelination, and is generally considered a universal marker of myelination in all vertebrates. L-Cycloserine (LCS) is an inhibitor of serine palmitoyltransferase (SPT), a rate-limiting enzyme for sphingolipid biosynthesis that is reported to show increased activity with development of the rat CNS. The present study examined the effects of dietary SM on CNS myelination during development in LCS-treated rats. From 8 d after birth, Wistar rat pups received a daily s.c. injection (100 mg/kg) of LCS. From 17 d after birth, the animals were fed an 810 mg/100g of bovine SM-supplemented diet (SM-LCS group) or a nonsupplemented diet (LCS group). At 28 d after birth, the animals were killed and subjected to biochemical and morphometric analyses. The myelin dry weight, myelin total lipid content, and cerebroside content were significantly lower in the SM-LCS and LCS groups than in a group not treated with LCS (the non-LCS group). However, these levels were significantly higher in the SM-LCS group than in the LCS group. Morphometric analysis of the optic nerve revealed that the axon diameter, nerve fiber diameter, myelin thickness, and g value (used to compare the relative thickness of myelin sheaths around fibers of different diameter) were significantly lower in the LCS group than in the other groups, but were similar in the SM-LCS and non-LCS groups. These findings suggest that dietary SM contributes to CNS myelination in developing rats with experimental inhibition of activity. Abbreviations SM, sphingomyelin LCS, L-cycloserine PC, phosphatidylcholine PE, phosphatidylethanolamine PI, phosphatidylinositol PS, phosphatidylserine SPT, serine palmitoyltransferase TLC, thin-layer chromatography SM is composed of phosphocholine as the polar head group and sphingosine as the backbone of the molecule, and it is therefore classified as one of the sphingolipids. Recent studies have demonstrated that sphingolipids are found in all eukaryotic and some prokaryotic organisms (1). These molecules are involved in the regulation of cell growth (2), cell differentiation, and diverse other functions, including cell-substratum interactions and intracellular signal transduction (3, 4). Human milk has a lower content of phospholipids compared with triglycerides. Bitman et al. (5) reported that human milk has a total phospholipid content of approximately 15 to 20 mg/dL, with SM accounting for approximately 37% of the phospholipid fraction. Although many foods contain a small amount of SM (6), its nutritional and physiologic roles have not been fully examined.CNS myelin has a higher lipid content (65-80%) than that of general cell membranes. SM and sphingolipid metabolites, such as cerebroside and sulfatide, are prominent components of the myelin sheath that surrounds the axons of some neurons. This sheath acts as an insulator for nerve impulses and controls the sal...

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Functional RNAs, such as microRNA (miRNA) and mRNA, are present in milk, but their roles are unknown. To clarify the roles of milk RNAs, further studies using experimental animals such as rats are needed. However, it is unclear whether rat milk also contains functional RNAs and what their time dependent expression profiles are. Thus, we prepared total RNA from whey isolated from rat milk collected on days 2, 9, and 16 postpartum and analyzed using microarrays and quantitative PCR. The concentration of RNA in colostrum whey (day 2) was markedly higher than that in mature milk whey (days 9 and 16). Microarray analysis detected 161 miRNAs and 10,948 mRNA transcripts. Most of the miRNAs and mRNA transcripts were common to all tested milks. Finally, we selected some immune- and development-related miRNAs and mRNAs, and analysed them by quantitative PCR (in equal sample volumes) to determine their time-dependent changes in expression in detail. Some were significantly more highly expressed in colostrum whey than in mature milk whey, but some were expressed equally. And mRNA expression levels of some cytokines and hormones did not reflect the protein levels. It is still unknown whether RNAs in milk play biological roles in neonates. However, our data will help guide future in vivo studies using experimental animals such as rats.