Immunotherapy for leukemia targeting the Wilms' tumor gene.

The Wilms' tumor (WT1) gene encodes a zinc finger transcription factor, which is preferentially expressed in acute leukemia cells and chronic myelogenous leukemia cells in blast crisis, but not in most normal cells. These findings strongly suggest that WT1 is a potential target of immunotherapy for human leukemia. We have established a CD8+ cytotoxic T lymphocyte (CTL) clone, designated TAK-1, which is specific for a WT1-derived 9-mer peptide consisting of HLA-A24-binding anchor motifs. TAK-1 lysed both HLA-A24-positive allogeneic cells and autologous cells that were loaded with a WT1-derived peptide. TAK-1 was cytotoxic to HLA-A24-positive leukemia cells, but not to HLA-A24-positive lymphoma cells that did not express WT1, to HLA-A24-negative leukemia cells, or to HLA-A24-positive normal cells. Treating leukemia cells with an antisense oligonucleotide complementary to WT1 reduced TAK-1-mediated cytotoxicity. TAK-1 did not inhibit colony formation of HLA-A24-positive normal bone marrow cells. Recently, other groups have also reported the establishment of HLA-A2-restricted anti-leukemic CTLs specific for WT1-derived peptide. In addition, a murine model of immunotherapy against WT1-expressing tumors has been reported. Recent studies have demonstrated that WT1 is also aberrantly expressed in various kinds of cancer cells. Taken together, these results suggest that immunotherapy targeting WT1 should be effective against both solid tumors and leukemia.

Transcriptional down-regulation of CXC chemokine receptor 4 induced by impaired association of transcription regulator YY1 with c-Myc in human herpesvirus 6-infected cells.

We have recently reported that down-regulation of CXC chemokine receptor (CXCR) 4 in CD4(+) T lymphocytes is induced by human herpesvirus (HHV) 6 infection. In this study, we further studied the mechanisms of HHV-6-induced CXCR4 down-regulation, focusing on the regulation of CXCR4 transcription. Down-regulation of CXCR4 transcription was detected in HHV-6A-infected JJHAN and HHV-6B-infected MT-4 cell lines, as we had previously reported for HHV-6-infected peripheral blood CD4(+) T lymphocytes. Luciferase assays revealed that a YY1-binding site around -320 relative to the transcription start site is important for down-regulation of CXCR4 transcription in HHV-6-infected cells. The binding activity of YY1, which is a repressor of CXCR4 transcription, to the CXCR4 promoter appeared to significantly increase in HHV-6-infected cells compared with the binding activity in mock-infected cells. Immunoprecipitation assays showed that in HHV-6-infected cells association of c-Myc with YY1 was decreased and that of Max with c-Myc was increased, whereas association of Mad with Max appeared to be decreased. The amounts of each of YY1, c-Myc, Max, and Mad proteins synthesized in cells were not altered by HHV-6 infection. These data indicate that the decreased association of YY1 with c-Myc that is caused by impaired interaction in the c-Myc/Max/Mad network results in increased binding activity of YY1 to the CXCR4 promoter, mediating down-regulation of CXCR4 production in HHV-6-infected cells.

HLA class I-restricted lysis of leukemia cells by a CD8(+) cytotoxic T-lymphocyte clone specific for WT1 peptide.

The Wilms tumor (WT1) gene has been reported to be preferentially expressed in acute leukemia cells, regardless of leukemia subtype and chronic myelogenous leukemia cells in blast crisis, but not in normal cells. This finding suggests strongly that WT1 protein is a potential target of immunotherapy for human leukemia. In this study, we established a CD8(+) cytotoxic T-lymphocyte (CTL) clone directed against a WT1-derived peptide and examined its immunologic actions on leukemia cells. A CD8(+) CTL clone, designated TAK-1, which lysed autologous cells loaded with a WT1-derived 9-mer peptide consisting of the HLA-A24 (HLA-A*2402)-binding motifs was established by stimulating CD8(+) T lymphocytes from a healthy individual repeatedly with WT1 peptide-pulsed autologous dendritic cells. TAK-1 was cytotoxic to HLA-A24-positive leukemia cells expressing WT1, but not to HLA-A24-positive lymphoma cells that did not express WT1, HLA-A24-negative leukemia cells, or HLA-A24-positive normal cells. Treating leukemia cells with an antisense oligonucleotide complementary to the WT1 gene resulted in reduced TAK-1-mediated cytotoxicity, suggesting that target antigen of TAK-1 on leukemia cells is the naturally processed WT1 peptide in the context of HLA-A24. TAK-1 did not inhibit colony formation by normal bone marrow cells of HLA-A24-positive individuals. Because WT1 is overexpressed ubiquitously in various types of leukemia cells, but not in normal cells, immunotherapy using WT1 peptide-specific CTL clones should be an efficacious treatment for human leukemia. (Blood. 2000;95:286-293)

Amplitude reduction of H-reflex during mental movement simulation in elite athletes.

In order to investigate the changes of motoneuron excitability during mental simulation of a voluntary movement (motor imagery; MI), the soleus H-reflex and several activities of autonomic effectors were recorded simultaneously when MI of speed skate sprint was performed. The subjects were seven elite speed skate athletes ranging in age from 18 to 24 years old. They were all skilled in MI, and could imagine full vivid skating movement internally as if they were really exercising. The subjects were awake, relaxed and blindfolded. At first, rest (5 min), positive relaxation (4 min) and concentration periods (2.5 min) were set up. Then, after the previous announcement for the start, MI was initiated by the sound of a signal gun which was recorded by a tape recorder. MIs were continued for each subject from about 36 s to 38 s, and these imaging times were very close to the actual personal best records of each subject. The autonomic effectors represented by skin conductance response (SCR), heart rate (HR), and respiration rate (RSR) became remarkably active during MI in all trials. SCR was increased by 51% on the average. Furthermore, HR and RSR were increased by 57% and 76% respectively, compared with those during resting period. These changes in the autonomic effectors were all significant and were those which were activated in actual movements. The amplitudes of H-reflex were almost all constant before MI initiation. However, the reduction of the H-reflex amplitude arose just after the start and lasted to the end of MI.(ABSTRACT TRUNCATED AT 250 WORDS)

[Urinary managements of 332 stroke patients in the chronic phase].

Urinary managements of 332 stroke patients in the chronic phase were performed at Bobath hospital. Cerebrovascular accidents (CVA) were caused by cerebral infarction in 178 (53.6%), intracerebral hemorrhage in 123 (37.1%) and subarachnoid hemorrhage in 31 (9.3%). Voluntary urination appeared in 124 patients before treatment, however in 29 of them occasional incontinence were observed. One hundred forty-three patients used diapers and 64 were controlled by indwelling catheters. The remaining one patient was treated by intermittent catheterization. Sixty-two patients who seemed to have communicative abilities in daily living were assessed with regard to their cerebrovascular dementia by Hasegawa's Dementia Rating Scale. After treatment 235 patients (70.8%) were able to urinate voluntarily, and only 15 of them remained incontinent and could use small pads successfully. TURP was effective for the stroke patients with benign prostatic hypertrophy (BPH) or bladder neck sclerosis (BNS). Fifty-three patients (16.0%) with persistent urinary incontinence were managed by diapers or a system of condom drainage. Thirty-nine patients (11.7%) were kept dry with intermittent catheterization at home, and long-standing use of indwelling catheters were required in the remaining 5 patients (1.5%). These results indicate that the lower level of activity, mobility and mental state tended to prevent the stroke patients from improvement of urinary disorders.