The imbalance between Treg and Th17 cells caused by FTY720 treatment in skin allograft rejection

OBJECTIVES: FTY720 modulates CD4+T cells by the augmentation of regulatory T cell activity, secretion of suppressive cytokines and suppression of IL-17 secretion by Th17 cells. To further understand the process of graft rejection/acceptance, we evaluated skin allograft survival and associated events after FTY720 treatment. METHODS: F1 mice (C57BL/6xBALB/c) and C57BL/6 mice were used as donors for and recipients of skin transplantation, respectively. The recipients were transplanted and either not treated or treated with FTY720 by gavage for 21 days to evaluate the allograft survival. In another set of experiments, the immunological evaluation was performed five days post-transplantation. The spleens, axillary lymph nodes and skin allografts of the recipient mice were harvested for phenotyping (flow cytometry), gene expression (real-time PCR) and cytokine (Bio-Plex) analysis. RESULTS: The FTY720 treatment significantly increased skin allograft survival, reduced the number of cells in the lymph nodes and decreased the percentage of Tregs at this site in the C57BL/6 recipients. Moreover, the treatment reduced the number of graft-infiltrating cells and the percentage of CD4+ graft-infiltrating cells. The cytokine analysis (splenocytes) showed decreased levels of IL-10, IL-6 and IL-17 in the FTY720-treated mice. We also observed a decrease in the IL-10, IL-6 and IL-23 mRNA levels, as well as an increase in the IL-27 mRNA levels, in the splenocytes of the treated group. The FTY720-treated mice exhibited increased mRNA levels of IL-10, IL-27 and IL-23 in the skin graft. CONCLUSIONS: Our results demonstrated prolonged but not indefinite skin allograft survival by FTY720 treatment. This finding indicates that the drug did not prevent the imbalance between Tr1 and Th17 cells in the graft that led to rejection.

Estudo comparativo dos efeitos da talidomida, da ciclosporina e do diclofenaco na sobrevida de aloenxertos cutâneos em coelho / Assessment of immunossupresion induced by thalidomide, cyclosporine and diclofenac on skin allograft survival in rabbits

OBJETIVO: Verificar se a talidomida é capaz de evitar a rejeição de aloenxertos de pele em coelhos, como droga isolada, ou melhorar a eficácia de doses subterapêuticas de ciclosporina, comparando seu efeito ao de doses terapêuticas da ciclosporina e também ao papel antiinflamatório do diclofenaco de sódio. MÉTODOS: Foram estudados 42 coelhos, distribuídos nos seguintes grupos (n=6): Grupo 1 - controle com auto-enxerto; Grupo 2 - controle com aloenxerto; Grupo 3 - aloenxerto sob o efeito de talidomida (100 mg/kg/dia); Grupo 4 - aloenxerto sob o efeito de diclofenaco de sódio (2 mg/kg/dia); Grupo 5 - aloenxerto sob o efeito de ciclosporina (10 mg/kg/dia); Grupo 6 - aloenxerto sob o efeito de ciclosporina (5 mg/kg/dia); Grupo 7 - aloenxerto sob o efeito de ciclosporina (5 mg/kg/dia) associada a talidomida (100 mg/kg/dia). Foram retirados enxertos circulares de pele total do dorso de uma das orelhas do animal. Os medicamentos foram administrados por cateter orogástrico, a partir do dia anterior ao transplante. Os enxertos foram trocados entre coelhos de raças diferentes. RESULTADOS: A ciclosporina a 10 mg/kg/dia prolongou a sobrevida dos enxertos de pele, sendo seu efeito comparável ao obtido com a ciclosporina em dose subterapêutica (5 mg/kg/dia) associada a talidomida a 100 mg/kg/dia. A talidomida isoladamente, mesmo em concentração de 100 mg/kg/dia, e o diclofenaco tiveram efeito mínimo na sobrevida média dos aloenxertos cutâneos. O número de eosinófilos no infiltrado inflamatório circunjacente à necrose foi maior nos grupos tratados com diclofenaco e com ciclosporina a 5 mg/kg/dia e menor no grupo em que se associou ciclosporina com talidomida. CONCLUSÃO: A talidomida pode ser uma droga útil para associar-se a baixas doses de ciclosporina no tratamento de aloenxertos cutâneos.

OBJECTIVE: Allografting is one of the therapeutic alternatives for extensive burn victims without sufficient skin donor areas. This research studied the effects of cyclosporine, as an immunosuppressor model, and thalidomide and dyclofenac as anti-inflammatory drugs on an experimental skin allograft research. METHODS: Forty-two rabbits were divided in the following groups (n=6): Group 1 - autografting control; Group 2 - allografting control; Group 3 - allografts under thalidomide effect (100 mg/kg/day); Group 4 - allografts under sodium dyclofenac effect (2 mg/kg/day); - Group 5 -allografts under cyclosporine effect (10 mg/kg/day); Group 6 - allografts under cyclosporine effect (5 mg/kg/day); Group 7- allografts under cyclosporine (5 mg/kg/day) plus thalidomide (100 mg/kg/day) effect. Drugs were given via orogastric tube since the day before transplantation and daily during the postoperative period. Circular total skin grafts of the ear were exchanged between California and White New Zealand rabbits. RESULTS: Cyclosporine 10 mg/kg/day increased allograft survival and this effect was comparable to the association of cyclosporine 5 mg/kg/day with thalidomide 100 mg/kg/day. Thalidomide as an isolated drug and dyclofenac had a minimum effect on the average survival of the skin allografts. The number of eosinophils around the necrotic skin was higher in the dyclofenac group and lower in the group receiving cyclosporine associated with thalidomide. CONCLUSION: This study showed that thalidomide may be an useful drug when associated with subtherapeutic doses of cyclosporine for treatment of skin allografts.

Colchicine-derived compound CT20126 promotes skin allograft survival by regulating the balance of Th1 and Th2 cytokine production

Colchicine has been shown to regulate the expression of inflammatory gene, but this compound possesses much weaker anti-inflammatory activity. In this study, we synthesized a new colchicine derivative CT20126 and examined its immunomodulatory property. CT20126 was found to have immunosuppressive effects by inhibiting lymphocyte proliferation without cytotoxicity and effectively inhibit the transcriptional expression of the inflammatory genes, iNOS, TNF-alpha, and IL-1beta, in macrophages stimulated by LPS. This effect was nearly comparable to that of cyclosporine A. This compound also significantly suppressed the production of nitric oxide and Th1-related pro-inflammatory cytokines, IL-1beta, TNF-alpha, and IL-2, with minimal suppression of Th2-related anti-inflammatory cytokines IL-4 and IL-10 in the sponge matrix allograft model. Moreover, administration of CT20126 prolonged the survival of allograft skins from BALB/c mice (H-2d) to the dorsum of C57BL/6 (H-2b) mice. The in vivo immune suppressive effects of CT20126 were similar to that of cyclosporine A. These results indicate that this compound may have potential therapeutic value for transplantation rejection and other inflammatory diseases.

IL-2 Pathway Blocking in Combination with Anti-CD154 Synergistically Establishes Mixed Macrochimerism with Limited Dose of Bone Marrow Cells and Prolongs Skin Graft Survival in Mice

To facilitate the establishment of mixed chimerism with limited dose of bone marrow (BM) cells, and to achieve tolerance in skin graft model, combined blocking of costimulatory pathway and IL-2 pathway was used in minimally myeloablative model using busulfan. BM cells (2.5 x 10(7)) of BALB/c were injected into C57BL/6 mice at day 0 with full thickness skin graft after single dose injection of busulfan (25 mg/kg) on day-1. Recipients were grouped and injected the anti-CD154, CTLA4-Ig, anti-IL-2R at days 0, 2, 4, and 6 according to protocol. Mixed macrochimerism were induced in groups treated with anti-CD154+anti-CTLA4-Ig, anti-CD154+anti-IL-2R, and anti-CD154+anti-CTLA4 Ig+anti-IL-2R. Three groups having chimerism enjoyed prolonged graft survival more than 6 months. Superantigen deletion study revealed deletion of alloreactive T cells in combined blockade treated groups. In graft versus host disease model using CFSE staining, CD4+ T cell and CD8+ T cell proliferation were reduced in groups treated with CTLA4-Ig or anti-IL-2R or both in combination with anti-CD154. However, anti-IL-2R was not so strong as CTLA4-Ig in terms of inhibition of T cell proliferation. In conclusion, IL-2 pathway blocking combined with anti-CD154 can establish macrochimerism with limited dose of BM transplantation and induce specific tolerance to allograft.

IL-2 Pathway Blocking in Combination with Anti-CD154 Synergistically Establishes Mixed Macrochimerism with Limited Dose of Bone Marrow Cells and Prolongs Skin Graft Survival in Mice

To facilitate the establishment of mixed chimerism with limited dose of bone marrow (BM) cells, and to achieve tolerance in skin graft model, combined blocking of costimulatory pathway and IL-2 pathway was used in minimally myeloablative model using busulfan. BM cells (2.5 x 10(7)) of BALB/c were injected into C57BL/6 mice at day 0 with full thickness skin graft after single dose injection of busulfan (25 mg/kg) on day-1. Recipients were grouped and injected the anti-CD154, CTLA4-Ig, anti-IL-2R at days 0, 2, 4, and 6 according to protocol. Mixed macrochimerism were induced in groups treated with anti-CD154+anti-CTLA4-Ig, anti-CD154+anti-IL-2R, and anti-CD154+anti-CTLA4 Ig+anti-IL-2R. Three groups having chimerism enjoyed prolonged graft survival more than 6 months. Superantigen deletion study revealed deletion of alloreactive T cells in combined blockade treated groups. In graft versus host disease model using CFSE staining, CD4+ T cell and CD8+ T cell proliferation were reduced in groups treated with CTLA4-Ig or anti-IL-2R or both in combination with anti-CD154. However, anti-IL-2R was not so strong as CTLA4-Ig in terms of inhibition of T cell proliferation. In conclusion, IL-2 pathway blocking combined with anti-CD154 can establish macrochimerism with limited dose of BM transplantation and induce specific tolerance to allograft.

Two-signal blockade with anti-CD45RB and anti-CD154 monoclonal antibodies inhibits graft rejection via CD4-dependent mechanisms in allogeneic skin transplantation

Blockade of signal 1 or 2 for T-cell activation by the use of anti-CD45RB and anti-CD154 monoclonal antibodies (mAb) (two-signal blockade) has been proven effective in preventing or delaying graft rejection. However, the mechanisms of its immunomodulatory effects are clearly unknown and the present studies were performed to determine how the two-signal blockade modulate allogeneic immune responses, especially T-cell mediated cellular immunity, in a murine skin allograft model. We now report on the profound inhibition of alloreactive T cells by two-signal blockade via CD4-dependent mechanisms. C57BL/6 mice of BALB/c skin allograft were treated with anti-CD45RB, anti-CD154, CTLA4-Ig, or their combinations. For depletion of CD4 or CD8 T cells, the recipients received CD4-depleting or CD8-depleting mAb. We confirmed that survival of skin allograft was markedly prolongated in the two-signal blockade-treated group. In depletion study, anti-CD45RB, anti-CD154 and CD4-depleting mAb-treated group showed acute rejection of skin allograft in contrast to CD8-depleting group treated with the two-signal blockade. In the group treated with the two-signal blockade, the proportions of CD4+CD45RB(low)and CD8+CTLA-4 regulatory T cells were increased while effector CD8+ T cells, including IFN-gamma-secreting and CD8+CD62L(low)T cells, were decreased when compared with non-treated group. In contrast, the CD4-depleted group treated with the two-signal blockade resulted in recovery from immunoregulatory effects of two-signal blockade. In addition, results of IL-4 and IL-10 production were also showed CD4-dependence. Therefore, the two-signal blockade is accompanied by CD4-dependent mechanisms in allogeneic skin transplantation.

Induçäo a tolerancia a aloantigenos por via oral em camundongos submetidos a alotransplante de pele / Tolerance indution to alloantigens by oral administration in submited mice to the skin allotransplantation

Na Imunologia dos Transplantes, um dos aspectos fundamentais e a tentativa de imunomodulaçäo do aloenxerto, sem a induçäo de efeitos deletereos secundários, como os observados em métodos clássicos de imunossupressao. As terapias imunossupressoras constituem uma pratica comum nos centros de transplantes, promovendo a inibiçäo preventiva da resposta imunologica. Os agentes supressores atualmente empregados apresentam uma eficacia consideravel em aumentar a sobrevida do enxerto. Entretanto, sua utilizaçäo prolongada e sua inespecificidade de açäo podem aumentar a suscetibilidade a infecçöes e ao desenvolvimento de neoplasias no hospedeiro. A tolerância oral, induzida com aloantigenos (celulas imunocompetentes), tem demonstrado ser uma terapia de imunomodulaçäo ao da resposta a aloantigenos...

Allosensitization induced suppression of various murine tumors: role of non-H-2 antigens in antitumor immunity.

Presence of alloantigens on various murine tumors was tested by tumor rejection in allosensitized Swiss mice. The results indicated the presence of alloantigen on immunogenic tumors like chemically induced fibrosarcoma (FS), ascitic sarcoma 180 (S 180) and immunogenic variant of lymphosarcoma (LS-A) in Swiss mice, while these antigens could not be detected by this procedure on spontaneous lymphosarcoma (LS). Allosensitization with skin graft was found to offer quantitatively higher antitumor resistance than the allosensitization achieved by allogeneic lymphocytes. Antitumor effect was not seen when tumor cells were inoculated earlier than day 3 of grafting. Further, host immunosuppression with whole body irradiation up to day of 3 of skin grafting abrogated the antitumor effect. H-2 compatible and non-H-2 incompatible skin graft sensitization of host could offer resistance against both S 180 and LS-A. Further, tumor immune mice rejected H-2 compatible, non-H-2 incompatible skin graft significantly earlier.

Eclampsia inducida por aloinjertos de piel en ratas espontáneamente hipertensas / Eclampsia induced by skin allografts in spontaneously hypertensive rats

Se intentió desarrolar un modelo experimental en eclampsia para estudiar su posible etiologia. Veinitdós ratas hembras de la cepa endocriada espontáneamente hipertensa (SHR) fueron injertadas con piel de machos de la cepa Holtzman. Se realizaron 4 injertos con intervalos de diez días. Cada SHR fue apareado con el macho donante correspondiente diez días después del último injerto. Como controles use usaron cinco SHR apareados con machos Holtzman si injertos previos. En la mayoría de las ratas experimentales que quedaron preñadas se encontraron alteraciones que consistieron en: bajo número de crías, fetos muertos, abortos y retardo dei crescimiento. La función renal fue evaluada antes y durante la preñez, mostrando un aumento fisiológico del filtrado glomerular del 7,5%, mientras que en la preñez normal se encotró un incremento del 166%. La histología renal mostró lesiones compatibles con coagulación intra-ratas puede afectar el normal desarrollo de la preñez y sugieren que podrían verse involucrados factores inmunológicos en el desarrollo de eclampsia