Milk-Borne Transmission of Human T-Cell Lymphotropic Virus Type I (HTLV-I) and Its Intervention in Nagasaki

Summary Human T-cell lymphotropic virus type I (HTLV-I), a causative virus of adult T-cell leukemia (ATL), transmits through both horizontal and vertical pathways. Since ATL develops in only carriers infected early in life, vertical transmission cycle is the most important target of intervention for the purpose of the prevention of ATL. Epidemiological studies in an endemic area, Nagasaki, Japan, and animal experiments identified milk-borne maternal transmission as the major vertical pathway. The prefecture-wide intervention in Nagasaki since 1987 has revealed that the refraining from breast-feeding by carrier mothers can prevent about 85% of maternal HTLV-I transmission. Pathways for the remaining 15% await for elucidation. However, our studies argued against the possibilities of intrauterine transmission and infection via saliva. Perinatal transmission remains to be evaluated as the alternative pathway. At present, refraining from breast-feeding is the most effective measure to break the cycle of maternal HTLV-I transmission in endemic areas. It is estimated that the intervention in Nagasaki for the past 10 years has prevented 1,000 maternal transmission and 50 future ATL cases. I am reasonably confident that incidence of ATL in Nagasaki will decline to the national average level over the next few generation if the intervention program stays alive

The Absence of Prion-Like Infectivity in Mice expressing Prion Protein-Like Protein

Cellular prion protein, PrP^C, undergoes pathogenic structural conversion into the proteinase K (PK)-resistant isoform, PrP^Sc, to constitute a nucleic acid-free infectious agent, so called a prion. To determine whether a recently identified PrP-like protein, named PrPLP/Dpl, could also be transformed to a prion-like protein, we intracerebrally inoculated a mouse-adapted Fukuoka-1 prion into Ngsk and Zrch I mice either homozygously (Prnp^0/0) or heterozygously (Prnp^0/+) devoid of PrP^C. Only the former expressed PrPLP/Dpl ectopically in the brains, particularly in neurons. Ngsk Prnp^0/+ and Zrch I Prnp^0/+ mice similarly developed the disease. The diseased Ngsk Prnp0/+ mice transmitted the disease to the mice expressing PrP^C but not to the mice expressing PrPLP/Dpl, showing abundant accumulation of PrP^Sc but not PK-resistant PrPLP/Dpl in the brains. Moreover, the inoculated Ngsk Prnp^0/0 mice neither developed the disease nor produced any infectivity transmissible to PrPLP/Dpl-expressing mice. These results indicate that PrPLP/Dpl have no potential to undergo pathogenic conversion to form a prion-like infectious particle

Impairment of cerebellar long‑term depression and GABAergic transmission in prion protein deficient mice ectopically expressing PrPLP/Dpl

Prion protein (PrPC) knockout mice, named as the “Ngsk” strain (Ngsk Prnp0/0 mice), show late-onset cerebellar Purkinje cell (PC) degeneration because of ectopic overexpression of PrPC-like protein (PrPLP/Dpl). Our previous study indicated that the mutant mice also exhibited alterations in cerebellum-dependent delay eyeblink conditioning, even at a young age (16 weeks of age) when neurological changes had not occurred. Thus, this electrophysiological study was designed to examine the synaptic function of the cerebellar cortex in juvenile Ngsk Prnp0/0 mice. We showed that Ngsk Prnp0/0 mice exhibited normal paired-pulse facilitation but impaired long-term depression of excitatory synaptic transmission at synapses between parallel fibres and PCs. GABAA-mediated inhibitory postsynaptic currents recorded from PCs were also weakened in Ngsk Prnp0/0 mice. Furthermore, we confirmed that Ngsk Prnp0/0 mice (7–8-week-old) exhibited abnormalities in delay eyeblink conditioning. Our findings suggest that these alterations in both excitatory and inhibitory synaptic transmission to PCs caused deficits in delay eyeblink conditioning of Ngsk Prnp0/0 mice. Therefore, the Ngsk Prnp0/0 mouse model can contribute to study underlying mechanisms for impairments of synaptic transmission and neural plasticity, and cognitive deficits in the central nervous system

Functional Loss of the HTLV-I Tax Protein Encoded by Variant Proviruses in Infected Individuals.

Accumulating evidence has indicated the presence of HTLV-I quasispecies in infected individuals. To elucidate their biological consequences, we amplified the whole Tax open reading frame (ORF) of HTLV-I proviruses by nested PCR from six infected individuals, including three HAM/TSP patients, and a cloned HTLV-I DNA, pMT2, and the products were introduced into an expression vector. The potential for transcriptional transactivation of protein products of independent 20-39 tax clones derived from each sample was evaluated by transfecting into pA18G-BHK-21 cells containing the HTLV-I LTR-driven lacZ gene. While all of 30 clones derived from pMT2 gave positive results, significant proportions, ranged between 16.0 and 35.0%, of the tax clones from the infected indiv iduals were functionally defective. The functional loss of these tax clones was confirmed by chloramphenicol acetyltransferase (CAT) assay in cells cotransfected with an HTLV-I LTR-CAT reporter. DNA sequence analysis revealed that the defective clones contained at least one nonsynonymous nucleotide substitutions from the consensus sequences of the individual. These findings strongly suggested that the accumulation of HTLV-I proviruses with defective tax was a common feature among infected individuals. Since the Tax protein is indispensable for viral replication, these defective viruses were likely to be generated in individuals after the event of infection. It is conceivable that the quasispecies plays a key role in the latency of HTLV-I infection and possibly in HTLV-I-related pathogenesis

Human papillomavirus DNA in plasma of patients with HPV16 DNA-positive uterine cervical cancer.

OBJECTIVES: The squamous cell carcinoma antigen is considered the most accurate serologic tumor marker for uterine cervical carcinoma. However, serum squamous cell carcinoma antigen levels were found to correlate significantly with clinical severity of atopic dermatitis and chronic renal failure. The present study was conducted in patients with human papillomavirus 16 DNA-positive uterine cervical cancer to determine the plasma level of human papillomavirus 16 DNA and the diagnostic values of plasma human papillomavirus DNA in these patients. METHODS: Forty-three human papillomavirus 16-positive patients with cervical intraepithelial neoplasia or uterine cervical squamous cell carcinoma were recruited in this study. The diagnosis was cervical cancer in 20 patients, high-grade squamous intraepithelial lesions in 21, low-grade squamous intraepithelial lesions in 1 and negative for intraepithelial lesion or malignancy in 3 patients. Before any treatment, blood samples were collected from all patients. For analysis of human papillomavirus DNA in plasma of patients with cervical cancer, quantitative polymerase chain reaction fluorescent assay for human papillomavirus 16 was performed using human papillomavirus 16 primers and SYBR Green dye using the LightCycler 480 SW1.5 apparatus. RESULTS: Plasma human papillomavirus 16 DNA was detected in only 30.0% of the patients with human papillomavirus 16-positive cervical cancer and in none of normal controls. The copy number of plasma human papillomavirus 16 DNA was higher in patients with invasive cancer than in those with cervical intraepithelial neoplasia (CIN3), micro-invasive cancer and in normal individuals. CONCLUSIONS: These results indicated that the plasma human papillomavirus DNA level could be potentially used as a marker of low-invasive cervical cancer tumors in patients with normal squamous cell carcinoma antigen levels before treatment

Hyperefficient PrP Sc amplification of mouse-adapted BSE and scrapie strain by protein misfolding cyclic amplification technique.

Abnormal forms of prion protein (PrP(Sc)) accumulate via structural conversion of normal PrP (PrP(C)) in the progression of transmissible spongiform encephalopathy. Under cell-free conditions, the process can be efficiently replicated using in vitro PrP(Sc) amplification methods, including protein misfolding cyclic amplification. These methods enable ultrasensitive detection of PrP(Sc); however, there remain difficulties in utilizing them in practice. For example, to date, several rounds of protein misfolding cyclic amplification have been necessary to reach maximal sensitivity, which not only take several weeks, but also result in an increased risk of contamination. In this study, we sought to further promote the rate of PrP(Sc) amplification in the protein misfolding cyclic amplification technique using mouse transmissible spongiform encephalopathy models infected with either mouse-adapted bovine spongiform encephalopathy or mouse-adapted scrapie, Chandler strain. Here, we demonstrate that appropriate regulation of sonication dramatically accelerates PrP(Sc) amplification in both strains. In fact, we reached maximum sensitivity, allowing the ultrasensitive detection of < 1 LD(50) of PrP(Sc) in the diluted brain homogenates, after only one or two reaction rounds, and in addition, we detected PrP(Sc) in the plasma of mouse-adapted bovine spongiform encephalopathy-infected mice. We believe that these results will advance the establishment of a fast, ultrasensitive diagnostic test for transmissible spongiform encephalopathies.The definitive version is available at www.blackwell-synergy.co

Escherichia coli contamination of menstrual blood and effect of bacterial endotoxin on endometriosis

To test the hypothesis that bacterial contamination of menstrual blood could be a local biologic event in the development of endometriosis, menstrual blood was cultured and bacterial endotoxin was measured in menstrual blood and peritoneal fluid. Our results suggest that compared with control women, higher colony formation of Escherichia coli in menstrual blood and endotoxin levels in menstrual fluid and peritoneal fluid in women with endometriosis may promote Toll-like receptor 4-mediated growth of endometriosis