wu, Z. | bioRxiv Science

bioRxiv2018

Effect of Lactobacillus reuteri on intestinal microflora and immune parameters: involvement of sex differences

Probiotic candidate L. reuteri was screened out for in vivo experiments based on a relatively higher gastrointestinal tolerance and moderate adhesiveness. As results shown in in-vivo experiments, a significantly higher level of IL-12 at low-dose group was found both in females and males. Higher levels of T-lymphocytes were also observed in females compared to control group, however, males displayed a reduction expcept for CD8-positive cells in ileum. In comparison to the control group, the relative abundance of phylotypes in the phylum Bacteroidetes (genus of Bacteroides, Prevotella) and Firmicutes (genus of ClostridiumIV) exihibited a reserve shift between sexes after L. reuteri intervened. Meanwhile, the relative abundance of several taxa (Acetobacteroides, Lactobcaillus, bacillus) also differed markedly in sexes at low-dose group, together with microbiota diversity, as indicated by Shannon index.\n\nImportanceSexual dimorphism has triggered researchers attention. However, the relationship between immune parameters and gut microbiota caused by Lactobacillus at different dosage are not fully elucidated. In present research, the possible probiotic role of L. reuteri DMSZ 8533 on immunomodulation and effect on fecal microbiota composition were investigated. Our findings demonstrate the importance of L. reuteri DMSZ 8533 as a potential probiotic strain with an immunomodulatory effect, which also alters the microflora composition depending on the sex of the host.

microbiology↗

bioRxiv2018

Characterisation of subpopulations of chicken mononuclear phagocytes that express TIM4 and the macrophage colony-stimulating factor receptor (CSF1R)

The phosphatidylserine receptor, TIM4, encoded by TIMD4, mediates the phagocytic uptake of apoptotic cells. We applied anti-chicken TIM4 monoclonal antibodies, in combination with CSF1R reporter transgenes to dissect the function of TIM4 in chick (Gallus gallus). During development in ovo, TIM4 was present on the large majority of macrophages but expression became more heterogeneous post-hatch. Blood monocytes expressed KUL01, class II MHC and CSF1R-mApple uniformly. Around 50% of monocytes were positive for surface TIM4. They also expressed many other monocyte-specific transcripts at a higher level than TIM4- monocytes. In liver, highly-phagocytic TIM4hi cells shared many transcripts with mammalian Kupffer cells and were associated with uptake of apoptotic cells. Although they expressed CSF1R mRNA, Kupffer cells did not express the CSF1R-mApple transgene, suggesting that additional CSF1R transcriptional regulatory elements are required by these cells. By contrast, CSF1R-mApple was detected in liver TIM4lo and TIM4- cells which were not phagocytic and were more abundant than Kupffer cells. These cells expressed CSF1R, alongside high levels of FLT3, MHCII, XCR1 and other markers associated with conventional dendritic cells (cDC) in mice. In bursa, TIM4 was present on the cell surface of two populations. Like Kupffer cells, bursal TIM4hi phagocytes co-expressed many receptors involved in apoptotic cell recognition. TIM4lo cells appear to be a sub-population of bursal B cells. In overview, TIM4 is associated with phagocytes that eliminate apoptotic cells in the chick. In the liver, TIM4 and CSF1R reporters distinguished Kupffer cells from an abundant population of DC-like cells.

immunology↗