B cell depletion in murine lupus using cytotoxic T lymphocytes in vivo: Feasibility and benefit.

Given the promising results in human lupus with B cell depletion, we tested whether in vivo cytotoxic T lymphocyte (CTL) could eliminate autoreactive B cells in the setting of murine lupus. Using the parent-into-F1 (P â†’ F1) model to generate CTL that eliminate B cells, we found that transfer ofNZB parental splenocytes into lupus-prone female NZB/W F1 mice resulted in profound B cell reduction whereas NZW â†’ F1 mice exhibited defective B cell elimination. Using pre-disease or early disease B/W mice as hosts, NZB â†’ F1 mice exhibited B cell depletion and improved proteinuria but no improvement in survival whereas NZW â†’ F1 mice had significantly reduced proteinuria and prolonged survival. Thus, despite the defective IL-2 environment in B/W F1 mice, generation of CTL and B cell depletion is feasible in NZB â†’ F1 mice. The surprising increase in survival for NZW â†’ F1 mice despite defective B cell elimination suggests that NZW splenocytes may contain a beneficial down regulatory cell.

Both perforin and FasL are required for optimal CD8 T cell control of autoreactive B cells and autoantibody production in parent-into-F1 lupus mice.

To test the relative roles of perforin (pfp) vs. FasL in CTL control of autoreactive B cell expansion, we used the parent-into-F1 model of murine graft-vs.-host disease in which donor CD8 CTL prevent lupus like disease by eliminating activated autoreactive B cells. F1 mice receiving either pfp or FasL defective donor T cells exhibited an intermediate short-term phenotype. Pairing of purified normal CD4 T cells with either pfp or FasL defective CD8 T cell subsets resulted in impaired host B cell elimination and mild lupus like disease that was roughly equivalent in the two experimental groups. Thus, in addition to major roles in tumor and intracellular pathogen control, pfp mediated CD8 CTL killing plays a significant role in controlling autoreactive B cell expansion and lupus downregulation that is comparable to that mediated by FasL killing. Importantly, both pathways are required for optimal elimination of activated autoreactive B cells.

Synthesis of Furan-Annelated BINOL Derivatives: Acid-Catalyzed Cyclization Induces Partial Racemization.

In this account, we describe the synthesis of a series of BINOL-based bis- and trisphosphoric acids 11d/e/f, which commonly feature an unusual phosphoric acid monoester motif. This motif is generated by an acid-catalyzed 5- endo- dig cyclization of the 3-alkynyl-substituted BINOL precursors to give the corresponding Furan-annelated derivatives, followed by phosphorylation of the remaining phenolic alcohols. In the cyclization reaction, we observed an unexpected partial racemization in the bis- and tris-BINOL scaffolds, leading to mixtures of diastereomers that were separated and characterized spectroscopically and by X-ray crystal structure analyses. The cyclization and racemization processes were investigated both experimentally and by DFT-calculations, showing that although the cyclization proceeds faster, the barrier for the acid-catalyzed binaphthyl-racemization is only slightly higher.

In vivo IL-4 prevents allo-antigen driven CD8+ CTL development.

IL-4 has been shown to suppress acute graft vs. host disease (GVHD) in irradiated hosts. Here we evaluated whether IL-4 suppresses acute GVHD in the un-irradiated parent-into-F1 GVHD model with relevance to renal allograft rejection. IL-4 completely suppressed CD8 CTL when administered with donor cells however this effect was lost if its administration was delayed 3days. IL-4 did not inhibit donor CD8+ T cell homing to the host spleen but rather prevented donor CD8+ T cell differentiation into CTLs. Studies with IL-4Rα-deficient donor cells or recipient mice demonstrated that IL-4 effects on the host, rather than, or in addition to IL-4 effects on donor cells, were critical for suppression of CTL. Because IL-4 decreased all splenic dendritic cell populations and increased neutrophil and CD8+ T cells, IL-4 may suppress donor CD8+ CTL by decreasing Ag presentation and/or increasing host myeloid and CD8+ T cell suppression of donor T cells.

Intrinsic Differences in Donor CD4 T Cell IL-2 Production Influence Severity of Parent-into-F1 Murine Lupus by Skewing the Immune Response Either toward Help for B Cells and a Sustained Autoantibody Response or toward Help for CD8 T Cells and a Downregulatory Th1 Response.

Using the parent-into-F1 model of induced lupus and (C57BL/6 × DBA2) F1 mice as hosts, we compared the inherent lupus-inducing properties of the two parental strain CD4 T cells. To control for donor CD4 recognition of alloantigen, we used H-2(d) identical DBA/2 and B10.D2 donor T cells. We demonstrate that these two normal, nonlupus-prone parental strains exhibit two different T cell activation pathways in vivo. B10.D2 CD4 T cells induce a strong Th1/CMI pathway that is characterized by IL-2/IFN-γ expression, help for CD8 CTLs, and skewing of dendritic cell (DC) subsets toward CD8a DCs, coupled with reduced CD4 T follicular helper cells and transient B cell help. In contrast, DBA/2 CD4 T cells exhibit a reciprocal, lupus-inducing pathway that is characterized by poor IL-2/IFN-γ expression, poor help for CD8 CTLs, and skewing of DC subsets toward plasmacytoid DCs, coupled with greater CD4 T follicular helper cells, prolonged B cell activation, autoantibody formation, and lupus-like renal disease. Additionally, two distinct in vivo splenic gene-expression signatures were induced. In vitro analysis of TCR signaling revealed defective DBA CD4 T cell induction of NF-κB, reduced degradation of IκBα, and increased expression of the NF-κB regulator A20. Thus, attenuated NF-κB signaling may lead to diminished IL-2 production by DBA CD4 T cells. These results indicate that intrinsic differences in donor CD4 IL-2 production and subsequent immune skewing could contribute to lupus susceptibility in humans. Therapeutic efforts to skew immune function away from excessive help for B cells and toward help for CTLs may be beneficial.

In vivo maturation of allo-specific CD8 CTL and prevention of lupus-like graft-versus-host disease is critically dependent on T cell signaling through the TNF p75 receptor but not the TNF p55 receptor.

A third signal is required for maturation of effector CD8 CTL in addition to TCR and CD28 engagement. Inflammatory cytokines can provide a third signal; however, in nonpathogen settings (i.e., antitumor responses), the identity of the third signal is not clear. A useful model for in vivo CD8 CTL in the absence of exogenous pathogens is the alloantigen-driven parent-into F1 model of acute graft-versus-host disease (GVHD) characterized by a strong TNF-dependent donor antihost CD8 CTL T cell response. To determine whether TNF acts directly on donor T cells in a signal 3 manner, F1 mice received TNFR 1 (p55) knockout (KO) and/or TNFR 2 (p75) KO donor T cells. Donor p75 KO but not p55KO donor T cells failed to induce acute GVHD phenotype and instead induced a lupus-like chronic GVHD both short and long term because of quantitative and qualitative donor T cell defects, that is, reduced perforin, IFN-γ, and TNF production. Transfer of mixed or matched purified CD4 and CD8 T cells from wild type or p75KO donors demonstrated that optimal CTL maturation required p75 signaling in both CD4 and CD8 T cells. Despite defective p75KO CD4 help for CD8 CTL, p75KO CD4 help for B cells and autoimmunity was intact. These results provide a mechanism by which impaired CD8 CTL could contribute to reduced antiviral and antitumor responses and autoimmunity reported in patients receiving TNF blockers. Our results support the idea that selective p55 blockade may be beneficial by reducing inflammation without compromising CD8 CTL.

Helminth protection against autoimmune diabetes in nonobese diabetic mice is independent of a type 2 immune shift and requires TGF-ß.

Leading hypotheses to explain helminth-mediated protection against autoimmunity postulate that type 2 or regulatory immune responses induced by helminth infections in the host limit pathogenic Th1-driven autoimmune responses. We tested these hypotheses by investigating whether infection with the filarial nematode Litomosoides sigmodontis prevents diabetes onset in IL-4-deficient NOD mice and whether depletion or absence of regulatory T cells, IL-10, or TGF-ß alters helminth-mediated protection. In contrast to IL-4-competent NOD mice, IL-4-deficient NOD mice failed to develop a type 2 shift in either cytokine or Ab production during L. sigmodontis infection. Despite the absence of a type 2 immune shift, infection of IL-4-deficient NOD mice with L. sigmodontis prevented diabetes onset in all mice studied. Infections in immunocompetent and IL-4-deficient NOD mice were accompanied by increases in CD4(+)CD25(+)Foxp3(+) regulatory T cell frequencies and numbers, respectively, and helminth infection increased the proliferation of CD4(+)Foxp3(+) cells. However, depletion of CD25(+) cells in NOD mice or Foxp3(+) T cells from splenocytes transferred into NOD.scid mice did not decrease helminth-mediated protection against diabetes onset. Continuous depletion of the anti-inflammatory cytokine TGF-ß, but not blockade of IL-10 signaling, prevented the beneficial effect of helminth infection on diabetes. Changes in Th17 responses did not seem to play an important role in helminth-mediated protection against autoimmunity, because helminth infection was not associated with a decreased Th17 immune response. This study demonstrates that L. sigmodontis-mediated protection against diabetes in NOD mice is not dependent on the induction of a type 2 immune shift but does require TGF-ß.

Sex differences in donor T cell targeting of host splenocyte subpopulations in acute and chronic murine graft-vs.-host disease: implications for lupus-like autoimmunity.

This study sought to compare in vivo sex differences in either a Th1-dominant CTL response or a Tfh-mediated lupus-like antibody response using the parent-into F1 murine model of acute or chronic GVHD respectively. In acute GVHD we observed no significant sex differences in the hierarchy of donor CD8 CTL elimination of splenocyte subsets. B cells were the most sensitive to elimination in both sexes; however, the male response was significantly stronger. Sex differences in chronic GVHD were more widespread; females exhibited significantly greater numbers of total splenocytes and host CD4 Tfh cells, B cells and CD8 T cells consistent with reports of greater female autoantibody production in this model. The more potent male CTL response in acute GVHD conflicts with reports of greater female CTL responses following infections or vaccines and may reflect the absence of exogenous innate immune stimuli in this model.

Donor CD8 T cells and IFN-gamma are critical for sex-based differences in donor CD4 T cell engraftment and lupus-like phenotype in short-term chronic graft-versus-host disease mice.

The transfer of unfractionated DBA/2J (DBA) splenocytes into B6D2F(1) (DBA → F(1)) mice results in greater donor CD4 T cell engraftment in females at day 14 that persists long-term and mediates greater female lupus-like renal disease. Although donor CD8 T cells have no demonstrated role in lupus pathogenesis in this model, we recently observed that depletion of donor CD8 T cells prior to transfer eliminates sex-based differences in renal disease long-term. In this study, we demonstrate that greater day 14 female donor CD4 engraftment is also critically dependent on donor CD8 T cells. Male DBA → F(1) mice exhibit stronger CD8-dependent day 8-10 graft-versus-host (GVH) and counter-regulatory host-versus-graft (HVG) responses, followed by stronger homeostatic contraction (days 10-12). The weaker day 10-12 GVH and HVG in females are followed by persistent donor T cell activation and increasing proliferation, expansion, and cytokine production from days 12 to 14. Lastly, greater female day 14 donor T cell engraftment, activation, and cytokine production were lost with in vivo IFN-γ neutralization from days 6 to 14. We conclude the following: 1) donor CD8 T cells enhance day 10 proliferation of donor CD4 T cells in both sexes; and 2) a weaker GVH/HVG in females allows prolonged survival of donor CD4 and CD8 T cells, allowing persistent activation. These results support the novel conclusion that sex-based differences in suboptimal donor CD8 CTL activation are critical for shaping sex-based differences in donor CD4 T cell engraftment at 2 wk and lupus-like disease long-term.

Enhancement of suboptimal CD8 cytotoxic T cell effector function in vivo using antigen-specific CD80 defective T cells.

T cell upregulation of B7 molecules CD80 and CD86 limits T cell expansion in immunodeficient hosts; however, the relative roles of CD80 separate from CD86 on CD4 versus CD8 T cells in a normal immune system are not clear. To address this question, we used the parent-into-F1 (P→F1) murine model of graft-versus-host disease and transferred optimal and suboptimal doses of CD80 and/or CD86 knockout (KO) T cells into normal F1 hosts. Enhanced elimination of host B cells by KO T cells was observed only at suboptimal donor cell doses and was greatest for CD80 KO→F1 mice. Wild-type donor cells exhibited peak CD80 upregulation at day 10; CD80 KO donor cells exhibited greater peak (day 10) donor T cell proliferation and CD8 T cell effector CTL numbers versus wild-type→F1 mice. Fas or programmed cell death-1 upregulation was normal as was homeostatic contraction of CD80 KO donor cells from days 12-14. Mixing studies demonstrated that maximal host cell elimination was seen when both CD4 and CD8 T cells were CD80 deficient. These results indicate an important role for CD80 upregulation on Ag-activated CD4 and CD8 T cells in limiting expansion of CD8 CTL effectors as part of a normal immune response. Our results support further studies of therapeutic targeting of CD80 in conditions characterized by suboptimal CD8 effector responses.

Donor CD8 T cell activation is critical for greater renal disease severity in female chronic graft-vs.-host mice and is associated with increased splenic ICOS(hi) host CD4 T cells and IL-21 expression.

Lupus-like renal disease in DBA/2-into-F1 (DBA --> F1) mice is driven by donor CD4 T cells and is more severe in females. Donor CD8 T cells have no known role. As expected, we observed that females receiving unfractionated DBA splenocytes (CD8 intact --> F1) exhibited greater clinical and histological severities of renal disease at 13 weeks compared to males. Surprisingly, sex-based differences in renal disease severity were lost in CD8 depleted --> F1 mice due to an improvement in females and a worsening in males. CD8 intact --> F1 female mice exhibited significantly greater donor and host effector (CD44(hi), CD62L(lo)) CD4 T cells and ICOS(hi) CD4 T follicular helper cells than males. CD8 depleted --> F1 female mice exhibited a reduction in the absolute numbers of host, but not donor CD4 Tfh cells and lost the significant increase in host CD4 effector cells vs. males. Greater female IL-21 expression, a product of Tfh cells, was seen in CD8 intact --> F1 and although reduced was still greater than male CD8 depleted --> F1 mice. Thus, donor CD8 T cells have a critical role in mediating sex-based differences in lupus renal disease severity possibly through greater host ICOS(hi) CD4 T cell involvement.

Response gene to complement 32 is required for C5b-9 induced cell cycle activation in endothelial cells.

Proliferation of vascular endothelial cells (EC) and smooth muscle cells (SMC) is a critical event in angiogenesis and atherosclerosis. We previously showed that the C5b-9 assembly during complement activation induces cell cycle in human aortic EC (AEC) and SMC. C5b-9 can induce the expression of Response Gene to Complement (RGC)-32 and over expression of this gene leads to cell cycle activation. Therefore, the present study was carried out to test the requirement of endogenous RGC-32 for the cell cycle activation induced by C5b-9 by knocking-down its expression using siRNA. We identified two RGC-32 siRNAs that can markedly reduce the expression of RGC-32 mRNA in AEC. RGC-32 silencing in these cells abolished DNA synthesis induced by C5b-9 and serum growth factors, indicating the requirement of RGC-32 activity for S-phase entry. RGC-32 siRNA knockdown also significantly reduced the C5b-9 induced CDC2 activation and Akt phosphorylation. CDC2 does not play a role in G1/S transition in HeLa cells stably overexpressing RGC-32. RGC-32 was found to physically associate with Akt and was phosphorylated by Akt in vitro. Mutation of RGC-32 protein at Ser 45 and Ser 47 prevented Akt mediated phosphorylation. In addition, RGC-32 was found to regulate the release of growth factors from AEC. All these data together suggest that cell cycle induction by C5b-9 in AEC is RGC-32 dependent and this is in part through regulation of Akt and growth factor release.

A secreted schistosome cathepsin B1 cysteine protease and acute schistosome infection induce a transient T helper 17 response.

The natural history of schistosome infection in the mammalian host is determined by CD4+ T helper responses mounted against different parasite life cycle stages. A T helper 2 (TH2) response to schistosome eggs is required for host survival and establishment of chronic infection. However, a TH2 cell-derived cytokine also contributes to an immune milieu that is conducive to schistosome growth and development. Thus, the same responses that allow for host survival have been co-opted by schistosomes to facilitate parasite development and transmission, underscoring the significance of CD4+ T cell responses to both worms and eggs in the natural history of schistosome infection. Here we show that a cathepsin B1 cysteine protease secreted by schistosome worms not only induces TH2 responses, but also TH1 and TH17 responses, by a mechanism that is dependent on the proteolytic activity of the enzyme. Further investigation revealed that, in addition to the expected TH1 and TH2 responses, acute schistosome infection also induces a transient TH17 response that is rapidly down-regulated at the onset of oviposition. TH17 responses are implicated in the development of severe egg-induced pathology. The regulation of worm-induced TH17 responses during acute infection could therefore influence the expression of high and low pathology states as infection progresses.

Arylallenes and the halogeno-B(C6F5)2 reagents: facile formation of 2-borylindenes.

Phenylallene reacts rapidly with ClB(C6F5)2 to give the respective 2-borylindene. Several substituted allenylarenes form the respective 2-B(C6F5)2 boryl-substituted indenes upon treatment with ClB(C6F5)2 or BrB(C6F5)2 as well. Bis- and tris-allenylarenes form the corresponding products featuring multiple five-membered ring annulations, including a symmetrical tris-borylated dihydro-1H-trindene derivative. The B(C6F5)2 borylindenes show fluorescence properties.

Alkylated Aromatic Thioethers with Aggregation-Induced Emission Properties-Assembly and Photophysics.

In this contribution, we present the synthesis and self-assembly of alkylated thioethers with interesting photophysical properties. To this end, the emission, absorption and excitation spectra in organic solvents and as aggregates in water were measured as well as the corresponding photoluminescence quantum yields and lifetimes. The aggregates in aqueous media were visualized and measured using transmission electron microscopy. Besides that, crystal structures of selected compounds allowed a detailed discussion of the structure-property relationship. Furthermore, the mesomorphic behavior was investigated using polarized optical microscopy (POM) as well as differential scanning calorimetry (DSC).

The parent-into-F1 murine model in the study of lupus-like autoimmunity and CD8 cytotoxic T lymphocyte function.

The transfer of homozygous C57Bl/6 (B6) or DBA/2 (DBA) parental strain T cells into normal B6D2F1 mice in the parent-into-F1 (p → F1) model results in a graft-vs.-host disease (GVHD) that takes one of the following two forms: (a) acute GVHD seen with B6 → F1 mice and mediated by donor CD8 cytotoxic T cells that eliminate host lymphocytes and (b) a chronic lupus-like GVHD seen with DBA → F1 mice and mediated by donor CD4 T cell cognate help to autoreactive B cells resulting in autoantibody production and renal disease similar to human lupus. Importantly, these two phenotypes can be distinguished by flow cytometry as early as 2 weeks after donor cell transfer. The p → F1 model can be used to screen for agents that alter lupus development. Additionally, the model is useful for preclinical screening of biologic agents with immunomodulatory potential. Agents that selectively inhibit CD8 T cell function will convert acute GVHD to chronic GVHD in B6 → F1 mice. Conversely, agents that promote CD8 CTL function will convert chronic GVHD to acute GVHD in DBA → F1 mice. Agents that completely suppress T cell function will block both phenotypes. The model is also useful for examining the effects of T cell mutations by transferring mutant T cells into wild-type hosts and assessing the effects on disease phenotype. Differences observed from wild-type T cells → F1 can be directly ascribed to alterations in mutant T cell function. Because of the early 2-week phenotype development, the p → F1 model is well suited to screening of potential immunomodulatory therapeutic compounds and the assessment of T cell mutations on in vivo function.