Kenichi Sakagami

Augmentation of antitumor effect on syngeneic murine solid tumors by an interleukin 2 slow delivery system, the IL-2 mini-pellet

We evaluated the antitumor effect of an interleukin 2 (IL-2) slow delivery system, the IL-2 mini-pellet, in two murine solid tumor models, and also investigated the enhancement of its therapeutic effect by serial administration. The IL-2 mini-pellet contains 1 × 106 units of IL-2 and releases it slowlyin vivo. In our experiment, the IL-2 mini-pellet was administered subcutaneously near the tumor site in combination with the intravenous injection of lymphokine-activated killer (LAK) cells. When this regimen was given on days 8 and 11 after the subcutaneous inoculation of Meth A fibrosarcoma into BALB/c mice, tumor growth was significantly inhibited (p < 0.05) compared to tumor growth in untreated controls. Moreover, the IL-2 mini-pellet alone was also effective in inhibiting tumor growth. In another experiment, MH134 hepatoma was inoculated into C3H/He mice. Both administration of the IL-2 minipellet alone and in combination with LAK cells resulted in complete tumor regression in four of five mice. In a third experiment, serial administration of the IL-2 mini-pellet at 3- or 5-day intervals prolonged the suppression of Meth A fibrosarcoma growth in BALB/c mice. These results suggested that the IL-2 mini-pellet could be applied to cancer immunotherapy and that its antitumor effect could be prolonged by serial administration.

Induction of antiidiotypic antibodies by donor-specific blood transfusions. Establishment of a human-mouse hybridoma secreting the MLR-inhibiting factor

We describe a patient transfused with 200 ml of donor fresh whole blood three times at 2-week intervals. Three weeks after the last transfusion, transplantation and splenectomy were done at the same time. Splenic cells from this DST pretreated patient were fused with murine myeloma cells (X63-Ag8, 653). With DST pretreatment, various clones were developed in vivo, and finally 69 human immunoglobulin-secreting clones were obtained. Modulation of the alloantigen-specific MLR by supernatants from 69 clones showed various degrees of suppression or augmentation. The hybridoma clone 7 and clone 2, which had been secreting IgG antibody for more than 6 months, showed some degree of suppression in the alloantigen-specific MLR (mean suppression = 63%, 46% respectively). According to the result of MLR, clone 7 antibody was directed against recipient lymphocytes and clone 2 antibody was against donor lymphocytes. Immunoprecipitation was carried out by clone 7-IgG and clone 2-IgG. Clone 7-IgG specifically precipitated 1 molecule from the recipient lymphocyte with a molecular weight of 120 KD, similar to the molecular weight range reported for T cell receptors. Clone 2-IgG precipitated a 20 KD molecule from the donor lymphocyte. The data suggest that DST induces antibodies directed against the blood donor alloantigen-specific receptors on the recipients T lymphocytes--and, at the same time, induces antibodies against donor lymphocyte antigens. These antibodies may be essential to prolongation of kidney allograft survival following DST.

Expression of the interleukin 2 receptor beta chain (p75) in renal transplantation--applicability of anti-interleukin-2 receptor beta chain monoclonal antibody.

The interaction of interleukin 2 with specific cellular receptors plays an essential role in the allostimulated proliferation and differentiation of T cells. Recent chemical linking studies have demonstrated that the human high-affinity IL-2 receptor is a membrane complex composed of at least two distinct subunits, which are the p55 (alpha-chain) and p75 (beta-chain) subunits. The IL-2R beta chain is supposed to play a role in the signal transduction of IL-2, but the exact mechanism is still unknown. In this study, we investigated the effects of a newly established anti-IL-2R beta chain monoclonal antibody (MoAb, TU-27) on the induction of cytotoxic T lymphocytes (CTLs) using the cell-mediated lympholysis (CML) assay. TU-27 in combination with H-31, a MoAb directed against the IL-2R alpha chain, produced inhibition of cytotoxicity, while TU-27 alone could not inhibit cytotoxicity, while TU-27 alone could not inhibit cytotoxicity at any concentration. TU-27 plus H-31 prevented the expansion of CD4+ cells and CD8++ cells in mixed lymphocyte culture (MLC). Furthermore, we examined the serial changes in the expression of the IL-2R beta chain on peripheral blood lymphocytes from renal transplant recipients using two-color immunofluorescence flow cytometry, so as to investigate correlations between IL-2R beta chain expression and the occurrence of allograft rejection. Here, we report that the IL-2R beta chain is expressed on CD4-positive (CD4+) cells and strongly CD8-positive (CD8(+)+) cells in association with acute rejection, indicating that IL-2R beta chain expression appears to increase on alloreactive T cells.

Immunosuppressive mechanism of 15-deoxyspergualin on sinusoidal lining cells in swine liver transplantation: Suppression of MHC class II antigens and interleukin-1 production

To elucidate the precise mechanism of action of 15-deoxyspergualin (DSG) in swine liver transplantation, the expression of MHC class II antigens (Ia) on hepatic sinusoidal lining cells (SLC) and their production of interleukin-1 (IL-1) were examined. In our previous study, we isolated sinusoidal endothelial cells (SEC) and Kupffer cells (KC) by enzymatic digestion and centrifugal elutriation, and demonstrated that both SEC and KC present alloantigens effectively and generated IL-1 in response to allogenic or lipopolysaccharide stimulation. Animals were divided into three groups: group 1, nontransplanted normal controls (n = 3); group 2, no immunosuppressive treatment following liver transplantation (n = 5); group 3, DSG (0.8 mg/kg/day) intravenously for 7 days following liver transplantation (n = 5). At 1 week after transplantation, the three liver grafts in groups 2 and 3 were processed for the study of Ia expression and IL-1 production on SEC and KC. The expression of Ia was detected in 21.5 +/- 4.7% of SEC and 24.3 +/- 11.1% of KC in group 1. In group 3, Ia expression was suppressed compared with group 2, being 3.6 +/- 2.8% versus 22.0 +/- 2.8% for SEC (P less than 0.02) and 15.5 +/- 11.3% versus 24.3 +/- 7.1% for KC. IL-1 production by SEC and KC was respectively 11,483 +/- 3311 cpm and 9077 +/- 2161 cpm in group 1. In group 3, IL-1 production was inhibited compared with that in group 2, being 7190 +/- 883 cpm versus 19,297 +/- 5182 cpm for SEC (P less than 0.05) and 16,130 +/- 3769 cpm versus 25,857 +/- 3963 cpm for KC.(ABSTRACT TRUNCATED AT 250 WORDS)

Antitumor effects of a new interleukin-2 slow delivery system on methylcholanthrene-induced fibrosarcoma in mice

SummaryThe interleukin-2 (IL-2) mini-pellet, the carrier material of which is a biocompatible and biodegradable atelocollagen refined from bovine skin, contains 1×106 units of IL-2 and can release IL-2 slowly in vivo by diffusion and dissolution. We have evaluated the antitumor effects of the IL-2 mini-pellet on an established solid murine tumor, methylcholanthrene-induced fibrosarcoma (Meth A). The subcutaneous administration of the IL-2 mini-pellet alone on days 8 and 11 after tumor inoculation significantly inhibited tumor growth. A significant inhibition was also seen when it was combined with the intravenous injection of 5×107 lymphokine-activated killer (LAK) cells, in comparison to the untreated controls. Moreover, therapy with the IL-2 mini-pellet alone or in combination with LAK cells also prolonged the survival of mice bearing Meth A fibrosarcoma. In order to determine the precise mechanism of action of these antitumor effects, we tested splenocytes of treated mice for cytotoxic activity in vitro and investigated tumor tissues by an immunohistochemical method. On day 2 after the administration of the IL-2 mini-pellet, the lytic activity of splenocytes against both YAC-1 and JTC-11 cells (i.e. NK and LAK activity) was significantly augmented, and on day 7 a massive accumulation of lymphocytes, which were mainly like Thy1+ and/or asialo-GM1+ LAK cells, was seen in the tumor. These findings indicate that the IL-2 mini-pellet is an appropriate system for local administration of IL-2 and can induce LAK-like effector cells at the target site.

A newly developed hydroxyl radical scavenger, EPC-K1 can improve the survival of swine warm ischemia-damaged transplanted liver grafts.

Using a swine orthotopic liver transplantation (SOLTx) model, we assessed the effect of a new hydroxyl radical scavenger EPC-K1 on warm ischemic damage of the liver graft and recipient survival. Animals were divided into 5 groups. The first group (control group 1) consisted of 5 pigs which were not operated on but served as controls for the indocianine green disappearance rate (K-ICG) determinations. In the second group (control group 2), 10 livers were transplanted without warm ischemia (WI) and the K-ICG values were measured. The third group (control group 3) was the main control group for the study groups and consisted of 5 liver transplants with 30 min of WI without any special treatment. The fourth and fifth groups served as study groups 1 and 2. Five transplants were carried out in each group, as in control group 3. In study group 1 recipients were treated with an additional 5 mg/kg i.v. EPC-K1 and in study group 2 with 20 mg/kg i.v. EPC-K1. Significant improvement in glutamic oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH) levels, K-ICG values and histological findings were observed in the EPC-K1 treated groups. The intravenous administration of this agent had a strong protective effect on warm ischemic damage after 30 min of WI and could significantly prolong the graft and recipient survival.

The effect of anti-interleukin 2 monoclonal antibody treatment on the survival of rat cardiac allograft

The effect of anti-interleukin 2 monoclonal antibody (anti-IL2 MoAb) and the accumulation of intravenously administered 125I-labeled anti-IL2 MoAb were examined in heterotopic rat cardiac allografts. Mouse anti-human recombinant IL2 MoAb was obtained by the hybridoma technique. The anti-IL2 MoAb, termed 8H-10, was an IgG2a which inhibited IL2-driven [3H]TdR incorporation in cytolytic T lymphocyte line cells at a dilution of 2(6). 8H-10 was injected iv at a dose of 200 micrograms/day for 8 consecutive days, beginning on the day of transplantation. Hearts from F344 rats (RT11v1) were transplanted into ACI recipient rats (RT1av1). The mean survival time was 7.6 +/- 0.8 days in untreated controls, 9.0 +/- 1.2 days in additional controls treated with mouse anti-sheep red blood cell monoclonal antibody, and 25.3 +/- 18.4 days in the anti-IL2 MoAb (8H-10)-treated group (P less than 0.05). Furthermore, the accumulation of intravenously administered 125I-labeled anti-IL2 MoAb (8H-10) was specifically seen in the grafted heart. In conclusion, these results suggest that IL2 may play an important role in allograft rejection and that anti-IL2 MoAb may serve as a useful immunosuppressive agent in clinical transplantation.

Successful pregnancy in renal transplant recipients.

Three cases of successful pregnancies in renal transplant recipients who had undergone transplantation in the Okayama University Medical School Hospital are reported. Two of the women had received an organ from a living relative and one woman received a cadaveric organ graft. These patients, aged 28-37 at the time of the delivery, had received their transplants 2-5 years prior to their conception. The periods of gestation ranged between 35 and 40 weeks. The weight of the babies at birth ranged from 2,380g to 2,500g and the apgar score at 1 min was 8 or 9. None of the infants showed any congenital abnormalities. Lower-segment cesarean section was performed in all of three cases. Serum creatinine levels, an indicator of renal graft function, did not deteriorate during the pregnancy or after delivery. Although further work is needed to solve problems regarding pregnancy in renal transplant recipients, these results encouraged us to meet their hope for a baby.

Bone metabolism on long-term follow-up after total parathyroidectomy with autotransplantation.

二次性副甲状腺機能亢進症による腎性骨異栄養症 (ROD) に対して上皮小体全摘一部自家移植術 (PTX-AT) が行われているが, 術後3年以上の遠隔期における骨代謝, 骨所見に関する報告は少ない. 過去8年で38例に, PTX-ATを施行した. このうち術後3年以上経過した27症例について骨代謝の生化学的指標と, 全身骨X線所見について検討した. 透析歴は120-235か月 (平均181.1±30.7か月), PTX-AT後36-89か月 (平均61.9±11.9か月) を経過していた. C-PTHは術直後より減少し, 術後3年で5ng/ml以下のものは22例で, 残り5例中4例は術後もほとんど減少せず, その後の検査で残存副甲状腺を確認した. 骨新生の指標となるオステオカルシンを, 術後症例 (PTX-AT群) とC-PTH 10ng/ml以上の二次性副甲状腺機能亢進症例 (2°HPT群) で比較検討すると, PTX-AT群 (n=26) は平均106.9±98.7ng/ml, 2°HPT群 (n=27) は平均230.9±157.9ng/mlで, 有意にPTX-AT群が低値を示した (p<0.005). また, PTX-AT群では100ng/ml以下のものは19例でその全例がC-PTH 5ng/ml以下であった. 100ng/ml以上の8例は, 2°HPT群と有意差を認めなかった. さらに, 両群においてオステオカルシンとC-PTHは正の相関が認められた (p=0.05). 全身骨X線所見を1. 手指骨 (Tuft resorption, TR), 2. 頭蓋骨 (Salt and pepper, SP), 3. 腰椎 (Rugger jersey, RJ) の骨吸収像に分けてPTX-AT前後で比較検討した.1) TR (n=23): 悪化例0, 不変例2, 改善例21, 2) SP (n=21): 悪化例0, 不変例1, 改善例20, 3) RJ (n=21): 悪化例1, 不変例10, 改善例10.以上より, PTX-ATにより手指骨, 頭蓋骨は著明に改善するが, 腰椎は半数が不変であり改善傾向が少なかった. また, 術後持続副甲状腺機能亢進症を呈する症例では, 骨所見改善に乏しく, 骨代謝の生化学的指標のC-PTH, オステオカルシンと骨所見は相関するものと考えられた.

Abdominal organ cluster transplantation in pigs and FK

Using a swine abdominal organ cluster transplantation model, we investigated the postoperative function and immunological reactions of a cluster graft and evaluated the immunosuppressive activity of FK506. The animals were divided into two groups. Group I (n = 6) served as controls, while in group II (n = 6) a daily dose of 0.1 mg/kg FK506 was given intramuscularly. Postoperative pancreatitis was the most important factor influencing the early outcome in both groups. In group I, the cause of late death was cachexia due to diabetes mellitus induced by pancreatic rejection. In group II, emaciation despite a well‐functioning graft was the principal cause of late death. Histologically, in group I the grade of rejection in the pancreas was more severe than in the liver, and no sign of rejection was observed in group II. In conclusion, the pancreas suffered more severe rejection than the liver, and FK506 could significantly prevent cluster allograft rejection in this model.