Loss of TET2 increases B-1 cell number and IgM production while limiting CDR3 diversity

Recent studies have demonstrated a role for Ten-Eleven Translocation-2 (TET2), an epigenetic modulator, in regulating germinal center formation and plasma cell differentiation in B-2 cells, yet the role of TET2 in regulating B-1 cells is largely unknown. Here, B-1 cell subset numbers, IgM production, and gene expression were analyzed in mice with global knockout of TET2 compared to wildtype (WT) controls. Results revealed that TET2-KO mice had elevated numbers of B-1a and B-1b cells in their primary niche, the peritoneal cavity, as well as in the bone marrow (B-1a) and spleen (B-1b). Consistent with this finding, circulating IgM, but not IgG, was elevated in TET2-KO mice compared to WT. Analysis of bulk RNASeq of sort purified peritoneal B-1a and B-1b cells revealed reduced expression of heavy and light chain immunoglobulin genes, predominantly in B-1a cells from TET2-KO mice compared to WT controls. As expected, the expression of IgM transcripts was the most abundant isotype in B-1 cells. Yet, only in B-1a cells there was a significant increase in the proportion of IgM transcripts in TET2-KO mice compared to WT. Analysis of the CDR3 of the BCR revealed an increased abundance of replicated CDR3 sequences in B-1 cells from TET2-KO mice, which was more clearly pronounced in B-1a compared to B-1b cells. V-D-J usage and circos plot analysis of V-J combinations showed enhanced usage of VH11 and VH12 pairings. Taken together, our study is the first to demonstrate that global loss of TET2 increases B-1 cell number and IgM production and reduces CDR3 diversity, which could impact many biological processes and disease states that are regulated by IgM

BCMA Is Essential for the Survival of Long-lived Bone Marrow Plasma Cells

Long-lived humoral immunity is manifested by the ability of bone marrow plasma cells (PCs) to survive for extended periods of time. Recent studies have underscored the importance of BLyS and APRIL as factors that can support the survival of B lineage lymphocytes. We show that BLyS can sustain PC survival in vitro, and this survival can be further enhanced by interleukin 6. Selective up-regulation of Mcl-1 in PCs by BLyS suggests that this α-apoptotic gene product may play an important role in PC survival. Blockade of BLyS, via transmembrane activator and cyclophilin ligand interactor–immunoglobulin treatment, inhibited PC survival in vitro and in vivo. Heightened expression of B cell maturation antigen (BCMA), and lowered expression of transmembrane activator and cyclophilin ligand interactor and BAFF receptor in PCs relative to resting B cells suggests a vital role of BCMA in PC survival. Affirmation of the importance of BCMA in PC survival was provided by studies in BCMA−/− mice in which the survival of long-lived bone marrow PCs was impaired compared with wild-type controls. These findings offer new insights into the molecular basis for the long-term survival of PCs

Proliferating CD8+ T Cell Infiltrates Are Associated with Improved Survival in Glioblastoma

Background: tumor-infiltrating lymphocytes are prognostic in many human cancers. However, the prognostic value of lymphocytes infiltrating glioblastoma (GBM), and roles in tumor control or progression are unclear. We hypothesized that B and T cell density, and markers of their activity, proliferation, differentiation, or function, would have favorable prognostic significance for patients with GBM. Methods: initial resection specimens from 77 patients with IDH1/2 wild type GBM who received standard-of-care treatment were evaluated with multiplex immunofluorescence histology (mIFH), for the distribution, density, differentiation, and proliferation of T cells and B cells, as well as for the presence of tertiary lymphoid structures (TLS), and IFNγ expression. Immune infiltrates were evaluated for associations with overall survival (OS) by univariate and multivariate Cox proportional hazards modeling. Results: in univariate analyses, improved OS was associated with high densities of proliferating (Ki67(+)) CD8(+) cells (HR 0.36, p = 0.001) and CD20(+) cells (HR 0.51, p = 0.008), as well as CD8(+)Tbet(+) cells (HR 0.46, p = 0.004), and RORγt(+) cells (HR 0.56, p = 0.04). Conversely, IFNγ intensity was associated with diminished OS (HR 0.59, p = 0.036). In multivariable analyses, adjusting for clinical variables, including age, resection extent, Karnofsky Performance Status (KPS), and MGMT methylation status, improved OS was associated with high densities of proliferating (Ki67(+)) CD8(+) cells (HR 0.15, p < 0.001), and higher ratios of CD8(+) cells to CD4(+) cells (HR 0.31, p = 0.005). Diminished OS was associated with increases in patient age (HR 1.21, p = 0.005) and higher mean intensities of IFNγ (HR 2.13, p = 0.027). Conclusions: intratumoral densities of proliferating CD8 T cells and higher CD8/CD4 ratios are independent predictors of OS in patients with GBM. Paradoxically, higher mean intensities of IFNγ in the tumors were associated with shorter OS. These findings suggest that survival may be enhanced by increasing proliferation of tumor-reactive CD8(+) T cells and that approaches may be needed to promote CD8(+) T cell dominance in GBM, and to interfere with the immunoregulatory effects of IFNγ in the tumor microenvironment

The Gaia-ESO Survey: Dynamical analysis of the L1688 region in Ophiuchus

The Gaia ESO Public Spectroscopic Survey (GES) is providing the astronomical community with high-precision measurements of many stellar parameters including radial velocities (RVs) of stars belonging to several young clusters and star-forming regions. One of the main goals of the young cluster observations is to study their dynamical evolution and provide insight into their future, revealing whether they will eventually disperse to populate the field rather than evolve into bound open clusters. In this paper we report the analysis of the dynamical state of L1688 in the ρ Ophiuchi molecular cloud using the dataset provided by the GES consortium. We performed the membership selection of the more than 300 objects observed. Using the presence of the lithium absorption and the location in the Hertzspung-Russell diagram, we identify 45 already known members and two new association members. We provide accurate RVs for all 47 confirmed members. A dynamical analysis, after accounting for unresolved binaries and errors, shows that the stellar surface population of L1688 has a velocity dispersion σ ~ 1.14 ± 0.35 km s-1 that is consistent with being in virial equilibrium and is bound with a ~80% probability. We also find a velocity gradient in the stellar surface population of ~1.0 km s-1 pc-1 in the northwest-southeast direction, which is consistent with that found for the pre-stellar dense cores, and we discuss the possibility of sequential and triggered star formation in L1688

Delayed anaphylaxis to alpha-gal, an oligosaccharide in mammalian meat

IgE-mediated hypersensitivity refers to immune reactions that can be rapidly progressing and, in the case of anaphylaxis, are occasionally fatal. To that end, identification of the associated allergen is important for facilitating both education and allergen avoidance that are essential to long-term risk reduction. As the number of known exposures associated with anaphylaxis is limited, discovery of novel causative agents is crucial to evaluation and management of patients with idiopathic anaphylaxis. Within the last 10 years several apparently separate observations were recognized to be related, all of which resulted from the development of antibodies to a carbohydrate moiety on proteins. Interestingly, the exposure differed from airborne allergens but was nevertheless capable of producing anaphylactic and hypersensitivity reactions. Our recent work has identified these responses as being due to a novel IgE antibody directed against a mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (“alpha-gal”). This review will present the historical summary of the identification of cetuximab hypersensitivity due to alpha-gal IgE and discuss the non-primate mammalian meat food allergy as well as current goals and directions of our research programs

Aim2 deficiency stimulates the expression of IFN-inducible Ifi202, a lupus susceptibility murine gene within the Nba2 autoimmune susceptibility locus

Murine Aim2 and p202 proteins (encoded by the Aim2 and Ifi202 genes) are members of the IFN-inducible p200 protein family. Both proteins can sense dsDNA in the cytoplasm. However, upon sensing dsDNA, only the Aim2 protein through its pyrin domain can form an inflammasome to activate caspase-1 and induce cell death. Given that the p202 protein has been predicted to inhibit the activation of caspase-1 by the Aim2 protein and that increased levels of the p202 protein in female mice of certain strains are associated with lupus susceptibility, we compared the expression of Aim2 and Ifi202 genes between Aim2-deficient and age-matched wild-type mice. We found that the Aim2 deficiency in immune cells stimulated the expression of Ifi202 gene. The increased levels of the p202 protein in cells were associated with increases in the expression of IFN-beta, STAT1, and IFN-inducible genes. Moreover, after knockdown of Aim2 expression in the murine macrophage cell line J774.A1, IFN-beta treatment of cells robustly increased STAT1 protein levels (compared with those of control cells), increased the activating phosphorylation of STAT1 on Tyr-701, and stimulated the activity of an IFN-responsive reporter. Notably, the expression of Aim2 in non-lupus-prone (C57BL/6 and B6.Nba2-C) and lupus-prone (B6.Nba2-ABC) splenic cells and in a murine macrophage cell line that overexpressed p202 protein was found to be inversely correlated with Ifi202. Collectively, our observations demonstrate an inverse correlation between Aim2 and p202 expressions. We predict that defects in Aim2 expression within immune cells contribute to increased susceptibility to lupus