Blockade of CD28 by a synthetical peptoid inhibits T-cell proliferation and attenuates graft-versus-host disease

Abstract Acute graft-versus-host disease (aGVHD) develops in more than half of patients after allogeneic hematopoietic cell transplantation (allo-HCT) despite poly-pharmacy immunoprophylaxis. Importantly, the dysregulated pathways responsible for this breakthrough disease remain largely unidentified. Thus, the discovery of these pathways represents one of the critical challenges for the field of allo-HCT. To address these needs, we have developed a model of aGVHD in rhesus macaques, which allows us to study the mechanisms of aGVHD both in its untreated state and in a variety of immunoprophylactic settings. Using a systems-based approach, we have created both a multiparameter flow cytometric and transcriptomic map of the immune landscape of aGVHD in allo-HCT recipients, in comparison to two critical control groups: (1) healthy untransplanted controls, and (2) those receiving autologous transplantation. We find that recipients of allo-HCT receiving 1) no immunoprophylaxis 2) monotherapy with CTLA4Ig or 3) monotherapy with sirolimus develop early fulminant aGVHD with multi-organ disease (Figure 1a-grouped as 'Primary GVHD'). The immunophenotype of T cells from the Primary GVHD cohort exhibits an effector/memory phenotype with robust proliferation and acquisition of cytotoxic function. Transcriptomic analysis reveals enrichment of Th1-associated transcripts (IL12RB2, CCR5, CXCR3) as well as programs of proliferation early in the post transplant period (Figure 1b). Flow cytometric data confirms an increase in the number of CD4 and CD8 T cells producing the Th1 cytokine, IFN-g at this time-point (Figure 1c). In contrast, standard-of-care Tacrolimus/Methotrexate (Tac/Mtx) as well as novel CTLA4Ig/sirolimus combination immunoprophylaxis (CoBS) both significantly improved survival of animals after allo-HCT. However, similar to human patients undergoing allo-HCT, these recipients often developed clinical signs of breakthrough aGVHD (starting around day 30 post-transplant) characterized by both gastrointestinal and skin pathology. This cohort was thus termed the "Breakthrough GVHD" cohort (Figure 1a). Unexpectedly, despite the presence of breakthrough clinical aGVHD, the Tac/Mtx and CoBS cohorts were still able to control programs of T cell proliferation, effector phenotype acquisition and Th1 cytokine skewing. However, both transcriptional and flow cytometric profiles demonstrated enrichment for molecules that reflect Th17/Th22 skewing (RORC, IL17A, AHR, and IL22) (Figure 2a) and production of IL17a (Figure 2b). These results suggest that while current methods of immunoprophylaxis are able to limit both T cell proliferation and Th1 polarization, breakthrough Th17/Th22 pathway activation occurs despite these therapies. These data suggest that emphasis should be placed on exploration of pharmacologic inhibitors of IL17/IL22 for the prevention/treatment of breakthrough aGVHD. Disclosures No relevant conflicts of interest to declare.

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Indoleamine 2,3-dioxygenase is a critical regulator of acute graft-versus-host disease lethality

Blood ◽

10.1182/blood-2007-06-096081 ◽

2008 ◽

Vol 111 (6) ◽

pp. 3257-3265 ◽

Cited By ~ 112

Author(s):

Lisa K. Jasperson ◽

Christoph Bucher ◽

Angela Panoskaltsis-Mortari ◽

Patricia A. Taylor ◽

Andrew L. Mellor ◽

...

Keyword(s):

Cell Proliferation ◽

T Cells ◽

T Cell ◽

Graft Versus Host Disease ◽

Tissue Injury ◽

T Cell Proliferation ◽

Colonic Inflammation ◽

Host Disease ◽

Graft Versus Host ◽

Indoleamine 2,3 Dioxygenase

AbstractGraft-versus-host disease (GVHD) is initiated after activation of donor T cells by host antigen-presenting cells (APCs). The immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) is expressed by APCs and parenchymal cells and is further inducible by inflammation. We investigated whether lethal conditioning and GVHD induce IDO and if IDO prevents tissue injury by suppressing immune responses at the induction site. We determined that IDO is a critical regulator of GVHD, most strikingly in the colon, where epithelial cells dramatically up-regulated IDO expression during GVHD. IDO−/− mice died more quickly from GVHD, displaying increased colonic inflammation and T-cell infiltration. GVHD protection was not mediated by control of T-cell proliferation, apoptosis, or effector mechanisms in lymphoid organs, nor did it require donor T regulatory cells. Instead, T cells in IDO−/− colons underwent increased proliferation and decreased apoptosis compared with their wild-type counterparts. This evidence suggests that IDO can act at the site of expression to decrease T-cell proliferation and survival, diminishing colonic inflammation and reducing disease severity. These studies are the first to identify a function for IDO in GVHD lethality and indicate that modulation of the IDO pathway may be an effective strategy for treatment of this disease.

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Graft-versus-Host Disease Impairs Vaccine Responses through Decreased CD4+and CD8+T Cell Proliferation and Increased Perforin-Mediated CD8+T Cell Apoptosis

The Journal of Immunology ◽

10.4049/jimmunol.1200391 ◽

2012 ◽

Vol 190 (3) ◽

pp. 1351-1359 ◽

Cited By ~ 11

Author(s):

Christian M. Capitini ◽

Nicole M. Nasholm ◽

Brynn B. Duncan ◽

Martin Guimond ◽

Terry J. Fry

Keyword(s):

Cell Proliferation ◽

T Cell ◽

Graft Versus Host Disease ◽

Cell Apoptosis ◽

Cd8 T Cell ◽

T Cell Proliferation ◽

Host Disease ◽

Graft Versus Host ◽

Vaccine Responses ◽

T Cell Apoptosis

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Donor Requirements For CD4+CD25+FoxP3+ Regulatory T Cells Capable Of Suppressing CD4+ and CD8+ Conventional T Cell Proliferation and Graft Versus Host Disease

Blood ◽

10.1182/blood.v122.21.4484.4484 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4484-4484 ◽

Cited By ~ 1

Author(s):

Antonio Pierini ◽

Lucrezia Colonna ◽

Maite Alvarez ◽

Dominik Schneidawind ◽

Byung-Su Kim ◽

...

Keyword(s):

Cell Proliferation ◽

T Cells ◽

T Cell ◽

Animal Models ◽

Graft Versus Host Disease ◽

Third Party ◽

T Cell Proliferation ◽

Graft Versus Host

Adoptive transfer of CD4+CD25+FoxP3+ regulatory T cells (Tregs) prevents graft versus host disease (GvHD) in several animal models and following allogeneic hematopoietic cell transplantation (HCT) in clinical trials. In these models donor derived Tregs have been mainly used as they share the same major histocompatibility complex (MHC) with conventional CD4+ and CD8+ T cells (Tcons) that are primarily responsible for GvHD onset and persistence. Third-party derived Tregs are a promising alternative tool for cellular therapy as they can be prepared in advance, screened for pathogens and activity and banked. In this study we explored MHC disparities between Tregs and Tcons in HCT to evaluate the impact of these different cell populations in GvHD prevention and survival after transplant. Methods and Results We evaluated the ability of highly purified Treg to suppress proliferation of C57BL/6 (H-2b) Tcons following exposure to irradiated splenocytes from BALB/C (H-2d) mice in vitro in a mixed lymphocyte reaction (MLR). Either donor derived C57BL/6 (H-2b) or third party FVB (H-2q) Tregs suppressed Tcon proliferation at the Treg/Tcon ratios of 1:2 and 1:4. The same Treg population effectively suppressed different MHC derived Tcons where BALB/C (H-2d) or FVB (H-2q, third-party) Tcons were incubated with irradiated splenocytes from C57BL/6 (H-2b) mice and were effectively suppressed with BALB/C (H-2d) Tregs. In the MLR, third-party Tregs present the same activation molecule expression patterns as MHC matched Tregs: CTLA4 and LAG3 expression is enhanced after stimulation with interleukin-2 (IL-2) and anti-CD3/CD28 beads, while MHC class II molecule expression is increased after 3-4 days of culture with Tcons and irradiated splenocytes. Furthermore third-party and MHC matched Tregs express the same levels of interleukin-10 (IL-10). We translated these results to in vivo studies in animal models. In these studies T cell depleted bone marrow (TCD BM) from C57BL/6 (H-2b) mice was injected into lethally irradiated (total body irradiation, 8 Gy) BALB/C (H-2d) recipient mice. 2 days later GvHD was induced by injecting luc+ donor derived Tcons (1x106/mouse). Using this model GvHD was evaluated following the adoptive transfer of freshly isolated CD4+CD25+FoxP3+ Tregs derived from BALB/C (H-2d, host type), C57BL/6 (H-2b, donor type), FVB (H-2q, third-party) or BALB/B (H-2b, minor mismatched with the donor, major mismatched with the host) mice at the different Treg/Tcon ratios of 1:1, 1:2 and 1:4. As expected, donor Tregs exerted the strongest dose dependent GvHD protection (p = 0.028), while host Tregs did not improve mouse survival (p = 0.58). Third-party and minor mismatched with the donor Tregs improved mouse survival (third-party and minor mismatched with the donor respectively, p = 0.028 and p = 0.17) but mice had worse GvHD score profiles (both p< 0.001) and could not recover their weight as well as mice treated with donor Tregs (both p< 0.001). In vivoTcon bioluminescent imaging confirmed these results showing a reduced Tcon proliferation in mice treated with donor, third-party and minor mismatched with the donor Tregs, the first exerting the strongest effect (after 6 weeks of observation, p< 0.001). Conclusions Our studies indicate that MHC disparities between Tregs and Tcons do not represent an insurmountable barrier for Treg function. In vitro and in vivo data strongly suggest that Tregs can suppress Tcon proliferation without requiring MHC matching. In vivo GvHD prevention efficiency was affected by MHC disparities with donor derived Treg being the most effective, however, third party Treg also resulted in GvHD attenuation. These studies indicate that both donor and third party Treg could be effective in clinical application raising the possibility of screening and banking Treg for use. Further, these studies highlight the need for activation of the Treg on host tissues to effectively suppress conventional T cell proliferation and GvHD induction. Disclosures: No relevant conflicts of interest to declare.

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