Prevention of islet allograft rejection with engineered myoblasts expressing FasL in mice

Allogeneic transplantation of islets of Langerhans was facilitated by the cotransplantation of syngeneic myoblasts genetically engineered to express the Fas ligand (FasL). Composite grafting of allogeneic islets with syngeneic myoblasts expressing FasL protected the islet graft from immune rejection and maintained normoglycemia for more than 80 days in mice with streptozotocin-induced diabetes. Graft survival was not prolonged with composite grafts of unmodified myoblasts or Fas-expressing myoblasts. Islet allografts transplanted separately from FasL-expressing myoblasts into the contralateral kidney were rejected, as were similarly transplanted third-party thyroid allografts. Thus, the FasL signal provided site- and immune-specific protection of islet allografts.     

Cotransplantation of allogeneic islets with allogeneic testicular cell aggregates allows long-term graft survival without systemic immunosuppression

We prepared single-cell suspensions of Lewis rat ?RT1(1/l)? testicular cells and cultured these in vitro for 48 h under conditions that promoted the formation of cellular aggregates. In the absence of systemic immunosuppression, the transplantation of a sufficient quantity of these aggregates (containing 11 x 10(6) cells, (75% Sertoli cells), together with 2,000 purified Lewis rat islets, reversed the diabetic state for >95 days in 100% (5/5) of the chemically diabetic Wistar-Furth ?RT1(u/u)? recipients. Similar grafts consisting of islets alone or islets plus 50% fewer testicular cell aggregates survived for only 10 days. Functioning composite allografts harvested from normoglycemic animals at approximately 100 days showed healthy beta-cells in close association with Fas ligand-expressing Sertoli cells. Because no gene therapy protocol is required, the transplantation of composite grafts consisting of purified human allogeneic islets plus human allogeneic testicular cell aggregates can be applied in clinical islet transplantation as soon as it has been proven in a large animal model.     

Allogeneic cell therapy for a murine mammary carcinoma

The effect of allogeneic cell therapy on tumor growth was studied in a murine model of mammary carcinoma (4T1) as an experimental model of solid tumors in humans. i.v. inoculation of 4T1 (H-2d) cells into syngeneic mice [BALB/c or (BALB/cXC57BL/6)F1] (F1) carrying the H-2d histocompatible antigens results in tumor colonies in the lungs that finally cause the death of all of the mice. Sublethally irradiated F1 mice were inoculated with 4T1 cells to simulate minimal residual disease and with immunocompetent splenocytes derived from naive donors of F1 (syngeneic), BALB/c (syngeneic to the tumor but semiallogeneic to the host), or C57BL/6 (allogeneic to the tumor and semiallogeneic to the host) mice. The survival of F1 tumor-bearing mice that were treated with allogeneic C57BL/6 splenocytes was significantly prolonged (P < 0.02) compared with hosts given F1 or BALB/c-derived splenocytes that are syngeneic to 4T1 tumor cells. Adoptive transfer of lung cells that were isolated from F1 primary mice inoculated with 4T1 cells and syngeneic BALB/c or F1 splenocytes led to local tumor growth and death in secondary recipients. In contrast, only 1 of 22 secondary recipients developed tumors when inoculated with lung cells derived from F1 mice given allogeneic C57BL/6 splenocytes. All of the 21 secondary hosts survived disease-free for a follow-up time of >200 days. These results indicate that immunocompetent cells allogeneic to the mammary carcinoma cells were able to inhibit tumor development in the primary hosts and to prevent tumor growth in the adoptive recipients, which suggests that allogeneic cell therapy may be an efficient antitumor tool to eradicate minimal residual disease in human solid tumors.     

Antagonistic effects of systemic interleukin 2 on immune Tcell-mediated graft-versus-leukemia reactivity

This study demonstrates that systemic interleukin 2 (IL-2) can decrease the homing of syngeneic immune T cells to the target organ of metastases and accelerate unwanted side effects of allogeneic immune T cells. As a tumor system, we used the well-characterized highly aggressive DBA/2 mouse leukemia ESb and its less aggressive adhesion variant, ESb-MP. Systemic IL-2 treatment was performed with recombinant human interleukin-2 (Proleukin), which was slowly released via an implanted osmotic pump or was modified with polyethylene glycol (PEG-IL-2) to achieve constant plasma levels. Allogeneic B10.D2 antitumor immune spleen cells (ISPL cells) exerted strong graft-versus-leukemia (GvL) reactivity after adoptive transfer into late-stage ESb-MP tumor-bearing DBA/2 mice. Mls(a) superantigen-reactive vbeta6 donor T cells were not eliminated or tolerized by in vivo priming with the tumor cells and were present in active proliferation in liver infiltrates. When exogenous PEG-IL-2 or Proleukin was applied in addition to ISPL cells in such mice, the strong GvL-mediated protective immunity was converted into a fatal graft-versus-host disease. IL-2 treatment alone had no toxic effect and caused a moderate protection effect in the absence of an effect on local tumor growth. Potentiation of GvH reactivity of B10.D2 ISPL by PEG-IL-2 was proven in non-tumor-bearing DBA/2 mice, in which graft-versus-host disease was characterized by: (a) heavy hepatic lymphocytic infiltration, (b) irreversible increase of serum glutamate-oxalacetate-transaminase and glutamate-pyruvate-transaminase levels, (c) weight loss, and (d) death. Antagonistic effects of systemic IL-2 on GvL were observed with syngeneic DBA/2 anti-ESb immune peritoneal effector cells (PECs). There was a detrimental effect of systemic IL-2 on liver target organ infiltration by immune T cells causing, at day 6 after transfer, a drop from 20-30 CD4 or CD8 T cells per liver lobule in the PEC group to <5 in the PEC plus IL-2 group. The results emphasize the importance of a better understanding of IL-2 function in vivo and of its interaction with immune cell function to improve protocols for optimal application in the clinic to achieve maximal GvL effects.     

Interleukin-4 or interleukin-10 expressed from adenovirus-transduced syngeneic islet grafts fails to prevent beta cell destruction in diabetic NOD mice

BACKGROUND: We performed ex vivo adenoviral gene transfer in a mouse pancreatic islet transplant model to test the efficacy of this expression system. We then determined whether adenoviral-mediated expression of mouse interleukin (IL) 4 or IL-10 from transduced syngeneic islet grafts could prevent disease recurrence in diabetic nonobese diabetic (NOD) mice. METHODS: An adenoviral vector expressing beta-galactosidase (AdCMV betaGal) was used to transduce BALB/c islets (2.5 x 10(3) plaque-forming units/islet), which were analyzed for glucose responsiveness, islet cell recovery, and efficiency of gene transfer. In vivo function and reporter gene expression were examined with AdCMV betaGal-transduced islet grafts in alloxan-induced diabetic syngeneic recipients. Adenoviruses expressing either IL-4 or IL-10 were used in a similar fashion to infect NOD islets, which were characterized in vitro, as well as transplanted into diabetic syngeneic recipients. RESULTS: In vitro functional studies showed no significant difference between control or transduced islets, with 50+/-4% of AdCMV betaGal-infected islet cells staining positive for beta-galactosidase. Transplant recipients became nomoglycemic within 48 hr after transplant, and, although beta-galactosidase expression decreased over time, it was detectable in the graft for up to 8 weeks. Despite the nanogram quantities of IL-4 or IL-10 produced/day from each graft equivalent in vitro, transduced and transplanted NOD islets failed to prevent disease recurrence. CONCLUSIONS: These results suggest that adenoviruses are efficient for at least medium term gene expression from islets in vivo, but neither IL-4 nor IL-10 alone can prevent autoimmune disease recurrence in NOD mice.     

Induction of mixed allogeneic chimerism for leukemia

Hybrid (C56BL/6 x DBA) (BDF1; H-2b/H-2d) mice bearing the P815 leukemia (H-2d) were grafted with a (CBA x C57BL/6)F1 (CBF1; H-2k/H-2b) cell suspension, comprising bone marrow cells (BMC; 25 x 10(6)/mouse) and spleen cells (SC; 55 x 10(6)/mouse) on day-4, then treated with cyclophosphamide (200 mg/kg) on day-2 and finally grafted once more with CBF1 cells (25 x 10(6) BMC + 7 x 10(6) SC) on day 0. Allogeneic cell graftings performed in this way induced durable mixed hematopoietic chimerism and significantly prolonged the survival of recipients, compared with that of leukemia-bearers grafted with syngeneic cells. The results obtained raise the possibility of using allogeneic hematopoietic tissue transplantation in combination with non-lethal cytoreductive therapy to induce a long-lasting graft-vs-leukemia effect.     

Prevention of autoimmune but not allogeneic destruction of grafted islets by different therapeutic strategies

Grafting autoimmune-diabetic recipients with allogeneic islets, graft rejection and disease recurrence as major problems of reaching indefinite survival and tolerance induction have to be solved. Anti-CD25 and anti-CD4 monoclonal antibodies were successfully used after allogeneic islet transplantation in experimentally diabetic rats. A temporary anti-CD25 therapy also prevented disease recurrence in autoimmune-diabetic BB rats, while this was not yet reported for an anti-CD4 treatment. In autoimmune-diabetic NOD mice disease recurrence can be successfully treated using an anti-CD4 monoclonal antibody. We, therefore, compared the efficacy of a short-term anti-CD25 and anti-CD4 treatment regarding the prevention of allograft rejection and disease recurrence in autoimmune-diabetic BB/OK rats. Both monoclonal antibodies were combined with low doses of Cyclosporin A. Untreated BB/OK rats relapsed into hyperglycaemia within 3 weeks independent of the islet donor, LEW.1A, LEW.1BB/OK or BB/OK rats. However, after grafting MHC-identical allogeneic (LEW.1BB/OK) or syngeneic (BB/OK) islets we observed about 30% spontaneous acceptance. Both the anti-CD25 and anti-CD4 therapy significantly prolonged the survival of allogeneic grafted islets. After MHC-identical allogeneic and syngeneic islet transplantation the temporary immunotherapy increased the proportion of permanent acceptors to 63% and 75%, respectively. The efficacy of both treatment strategies in prolonging allograft survival and prevention of disease recurrence was identical. In summary, anti-CD25 as well as anti-CD4 therapy prevented autoimmune but not allogeneic islet destruction in autoimmune-diabetic BB/OK rats. In conclusion, targeting different immune cells by monoclonal antibodies with different specificities can lead to very similar results with respect to an interruption of allograft rejection and autoimmune reaction.     

Fas ligand-mediated lysis of self bystander targets by human papillomavirus-specific CD8+ cytotoxic T lymphocytes

Mouse cytotoxic T lymphocytes (CTL) reactive with a H-2Db-presented 9-mer peptide of the human papillomavirus type 16 protein E7(49-57) (RAHYNIVTF) were generated from the spleen cells of wild-type C57BL/6 (B6) or B6 perforin-deficient (B6.P0) mice. CD8(+) B6 CTL displayed peptide-specific perforin- and Fas-mediated lysis of E7-transfected mouse RMA lymphoma cells (RMA-E7), while CD8(+) CTL from B6.P0 mice lysed RMA-E7 cells via Fas ligand (FasL) exclusively. Rapid and efficient lysis of syngeneic bystander B6 blasts or RMA cells by either B6 or B6.P0 Ag-activated CTL was mediated by a FasL-Fas mechanism. Fas-resistant bystanders were not lysed, nor were allogeneic Fas-sensitive C3H/HeJ (H-2(k)) or BALB/c (H-2(d)) bystander blasts. Interestingly, however, phorbol myristate acetate-ionomycin preactivation of B6.P0 effectors enabled lysis of allogeneic H-2(k) and H-2(d) bystanders even in the absence of antigenic stimulation. Lysis of syngeneic bystander cells was always FasL-Fas dependent and required effector-bystander contact and, in particular, an interaction between CTL LFA-1 and bystander ICAM-1. Thus, in the context of major histocompatibility complex class I molecule-peptide ligation of the T-cell receptors of CD8(+) CTL, neighboring bystander cells that are syngeneic and Fas sensitive and express the adhesion molecule ICAM-1 are potential targets of CTL attack.     

Prevention of autoimmune destruction of syngeneic islet grafts in spontaneously diabetic nonobese diabetic mice by a combination of a vitamin D3 analog and cyclosporine

BACKGROUND: Type 1 diabetes is characterized by the presence of an autoimmune memory, responsible for the destruction of even syngeneic islet grafts. This recurrence of autoimmunity is partly responsible for the need of extensive immunosuppression in pancreas and islet transplantation in type 1 diabetic patients. The aim of the study was to evaluate the capacity of a 20-epi-analog of vitamin D3, KH1060, both alone and in combination with cyclosporine (CsA) to prevent diabetes recurrence in syngeneic islet grafts in nonobese diabetic (NOD) mice. METHODS: Spontaneously diabetic NOD mice grafted with syngeneic islets (n=500) under the kidney capsule were treated with KH1060, CsA, or a combination of both drugs from the day before transplantation until recurrence or 60 days after transplantation. RESULTS: Vehicle-treated mice showed a recurrence of diabetes in 100% of cases (n=17) within 4 weeks. Treatment with high doses of CsA (15 mg/kg/day) or KH1060 (1 microg/kg/2 days) significantly prolonged islet survival (60 days and 50 days, respectively, versus 9.5 days in controls; P<0.001 and P<0.0001). Mice treated with subtherapeutical doses of both drugs combined (KH1060 0.5 microg/kg/2 days + CsA 7.5 mg/kg/day) had significant prolongation of graft survival (48 days; P<0.001) and more importantly, four of five mice that were still normoglycemic 60 days after transplantation showed no recurrence after discontinuation of all treatment. Histology of the grafts of control and combination-treated mice demonstrated that graft infiltration and islet destruction were less severe in grafts of combination-treated mice. Cytokine mRNA analysis in the grafts 6 days after transplantation revealed a clear suppression of interleukin-12 and T helper 1 cytokines and higher levels of interleukin-4 in combination-treated mice. CONCLUSIONS: KH1060, an analog of 1,25(OH)2D3, delays autoimmune disease recurrence after syngeneic islet transplantation in NOD mice, both alone and especially in combination with CsA, possibly restoring tolerance to beta cells in 30% of cases.     

Accelerated rejection of Fas ligand-expressing heart grafts

The Fas/Fas ligand (FasL) system plays an important role in the induction of lymphoid apoptosis and has been implicated in the suppression of immune responses. Recently, there has been renewed interest in immune privilege, as it was shown that two privileged sites (the eye and testes) constitutively express FasL, which kills lymphoid cells that invade these areas. We have established murine FasL-transgenic mice (B6) under the control of the cardiac alpha-myosin heavy chain promotor, and transplanted FasL-expressing F1(B6 x C3H/HeJ) heart grafts into syngeneic (F1) and allogeneic (C3H/HeJ) recipients. FasL-expressing F1 heart allografts placed in C3H/HeJ recipients as well as FasL-expressing F1 isografts placed in nontransgenic and FasL-transgenic F1 were more rapidly rejected, and their survival was much shorter than that of nontransgenic control F1 allografts placed in C3H/HeJ. Native control and FasL-expressing hearts looked normal in mice up to 8 wk of age on hematoxylin-eosin staining. Control heart allografts undergoing ordinally acute rejection showed moderate focal lymphocyte infiltrates, while FasL-expressing F1 allografts and isografts showed massive hemorrhage, edema, and massive neutrophil infiltration as early as 1 day after transplantation. In conclusion, FasL expression and surgical procedure (ischemia/reperfusion) were synergistic in the induction of accelerated heart graft rejection, while allogenicity was not necessary. It may be necessary to find ways of controlling neutrophilic reaction/apoptosis in infiltrating lymphocytes to use FasL in clinical organ transplantation.     

Induction of donor-specific ACAID can prolong orthotopic corneal allograft survival in "high-risk" eyes

PURPOSE: To examine the effect of donor-specific anterior chamber-associated immune deviation (ACAID) induction on the survival of orthotopic corneal allografts in neovascularized graft beds. METHODS: To induce donor-specific ACAID in recipients, peritoneal exudate cells (PEC) from C57BL/6 mice were incubated overnight with transforming growth factor (TGF)-beta. Cultured PEC were injected intravenously (i.v.) into BALB/c mice, and, 1 week later, these animals received orthotopic corneal allografts from C57BL/6 donors into neovascularized graft beds. Control mice received i.v. injection of syngeneic (BALB/c) PEC, cultured overnight with TGF-beta, and then received orthotopic corneal allografts from C57BL/6 donors. RESULTS: All corneal allografts (15 out of 15) were rejected within 2 weeks after grafting in the neovascularized graft beds of control animals. However, only 6 out of 16 (37.5%) of corneal allografts were rejected in recipients in which donor-specific ACAID had been induced by injection of allogeneic PEC cultured with TGF-beta. CONCLUSION: Previous studies revealed that rejection of orthotopic corneal allografts in neovascularized graft beds in mice correlated with acquisition of donor-specific delayed hypersensitivity (DH). The results of this study suggest that induction of donor-specific ACAID, which selectively impairs DH responses to donor antigens, effectively prolongs corneal allograft survival in "high-risk" eyes.     

Prevention of graft-versus-host disease and the induction of transplant tolerance by low-dose UV-B irradiation of BM cells combined with cyclosporine immunosuppression

GVHD is prevented and stable chimerism is induced in the rat BMT model by 700 J/m2 but not 100-500 J/m2 UV-B irradiation of allogeneic BM cells. Paradoxically, CsA which prevents GVHD in clinical BMT causes an aggressive autoimmune disease termed syngeneic GVHD in irradiated syngeneic BMT recipients after its withdrawal. Recently, we have shown that while 500-700 J/m2 UV-B irradiation of syngeneic BM cells combined with a 30-day course of CsA recipient immunosuppression impairs hemopoiesis due to lack of hemopoietic factors, a low dose of 100-300 J/m2 UV-B is effective in preventing CsA-induced autoimmune disease without endangering BM engraftment. This study extends these findings to the P-to-F1 hybrid and fully allogeneic rat BMT models and examines the effectiveness of low-dose UV-B irradiation of BM cells combined with a short course of CsA treatment in the prevention of GVHD and induction of transplant tolerance. Lethally gamma-irradiated (10.5 Gy) LBNF1 recipients of naive or UV-B irradiated (100-700 J/m2) BMT were treated with CsA (12.5 mg/kg/day) for 30 consecutive days after BMT. All lethally irradiated LBNF1 that did not receive BMT died in < 16 days, while animals transplanted with UV-B (700 J/m2) BMT survived > 1 year without GVHD. In contrast, all recipients of naive BMT died of lethal GVHD in < 50 days. Similarly, all recipients of naive BMT that received a 30-day course of CsA therapy developed severe GVHD with 60% mortality after cessation of CsA therapy. CsA-treated recipients of BMT irradiated with 700 J/m2 died between 12 and 25 days from failure of hemopoiesis. In contrast, CsA-treated recipients of 100-200 J/m2 UV-B irradiated BMT showed full BM engraftment without GVHD after cessation of CsA and survived > 1 year. These results were reproducible in the fully allogeneic UV-B BMT model. To test for donor-specific tolerance, the animals challenged 100 days after BMT with cardiac allografts accepted permanently (> 100 days) Lewis but not BN (non-BMT parental donor) cardiac allografts. Our results confirm that 700 J/m2 UV-B irradiation of BM cells combined with CsA recipient immunosuppression impairs the recovery capacity of stem cells while the use of lower UV-B (100-200 J/m2) is effective in preventing CsA-induced autoimmune disease without endangering BM engraftment and leads to induction of transplant tolerance.     

Allogeneic tumor-syngeneic muscle sandwich grafts: a method for promoting nonspecific growth

In H-2-incompatible mice, four strain-specific transplantable murine tumors grew when sandwiched between layers of muscle syngeneic to the intended recipient. The allogeneic tumor-syngeneic muscle sandwich (TMS) graft did not grow in recipients presensitized to the allogeneic tumor and in recipients immunized concurrently with tumor or skin allografts from the same strain as the sandwiched tumor. Third-party muscle, allogeneic to both tumor and host, also was effective in promoting nonspecific growth. The escape of the allogeneic tumor from immunologic destruction when it was implanted as a TMS graft may have been due to an afferent blockade.     

Characterization of mixed syngeneic-allogeneic and syngeneic-xenogeneic islet-graft rejections in mice. Evidence of functional impairment of the remaining syngeneic islets in xenograft rejections

Allogeneic mouse islets or xenogeneic rat islets, or fetal porcine islets were implanted under the renal capsule of C57BL/6 mice either alone or carefully mixed with syngeneic islets. With this experimental model the syngeneic islets, although not rejected themselves, are exposed to cytokines and inflammatory mediators released during either allograft or xenograft rejection. No differences in insulin content could be observed between mixed islet grafts and pure syngeneic islet grafts 6 wk after transplantation. Neither was there any morphological evidence of a non-specific destruction of syngeneic islets. These findings suggest that the mechanisms of both allograft and xenograft rejections are highly specific. The hormone release from the mixed syngeneic-allogeneic grafts was similar to that from pure syngeneic islet grafts. In contrast, a pronounced impairment of both the first and second phases of insulin release was observed 2 wk after implantation in mixed syngeneic-xenogeneic islet grafts. When perfusing the mixed islet graft after completed rejection of the concordant xenogeneic rat islets (6 wk after implantation), the insulin release from the remaining syngeneic mouse islets was identical to that of control grafts. However, syngeneic mouse islets exposed to the rejection mechanism of the discordant xenogenic pig islet-like cell clusters did not attain a complete functional recovery.     

Selective training of the vastus medialis muscle using electrical stimulator for chondromalacia patella

Islet allografts transplanted into Type I diabetic recipients may be destroyed by allorejection or recurrent autoimmune diabetes. We studied islet transplantation in three murine models in order to determine the relative sensitivity of autoimmunity and alloimmunity to two immunosuppressive agents that may be useful in clinical islet transplantation: 15-deoxyspergualin (DSG) and anti-CD4 antibody (GK 1.5). In the model in which only allorejection occurs (BALB/c islets transplanted into streptozotocin-induced diabetic CBA or streptozotocin-induced diabetic NOD recipients), both DSG and anti-CD4 antibody treatment led to indefinite survival of allogeneic islets (>100 days in both treatments). In the second model in which only recurrent autoimmunity can destroy islet grafts (islets from NOD donors transplanted into spontaneously diabetic NOD recipients), only anti-CD4 treatment caused prolonged graft survival [MST 36.7 +/- 6.8 days vs 9.8 +/- 1.8 days (controls), P < 0.0002]. Treatment with DSG did not cause any increase in graft survival (MST 12.6 +/- 5.4 days, NS). Finally, using a model in which both autoimmunity and allorejection may occur (BALB/c to spontaneously diabetic NOD mice), treatment with anti-CD4 caused marked graft prolongation [42.0 +/- 14.5 days vs 7.2 +/- 0.8 days (control), P < 0.002] while DSG again did not prolong graft survival with respect to untreated recipients (9.8 +/- 3.0, NS). We conclude that recurrent autoimmunity in the NOD mouse involves a CD4+ T cell that is not sensitive to DSG. Anti-CD4 antibody may be useful in human clinical islet transplantation trials because it seems to prevent both allorejection and recurrent autoimmunity.     

Long-lasting unresponsiveness to polyclonal T cell-binding immunoglobulins

We have shown that mice after a single injection of anti-T cell antibody followed by multiple injections of a second xeno-, allo- or syngeneic anti-T cell antibody differing from the former in species origin developed specific, long-lasting tolerance to the second antibody. To characterize the mechanism of this anti-antibody unresponsiveness and the modalities accompanying the preinjection step, we injected mice with anti-pan T, anti-CD4 or anti-CD8 monoclonal antibodies, followed by multiple injections of polyclonal rabbit anti-mouse thymocyte globulin (RbATG). Our observations indicate that: (i) Depletion of CD4+ cells is the most important factor for tolerance induction to subsequently injected RbATG. Non-depleting mAb were less effective, and antibody-induced CD4 modulation or blockade were inconsequential. (ii) The prevention of anti-antibody responses involves specific B cell tolerance, as shown by suppression of anti-RbATG but not anti-bovine serum albumin (BSA) antibodies after challenge of tolerant mice with RbATG-BSA conjugates. (iii) Suppression of anti-antibody responses involves T cell unresponsiveness rather marginally, as demonstrated by in vitro spleen cell restimulation with RbATG and in vivo antibody response to RbATG-fluorescein isothiocyanate hapten conjugate. (iv) Analysis of isotypes of anti-RbATG antibodies does not suggest alterations in Th1/Th2 tuning as being responsible for this kind of tolerance. (v) Over 150-day survival of fully allogeneic skin grafts (CBA-to-C57BL/6) was observed in mice preinjected with anti pan-T or anti-CD4 mAb followed by RbATG. Mice treated with anti-CD4 mAb alone rejected allografts within 21 days and induced anti-antibodies. Taken together, our experiments suggest B cell tolerance as main mechanism in this type of acquired long-term humoral unresponsiveness to foreign, polyclonal, T cell-binding immunoglobulins.     

Cytokine mRNA levels in the hearts of inbred mice that develop different degrees of cardiomyopathy during infection with Trypanosoma cruzi

Profiles of cytokine mRNA expression were examined by semiquantitative RT-PCR in the hearts of DBA/2 (pathopermissive) and B10.D2 (pathoresistant) mice during infection with the Brazil strain of Trypanosoma cruzi. The levels and time-course profiles of IFNgamma, IL-1beta and IL-10 mRNA expression were similar in each strain. TNFalpha, iNOs, and IL-13 mRNA expression peaked at comparable levels and times after infection in each strain, but declined more rapidly in B10.D2 than in DBA/2 mice. Peak IL-2 mRNA levels were also similar between the two strains, but occurred earlier in DBA/2 than in B10.D2 mice. Levels of IL-4, IL-6 and IL-12 mRNA were significantly higher in DBA/2 than in B10.D2 mice from day 10 through day 50 of infection. With the exception of IL-1beta, which was expressed constitutively in both strains, the levels of mRNA of all other cytokines examined reached their peak no later than day 20 and declined significantly by day 50 after infection. The inflammatory infiltrate paralleled the latter cytokines; starting at day 10 in DBA/2 mice and at day 15 in the B10.D2 s, peaking between days 20 and 30 in both strains, decreasing to minimal levels by day 50 in the pathoresistant mice, but maintaining a mild amount through day 70 in the pathopermissive strain. The inflammation was composed mostly of lymphocytes and histiocytes throughout the entire process. These data demonstrate differences in the profiles of cytokine mRNA that may be related to the differential degree of cardiac pathology that develops in these two strains of mice upon infection with T. cruzi.     

The antigen-bearing eye and the spleen are indispensable in maintaining anterior chamber-associated immune deviation

PURPOSE: To investigate the role of the eye and the spleen in maintaining suppression of delayed-type hypersensitivity (DTH) after anterior chamber (AC) inoculation of allogeneic splenocytes. METHODS: Suppression of DTH response was tested in BALB/c mice after AC inoculation of allogeneic B10.D2 splenocytes. Seven days after AC injection, the antigen-inoculated eyes were enucleated or the spleens were removed. After enculeation or splenectomy at different time intervals, DTH responses in groups of the BALB/c mice were examined. Spleen components obtained from BALB/c mice that had been primed by B10.D2 splenocytes in the AC 7 days earlier were transferred intravenously to groups of naive syngeneic acceptors. At various intervals after adoptive transfer, variations of DTH responses were tested. RESULTS: Inoculation of B10.D2 splenocytes to the AC of BALB/c mice induced antigen-specific suppression of DTH. Either enucleation of the antigen-inoculated eyes or splenectomy weakened the DTH-suppressive effect within 5 weeks and abolished it within 9 weeks, whereas the mice retaining both antigen-inoculated eyes and spleens maintained longstanding DTH suppression. Adoptive transfer of spleen components to syngeneic acceptors demonstrated DTH suppression for only 3 weeks. CONCLUSIONS: The antigen-inoculated eye and spleen are required for long-standing suppression of DTH after AC inoculation of allogeneic splenocytes.     

Adoptive immunotherapy of murine lymphosarcoma: comparative study using allo-immune or tumor-immune T cells

The antitumor effect of allosensitization with lymphocytes and skin graft of DBA/2 mice was evaluated using immunogeneic, transplantable Lymphosarcoma (LS-A) syngeneic to Swiss mice. A dose dependent tumor inhibitory effect in terms of tumor free mice was observed in mice sensitized i.p. with lymphocyte doses between 10-100 million per animal. Sensitization with allogeneic primary skin graft was more effective than lymphocyte immunization. The antitumor immunity could be adoptively transferred in syngeneic Swiss mice using either allo-immune or tumor-immune T cells. Analysis of T cell phenotypes using monoclonal antibodies against cell surface markers CD4 and CD8, indicated absolute dependence on the CD4+ T cells subset in tumor cure in case of allo-immune as well as tumor-immune T cells. CD8+ T cell subset was found essential only in case of allo-immune T cell therapy. Immunosuppression of mice with whole body gamma irradiation (4 Gy), 6 hr before transfer of allo-immune or tumor-immune T cells did not abrogate the therapeutic ability of allo-immune or tumor-immune T cells. Our results suggest that allosensitization could be an effective method of generating effector lymphocyte populations that might be used to treat tumors that exhibit detectable immunogenecity.     

Hippocampal lesions cause learning deficits in inbred mice in the Morris water maze and conditioned-fear task.

This study examined the effect of hippocampal lesions on acquisition of the Morris water maze and conditioned-fear task in inbred mice. C57BL/6J, DBA/2J, and B6D2F1 hybrid mice were given hippocampal lesions or sham surgery and then tested. The lesioned C57BL/6J and B6D2F1 mice failed to learn the Morris task relative to sham-operated controls, and no DBA group learned the task. In the contextual component of conditioned fear, lesions decreased freezing in all strains. But the lesions only affected freezing to the conditioned stimulus in the DBA/2J and B6D2F1 strains. These data demonstrate that C57BL/6J and B6D2F1 mice use the hippocampus to solve the Morris water maze and conditioned-fear task, and the DBA mice use the hippocampus, to some degree, in the conditioned-fear task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)