Supplementary MaterialsSupplementary Information 41467_2019_10144_MOESM1_ESM

Supplementary MaterialsSupplementary Information 41467_2019_10144_MOESM1_ESM. contact with M cells in the subepithelial dome (SED). Using in situ photoactivation analysis of antigen-specific SED B cells, we find migration of cells towards the GC. Following antigen injection into ligated intestinal loops containing PPs, 40% of antigen-specific SED B cells bind antigen within 2?h, whereas unspecifc cells do not, indicating B cell-receptor involvment. Antigen-loading is not observed in M cell-deficient mice, but is unperturbed in mice depleted of classical dendritic cells (DC). Thus, we report a M cell-B cell antigen-specific transporting pathway in PP that is independent of DC. We propose that this antigen transporting pathway has a critical role in gut IgA responses, and should be taken into account when developing mucosal vaccines. (and genes,?which control positioning of the B cell in the follicle37. The GC is organized into a light (LZ) and a dark zone (DZ) and the former hosts the FDC network that carries antigen-complexes, critical for clonal selection and affinity maturation through somatic hyper mutation (SHM) of the IgA response38C40. In the DZ activated B cells undergo extensive cell divisions and this compartment hosts a network of CXCL12+ reticular cells (CRCs) that attract CXCR4high B cells to migrate into this zone38,39. Despite much progress in recent years we still lack a detailed understanding of how IgA induction is regulated in PP and, in particular, the specialized functions of the GC and SED2C4,16. We have developed a Tipifarnib S enantiomer model system to study mucosal antigen-specific B cell responses based on GFP-labeled NP-specific B1C8hi IgH knock-in B cells and oral immunization with the hapten (4-hydroxy-3-nitrophenyl acetyl; NP) conjugated to cholera toxin (CT)16,32,41. Using this model, we here have?explored the regulation of Mouse monoclonal antibody to TBL1Y. The protein encoded by this gene has sequence similarity with members of the WD40 repeatcontainingprotein family. The WD40 group is a large family of proteins, which appear to have aregulatory function. It is believed that the WD40 repeats mediate protein-protein interactions andmembers of the family are involved in signal transduction, RNA processing, gene regulation,vesicular trafficking, cytoskeletal assembly and may play a role in the control of cytotypicdifferentiation. This gene is highly similar to TBL1X gene in nucleotide sequence and proteinsequence, but the TBL1X gene is located on chromosome X and this gene is on chromosome Y.This gene has three alternatively spliced transcript variants encoding the same protein GC B cells in PP and compared this with systemic lymphoid tissues. In particular, we investigated the expression of GL7 and whether this expression correlates to a B cell function or a stage of differentiation. Most importantly we investigated the role of GL7-negative GFP+ B cells that express CCR6 and are in close contact with the M cells in the SED. We found?that these NP-specific B cells bound?antigen injected into a ligated loop of the small intestine, and then migrated from the SED to the GC. This M?cell-B cell pathway was?lost in M?cell deficient mice, but was?found intact in mice depleted of DC. We propose that?this pathway plays an important role in maintaining the GC response in the PP and subsequently also?for gut IgA responses. Results Most antigen-specific GC B cells in PP are GL7-negative Since PP constantly host GCs, it has been nearly impossible to study antigen-specific B cell responses using traditional mouse models and immunization approaches. To overcome this limitation, we have developed an adoptive transfer model based Tipifarnib S enantiomer on Tipifarnib S enantiomer NP-specific B1C8hi IgH knock-in -expressing GFP+ splenic B cells and NP-hapten conjugated to cholera toxin (NP-CT) as an oral immunogen to study gut IgA responses16,32,41 (Fig.?1a, b). GL7 is a B cell activation marker that is upregulated before and during a GC response42. Following an oral immunization with NP-CT we found that a majority of NP-specific GFP+ B cells in the PPs were found in the GC compartment (Fig.?1c). Surprisingly, whereas most of the GFP+ B cells were IgD? ( 90%), only 20C25% of these cells expressed GL7 (Fig.?1d). This phenotype was specific for PP as following an i.p. immunization with NP-CT we identified that 80% of the activated IgD? GFP+ B cells in the spleen were GL7+ and found in classical GC, suggesting that the regulatory microenvironments may differ between the two sites (Fig.?1c, d). Of note, neither the route or number of immunizations, the source of adoptively transferred na?ve NP-specific B cells, Tipifarnib S enantiomer splenic or isolated from Tipifarnib S enantiomer the PP, or the time after immunization changed the uniquely low frequency of GL7-expressing activated B cells in the PP following oral immunization (Supplementary Fig.?1aCe). Open in a separate window Fig. 1 A majority of Peyers patch (PP) germinal center (GC) B cells lack expression of GL7. a A schematic depiction of the experimental model used to study specific B cell responses in the PP and spleen following per oral (p.o.) or intraperitoneal (i.p.) immunization. b Gating strategy and percentage of NP-specific GFP+ B cells of all CD19+ B cells in PP on day four and ten or in the spleen (Spl) on day ten after a single NP-CT p.o. or i.p. immunization. c Representative.