IL-4/IL-13 independent goblet cell hyperplasia in experimental helminth infections

BACKGROUND: Intestinal mucus production by hyperplasic goblet cells is a striking pathological feature of many parasitic helminth infections and is related to intestinal protection and worm expulsion. Induction of goblet cell hyperplasia is associated with TH2 immune responses, which in helminth infections are controlled primarily by IL-13, and also IL-4. In the study presented here we examine the goblet cell hyperplasic response to three experimental parasitic helminth infections; namely Nippostrongylus brasiliensis, Syphacia obvelata and Schistosoma mansoni. RESULTS: As expected N. brasiliensis infection induced a strong goblet cell hyperplasia dependent on IL-4/IL-13/IL-4Ralpha expression. In contrast, and despite previously published transiently elevated IL-4/IL-13 levels, S. obvelata infections did not increase goblet cell hyperplasia in the colon. Furthermore, induction of goblet cell hyperplasia in response to S. mansoni eggs traversing the intestine was equivalent between BALB/c, IL-4/IL-13-/- and IL-4Ralpha-/- mice. CONCLUSION: Together these data demonstrate that intestinal goblet cell hyperplasia can be independent of TH2 immune responses associated with parasitic helminth infections

IL-4Rα-Independent Expression of Mannose Receptor and Ym1 by Macrophages Depends on their IL-10 Responsiveness

IL-4Rα-dependent responses are essential for granuloma formation and host survival during acute schistosomiasis. Previously, we demonstrated that mice deficient for macrophage-specific IL-4Rα (LysMcreIl4ra−/lox) developed increased hepatotoxicity and gut inflammation; whereas inflammation was restricted to the liver of mice lacking T cell-specific IL-4Rα expression (iLckcreIl4ra−/lox). In the study presented here we further investigated their role in liver granulomatous inflammation. Frequencies and numbers of macrophage, lymphocyte or granulocyte populations, as well as Th1/Th2 cytokine responses were similar in Schistosoma mansoni-infected LysMcreIl4ra−/lox liver granulomas, when compared to Il4ra−/lox control mice. In contrast, a shift to Th1 responses with high IFN-γ and low IL-4, IL-10 and IL-13 was observed in the severely disrupted granulomas of iLckcreIl4ra−/lox and Il4ra−/− mice. As expected, alternative macrophage activation was reduced in both LysMcreIl4ra−/lox and iLckcreIl4ra−/lox granulomas with low arginase 1 and heightened nitric oxide synthase RNA expression in granuloma macrophages of both mouse strains. Interestingly, a discrete subpopulation of SSChighCD11b+I-A/I-EhighCD204+ macrophages retained expression of mannose receptor (MMR) and Ym1 in LysMcreIl4ra−/lox but not in iLckcreIl4ra−/lox granulomas. While aaMφ were in close proximity to the parasite eggs in Il4ra−/lox control mice, MMR+Ym1+ macrophages in LysMcreIl4ra−/lox mice were restricted to the periphery of the granuloma, indicating that they might have different functions. In vivo IL-10 neutralisation resulted in the disappearance of MMR+Ym1+ macrophages in LysMcreIl4ra−/lox mice. Together, these results show that IL-4Rα-responsive T cells are essential to drive alternative macrophage activation and to control granulomatous inflammation in the liver. The data further suggest that in the absence of macrophage-specific IL-4Rα signalling, IL-10 is able to drive mannose receptor- and Ym1-positive macrophages, associated with control of hepatic granulomatous inflammation

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

The role of IL-4 and IL-13 responsiveness during Schistosoma mansoni induced inflammation

Includes abstract.Includes bibliographical references (leaves 117-129).Schistosoma mansoni egg passage through intestinal tissue into the faecal stream is a critical event for completion of the life cycle of the helminth and involves induction of a type 2 immune response, which is necessary for the host’s survival. Where as T cell-specific IL-4Rα has been shown not to be essential for survival, macrophage/neutrophil-specific IL-4 receptor α-deficient mice (LysMIcre L-4Rα-/lox ), mice lacking alternative macrophages (AAMФ), had severe intestine pathology and high endotoxin levels due to poor egg excretion and dysregulated granuloma formation. This resulted in increased mortality. To determine the role of AAMФ in granuloma we aimed to describe S.mansoni egg induced granuloma formation in the presence and absence of AAMФ using LysMcreIL-4Rα-/lox mice

Plasma and leukocyte gelatinases in health and disease

Includes bibliographical references

TLR7 ligand R848 prevents mouse graft-versus-host disease and cooperates with anti-IL-27 antibody for maximal protection and Treg upregulation.

In spite of considerable therapeutic progress, acute graft-versus-host disease still limits allogeneic hematopoietic cell transplantation. We recently reported that mouse infection with nidovirus lactate dehydrogenase elevating virus impairs disease in non-conditioned B6D2F1 recipients of parental B6 spleen cells. As this virus activates TLR7, we tested pharmacologic TLR7 ligand R848 in this model and observed complete survival if donor and recipients were treated before transplantation. Mixed lymphocyte culture performed 48 h after R848-treatment of normal mice demonstrated that both T cell allo-responsiveness and antigen presentation by CD11b+ and CD8α+ dendritic cells were inhibited. These inhibitions were dependent on IFNAR-1 signaling. In the B6 to B6D2F1 transplantation model, R848 decelerated, but did not abrogate, donor T cell implantation and activation. However, it decreased IFNγ, TNFα and IL-27 while upregulating active TGF-β1 plasma levels. In addition, donor and recipient Foxp3+ regulatory T cell numbers were increased in recipient mice and their elimination compromised disease prevention. R848 also strongly improved survival of lethally irradiated BALB/c recipients of B6 hematopoietic cells and this also correlated with an upregulation of CD4 and CD8 Foxp3+ regulatory T cells that could be further increased by IL-27 inhibition. The anti-IL-27p28 monoclonal antibody and R848 combination also showed strong synergy in preventing disease in the B6 to B6D2F1 transplantation model when recipients were sublethally irradiated and this also correlated with Treg upregulation. We conclude that R848 modulates multiple aspects of graft-versus-host disease and offers potential for safe allogeneic bone marrow transplantation that can be further optimized by IL-27 inhibition

IL-4Ralpha responsive CD4+CD25−CD103+FoxP3− cells control Schistosoma mansoni egg-induced inflammation by secreted IL-10

IL-4Ralpha signalling drives Th2-type responses that mediate resistance to parasitic helminth infections. We generated a novel mouse model lacking IL-4Ralpha expression specifically on all T cells (iLckcreIl4ra−/lox) to investigate IL-4Ralpha-dependent T cell responses during Schistosoma mansoni egg-driven inflammation. These mice showed higher mortality during acute schistosomiasis compared with Il4ra−/lox controls and previously established CD4+ T cell specific IL-4Ralpha deficient mice (LckcreIl4ra−/lox). iLckcreIl4ra−/lox mice developed a liver restricted pathology associated with drastic reductions of both Th2/type 2 responses and alternative macrophage activation within the granulomas. Additionally, iLckcreIl4ra−/lox mice had (i) increased FoxP3+ Treg cell responses in the granulomas, which was explained by IL-4 mediated inhibition of FoxP3 induction, and (ii) reduction of antigen-specific production of IL-10 by CD4+CD103+FoxP3− cells. In a footpad model of S. mansoni egg-induced inflammation with subsequent IL-10 neutralisation and adoptive cell transfer experiments we found evidence that the increased inflammation in iLckcreIl4ra−/lox mice was due to the impaired development of IL-10-secreting CD4+CD25−CD103+FoxP3− cells. Together, these data demonstrate that IL-4Ralpha responsiveness by T cells promote IL-10-secreting CD4+CD25−CD103+FoxP3− cells and alternatively activated macrophages, which act in concert to control egg-induced inflammation

Mouse nidovirus LDV infection alleviates graft versus host disease and induces type I IFN-dependent inhibition of dendritic cells and allo-responsive T cells

Introduction: Viruses have developed multiple mechanisms to alter immune reactions. In 1969, it was reported that lactate dehydrogenase-elevating virus (LDV), a single stranded positive sense mouse nidovirus, delays skin allograft rejection and inhibits spleen alterations in graft versus host disease (GVHD). As the underlying mechanisms have remained unresolved and given the need for new therapies of this disease, we reassessed the effects of the virus on GVHD and tried to uncover its mode of action. Methods: GVHD was induced by transfer of parent (B6) spleen cells to non-infected or LDV-infected B6D2F1 recipients. In vitro mixed-lymhocyte culture (MLC) reactions were used to test the effects of the virus on antigen-presenting cells (APC) and responder T cells. Results: LDV infection resulted in a threefold increase in survival rate with reduced weight loss and liver inflammation but with the establishment of permanent chimerism that correlated with decreased interleukine (IL)-27 and interferon (IFN)γ plasma levels. Infected mice showed a transient elimination of splenic CD11b+ and CD8α+ conventional dendritic cells (cDCs) required for allogeneic CD4 and CD8 T cell responses in vitro. This drop of APC numbers was not observed with APCs derived from toll-like receptor (TLR)7-deficient mice. A second effect of the virus was a decreased T cell proliferation and IFNγ production during MLC without detectable changes in Foxp3+ regulatory T cell (Tregs) numbers. Both cDC and responder T cell inhibition were type I IFN dependent. Although the suppressive effects were very transient, the GVHD inhibition was long-lasting. Conclusion: A type I IFN-dependent suppression of DC and T cells just after donor spleen cell transplantation induces permanent chimerism and donor cell implantation in a parent to F1 spleen cell transplantation model. If this procedure can be extended to full allogeneic bone marrow transplantation, it could open new therapeutic perspectives for hematopoietic stem cell transplantation (HSCT)