Biomedical subjects

Yasuo Morishima

Publications and source records attributed to Yasuo Morishima.

At least 55 records · Page 3Linked to original sources

PubMed2004

Comparison of genetic aberrations in CD10+ diffused large B-cell lymphoma and follicular lymphoma by comparative genomic hybridization and tissue-fluorescence in situ hybridization.

CD10 is one of the hallmarks of germinal center B-cells where follicular lymphomas (FL) originate. It has not been clearly established, however, whether CD10(+) diffuse B-cell lymphomas (DLBCL) are genetically similar to FL. We therefore examined 19 CD10(+) DLBCL and 40 FL by means of comparative genomic hybridization (CGH) and tissue-fluorescence in situ hybridization (T-FISH). Chromosomal imbalance was more frequently detected in CD10(+) DLBCLs (19/19) than in FLs (24/40). Significant differences were found in eight frequently imbalanced regions, namely those with gains of chromosomes 7q and 12 and those with losses of chromosomes 1p, 4p, 6q, 15q, 16p and 17. Amplification of the 3q region where BCL6 is located is reported to occur frequently in DLBCL, but it was only found in one of the 19 CD10(+) DLBCL cases we examined. The involvement of t(14;18) in CD10(+)+ DLBCL (31%) and in FL (73%) was significantly different (P = 0.0064). The CGH pattern of CD10(+) DLBCL with t(14;18) was also different from that of FL with t(14;18). Taken together, our results indicate that CD10(+) DLBCL constitutes a unique subtype entity with genetic characteristics significantly different from those of FL and DLBCL.

Aged↗

PubMed2004

Clinical relevance of a newly identified HLA-A24-restricted minor histocompatibility antigen epitope derived from BCL2A1, ACC-1, in patients receiving HLA genotypically matched unrelated bone marrow transplant.

Minor histocompatibility antigens (mHAs) are major histocompatibility complex (MHC)-associated peptides, which trigger T-cell responses that mediate graft versus host disease (GVHD) and graft versus leukaemia effects. We recently identified a new mHA epitope, termed ACC-1, which is presented by HLA-A*2402 and encoded by BCL2A1, whose expression is restricted to haematopoietic cells including leukaemic cells. HLA-A24/ACC-1 tetramer detected the presence of ACC-1-specific CD8+ cells in the peripheral blood of a patient up to 7 months following transplantation, and these tetramer-positive cells were expandable in vitro by ACC-1 peptide stimulation. A retrospective analysis of 320 patients with HLA-A*2402 who had received a human leucocyte antigen (HLA) genotypically matched unrelated donor through the Japan Marrow Donor Programme was conducted to determine whether ACC-1 disparity is associated with adverse clinical outcomes such as GVHD. Among these patients, ACC-1 disparity was detected in 55 (17.2%) donor/recipient pairs. After adjusting for known risk factors, the hazard ratios or odds ratios of acute and chronic GVHD, relapse and disease-free survival were not statistically different between patients receiving ACC-1 compatible and incompatible transplantation. These data suggest that disparity of haematopoietic cell-specific mHA, ACC-1, is unlikely at least to augment GVHD, and that T cells specific for ACC-1 may also be used for immunotherapy of recurring leukaemia without GVHD.

Adolescent↗

PubMed2004

Efficacy and safety of imatinib mesylate for patients in the first chronic phase of chronic myeloid leukemia: results of a Japanese phase II clinical study.

Imatinib mesylate is a relatively new drug that targets the BCR-ABL chimeric protein, the molecular basis of chronic myeloid leukemia (CML). A phase II clinical trial in 39 Japanese patients in the first chronic phase of CML was conducted with imatinib mesylate at a dose of 400 mg/day. Hematologic complete response was obtained in 92.3% of the patients, complete cytogenetic response (CR) was obtained in 43.6%, and major partial CR was obtained in 20.5% of the patients. Although 29 of 39 patients required an adjustment of dosing because of grade 3 or 4 adverse events, most of the events were reversible, and 25 of the 29 patients were able to resume therapy. Between day 15 and day 35, grade 3 or 4 neutropenia and/or leukocytopenia occurred in 13 patients, and grade 3 thrombocytopenia occurred in 5 patients. Overall, nonhematologic grade 3 adverse events occurred in 28.2% of the patients. These data support the use of imatinib mesylate as the treatment of choice for chronic-phase CML patients.

Adult↗

PubMed2004

Durable response but prolonged cytopenia after cladribine treatment in relapsed patients with indolent non-Hodgkin's lymphomas: results of a Japanese phase II study.

We conducted a phase II study to evaluate the efficacy and safety of cladribine (2-chlorodeoxyadenosine [2-CdA]) for patients with refractory or relapsed indolent B-cell lymphoma or mycosis fungoides. Forty-five patients were enrolled, and 43 patients, including 34 with follicular lymphoma, were eligible. 2-CdA was given by continuous intravenous infusion at a dose of 0.09 mg/kg daily for 7 consecutive days, and this schedule was repeated every 4 weeks up to a maximum of 6 cycles. The overall and complete response rates were 58.1% (25/43; 90% confidence interval, 44.5%-70.9%) and 14.0% (6/43), respectively. The disease progression-free proportions of all 43 eligible and all 25 responding patients at 2 years were 30.3% and 48.1%, respectively. Neutropenia and thrombocytopenia of grade 3 or 4 were observed in 53.3% and 37.8% of patients, respectively, with prolonged cytopenia observed in patients with increased numbers of treatment cycles. Nonhematologic toxicities of grade 3 or greater included diarrhea, arrhythmia, malaise, and gastrointestinal bleeding in 1 patient each, an increase in glutamic-pyruvic transaminase level in 2 patients, and infection in 5 patients. Two treatment-related deaths were observed. Four patients developed myelodysplastic syndrome (MDS) at 13 months to 2 years after completion of the 2-CdA treatments. 2-CdA is an active agent with acceptable toxicity for refractory or relapsed indolent lymphoma; however, prolonged myelosuppression and the potential development of MDS should be carefully monitored.

Adult↗

PubMed2003

Unrelated bone marrow transplantation for non-Hodgkin lymphoma: a study from the Japan Marrow Donor Program.

There is little information available regarding the outcome of unrelated bone marrow transplantation (BMT) for non-Hodgkin lymphoma (NHL). Therefore, we retrospectively analyzed the data of 124 patients who underwent unrelated BMT through the Japan Marrow Donor Program (JMDP) between July 1992 and August 2001. The overall survival (OS), progression-free survival (PFS), cumulative incidences of disease progression, and nonprogression mortality at 3 years after BMT were 49.7%, 42.6%, 24.5%, and 32.9%, respectively, with a median follow-up duration of 565 days among survivors. The incidence of grades II-IV acute graft-versus-host disease (GVHD) was 40.9%. Recipient age, previous history of autologous transplantation, and chemosensitivity at transplantation were independent prognostic factors for OS and PFS. The development of grades II-IV acute GVHD was associated with lower incidence of disease progression after transplantation, which suggested the existence of a graft versus lymphoma effect. Unrelated BMT should be considered as a treatment option for patients with high-risk NHL without an HLA-matched related donor.

Adolescent↗

PubMed2003

Identification of novel CTL epitopes of CMV-pp65 presented by a variety of HLA alleles.

Cytomegalovirus (CMV)-specific T-cell immunity plays an important role in protection from CMV disease in immunocompromised patients. Identification of cytotoxic T-lymphocyte (CTL) epitopes is essential for monitoring T-cell immunity and also for immunotherapy. In this and previous studies, CMV-pp65-specific CTL lines were successfully generated from all of 11 CMV-seropositive healthy donors, using pp65-transduced CD40-activated B (CD40-B) cells as antigen-presenting cells. By use of enzyme-linked immunospot (ELISPOT) assays, individual CTL epitopes could be mapped with truncated forms of the pp65 gene. For human leukocyte antigen (HLA) alleles with a known binding motif, CTL epitopes within the defined regions were predicted by computer algorithm. For HLA alleles without a known binding motif (HLA-Cw*0801, -Cw*1202, and -Cw*1502), the epitopes were alternatively identified by step-by-step truncations of the pp65 gene. Through this study, a total of 14 novel CTL epitopes of CMV-pp65 were identified. Interestingly, 3 peptides were found to be presented by 2 different HLA class I alleles or subtypes. Moreover, use of CD40-B cells pulsed with a mixture of synthetic peptides led to generation of pp65-specific CTL lines from some of seronegative donors. The study thus demonstrated an efficient strategy for identifying CTL epitopes presented by a variety of HLA alleles.

Amino Acid Sequence↗

PubMed2003

Identification of a polymorphic gene, BCL2A1, encoding two novel hematopoietic lineage-specific minor histocompatibility antigens.

We report the identification of two novel minor histocompatibility antigens (mHAgs), encoded by two separate single nucleotide polymorphisms on a single gene, BCL2A1, and restricted by human histocompatibility leukocyte antigen (HLA)-A*2402 (the most common HLA-A allele in Japanese) and B*4403, respectively. Two cytotoxic T lymphocyte (CTL) clones specific for these mHAgs were first isolated from two distinct recipients after hematopoietic cell transplantation. Both clones lyse only normal and malignant cells within the hematopoietic lineage. To localize the gene encoding the mHAgs, two-point linkage analysis was performed on the CTL lytic patterns of restricting HLA-transfected B lymphoblastoid cell lines obtained from Centre d'Etude du Polymorphisme Humain. Both CTL clones showed a completely identical lytic pattern for 4 pedigrees and the gene was localized within a 3.6-cM interval of 15q24.3-25.1 region that encodes at least 46 genes. Of those, only BCL2A1 has been reported to be expressed in hematopoietic cells and possess three nonsynonymous nucleotide changes. Minigene transfection and epitope reconstitution assays with synthetic peptides identified both HLA-A*2402- and B*4403-restricted mHAg epitopes to be encoded by distinct polymorphisms within BCL2A1.

Amino Acid Sequence↗

PubMed2003

Prognostic significance of CD7+CD56+ phenotype and chromosome 5 abnormalities for acute myeloid leukemia M0.

Myeloid/natural killer (NK) cell precursor acute leukemia is an entity of acute leukemia characterized by poor prognosis and a CD7+CD56+ myeloid antigen+ phenotype without light-microscopic myeloperoxidase reactivity. This disease shares several clinical characteristics with acute myeloid leukemia (AML) M0. To clarify the relationship between these 2 leukemias, we analyzed 105 cases of AML M0. Among them, 17 were CD7+ and CD56+, 77 were negative for either antigen, and 11 could not be determined. CD7+CD56+ AML M0 showed onset at significantly lower patient age (median 46 versus 63 years, P = .004). The disease localization and the hematological manifestations were significantly different: CD7+CD56+ AML showed more frequent extramedullary involvement, fewer circulating leukemic blasts, less anemia, and less thrombocytopenia than did AML M0. The cytogenetic aberrations were also unique, because no 5q abnormalities were found in CD7+CD56+ M0. The prognosis of CD7+CD56+ M0 was poor in patients younger than 46 years (P = .03). Multivariate analysis showed that the CD7+CD56+ phenotype was a significant prognostic factor for AML M0, as well as age, circulating blast percentage, and chromosome 5 abnormalities These findings suggest that AML M0 consists of heterogeneous subgroups to be managed separately, and CD7+CD56+ M0 constitutes a distinct subtype of AML M0.

Acute Disease↗

PubMed2003

Pilot phase I/II study of new salvage therapy (CHASE) for refractory or relapsed malignant lymphoma.

A pilot phase I/II study was conducted as a single-institute trial for evaluation of the feasibility and efficacy of a new salvage chemotherapy, CHASE, for patients with refractory or relapsed lymphoma . The CHASE regimen, consisting of cyclophosphamide, cytosine arabinoside, etoposide, and dexamethasone, was administered every 3 weeks in a maximum of 5 courses. A total of 16 patients were eligible and registered for this study. Myelosuppression was the major toxicity. Although grade 4 leukopenia and grade 3 thrombocytopenia were identified in 15 and 16 patients, respectively, duration of the nadir was brief (median, 3 days). Nonhematological grade 4 toxicity was not observed, and transient elevations of bilirubin and grade 3 aspartate aminotransferase/alanine aminotransferase (AST/ALT) were observed in 2 and 3 courses, respectively, in a total of 57 courses. Complete and partial response rates were 71.4% (10/14) and 7.1% (1/14), respectively. The median percentage of maximal CD34+ cells was 6.1% on day 15, and a median number of 1.88 x 10(6) CD34+ cells/kg per apheresis were obtained. Thirteen patients received high-dose chemoradiotherapy followed by autologous peripheral blood stem cell transplantation. With a median follow-up time of 36 months from the start of CHASE, the overall survival rate for the 16 patients was 66.6%. These results indicated that CHASE is a safe and effective salvage regimen for malignant lymphoma, has sufficient mobilizing effect on peripheral blood stem cells, and warrants further phase II study.

Adult↗

PubMed2003

Polymorphism in the hMSH2 gene (gIVS 12-6T-->C) and risk of non-Hodgkin lymphoma in a Japanese population.

We conducted a hospital-based prevalent case-control study in a Japanese population (cases=103, controls=487) to ascertain the previous report about the association between the polymorphism in exon 13 of the hMSH2 gene (gIVS 12-6T-->C) and the risk of non-Hodgkin lymphoma in an Ecuadorian population. When the TT genotype was defined as the reference, none of the CT genotypes (OR=1.52; 95% CI, 0.97-2.37), CC genotypes (OR=1.06, 95% CI, 0.44-2.54), or CT and CC genotypes combined together (OR=1.44, 95% CI, 0.94-2.23) demonstrated significant OR. Further investigations with sufficiently larger populations and in other ethnicities are required to verify this association.

Adenosine Triphosphatases↗

PubMed2003

Potential limitations in using minor histocompatibility antigen-specific cytotoxic T cells for targeting solid tumor cells.

We have shown previously that KIAA0223, a gene encoding a minor histocompatibility antigen, HA-1, whose expression was believed to be restricted to the hematopoietic cells, is aberrantly expressed in some solid tumor cell lines. However, its significance in tumor immunity needs to be determined. Cytotoxic activity of HA-1(H)-specific cytotoxic T lymphocytes (CTLs) was assessed against solid tumor cell lines expressing KIAA0223 using (51)Cr release assays. Five of seven cell lines were lysed when HLA-A*0201 was adequately expressed. One of the two CTL-resistant cell lines became susceptible after treatment with IFN-gamma and TNF-alpha, while the other was lysed only after pulsing with HA-1(H) peptide. In most cell lines tested, HA-1(H) peptide was properly generated and presented for recognition by the CTL. However, impaired antigen processing and presentation observed in this study may result in escape from CTL recognition in vivo, as well as in vitro, as observed in this study.

Gene Expression Regulation, Neoplastic↗

PubMed2003

Phenotypic analysis of peripheral T/NK cell lymphoma: study of 408 Japanese cases with special reference to their anatomical sites.

The World Health Organization (WHO) classification of malignant lymphoma presented a list of disease entities well defined by clinical, immunological and genetic features. Therefore, the current diagnosis of peripheral T/NK-cell lymphomas (PTNKLs) essentially requires the inclusion of anatomical sites of disease and phenotypical features. We analyzed 408 Japanese cases of PTNKLs in order to clarify the relationship between anatomical sites of disease and phenotypical features and to translate the functional subsets of T and NK cells into their diagnoses for further understanding lymphomatic biology. The T/NK-cell lymphoma entities were allocated into three categories: (i) cytotoxic memory T-cell and/or NK-cell lymphoma (n = 151) consisting of extranodal NK/T-cell tumors other than mycosis fungoides (MF); (ii) non-cytotoxic memory T-cell lymphoma (n = 142) consisting of nodal and cutaneous tumors such as angioimmunoblastic T-cell lymphoma, adult T-cell lymphoma/leukemia and MF; and (iii) anaplastic lymphoma kinase positive anaplastic large cell lymphoma (n = 110) that has unique features and might be regarded as cytotoxic 'naive' T-cell lymphoma. Overall, these three categories were significantly correlated with age of onset, anatomical sites, the level of expression of cytotoxic molecules and CD45RO, and association with Epstein-Barr virus. This concept might provide a new insight enabling further understanding of the interrelationships among WHO T/NK-cell disease entities.

Adolescent↗

PubMed2003

A dose-finding study of glycosylated G-CSF (Lenograstim) combined with CHOP therapy for stem cell mobilization in patients with non-Hodgkin's lymphoma.

BACKGROUND: Peripheral blood stem cell (PBSC) reinfusion has been widely used for hematopoietic reconstitution after high-dose chemotherapy. However, the optimal dose of granulocyte colony-stimulating factor (G-CSF) for PBSC mobilization in combination with chemotherapy for autograft remains unknown. METHODS: To find the optimal dose of glycosylated G-CSF (lenograstim) for PBSC mobilization in combination with chemotherapy for aggressive non-Hodgkin's lymphoma (NHL), we conducted a dose-finding study on 43 newly diagnosed patients who had unfavorable prognostic factors. They received four to six courses of cyclophosphamide, doxorubicin, vincristine and prednisolone combined with lenograstim every 2 weeks (biweekly CHOP therapy). PBSC apheresis was started after the third course of biweekly CHOP therapy. Lenograstim was given daily from day 3 until the day of the last apheresis. The optimum dose of lenograstim was assessed based on mobilization efficacy and safety profiles at a daily single dose of 2, 5 and 10 microg/kg for eight patients in each level. RESULTS: The collected number of CD34+ cells in the first apheresis products was higher in the 5 microg/kg group than in the 2 microg/kg group (median, 4.22 x 10(6) vs 2.49 x 10(6) CD34+ cells/kg, P = 0.051). The highest dose of 10 microg/kg (median, 2.99 x 10(6) CD34+ cells/kg) failed to show a dose dependence in PBSC mobilization. The efficacy and safety of the 5 microg/kg dose were further confirmed in an additional 19 patients. CONCLUSIONS: The present study suggests that the recommended dose of lenograstim for PBSC mobilization with CHOP therapy in untreated NHL is 5 microg/kg.

Adjuvants, Immunologic↗

PubMed2003

Senile EBV+ B-cell lymphoproliferative disorders: a clinicopathologic study of 22 patients.

Twenty-two Epstein-Barr virus-associated B-cell lymphoproliferative disorders (LPDs) without predisposing immunodeficiencies were evaluated clinically and pathologically. All patients were Japanese and negative for anti-human immunodeficiency virus antibody. They were all more than 60 years old with a median age of 75.5 years. Eighteen (82%) patients showed extranodal involvement. Biopsied specimens contained variable numbers of centroblasts, immunoblasts, and Reed-Sternberg-like giant cells often with necrosis and an angiocentric pattern. The 13 cases showing polymorphous composition and inflammatory background were categorized as polymorphic LPD subtype. The other nine cases contained diffuse proliferative lesions of large lymphoid cells and were categorized as large cell lymphoma subtype. Tumor cells expressed CD20 and/or CD79a, and in situ hybridization showed them to be associated with Epstein-Barr virus. LMP1 was detected in all cases and EBNA2 in seven. Eighteen patients initially received combination chemotherapy, and 12 achieved complete remission. However, six patients were refractory to chemotherapy and four patients with complete remission later relapsed. Eight of the 18 patients who received chemotherapy showed an aggressive disease course within a year after the diagnosis. There was a significant difference in prognosis between the group with polymorphic LPDs and the one with large cell lymphomas (p = 0.003). Although the disease profile of the 22 cases was analogous to that of immunodeficiency-associated B-cell LPDs, none of the patients showed evidence of underlying immunodeficiency-related diseases. These findings suggest that Epstein-Barr virus-associated LPD without immunodeficiency mainly occurs in elderly patients. Further investigations are needed to clarify the pathogenesis of this disease and to determine the optimal treatment strategy.

Aged↗

PubMed2003

Associations between polymorphisms in the thymidylate synthase and serine hydroxymethyltransferase genes and susceptibility to malignant lymphoma.

BACKGROUND AND OBJECTIVES: Polymorphisms in thymidylate synthase (TS) 28-bp tandem repeats in the promoter region and in cytosolic serine hydroxymethyltransferase (SHMT1 C1420T) have been reported to modulate the risk of adult acute lymphocytic leukemia (ALL). We examined the associations between susceptibility to malignant lymphoma and these polymorphisms. DESIGN AND METHODS: A hospital-based prevalent case-control study was conducted in Aichi Cancer Center. One hundred and eight patients with histologically confirmed lymphoma and 494 control subjects without cancer were evaluated. RESULTS: In a risk estimation of each genotype, those who harbored at least one TS 2 repeat (2R) allele had a 1.6-fold increase in the risk of malignant lymphoma (OR=1.63; 95%CI, 1.05-2.53, p=0.030) when using those without the TS 2R allele as a reference. For the SHMT1 C1420T polymorphism, those harboring at least one T allele showed a 2.2-fold decrease in risk (OR =0.46; 95% CI, 0.23-0.93, p=0.031). Moreover, combined analysis of TS and SHMT1 polymorphisms revealed that the OR for lymphoma in patients with SHMT1 1420 CC and the TS 2R allele, which might be expected to provide the basis for the highest susceptibility, was 2.88 (95% CI, 1.26-6.58, p=0.013). INTERPRETATIONS AND CONCLUSIONS: This study suggests that genetic traits involving low penetrance polymorphisms in folate-metabolizing genes may modulate the risk of malignant lymphoma.

Adult↗

PubMed2002

Targeted cloning of cytotoxic T cells specific for minor histocompatibility antigens restricted by HLA class I molecules of interest.

BACKGROUND: T cells specific for minor histocompatibility antigens (mHAgs) play a major role in both graft-versus-host disease and the graft-versus-tumor effect after HLA-identical bone marrow transplantation (BMT). However, characterization of individual T-cell responses to mHAgs is difficult and has generally involved extensive screening of T-cell clones isolated from bulk T-cell cultures generated from BMT recipients. In this report, we describe a new approach that permits both direct visualization of CD8 T-cell responses to mHAgs and cloning of T cells reacting with mHAgs presented by individual HLA alleles of interest. METHODS AND RESULTS: Panels of Epstein-Barr virus-transformed B-cell lines (B-LCL) expressing retrovirally transduced HLA cDNA were used as stimulator cells in an enzyme-linked immunospot (ELISPOT) assay to identify CD8 T cells reacting with mHAgs in cultures generated from postBMT recipient peripheral blood. T cells specific for mHAgs presented by selected HLA alleles could then be captured and cloned using an interferon-gamma secretion assay and magnetic bead selection. A majority of T-cell clones thus isolated exhibited cytolytic activity against the same HLA-transfected B-cell lines used for the ELISPOT assay. CONCLUSION: The ELISPOT assay was useful for identification of the HLA alleles presenting mHAgs recognized by individual T-cell lines. This approach for isolating mHAgs-specific CD8 T-cell clones should assist in characterizing responses restricted by HLA alleles of interest, which are common in a certain ethnic group.

Alleles↗

PubMed2002

Tetramer-assisted identification and characterization of epitopes recognized by HLA A*2402-restricted Epstein-Barr virus-specific CD8+ T cells.

We determined cytotoxic T lymphocyte (CTL) epitopes through screening with a computer-assisted algorithm and an enzyme-linked immunospot (ELISPOT) assay using in vitro-reactivated polyclonal Epstein-Barr virus (EBV)-specific CD8(+) T cells as responders. In addition, to confirm that the epitopes were generated after endogenous processing and presentation of the EBV proteins, a novel T-cell receptor (TCR) down-regulation assay was introduced, in which a fluorescent tetrameric major histocompatibility complex (MHC)/peptide complex was employed for detecting TCR down-regulation after stimulation with the epitope presented on antigen-presenting cells. Through such screening, 3 HLA A*2402-restricted epitopes were identified: IYVLVMLVL, TYPVLEEMF, and DYNFVKQLF, derived from LMP2, BRLF1, and BMLF1 proteins, respectively. TCR down-regulation assays disclosed that, in contrast to the other 2 epitopes, IYVLVMLVL was not presented on HLA A24-positive fibroblast cells infected with recombinant vaccinia viruses expressing LMP2. Furthermore, ELISPOT assays with an epitope-specific CTL clone demonstrated that the presentation was partially restored by pretreatment of the fibroblast cells with interferon-gamma. The epitope was presented on transporters associated with antigen processing (TAP)-negative T2 cells transfected with plasmids encoding HLA A*2402 and the minimal epitope, indicating that the presentation is TAP independent. In conclusion, the 3 epitopes thus defined could be useful for studying EBV-specific CD8(+) T-cell responses among populations positive for HLA A*2402.

Algorithms↗

PubMed2002

Efficient generation of antigen-specific cytotoxic T cells using retrovirally transduced CD40-activated B cells.

The development of rapid, efficient, and safe methods for generating Ag-specific T cells is necessary for the clinical application of adoptive immunotherapy. We show that B cells stimulated with CD40 ligand and IL-4 (CD40-B cells) can be efficiently transduced with retroviral vectors encoding a model Ag, CMV tegument protein pp65 gene, and maintain high levels of costimulatory molecules after gene transfer. CTL lines specific for pp65 were readily generated in all four healthy CMV-seropositive donors by stimulating autologous CD8(+) T cells with these transduced CD40-B cells, both of which were derived from 10 ml peripheral blood. ELISPOT assays revealed that the CTL lines used multiple HLA alleles as restricting elements. Thus, CD40-B cells transduced retrovirally with Ag-encoding cDNA can be potent APC and facilitate to generate Ag-specific CTL in vitro.

Alleles↗