Spherical Lactic Acid Bacteria Activate Plasmacytoid Dendritic Cells Immunomodulatory Function via TLR9-Dependent Crosstalk with Myeloid Dendritic Cells

Plasmacytoid dendritic cells (pDC) are a specialized sensor of viral and bacterial nucleic acids and a major producer of IFN-α that promotes host defense by priming both innate and acquired immune responses. Although synthetic Toll-like receptor (TLR) ligands, pathogenic bacteria and viruses activate pDC, there is limited investigation of non-pathogenic microbiota that are in wide industrial dietary use, such as lactic acid bacteria (LAB). In this study, we screened for LAB strains, which induce pDC activation and IFN-α production using murine bone marrow (BM)-derived Flt-3L induced dendritic cell culture. Microbial strains with such activity on pDC were absent in a diversity of bacillary strains, but were observed in certain spherical species (Lactococcus, Leuconostoc, Streptococcus and Pediococcus), which was correlated with their capacity for uptake by pDC. Detailed study of Lactococcus lactis subsp. lactis JCM5805 and JCM20101 revealed that the major type I and type III interferons were induced (IFN-α, -β, and λ). IFN-α induction was TLR9 and MyD88-dependent; a slight impairment was also observed in TLR4-/- cells. While these responses occurred with purified pDC, IFN-α production was synergistic upon co-culture with myeloid dendritic cells (mDC), an interaction that required direct mDC-pDC contact. L. lactis strains also stimulated expression of immunoregulatory receptors on pDC (ICOS-L and PD-L1), and accordingly augmented pDC induction of CD4+CD25+FoxP3+ Treg compared to the Lactobacillus strain. Oral administration of L. lactis JCM5805 induced significant activation of pDC resident in the intestinal draining mesenteric lymph nodes, but not in a remote lymphoid site (spleen). Taken together, certain non-pathogenic spherical LAB in wide dietary use has potent and diverse immunomodulatory effects on pDC potentially relevant to anti-viral immunity and chronic inflammatory disease

Cryo-thawed embryo transfer: natural versus artificial cycle. A non-inferiority trial.(ANTARCTICA trial)

Background: frozen thawed embryo transfer (FET) is a cost-effective adjunct to IVF or IVF-ICSI treatment. In order to optimize treatment outcome, FET should be carried out during a period of optimal endometrial receptivity. To optimize implantation several methods for endometrium preparation have been proposed. In natural cycle FET (NC-FET), the endometrium develops under endogenous hormonal stimulation. The development of the dominant follicle and endometrium is monitored by ultrasound and FET is timed after triggering ovulation induction or determination of the spontaneous LH surge. In an artificial cycle FET (AC-FET) estrogens and progesterone are administered to prepare the endometrium for implantation. While the currently available data show no significant difference in pregnancy rates between these methods, well designed randomized controlled trials are lacking. Moreover there is little literature on difference in cancellation rates, cost-efficiency and adverse events.Methods and design: this randomized, multi-centre, non-inferiority trial we aim to test the hypothesis that there is no significant difference in live birth rates between patients undergoing NC-FET versus AC-FET. The primary outcome will be live birth rate per embryo transfer procedure. Secondary outcomes will be ongoing and clinical pregnancy rate, cancellation rate, (serious) adverse events and cost-efficiency. Based on a live birth rate of 20% and a minimal clinical important difference of 7.5% (one-sided alpha 2.5%, beta 20%) a total of 1150 patients will be needed. Analyzes will be performed using both per protocol as well as intention to treat analyses.Discussion: this prospective, randomized, non-inferiority trial aims to address the hypothesis that there is no significant difference in live birth rates between patients undergoing NC-FET versus patients undergoing AC-FET. Moreover it addresses cost-efficiency as well as the perceived burden of both treatments. TRIAL REGISTER: Netherlands trial register (NTR): 1586