Living Donor Kidney Transplantation After Brachytherapy for Prostate Cancer: Case Report.

INTRODUCTION: There is no obvious criterion about kidney transplantation for patients with pretransplant malignancy. Minimum tumor-free waiting periods differ according to type of cancer, staging, site of occurrence, response to therapy, and risk of cancer recurrence. We report a case of living donor kidney transplantation (LDKT) in a patient after brachytherapy for prostate cancer. CASE REPORT: The patient was a 65-year-old man with chronic kidney disease due to chronic glomerular nephritis. He received hemodialysis 3 times a week. His prostate-specific antigen level (PSA) was high (6.57 ng/mL), and he was diagnosed with prostate cancer (T1cN0M0, Gleason Score 3 + 4 = 7, 3/10) by needle biopsy in urology. He was treated with maximum androgen blockade (MAB) therapy and brachytherapy in May 2014. He underwent LDKT from a spousal donor at our department in December 2015, because urologists concluded that the prostate cancer was completely cured. Immunosuppression consisted of induction with basiliximab and maintenance with tacrolimus, mizoribine, and steroids. The postoperative course was uneventful. He discharged at postoperative day 29 with a serum creatinine level of 1.30 mg/dL. Three months after LDKT, his PSA level was 0.477 ng/mL, and there was no evidence of prostate cancer recurrence. CONCLUSION: This is the first case of LDKT for patients with prostate cancer after brachytherapy in combination with MAB. There is no recurrence of prostate cancer so far; however, careful follow-up including PSA is necessary and important.

Influences of Pre-formed Donor-Specific Anti-Human Leukocyte Antigen Antibodies in Living-Donor Renal Transplantation: Results With Graft Immunocomplex Capture Fluorescence Analysis.

BACKGROUND: Advances in immunosuppressants enable organ transplantation for sensitized patients. However, influences of pre-formed donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) have not been fully understood in renal transplantation (RT). On the other hand, immunocomplex capture fluorescence analysis (ICFA) is a reliable method to detect donor-specific anti-HLA antibodies and HLA antigen complexes. Graft ICFA can detect DSA in an allograft (g-DSA). METHODS: To elucidate the consequences of pre-formed DSA, 198 patients who underwent living-donor RT were enrolled for this study (observation period: 57.8 ± 34.9 months); 187 patients in the DSA- group (excluding ABO-incompatible cases) and 11 patients in the DSA+ group. Before RT, all DSA+ patients had undergone rituximab administration and plasmapheresis. For a graft ICFA, the biopsy specimen (1 × 105 cells) was dissolved, and HLA antigens were captured by anti-HLA beads. Finally, DSA-HLA complexes were detected by means of PE-conjugated anti-human IgG antibodies and analyzed by use of a Luminex system. A ratio (sample/blank beads, mean of fluorescence intensity) was calculated: ≥1.0 was determined as positive g-DSA. RESULTS: There were no significant differences in 5-year graft survival (87.9%/100% in the DSA-/DSA+ groups, respectively). In terms of antibody-mediated rejection (AMR), within 1 month after RT, pathologically determined AMR occurred 3.2% and 63.4% in the DSA- and DSA+ groups, respectively (P < .0001). However, interestingly, more than half of them (57.1%) indicated only subclinical AMR, that is, no fluctuation of S-Cr. As representative of 2 cases of subclinical AMR, g-DSA deposition could be confirmed (1.15 ± 0.04) at 1 hour after reperfusion by graft ICFA. Furthermore, g-DSA shifted to 2.20 ± 0.98 at 3 weeks after transplantation, along with a decline in s-DSA mean of fluorescence intensity (1718-506.5). CONCLUSIONS: Although pathologically determined AMR occurred more frequently in pre-formed DSA+ recipients, it can be argued that a successful de-sensitization protocol inhibits further production of DSA and graft destruction.

Effectiveness of the Combination of Everolimus and Tacrolimus With High Dosage of Mizoribine for Living Donor-Related Kidney Transplantation.

BACKGROUND: Everolimus (EVR) has been used widely for the purpose of reducing the dosage of calcineurin inhibitor (CNI), leading to decreasing CNI nephrotoxicity. In Japan, high-dose mizoribine (MZR) (6 mg/kg/day) has been increasingly used because of incidences of virus infection and gastrointestinal disorder in kidney transplant recipients. However, the efficacy and safety of EVR and MZR combination therapy is still uncertain. METHODS: A total of 29 living kidney transplant recipients from October 2012 to June 2014 were analyzed. Tacrolimus (TAC), MZR, basiliximab, and prednisolone were administered to all recipients. EVR was added to the regimen for 10 recipients from postoperative day 10 to 14; TAC trough levels were minimized simultaneously (EVR group). The remaining 19 recipients were defined as the control group. We evaluated the outcomes between the 2 groups. RESULTS: The mean TAC trough level was 5.17 ng/mL at 1 month after transplantation in the EVR group, and 7.89 ng/mL in the control group (P = .007), respectively. The mean TAC trough level was 4.0 ng/mL at 18 months after transplantation in the EVR group, and 6.97 ng/mL in the control group (P = .003) respectively. There were no differences in the rate of acute rejection and serum creatinine level. There was no significant difference in the incidence of histological nephrotoxicity between the 2 groups in the 1-year biopsy results. CONCLUSIONS: We succeeded in reducing TAC trough level immediately after transplantation by adding EVR. Our study results suggest that this combination therapy is effective for kidney transplantation recipients.

Activation of cerebral sodium-glucose transporter type 1 function mediated by post-ischemic hyperglycemia exacerbates the development of cerebral ischemia.

The regulation of post-ischemic hyperglycemia plays an important role in suppressing neuronal damage in therapeutic strategies for cerebral ischemia. We previously reported that the cerebral sodium-glucose transporter (SGLT) was involved in the post-ischemic hyperglycemia-induced exacerbation of cerebral ischemic neuronal damage. Cortical SGLT-1, one of the cerebral SGLT isoforms, is dramatically increased by focal cerebral ischemia. In this study, we focused on the involvement of cerebral SGLT-1 in the development of cerebral ischemic neuronal damage. It was previously reported that activation of 5'-adenosine monophosphate-activated protein kinase (AMPK) increases SGLT-1 expression. Moreover, ischemic stress-induced activation of AMPK exacerbates cerebral ischemic neuronal damage. Therefore, we directly confirmed the relationship between cerebral SGLT-1 and cerebral AMPK activation using in vitro primary culture of mouse cortical neurons. An in vivo mouse model of focal cerebral ischemia was generated using a middle cerebral artery occlusion (MCAO). The development of infarct volume and behavioral abnormalities on day 3 after MCAO were ameliorated in cerebral SGLT-1 knock down mice. Cortical and striatal SGLT-1 expression levels were significantly increased at 12h after MCAO. Immunofluorescence revealed that SGLT-1 and the neuronal nuclear antigen (NeuN) were co-localized in the cortex and striatum of MCAO mice. In the in vitro study, primary cortical neurons were cultured for five days before each treatment with reagents. Concomitant treatment with hydrogen peroxide and glucose induced the elevation of SGLT-1 and phosphorylated AMPK/AMPK ratio, and this elevation was suppressed by compound C, an AMPK inhibitor in primary cortical neurons. Moreover, compound C suppressed neuronal cell death induced by concomitant hydrogen peroxide/glucose treatment in primary cortical neurons. Therefore, we concluded that enhanced cerebral SGLT-1 function mediated by post-ischemic hyperglycemia exacerbates the development of cerebral ischemic neuronal damage. One of the mechanisms of cerebral SGLT-1 up-regulation may be involved in the AMPK activation after cerebral ischemia.

Evaluation of rituximab dosage for ABO-incompatible living-donor kidney transplantation.

BACKGROUND: The introduction of rituximab has led to a growing tendency to perform ABO-incompatible living-donor kidney transplantation (LDKT) without splenectomy. However, the optimal dosage of rituximab is undefined. METHOD: Fifty-five LDKT recipients who had neither a history of hepatitis B infection nor positive crossmatch were enrolled between October 2005 and June 2014. Recipients were divided into three groups by year of transplantation: 2005 to 2008; 2009 to 2011; and 2012 to 2014. Percentages of CD20-positive B lymphocytes and blood-group antibody titers were monitored before renal transplantation. An initial rituximab dosage of 100 mg/body (for titers below 64) or 200 mg/body (for titers above 128) was administered 2 weeks before transplantation. If the percentage of peripheral B lymphocytes remained greater than 0.5%, additional rituximab (100 mg or 200 mg) was administered. Patient demographics, patient survival, graft survival, and complication rates were compared. RESULTS: Nine patients received rituximab 100 mg/body (low-dose rituximab [LDR] group). Overall survival and graft survival rates did not differ significantly between the LDR group and other cases. The incidences of myelosuppression and viral infection were lower in the LDR group than the other cases. CONCLUSION: A low dose of rituximab (100 mg/body) is adequate in ABO-incompatible LDKT, especially in cases with low blood-type antibody titer against ABO-antigens. Rituximab dosage reduction has been successful in our hospital without serious complications. Moreover, as over-dosage of rituximab may cause myelosuppression, it is reasonable to believe that LDR is a suitable option to safely perform ABO-incompatible LDKT without splenectomy.

Histopathologic impacts of everolimus introduction on kidney transplant recipients.

BACKGROUND: Introduction of everolimus (RAD) has been established as a new immunosuppressive medication for kidney transplant (KT) recipients. Administration of RAD is capable of reducing the dosage of coadministrated calcineurin inhibitors (CNI). However, histological investigations have rarely been performed. METHODS: To clarify histopathologic effects of RAD, a total of 9 adult KT recipients were enrolled (RAD group, n = 5; Mycophenolate mofetil (MMF) group, n = 4). Renal graft biopsies had been performed at 3 weeks and 1 year following KT. RESULTS: There were no differences in 1-, 3-, and 5-year graft survival rates (RAD group: 100%, 100%, and 80%, respectively; MMF group: 100%, 100%, and 75%, respectively), and patient survival between the 2 groups (no deaths during the 5 years post-transplantation). Interestingly, although 2 patients in the RAD group had developed CNI nephrotoxicity clinically, renal biopsies had proven no CNI-related lesions 1 year later, which might be due to the reduction in CNI. On the other hand, 1 patient, in the MMF group, had been diagnosed histologically with new-onset CNI nephrotoxicity 1 year following KT. Importantly, the frequency and mean arteriolar hyalinosis (ah) scores, which reflect CNI nephrotoxicity, were significantly higher in the MMF group at 1-year biopsy (P < .05, P < .0001). Two patients in the RAD group improved their ah scores between 3 weeks and 1 year. CONCLUSIONS: Pathological findings revealed that reversible CNI nephrotoxicity can be improved by RAD with reduced CNI maintenance therapy. It is reasonable to believe, therefore, that introduction of RAD is useful for patients who have been diagnosed with CNI nephrotoxicity.

Evaluation of renal allograft fibrosis by transient elastography (Fibro Scan).

BACKGROUND: Chronic allograft injury (CAI) is one of the most important factors for graft failure after renal transplantation. Protocol biopsy is the most valuable tool for revealing subclinical renal allograft failure. Transient elastography (TE) is a noninvasive technique that has shown utility for the assessment of hepatic and renal fibrosis. This study sought to evaluate whether TE was a viable and effective method for the assessment of renal allograft failure. PATIENTS AND METHODS: Thirty-five patients underwent TE by Fibro Scan (Echosense, Paris, France). Biopsies were performed in 27 patients, allowing classification according to Banff chronic changes in the interstitium grade 0, grade 1 or grade 2. RESULTS: Measurement of parenchymal stiffness was successful in 31 of 35 patients (91%). Stiffness was significantly correlated with interstitial fibrosis (P < .05) and inversely related with estimated glomerular filtration rate (eGFR; P < .05). Stiffness values of patients with eGFR > 50 mL/min were lower than those of patients with eGFR < 50 mL/min (P < .05). Patients classed as CAI Banff grade 0 had significantly less parenchymal stiffness than patients with Banff grade 1 or grade 2 CAI (P < .05). Parenchymal stiffness measured by TE reflected interstitial fibrosis in renal allograft. CONCLUSION: Assessment of parenchymal renal allograft stiffness by TE was effective for identifying patients with CAI who may subsequently benefit from biopsy and modification of the immunosuppressive regimen. Assessment of parenchymal renal allograft stiffness can be effective for identifying patients with CAI. TE has the potential to reduce the number of renal allograft biopsies required for accurate assessment of CAI.

Usefulness of follow-up biopsies at one year after ABO-incompatible kidney transplantation.

BACKGROUND: Due to the shortage of deceased donor kidneys, we have expanded the indications for living-donor kidney transplantation (LKT) including ABO-incompatible (ABO-i) donors in Japan. In this study, the utility of protocol biopsies was discussed in ABO-i LKT. METHODS: Protocol biopsies have been performed on kidney graft 1 hour, 3 weeks, and 1 year after LKT in our institution. The relationship between biopsies and clinical courses was considered retrospectively in 38 cases of ABO-i LKT. The immunosuppressive regimen consisted of anti-CD20 antibody, mycophenolate mofetil, prednisolone, calcineurin inhibitor (cyclosporine or tacrolimus), and anti-CD25 antibody. Anti-ABO blood type antibody removal by plasmapheresis was performed before LKT up to 32 times. The post-transplantation regimen consisted of mycophenolate mofetil or mizoribine as an antimetabolite. RESULTS: Episode biopsies have been performed in 6 cases within 3 weeks post-transplantation. Each pathological diagnosis was as follows: antibody-mediated rejection (AMR; 5 cases) and calcineurin inhibitor (CNI) nephrotoxicity (1 case). Subclinical chronic active AMR was found at 1 year post-transplantation follow-up biopsies in 4 of the 6 cases. Episode biopsies have been done in the other 6 cases from 1 month to 1 year post-transplantation. Each pathological diagnosis was as follows: acute T-cell-mediated rejection (TMR; 1 case), vesicoureteral reflux (VUR; 3 cases), CNI nephrotoxicity (2 cases), and VUR + CNI nephrotoxicity (1 case). AMR was also not found at 1 year post-transplantation follow-up biopsies in them. In all cases episode biopsies were performed based on pathological diagnosis and had no graft dysfunction after that. CONCLUSIONS: Pathological study revealed that acute AMR was found early (ie, within 3 weeks) following transplantation. Although appropriate treatment made AMR go into remission once, chronic active AMR was often found at 1-year follow-up biopsies.

How long should we follow the post-transplantation patient after graft loss? A case report of renal cancer in the grafted kidney that occurred 16 years after graft loss.

BACKGROUND: Renal cancers commonly occur in the native kidneys of renal transplant recipients, whereas renal cancer in the grafted kidney has been reported occasionally. Renal cancer in the grafted kidney occurred 16 years after graft loss in this case, which would be a more rare case. CASE REPORT: A 60-year-old man who had a kidney transplant from his mother at the age of 31 years and had hemodialysis again because of chronic rejection from the age of 44 years had right lower abdominal pain. Computerized tomography (CT) showed tumor involvement in the grafted kidney. Positron-emission tomography-CT also showed hot spots in the liver, cervical vertebra, and costal bone. Needle biopsy for grafted kidney and liver tumors were done, and pathologic findings revealed renal cancer of grafted kidney and metastatic liver tumor. Graftectomy was done, and renal cancer was diagnosed as spindle cell carcinoma. Irradiation for cervical bone metastasis was done after the surgery. He complained of abdominal pain and eating disturbance 2 months after the surgery. CT showed a huge recurrence tumor and multiple tumor dissemination. Small intestine was involved and obstructed by the main tumor. He died of recurrence of renal cancer 3 months after the surgery. CONCLUSIONS: It is reported that the rate of renal cell carcinoma in the grafted kidney was 0.19%-0.5% and it occurred at a mean of 12.6 years after renal transplantation. Herein, we report a rare case of renal cancer that occurred 29 years after renal transplantation. Long-term observation should be required for recipients who had rehemodialysis.

Acute renal failure caused by hyperuremic acidemia in ABO-incompatible kidney transplant maintained with cyclosporine and high-dose mizoribine: a case report.

INTRODUCTION: The shortage of cadaver organs has led to expansion of living donor kidney transplantations with, 30% increase among ABO-incompatible cases in Japan and the use of marginal extended donors. Herein we have reported the outcome after an ABO-incompatible kidney transplantation from an aged living-related donor who suffered from mild diabetes mellitus and hypertension. CASE REPORT: A 48-year-old man underwent ABO-incompatible kidney transplantation from his 76-year-old father, using anti-CD20 antibody induction, followed by cyclosporine (CsA), mycophenolate mofetil (MMF), and prednisolone. After the operation, MMF was switched to high-dose mizoribine (MZ). He was discharged from the hospital on postoperative day (POD) 28 with a serum creatinine (sCr) of 1.47 mg/dL. On POD 34 when the sCr was 8.14 mg/dL, his urine examination showed uric acid crystals with serum uric acid of 24.6 mg/dL. Biopsy findings showed no evidence of acute rejection but mild tubulointerstitial injury. Hemodialysis performed twice to reduce uric acid was accompanied by hydration. CsA/MZ was switched to tacrolims/MMF; benzbromarone, to febuxostat to treat hyperuric acidemia. On POD 58, sCr reduced to 1.75 mg/dL he was discharged. On POD 416, graft function was stable with sCr of 1.70 mg/dL. CONCLUSION: Common side effect of MZ is hyperuricemia which presumably caused acute renal failure of this aged marginal donor kidney.

Role of transcription factors in small intestinal ischemia-reperfusion injury and tolerance induced by ischemic preconditioning.

BACKGROUND: Small intestinal ischemia-reperfusion (I/R) injury, a clinically important condition, induces severe organ damage. Ischemic preconditioning (IPC) produces tolerance to long-term I/R by inducing a short-term I/R. Herein, we have examined the reduction in the extent of injury by IPC. METHODS: Small intestinal I/R injury was induced in rats by clamping the superior mesenteric artery (SMA) for 30 minutes followed by reperfusion for various 30 minutes. The IPC + I/R group underwent a short-term I/R (IPC) prior to long-term I/R. Nuclear factor-κB (NF-κB) activity was analyzed by an electrophoretic mobility shift assay and cytokine mRNA levels, by reverse transcription-polymerase chain reaction. Apoptosis-related genes were analyzed by Western blotting and immunohistochemistry, and apoptotic cells, by TUNEL staining. RESULTS: The animals were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion. NF-κB activity increased in the I/R group and decreased in the IPC + I/R group. The IPC + I/R group showed decreased cytokine in mRNA levels. Expression of the proapoptotic gene caspase-3 was increased in the I/R and decreased in the IPC + I/R group. Expression of the antiapoptotic gene Bcl-xL was increased in the IPC + I/R group. The number of apoptotic cells was increased in the I/R and decreased in the IPC + I/R group. CONCLUSION: Small intestinal I/R injury was reduced by IPC produced by clamping the SMA; thus, IPC may have potential clinical applications in the future.

A novel nonsecosteroidal VDR agonist (CH5036249) exhibits efficacy in a spontaneous benign prostatic hyperplasia beagle model.

To date, there have been no reports showing the efficacy of nonsecosteroidal vitamin D receptor (VDR) agonists in a benign prostatic hyperplasia (BPH) animal model. To examine the efficacy of CH5036249, a novel nonsecosteroidal VDR agonist, we orally administered the compound at 0.03 microg/kg to a beagle model with spontaneous BPH. Prostate volume was checked by rectal ultrasonic probe periodically during 11 months of administration and the prostate tissues histologically examined. CH5036249 inhibited prostate growth in two out of three dogs compared with vehicle-treated dogs. In the prostate specimens, substantial atrophy of the epithelium was observed in all dogs administered CH5036249. At the dose given, serum calcium levels slightly increased in the CH5036249-treated dogs but stayed within a normal range. We next examined the cell growth inhibition of CH5036249 using human prostate stromal cells and found the cell growth inhibitory activity of CH5036249 to be comparable to that of 1alpha,25(OH)2D3. The bioavailability from oral administration in rats was 95.1% with a t1/2 of 17.6 h. Both micro-AMES and micronucleus tests were negative. Although the results are still preliminary, we consider the novel nonsecosteroidal VDR agonist CH5036249 to be a possible new drug candidate for the treatment of BPH in humans.

[Vacuum-assisted closure therapy for the treatment of sternal wound infection after cardiac surgery].

Sternal wound infection is still one of the critical and challenging complications after cardiac surgery. Vacuum-assisted closure (VAC) therapy is a unique and simple system that helps promote wound healing. We report 3 cases with the sternal wound infection after cardiac surgery, in which VAC therapy was applied between January, 2005 and April, 2007. Two of them had good response to VAC therapy and had their wound healed after 3 and 5 weeks, respectively. However, the remaining case, in which bilateral internal thoracic artery had been taken down for coronary artery bypass grafting (CABG) and osteomyelitis of the sternum was not well controlled, did not respond to VAC therapy. Our results suggested that VAC might facilitate wound healing of the patients with sternal wound infection only after abscess was drained and opened, while it might not be useful for the patents with osteomyelitis.

Vacuum-assisted closure for bilateral severe ischemic foot after revascularization: a case report.

Vacuum-assisted closure (VAC) therapy is a unique system that helps promote wound healing. We report a case of severe ischemic foot in which VAC therapy markedly improved wound healing. A 73-year-old man underwent left axillopopliteal bypass and left 3rd, 4th , and 5th digital amputations for gangrene. Although his amputation stumps were complicated with methicillin-resistant Staphylococcus aureus (MRSA) infection, the stumps were successfully healed by VAC. He also had gangrene in his right 1st toe, which could not healed by VAC alone, and we performed right femoropopliteal bypass and right 1st digital amputation. The stump with MRSA infection was also successfully healed by VAC. Histopathologic examination revealed a lot of microvessels in the increased granulation tissue.

Prostaglandin E2 (PGE2) increases the number of rat bone marrow osteogenic stromal cells (BMSC) via binding the EP4 receptor, activating sphingosine kinase and inhibiting caspase activity.

Prostaglandin E(2) (PGE(2)) is bone-anabolic, i.e. stimulates bone formation and increases bone mass. In this study, we explored possible intracellular mechanisms of its increase of osteogenic cells in rat bone marrow. Adherent rat bone marrow cells were counted after 12-48 h or cultured for 21 days and mineralized nodules were counted. Also, apoptosis of marrow cells was measured after in vivo PGE(2) injection. PGE(2) (100 nM) increased 2-3 fold the number of adherent BMSC, an effect which was mediated via binding the EP(4) receptor since it was mimicked by forskolin and 11-deoxy-prostaglandin E(1) (PGE(1)) and was blocked by DDA and L-161982 (EP(4) antagonist). PGE(2) stimulated sphingosine kinase (SPK) activity since its effects were blocked by DMS (SPK inhibitor) and mimicked by SPP (SPK product). PGE(2) reduced the activity of caspase-3 and -8 in BMSC and their inhibitors increased BMSC number and nodule formation. In vivo, PGE(2) prevented the increase in the apoptosis of bone marrow cells caused by indomethacin. We propose that PGE(2) exerts an anti-apoptotic effect on BMSC, thereby increasing their number and subsequent osteoblastic differentiation. Such an effect could explain how PGE(2) stimulates bone formation in vivo.

Possible association between nonsynonymous polymorphisms of the anaplastic lymphoma kinase (ALK) gene and schizophrenia in a Japanese population.

We examined, for the first time, the possible association between schizophrenia and the anaplastic lymphoma kinase (ALK) gene which plays an important role in neurodevelopment. When two nonsynonymous polymorphisms (Arg1491Lys and Glu1529Asp) were examined, there were significant differences in genotype and allele distributions between patients and controls. Individuals homozygous for the minor allele (1491Lys-1529Asp) were more common in patients than in controls (p = 0.0064, odds ratio 2.4, 95% CI 1.3-4.6). These results suggest that genetic variations of the ALK gene might confer susceptibility to schizophrenia.

Telomere size and telomerase activity in Epstein-Barr virus (EBV)-positive and EBV-negative Burkitt's lymphoma cell lines.

The telomere repeat lengths of BL cell lines were quantified by measuring terminal restriction fragment (TRF). Epstein-Barr virus (EBV)-positive Namalwa, Raji, and EB-3 cell lines have long telomeres, i.e. TRFs 10-19 kbp, whereas the Daudi cell line, producing a transformation-defective EBV mutant, has TRFs approximately 2.2 kbp. EBV-negative BJAB and DG75 cell lines have short TRFs 3.9-5.4 kbp, shorter than the approximately 12 kbp TRFs in PBLs. Telomerase activities of these BL cell lines are similar. TRFs of non-BL lymphoma cell lines are 2.3-5.5 kbp. Fluorescent in situ hybridization (FISH) studies of these cell lines showed remarkable heterogeneity of telomere size in chromosomes in the same BL cell. These results suggest that EBV-positive and EBV-negative BL cell lines have experienced various telomere dynamics.

A monoclonal antibody that recognizes Epstein-Barr virus nuclear antigen 2 (EBNA 2) amino acids 1-58 does not react with EBNA 2 in native form, consistent with the self-association of EBNA 2 through the amino-terminus.

We have generated a mouse IgG1 monoclonal antibody (mAb) that recognizes amino acids 1-58 of Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA 2) of type 1 EBV strain B95-8. mAb Y101 also reacted with EBNA 2 of EBV type 2 strains MISP and Jijoye in immunoblots, whereas Jijoye EBNA 2 was not detected by the widely used mAb PE2. mAb Y101, in contrast to mAb PE2, reacted with faster migrated, hypophosphorylated proteins of type 1 EBNA 2 as intensely as slower migrated, hyperphosphorylated ones. mAb Y101 did not react in fixed-cell immunostaining or cell extract immunoprecipitation. The results implicate that the amino-terminal epitope is not exposed in a native form, consistent with the previously reported idea of self-association of EBNA 2 through the amino-terminus. mAb Y101 is the first mAb to the EBNA 2 amino-terminus and will be useful for further analyses of the structure and function of EBNA 2.