An endoscopic hydro-mastoidectomy technique for cholesteatoma surgery.

OBJECTIVE: Endoscopic hydro-mastoidectomy, in which mastoidectomy is performed underwater, can be employed during transcanal endoscopic ear surgery for cholesteatoma removal. It was hypothesised that endoscopic hydro-mastoidectomy might take less time than endoscopic non-underwater mastoidectomy because the endoscope does not need to be removed for cleaning. METHODS: This study compared the mastoidectomy and total operative durations between the endoscopic hydro-mastoidectomy (n = 25) and endoscopic non-underwater drilling (control, n = 8) groups. Moreover, it compared the size of resected areas of the external auditory canal between the two groups. RESULTS: The mastoidectomy time of the endoscopic hydro-mastoidectomy group was significantly shorter than that of the control group (p < 0.01). The total operative time did not differ significantly between the endoscopic hydro-mastoidectomy and control groups (p = 0.17). The resected area was significantly larger in the endoscopic hydro-mastoidectomy group than in the control group (p < 0.05). CONCLUSION: Endoscopic hydro-mastoidectomy enables more extensive bone resection within a shorter period.

Two Cases of Equine Multinodular Pulmonary Fibrosis in Japan.

Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings. In both cases, significant gross lesions, restricted to the lungs, consisted of numerous firm and coalescing nodules widely distributed throughout the lung. The nodules were <3 cm in diameter and pale white to tan in colour. Microscopically, they showed severe interstitial fibrosis and infiltration of macrophages, neutrophils, lymphocytes and a few eosinophils. The residual alveoli were lined by cuboidal epithelial cells (type II pneumocytes) and filled with many macrophages, which rarely displayed oval eosinophilic to amphophilic intranuclear inclusion bodies. Polymerase chain reaction and sequence analyses identified the glycoprotein H gene of EHV-5, and in-situ hybridization detected EHV-5 in the alveolar macrophages in the lesions. In one case, electron microscopy revealed herpesvirus-like particles and EHV-5 was isolated from pulmonary lesions.

Effect of Perioperative Blood Transfusions in Renal Transplant Patients.

BACKGROUND: In patients eligible for organ transplantation, the Kidney Disease Improving Global Outcomes (KDIGO) guidelines specifically recommend avoiding red blood cell transfusions (RBCT) when possible to minimize the risk of allosensitization. OBJECTIVE: To assess the effect of perioperative RBCT on outcomes in living-related kidney transplantation (LRKT) recipients. METHODS: We retrospectively assessed 97 patients who underwent LRKT and whose data were evaluable at our institution between March 2009 and May 2016. We measured serum creatinine levels and calculated the estimated glomerular filtration rate (eGFR) at 3 months, 6 months, and 1 year after kidney transplantation (KTx). We evaluated the rejection rate within a year after KTx. We compared the renal function and rejection rate between those who received blood transfusions (n = 21) and those who did not (n = 76) during the perioperative period. RESULTS: Among patient characteristics, the rate of ABO-incompatible KTx and the mean hemoglobin levels before KTx differed significantly between the groups. The serum creatinine levels and eGFR within 1 year after KTx did not differ significantly between the two groups. The rejection rate in those who received blood transfusions and those who did not was 28.6% (6/21 patients) and 25.0% (19/76 patients) (P = .741), respectively. CONCLUSIONS: We found that the rejection rate was slightly higher in patients who received perioperative RBCT than in those who did not, but the difference was not significant within a year after KTx. Perioperative RBCT may not affect renal function within a year after KTx.

Effect of Influenza Vaccine in Patients With Kidney Transplant.

BACKGROUND: Among infectious diseases, influenza is the most common cause of infection in Japan and worldwide. We aimed to evaluate the effect of influenza vaccination in kidney transplantation (KTx) recipients. METHODS: We retrospectively evaluated the records of 98 participants who underwent KTx at our institution between March 2009 and May 2016. All patients received tacrolimus or cyclosporine, mycophenolate mofetil, and methylprednisolone for maintenance immunosuppression after KTx. In accordance with the criteria of our institution, everolimus was administered for the maintenance of immunosuppression after KTx. We compared the rate of influenza infection during the 2016-2017 season (8 months, from October 2016-May 2017) between KTx patients treated with 1 or 2 doses of influenza vaccine (treatment group, n = 71) and KTx patients who did not receive a vaccine (nontreatment group, n = 27). RESULTS: Among patient characteristics, only the prevalence of diabetes mellitus differed significantly between the groups (treatment group: 9.9%, 7 of 71 patients; nontreatment group: 29.6%, 8 of 21 patients; P = .02). Influenza infection occurred at similar rates in the 2 groups (treatment group, 5.63% 4 of 71 patients; nontreatment group: 3.70%, 1 of 27 patients; P = .70). CONCLUSIONS: Among KTx patients managed in our institution, treatment with 1 or 2 doses of influenza vaccine did not reduce the rate of influenza infection in the 2016-2017 season, suggesting that influenza vaccination may currently be ineffective in KTx patients.

Type-1 polarised dendritic cells are a potent immunogen against Mycobacterium tuberculosis.

OBJECTIVE: Application of immunotherapy using dendritic cells (DCs) is considered an effective treatment strategy against persistent Mycobacterium tuberculosis infection. With the goal of developing improved therapeutic vaccination strategies for patients with tuberculosis (TB), we tested the ability of ex vivo-generated DCs to induce an effective TB antigen-specific type-1 immune response. METHODS: Monocyte-derived DCs from TB patients were induced to mature using a 'standard' cytokine cocktail (interleukin [IL] 1ß, tumour necrosis factor alpha [TNF-α], IL-6 and prostaglandin E2) or a type 1-polarised DC (DC1) cocktail (IL-1ß, TNF-α, interferon [IFN] α, IFN-γ and polyinosinic:polycytidylic acid), and were loaded with the established TB antigen 6-kDa early secretory antigenic target protein (ESAT-6). RESULTS: Although DC1s from TB patients expressed the same levels of multiple co-stimulatory molecules (CD83, CD86, CD80 and CD40) as the standard DCs (sDCs), DC1s secreted substantially higher levels of IL-12p70. Furthermore, when DCs pulsed with or without ESAT-6 were cultured with lymphocytes from the same patients, DC1s induced much higher numbers of ESAT-6-specific IFN-γ-producing T-cells than sDCs, as manifested by their superior induction of natural killer cell activation and antigen-independent suppression of regulatory T-cells. CONCLUSION: TB antigen-loaded DC1s are potent inducers of antigen-specific T-cells, which could be used to develop improved immunotherapies of TB.

Utility of the Japanese Glomerular Filtration Rate Equation in Estimating Glomerular Filtration Rate of Donor Kidney.

BACKGROUND: An equation for the estimated glomerular filtration rate (eGFR) is generally used for evaluating renal function in Japan. OBJECTIVE: To assess the accuracy of the preoperative eGFR for estimating kidney donors' measured glomerular filtration rate (mGFR). METHODS: Between April 2009 and August 2014, 91 Japanese living kidney donors were included in this study. The eGFR was calculated as follows: eGFR = 194 × serum creatinine(-1.094) × Age(-0.287) (and × 0.739 for women), and the mGFR was evaluated using inulin clearance. The preoperative eGFR was then compared with the mGFR. RESULTS: Patients included 27 men and 64 women with a mean age of 56.8 ± 9.5 years (range, 36-79 years), mean body surface area of 1.56 ± 0.14 m(2) (range 1.27-1.92 m(2)), mean body mass index of 22.3 ± 2.3 kg/m(2) (range 14.0-27.0 kg/m(2)), and mean serum creatinine level of 0.66 ± 0.14 mg/dL (range 0.39-0.97 mg/dL). The mean eGFR was 81.3 ± 14.2 mL/min/1.73 m(2) (range 45.5-125.9 mL/min/1.73 m(2)), and the mean mGFR was 89.0 ± 15.5 mL/min/1.73 m(2) (range 45.4-130.7 mL/min/1.73 m(2)). The eGFR was significantly lower than the mGFR (P < .001). The correlation coefficient for the relationship between the eGFR and mGFR values was 0.503, and the mean difference between the 2 values was -7.8 (8.7%). CONCLUSIONS: Although the eGFR correlated with the mGFR, the eGFR values did not accurately estimate the mGFR in living kidney donors. Therefore, it is necessary to evaluate the mGFR, especially in marginal kidney donors.

The potential impact of a single amino-acid substitution on the efficacy of equine influenza vaccines.

REASONS FOR PERFORMING STUDY: The protection induced by an equine influenza (EI) vaccine strain depends on its antigenic relatedness to the challenge virus. Although the World Organisation for Animal Health (OIE) recommend that both Florida sublineage clade 1 (Fc1) and clade 2 (Fc2) viruses should be included in EI vaccines, Japanese EI vaccines have not, thus far, been updated to include a Fc2 virus. OBJECTIVES: To evaluate the efficacy of antibodies raised against Japanese EI vaccine strains in the neutralisation of recent Fc2 viruses. STUDY DESIGN: Antigenic analysis. METHODS: Virus neutralisation tests were performed using antisera from experimentally infected horses and from horses that had received a primary course of the currently available vaccines. RESULTS: Antiserum raised against the Japanese EI vaccine strain, A/equine/La Plata/1993, exhibited poor cross-neutralising activity against the Fc2 viruses isolated recently in Ireland and the UK, which have the substitution of alanine to valine at position 144 in antigenic site A of the haemagglutinin gene. In contrast, the antiserum exhibited good cross-neutralising activity against the Fc2 viruses without the substitution. This finding was supported in experiments with antisera collected from vaccinated horses. CONCLUSIONS: This suggests that the efficacy of the Japanese EI vaccine for some of the recent Fc2 viruses is suboptimal and that vaccines should be updated in accordance with the OIE recommendations.

Immunogenicity of dormancy-related antigens in individuals infected with Mycobacterium tuberculosis in Japan.

SETTING: DosR regulon genes are considered essential for Mycobacterium tuberculosis dormancy, and their products are demonstrated to have immunogenicity in M. tuberculosis-infected individuals, suggesting that DosR regulon-encoded proteins are suitable targets for vaccines to control the reactivation of dormant M. tuberculosis. OBJECTIVE: Prospective analysis of T-cell and antibody responses against DosR regulon-encoded antigens in M. tuberculosis-infected individuals in Japan to identify effective vaccine targets. DESIGN: T-cell responses against 33 DosR regulon-encoded antigens were investigated in 26 consecutive M. tuberculosis-infected individuals--14 with latent tuberculosis infection (LTBI) and 12 with active pulmonary tuberculosis (PTB)--using enzyme-linked immunosorbent spot assay, and antibody responses in 42 consecutive individuals, 14 with LTBI and 28 with PTB. RESULT: Six antigens (Rv0570, Rv1996, Rv2004c, Rv2028c, Rv2029c and Rv3133c) induced stronger T-cell responses in LTBI than in PTB, In contrast, antigen-specific antibody responses to five antigens (Rv0080, Rv1738, Rv2007c, Rv2031c and Rv2032) were found to be stronger in PTB than in LTBI cases. CONCLUSION: T-cell responses to six antigens might contribute to natural protection against dormant M. tuberculosis. These antigens are therefore considered to be potential targets of novel vaccines to control M. tuberculosis reactivation in the Japanese population.

Intracellular interferon-γ staining analysis of donor-specific T-cell responses in liver transplant recipients.

OBJECTIVE: Biomarkers that accurately reflect, detect, and/or predict detrimental immune responses to grafts are important in organ transplantation. We established a new detection method for alloreactive T cells on the basis of intracellular staining for interferon (IFN)-γ, using CD40-activated B cells as stimulators, and assessed temporal changes in alloreactive T-cell frequencies in patients who received liver transplantation. METHODS: Peripheral blood mononuclear cells and CD40-activated B cells were used as responder and stimulator cells, respectively. The responder cells were cultured with the stimulator cells for 7 days, restimulated for 5 hours, and flow cytometrically tested by intracellular staining for IFN-γ. RESULTS: The relative postoperative-preoperative ratio of donor-specific CD8+ T cells in the nonrejection group was significantly lower than that in the rejection group and found to be <1 in most individuals of the group throughout the postoperative periods, indicating an induction of donor-specific suppression of the CD8+ T-cell responses. In contrast, such differences were not found in the donor-specific CD4+ T cells. These results suggest that the relative postoperative-preoperative ratio of the donor-specific CD8+ T cells is a good indicator of graft rejection. CONCLUSION: We established a new flow cytometric method for the detection of alloreactive T cells by intracellular staining for IFN-γ, using CD40-activated B cells as stimulator cells. Using this system, we found that the relative postoperative-preoperative ratio of the donor-specific CD8+ T cells is a possible evaluative indicator of the risk for graft rejection.

The HLA-A*0201-restricted minor histocompatibility antigen HA-1H peptide can also be presented by another HLA-A2 subtype, A*0206.

HA-1(H) is one of the most attractive minor histocompatibility antigens (mHA) as a target for immunotherapy of hematopoietic malignancies, but HLA-A*0201 and HLA-B60 molecules capable of presenting HA-1(H)-derived peptides are less common in eastern Asian populations when compared with Caucasian populations. Therefore, an attempt was made to search for novel epitopes presented by HLA alleles other than those previously reported by generating CTL lines from patients undergoing HLA-identical, HA-1 disparate hematopoietic stem cell transplantation (hematopoietic SCT) by stimulation with a 29-mer HA-1(H) peptide spanning a central polymorphic histidine (His). Two CTL clones established were found to be restricted by HLA-A*0206, which is the second or third most common HLA-A2 subtype worldwide. Epitope mapping revealed that the clones recognized the same nonameric peptide as A*0201-restricted HA-1(H), VLHDDLLEA. This epitope was unexpected, since it does not contain any preferred anchor motifs for HLA-A*0206. However, an HLA peptide binding assay revealed stronger binding of this peptide to A*0206 than to A*0201. Interestingly, HLA-A*0206-restricted CTL clones could lyse both HLA-A*0206(+) and HLA-A*0201(+) targets (including leukemic blasts) that express HA-1(H) peptide endogenously, whereas an HLA-A*0201-restricted, HA-1(H)-specific CTL clone failed to lyse HLA-A*0206(+) targets. This finding will expand the patient population who can benefit from HA-1(H)-based immunotherapy.

The human cathepsin H gene encodes two novel minor histocompatibility antigen epitopes restricted by HLA-A*3101 and -A*3303.

Minor histocompatibility antigens (mHags) play crucial roles in the induction of graft versus host disease (GVHD) and/or graft versus leukaemia (GVL) effects following human leucocyte antigen (HLA)-identical haematopoietic stem cell transplantation (HSCT). Using HLA-A*3101- and -A*3303-restricted cytotoxic T lymphocyte (CTL) clones generated from different post-HSCT recipients, we identified two novel mHag epitopes encoded by the leader sequence of cathepsin H (CTSH) isoform a. The nonameric sequence ATLPLLCAR was defined as an HLA-A*3101-restricted epitope (CTSH(R)/A31), while a decameric peptide featuring a one N-terminal amino acid extension, WATLPLLCAR, was presented by HLA-A*3303 (CTSH(R)/A33). The immunogenicity of both epitopes was totally dependent on the polymorphic C-terminal arginine residue and substitution with glycine completely abolished binding to the corresponding HLA molecules. Thus, the immunogenicity of this mHag is exerted by differential HLA binding capacity. CTSH is relatively ubiquitously expressed at protein levels, thus it may be involved in GVHD and anti-leukaemic/tumour responses. Interestingly, however, CTL clones predominantly lysed targets of haematopoietic cell origin, which could not be explained in terms of the immunoproteasome system. Although the mechanisms involved in the differential susceptibility remain to be determined, these data suggest that CTSH-encoded mHags could be targets for GVL effects.

Retroviral vector backbone immunogenicity: identification of cytotoxic T-cell epitopes in retroviral vector-packaging sequences.

Retroviral vectors are the frequently applied gene delivery vehicles for clinical gene therapy, but specificity of the immunogenicity to the protein encoded by the inserted gene of interest is a problem which needs to be overcome. Here, we describe human cytotoxic T-lymphocyte (CTL) clones recognizing epitopes derived from the protein encoded by the retroviral vector backbone, which were established during the course of our attempts to generate CTLs against cytomegalovirus (CMV) or human papilloma virus (HPV) in vitro. In the case of healthy CMV-seronegative donors, CTL lines specific for retrovirally transduced cells were generated in four out of eight donors by stimulating CD8 T cells with CD40-activated B (CD40-B) cells retrovirally transduced with CMV-pp65. Two CTL clones derived from one of the CTL lines were found to recognize epitopes from gag in the context of HLA-B(*)4403 and -B(*)4601, respectively. Similarly, an HLA-B(*)3501-restricted CTL clone from a cervical cancer patient recognized an epitope located in the junctional regions of the gag and pol sequences. These results show that polypeptides encoded by components of the retroviral vector backbone are in fact immunogenic, generating CTLs in vitro in human cells. Thus, potential CTL responses to retroviral products should also be considered in clinical settings.

Identification of an epitope from the epithelial cell adhesion molecule eliciting HLA-A*2402-restricted cytotoxic T-lymphocyte responses.

Because the epithelial cell adhesion molecule (Ep-CAM) is expressed in almost all carcinomas and human leucocyte antigen (HLA)-A*2402 is the most common allele in many ethnic groups, including Japanese, the identification of peptide sequences, which elicit HLA-A*2402-restricted Ep-CAM-specific cytotoxic T-lymphocyte (CTL) responses, would facilitate specific immunotherapy for various histological types of carcinomas. An epitope was identified through the following steps: (i) computer-based epitope prediction from the amino acid sequence of Ep-CAM, (ii) major histocompatibility complex (MHC) stabilization assay to determine the affinity of the predicted peptide with HLA-A*2402 molecules, (iii) stimulation of CD8+ T cells with peptide-pulsed dendritic cells and (iv) testing the CTL specificity by means of enzyme-linked immunospot (ELISPOT) assays, CTL assays and MHC/peptide-tetramer staining. Peripheral CD8+ T cells of four of five healthy donors after three rounds of stimulation with the peptide Ep-CAM173-181 (RYQLDPKFI) secreted interferon-gamma in ELISPOT assays when exposed to the peptide. A CTL clone specific to the peptide efficiently lysed Ep-CAM-expressing cancer cell lines in an HLA-A*2402-restricted fashion. Endogenous processing and presentation of the peptide in a lung cancer cell line were confirmed by means of cold target inhibition assays. The CTL clone was also lytic to normal bronchial epithelial cells but to a lesser extent at low effector: target ratios. All these data suggest that the peptide-specific CTL responses may play some roles both in anti-cancer and autoimmune reactions. The peptide should prove useful to study anti-Ep-CAM CTL responses among population possessing HLA-A*2402.

The binding of thymus leukemia (TL) antigen tetramers to normal intestinal intraepithelial lymphocytes and thymocytes.

Thymus leukemia (TL) Ags belong to the family of nonclassical MHC class I Ags and can be recognized by both TCRalphabeta and TCRgammadelta CTL with TL, but not H-2 restriction. We previously reported that the CTL epitope is TAP independent, but the antigenic molecule(s) presented by TL has yet to be determined. In the present study, TL tetramers were prepared with T3(b)-TL and murine beta(2)-microglobulin, not including antigenic peptides, and binding specificity was studied. CTL clones against TL Ags were stained with the T3(b)-TL tetramer, and the binding shown to be CD3 and CD8 dependent. Normal lymphocytes from various origins were also studied. Surprisingly, most CD8(+) intraepithelial lymphocytes derived from the small intestines (iIEL), as well as CD8(+) and CD4(+)CD8(+) thymocytes, were stained, while only very minor populations of CD8(+) cells derived from other peripheral lymphoid tissues, such as spleen and lymph nodes, were positive. The binding of T3(b)-TL tetramers to CD8(+) iIEL and thymocytes was CD8 dependent, but CD3 independent, in contrast to that to TL-restricted CTL. These results altogether showed that TL-restricted CTL can be monitored by CD3-dependent binding of T3(b)-TL tetramers. In addition, CD3-independent T3(b)-TL tetramer binding to iIEL and thymocytes may imply that TL expressed on intestinal epithelium and cortical thymocytes has a physiological function interacting with these tetramer(+)CD8(+) T lymphocytes.

Dendritic cells pulsed with tumor extract-cationic liposome complex increase the induction of cytotoxic T lymphocytes in mouse brain tumor.

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that locate in peripheral organs. It has been thought that a systemic immune response does not play a role in regression of central nervous system (CNS) tumors, because the CNS is an immunologically privileged site. However, recent advances in immunology have led to the possibility of immunotherapy using peripheral DCs against CNS tumors. Here, we investigated whether DCs pulsed with tumor extract could induce an antitumor effect against malignant glioma. Furthermore, we also investigated whether the antitumor effect become higher by pulsation with tumor extract-liposome complex, compared to pulsation with tumor extract alone. As a liposome, we used cationic small unilamellar vesicles composed of N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride (TMAG), dilauroylphosphatidylcholine (DLPC), and dioleoylphosphatidylethanolamine (DOPE) in a molar ratio of 1:2:2. After intracerebral inoculation of mouse malignant glioma GL261 cells into syngeneic C57BL/6 mice, DCs pulsed with extract from the glioma cells by sonication were administered intraperitoneally thrice weekly on days 7, 14 and 21. Tumor growth inhibition was evaluated by measuring the tumor size 1 month after the tumor inoculation. The group treated with DCs pulsed by tumor extract was inhibited in tumor progression compared with the control non-pulsed DCs group, and the group treated with DCs pulsed by tumor extract and liposomes showed substantial tumor volume reductions in all the mice. Among the mice, there were several with no visible masses in their brains. Immunohistochemical study showed that the CD8-positive cytotoxic T cells (CTLs) were strongly recognized among the almost disappearing tumor cells of pulsed DCs groups. The CTLs showed a specific antitumor activity for GL261 mouse glioma cells. These findings indicated that DCs pulsed with tumor extract and liposomes might play an important role in the activation of an immune response in malignant glioma.

Comparison of anti-tumor responses against TL positive lymphoma induced by skin grafting and dendritic cell immunization.

When the skin of Tg.Con.3-1 transgenic mice expressing the TL (thymus leukemia) antigen in most tissues is grafted on syngeneic C3H mice, it is rejected, and a cytotoxic T cell (CTL) response against the TL antigen is induced. In this study, we first demonstrated that growth of TL positive lymphoma is suppressed in mice immunized by skin grafting. Immunization with bone marrow derived dendritic cells (DCs) from Tg.Con.3-1, was also found to be associated with an anti-tumor response, but less potent than skin grafting. Relative CTL precursor frequency with DC immunization was also approximately only one third that of skin grafting. The numbers of IFN-gamma producing cells in responder CD8 and CD4 T cell populations were higher with DC immunization than with skin grafting. However, DC immunization seems to induce non-specific immune responses, as re-stimulation with TL negative C3H spleen cells resulted in induction of almost half the number observed with TL positive cells. Thus, the actual number of IFN-gamma producing cells in specific responses to TL is not necessarily larger than with skin grafting immunization. The present results altogether suggest that DC immunization is capable of inducing an anti-tumor reaction, but also possibly unwanted immune responses. In vitro monitoring of specific and non-specific responses in the immune system, thus, is of particular importance for future development of cancer immunotherapy.

The epitope detected by cytotoxic T lymphocytes against thymus leukemia (TL) antigen is TAP independent.

Thymus leukemia (TL) antigens belong to the family of MHC class Ib antigens. We have shown in our previous studies that they serve as transplantation antigens, and can be recognized by both TCR alpha beta and TCR gamma delta cytotoxic T lymphocytes (CTL) with TL but not H-2 restriction. Although TL are known to be expressed TAP independently, it is unclear whether peptide loading on TL molecules is necessary for the formation of CTL epitopes. In the present study, we first showed that TL expression is beta(2)-microglobulin (beta(2)m)-dependent but TAP1 independent by flow cytometric analysis of thymocytes from beta(2)m- or TAP1-deficient mice crossed with TL transgenic mice expressing Tla(a)-3-TL on their thymocytes. Subsequently, we investigated the epitope recognized by CTL derived from C3H mice immunized with skin from a transgenic mouse expressing T3(b)-TL ubiquitously. Bulk CTL lines against TL from primary mixed lymphocyte cultures showed comparable cytotoxicity against T3(b)-TL transfectants of TAP2-deficient murine RMA-S grown at 37 degrees C to that against those grown at 25 degrees C. Furthermore, TCR alpha beta and TCR gamma delta CTL clones against TL recognized TL expressed on T3(b)-TL transfectants of RMA-S and Drosophila melanogaster cells having broad defects in peptide loading of MHC, and lysed these target cells. These results together indicate that TL-specific CTL populations primarily recognize epitopes expressed TAP independently.

IFN-beta gene therapy induces systemic antitumor immunity against malignant glioma.

We previously demonstrated that intratumoral administration of liposomes containing the murine interferon beta (IFN-beta) gene [lip(pSV2muIFN-beta)] resulted in stronger growth-inhibitory effect on GL261 (H-2b) mouse glioma inoculated in brains of syngeneic C57BL/6 mice than conventional exogenous IFN-beta administration, and histologic evaluation revealed the massive infiltration of T lymphocytes (CD8 > CD4) within the residual tumor. The present study was aimed at determining whether such tumor-infiltrating lymphocytes (TIL) have any tumor-specific cytotoxic effects. Intratumoral administration of lip(pSV2muIFN-beta) resulted in prolonged survival time and a 50% tumor-free incidence in the mice treated. The surviving animals were subsequently re-challenged with either subcutaneous or intracranial injection of GL261 cells, and no tumors were found to develop over a 50-day period. In vivo depletion of CD8, but not CD4 cells decreased the efficacy of lip(pSV2muIFN-beta). Specific cytotoxic T lymphocytes (CTL) against GL261 cells were generated from both TIL and spleen cells of the mice treated. The results of flow cytometric analysis and antibody blocking test revealed that the bulk CTL lines thus prepared were T cell receptor (TCR) alphabeta, CD8 T lymphocytes with H-2b restriction. These findings suggest that, in addition to direct growth-inhibitory effects by the IFN-beta gene on the tumor cells, activation of systemic cellular immunity may participate in antitumor effects in vivo, despite the fact that central nervous system is generally regarded as an immunologically privileged site.

A serosurvey of Borna disease virus infection in wild rats by a capture ELISA.

For a serological diagnostic test for Borna disease (BD), we developed a capture ELISA with specificity and sensitivity based on detection of antibodies against BD virus (BDV) p40 protein. Using our capture ELISA system, the antibody response of rats inoculated intracerebrally with BDV at 4 weeks after birth showed a sharp increase from 1 to 4 weeks postinoculation (p.i.) and a steady level after 5 weeks p.i. To investigate prevalence of BDV infection among wild rats, we examined sera of Rattus norvegicus in Kami-iso town, Oshima district, Hokkaido, suggesting that rats in this area had not been infected by BDV.

Two types of anti-TL (thymus leukemia) CTL clones with distinct target specificities: differences in cytotoxic mechanisms and accessory molecule requirements.

TCRalphabeta CTL clones recognizing mouse thymus leukemia (TL) Ags were established and categorized into two groups: those killing any TL+ target cells (type I) and those killing only TL+ Con A blasts (type II). Cold target inhibition assays showed that the antigenic determinant(s) recognized by type II clones are expressed not only on TL+ Con A blasts but also on other TL+ target cells. The relation of the target specificity to the killing machinery and the accessory molecules involved in cytotoxicity were therefore analyzed using four representative clones selected from each type. Of the target cells tested, Fas was only expressed on Con A blasts, indicating that Fas ligand (FasL)-dependent cytotoxicity is limited to such cells. All four type II and one of four type I clones expressed FasL on the surface, while both types contained perforin in the cytoplasm. Blocking studies using neutralizing anti-FasL mAbs and concanamycin A (CMA), a selective inhibitor of the perforin pathway, suggested that type I clones kill target cells by way of perforin, while type II clones kill TL+ Con A blasts through FasL together with perforin. For their cytotoxicity, type I CTLs require a signal through CD8, while type II require LFA-1/ICAM-1 interactions. Type II clones also need a co-stimulatory signal through an unknown molecule for perforin-dependent cytotoxicity. These results taken together suggest that the difference in the target specificity of anti-TL CTL clones is due to variation in the killing machineries and the dependence on accessory molecules.