Evaluation of in-house loop-mediated isothermal amplification for tuberculosis diagnosis compared with Xpert MTB/RIF

Introduction: To evaluate the diagnostic performances of an in-house loop-mediated isothermal amplification (LAMP) kit and the Xpert MTB/RIF test for the diagnosis of pulmonary tuberculosis in a resource-limited setting, this study was performed at the University Teaching Hospital, Ministry of Health, the Republic of Zambia. Methodology: Two hundred sputum specimens obtained from new tuberculosis (TB) suspects were used for the evaluation of the diagnostic performance of an in-house LAMP kit in comparison with the Xpert MTB/RIF kit. Results: The sensitivity of in-house LAMP and Xpert MTB/RIF was 96.9% and 95.4% in smear-positive samples, 96.8% and 100% in smear-positive/culture-positive samples, and 39.1% and 73.9% in smear-negative/culture-positive samples, respectively. The specificity of in-house LAMP and MTB/RIF kits with culture was 96.5% and 94.5%, respectively. This indicated the superiority of the Xpert MTB/RIF kit; however, mechanical errors during sample processing and the insufficient quantity of samples by Xpert MTB/RIF kit occurred at 2.0% and 19.7%, respectively, comparing to the 100% accessibility of in-house LAMP. Conclusions: Considering the results obtained in this study together with the easy setup with much simpler equipment, such as an aluminum heat block or water bath, in in-house LAMP compared with real-time polymerase chain reaction equipment in Xpert MTB/RIF kit, the applicability of in-house LAMP for the screening of tuberculosis directly from sputum in resource-limited setting seemed to be high.

Direct detection of falciparum and non-falciparum malaria DNA from a drop of blood with high sensitivity by the dried-LAMP system

BACKGROUND

Because of the low sensitivity of conventional rapid diagnostic tests (RDTs) for malaria infections, the actual prevalence of the diseases, especially those caused by non-Plasmodium falciparum (non-Pf) species, in asymptomatic populations remain less defined in countries lacking in well-equipped facilities for accurate diagnoses. Our direct blood dry LAMP system (CZC-LAMP) was applied to the diagnosis of malaria as simple, rapid and highly sensitive method as an alternative for conventional RDTs in malaria endemic areas where laboratory resources are limited.

RESULTS

LAMP primer sets for mitochondria DNAs of Plasmodium falciparum (Pf) and human-infective species other than Pf (non-Pf; P. vivax, P. ovale, P. malariae) were designed and tested by using human blood DNA samples from 74 residents from a malaria endemic area in eastern Zambia. These malaria dry-LAMPs were optimized for field or point-of-care operations, and evaluated in the field at a malaria endemic area in Zambia with 96 human blood samples. To determine the sensitivities and specificities, results obtained by the on-site LAMP diagnosis were compared with those by the nested PCR and nucleotide sequencing of its product. The dry LAMPs showed the sensitivities of 89.7% for Pf and 85.7% for non-Pf, and the specificities of 97.2% for Pf and 100% for non-Pf, with purified blood DNA samples. The direct blood LAMP diagnostic methods, in which 1 μl of anticoagulated blood were used as the template, showed the sensitivities of 98.1% for Pf, 92.1% for non-Pf, and the specificities of 98.1% for Pf, 100% for non-Pf. The prevalences of P. falciparum, P. malariae and P. ovale in the surveyed area were 52.4, 25.3 and 10.6%, respectively, indicating high prevalence of asymptomatic carriers in endemic areas in Zambia.

CONCLUSIONS

We have developed new field-applicable malaria diagnostic tests. The malaria CZC-LAMPs showed high sensitivity and specificity to both P. falciparum and non-P. falciparum. These malaria CZC-LAMPs provide new means for rapid, sensitive and reliable point-of-care diagnosis for low-density malaria infections, and are expected to help update current knowledge of malaria epidemiology, and can contribute to the elimination of malaria from endemic areas.

Studies of trypanosomiasis in the Luangwa valley, north-eastern Zambia

Background

The present study, conducted in Zambia’s Luangwa valley where both animal African trypanosomiasis (AAT) and human African trypanosomiasis (HAT) are endemic, combined the use of microscopy and molecular techniques to determine the presence of trypanosome species in cattle, goats and tsetse flies.

Methods

This study was conducted between 2008 and 2010 in Petauke, Chama and Isoka districts, north-eastern Zambia. A total of 243 cattle, 36 goats and 546 tsetse flies, were examined for presence of trypanosome species using microscopy, PCR and loop-mediated isothermal amplification (LAMP).

Results

There was poor agreement among the test methods used for detection of trypanosomes species in animal blood and tsetse flies. Trypanosomes were observed in 6.1 % (95 % CI: 3.3-8.9 %) of the animals sampled by microscopy, 7.5 % (95 % CI: 4.4–10.6 %) by PCR and 18.6 % (95 % CI: 13.6–23.6 %) by PFR-LAMP. PFR-LAMP was more sensitive for detecting Trypanozoon than KIN-PCR. The highest occurrence of AAT was recorded in cattle from Petauke (58.7 %, 95 % CI: 44.7–72.7 %) while the lowest was from Isoka (5.4 %, 95 % CI: 0.8–10.0 %). Infection of both cattle and goats with Trypanosoma congolense and T. vivax was associated with clinical AAT.

Conclusion

When selecting molecular techniques for AAT surveillance in endemic regions, the KIN-PCR and species-specific PCR may be recommended for screening animal or tsetse fly samples for T. congolense and T. vivax, respectively. On the other hand, species-specific PCR and/or LAMP might be of greater value in the screening of animal and human body fluids as well as tsetse fly samples for Trypanozoon.

Direct blood dry LAMP: a rapid, stable, and easy diagnostic tool for Human African Trypanosomiasis

Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive tool used for the diagnosis of a variety of infectious diseases. One of the advantages of this method over the polymerase chain reaction is that DNA amplification occurs at a constant temperature, usually between 60–65°C; therefore, expensive devices are unnecessary for this step. However, LAMP still requires complicated sample preparation steps and a well-equipped laboratory to produce reliable and reproducible results, which limits its use in resource-poor laboratories in most developing countries. In this study, we made several substantial modifications to the technique to carry out on-site diagnosis of Human African Trypanosomiasis (HAT) in remote areas using LAMP. The first essential improvement was that LAMP reagents were dried and stabilized in a single tube by incorporating trehalose as a cryoprotectant to prolong shelf life at ambient temperature. The second technical improvement was achieved by simplifying the sample preparation step so that DNA or RNA could be amplified directly from detergent-lysed blood samples. With these modifications, diagnosis of HAT in local clinics or villages in endemic areas becomes a reality, which could greatly impact on the application of diagnosis not only for HAT but also for other tropical diseases.

Human African trypanosomiasis (HAT) is an endemic protozoan disease affecting many African countries, predominantly in rural areas where the tsetse fly vector is present. HAT diagnosis currently relies on conventional microscopy techniques, which provide relatively low sensitivity and are often unable to distinguish between the two different HAT-causing subspecies, T. b. rhodesiense and T. b. gambiense. A delay in HAT diagnosis can result in disease progression from an early stage (hemolymphatic) to a late stage (meningoencephalitic); therefore, a rapid and sensitive diagnostic test is crucial to its successful treatment. In this study, we developed a simple and highly sensitive molecular technique for HAT diagnosis. Loop-mediated isothermal amplification (LAMP) is a method that rapidly amplifies DNA with high sensitivity under isothermal conditions. We optimized and modified the technique by stabilizing the reagents and simplifying the sample preparation for the diagnosis of HAT. The whole protocol is so simple that local staff can perform it without the need for costly equipment and expertise.

Determination of the prevalence of African trypanosome species in indigenous dogs of Mambwe district, eastern Zambia, by loop-mediated isothermal amplification

Background

Dogs have been implicated to serve as links for parasite exchange between livestock and humans and remain an important source of emerging and re-emerging diseases including trypanosome infections. Yet, canine African trypanosomosis (CAT), particularly in indigenous dogs (mongrel breed) remains under- reported in literature. This study evaluated the performance of loop-mediated isothermal amplification (LAMP) in detecting trypanosomes in blood from indigenous dogs of tsetse-infested Mambwe district in eastern Zambia.

Methods

A cross sectional survey of CAT was conducted within 5 chiefdoms (Msoro, Kakumbi, Munkanya, Nsefu, Malama) of Mambwe district, eastern Zambia, during October 2012. Blood samples from 237 indigenous hunting dogs were collected and screened by microscopy and LAMP.

Results

Of the 237 dogs screened for CAT, 14 tested positive by microscopy (5.9%; 95% CI: 2.9 – 8.9%), all of which also tested positive by LAMP. In addition, LAMP detected 6 additional CAT cases, bringing the total cases detected by LAMP to 20 (8.4%; 95% CI: 4.9 – 12.0%). Irrespective of the detection method used, CAT was only recorded from 3 chiefdoms (Munkanya, Nsefu, Malama) out of the 5. According to LAMP, these infections were caused by Trypanosoma congolense, Trypanosoma brucei brucei and the zoonotic Trypanosoma brucei rhodesiense. Although these CAT cases generally did not manifest clinical illness, an association was observed between infection with Trypanosoma brucei subspecies and occurrence of corneal opacity.

Conclusions

This communication reports for the first time the occurrence of CAT in indigenous Zambian dogs. Our study indicates that LAMP is a potential diagnostic tool for trypanosome detection in animals. LAMP was more sensitive than microscopy and was further capable of distinguishing the closely related T. b. brucei and T. b. rhodesiense. In view of the sporadic cases of re-emerging HAT being reported within the Luangwa valley, detection of the human serum resistant associated (SRA) gene in trypanosomes from mongrels is intriguing and indicative of the risk of contracting HAT by local communities and tourists in Mambwe district. Consequently, there is a need for continuous trypanosome surveillances in animals, humans and tsetse flies using sensitive and specific tests such as LAMP.

Preparation and Functional Analysis of Tumor-Infiltrating Stroma Cells Using Bone Marrow Chimera Mice

Tumor-infiltrating stroma cells (TISC) as well as tumors themselves are thought to be involved in tumor-related immunosuppression, which is one of the critical mechanisms of tumor escape from immune surveillance. However, preparation of TISC is difficult because of the small proportion of TISC in established tumors. Thus, the cells thought to be involved in tumor-related immunosuppression are generally prepared from spleens or draining lymph nodes in tumor-bearing mice. In this study, we developed a method for directly preparing TISC from established tumors in order to analyze their function. Using green fluorescent protein (GFP) transgenic (Tg) mice and C57BL/6 mice transplanted with bone marrow (BM) cells of GFPTg mice, we detected three subpopulations of TISC: one is compatible with immature myeloid cells (ImC) derived from BM and the two other subpopulations, CD11b(+) cells and CD11b(-) cells, do not originate from BM. The TISC including these subpopulations but not each subpopulation independently after culturing with tumors in the presence of GM-CSF could suppress T cell proliferation induced by anti-CD3. In our system, tumors did not inhibit T cell responses directly, but unknown factors from tumors affected immunosuppression by TISC.

Phenotypic Stability of Mature Dendritic Cells Tuned by TLR or CD40 to Control the Efficiency of Cytotoxic T Cell Priming

It is generally accepted that after stimulation immature DCs turn into mature DCs, which present exogenous antigens together with their MHC class I molecules and then activate the antigen-specific CTLs. Although both TLR and CD40 stimulation appeared to provide the same effects on DC maturation, CD40-dependent CTL activation is much more potent than CTL activation through LPS stimulation. Despite their different outcomes, the factors that lead mature DCs to different functions remain largely undefined. In this study, we defined the transient maturation and subsequent deactivation of DCs by TLR stimuli, including those by LPS and CpG-ODN. In contrast, CD40 stimulation induced stable mature DCs that elicited sufficient CTL proliferation. The deactivated DCs, which we defined as "expired DCs," were phenotypically similar to immature DCs, except for their phenotype stability, MHC class I expression level and IL-10 production. Moreover, the functions of expired DCs were comparable to those of immature DCs in terms of CTL induction and tolerogenicity. These results may provide an explanation for the role of CD40 stimulation in antigen-specific CTL induction.

Gold nanoparticles as a vaccine platform: influence of size and shape on immunological responses in vitro and in vivo

This paper demonstrates how the shape and size of gold nanoparticles (AuNPs) affect immunological responses in vivo and in vitro for the production of antibodies for West Nile virus (WNV). We prepared spherical (20 and 40 nm in diameter), rod (40 × 10 nm), and cubic (40 × 40 × 40 nm) AuNPs as adjuvants and coated them with WNV envelope (E) protein. We measured anti-WNVE antibodies after inoculation of these WNVE-coated AuNPs (AuNP-Es) into mice. The 40 nm spherical AuNP-Es (Sphere40-Es) induced the highest level of WNVE-specific antibodies, while rod AuNP-Es (Rod-Es) induced only 50% of that of Sphere40-E. To examine the mechanisms of the shape-dependent WNVE antibody production, we next measured the efficiency of cellular uptake of AuNP-Es into RAW264.7 macrophage cells and bone-marrow-derived dendritic cells (BMDCs) and the subsequent cytokine secretion from BMDCs. The uptake of Rod-Es into the cells proceeded more efficiently than those of Sphere-Es or cubic WNVE-coated AuNPs (Cube-Es), suggesting that antibody production was not dependent on the uptake efficiency of the different AuNP-Es. Cytokine production from BMDCs treated with the AuNP-Es revealed that only Rod-E-treated cells produced significant levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18), indicating that Rod-Es activated inflammasome-dependent cytokine secretion. Meanwhile, Sphere40-Es and Cube-Es both significantly induced inflammatory cytokine production, including tumor necrosis factor-α (TNF-α), IL-6, IL-12, and granulocyte macrophage colony-stimulating factor (GM-CSF). These results suggested that AuNPs are effective vaccine adjuvants and enhance the immune response via different cytokine pathways depending on their sizes and shapes.

Preliminary investigation of trypanosomosis in exotic dog breeds from Zambia's Luangwa and Zambezi valleys using LAMP

Abstract. Canine African trypanosomosis (CAT) is rarely reported in the literature. In this preliminary study, we evaluated the performance of loop-mediated isothermal amplification (LAMP) against microscopy to detect CAT in six exotic dog breeds naturally infected with trypanosomes from Zambia's South Luangwa National Park and Chiawa Game Management Area. To our knowledge, this is the first report of CAT in Zambia. The patients exhibited a variety of aspecific clinical signs. The LAMP did not only confirm all six parasitologically positive CAT cases detected passively between April 2010 and January 2012, but was also critical in trypanosome speciation. According to LAMP, the majority of the dogs had monolytic infections with either Trypanosoma congolense or Trypanosoma brucei rhodesiense. The LAMP is thus a potential simple and cost-effective tool for trypanosome diagnosis in endemic regions. The rare report of zoonotic trypanosomes in dogs in Zambia has public health implications and justifies further investigations of CAT.

Emulsified phosphatidylserine, simple and effective peptide carrier for induction of potent epitope-specific T cell responses

Background

To induce potent epitope-specific T cell immunity by a peptide-based vaccine, epitope peptides must be delivered efficiently to antigen-presenting cells (APCs) in vivo. Therefore, selecting an appropriate peptide carrier is crucial for the development of an effective peptide vaccine. In this study, we explored new peptide carriers which show enhancement in cytotoxic T lymphocyte (CTL) induction capability.

Methodology/Principal Findings

Data from an epitope-specific in vivo CTL assay revealed that phosphatidylserine (PS) has a potent adjuvant effect among candidate materials tested. Further analyses showed that PS-conjugated antigens were preferentially and efficiently captured by professional APCs, in particular, by CD11c⁺CD11b⁺MHCII⁺ conventional dendritic cells (cDCs) compared to multilamellar liposome-conjugates or unconjugated antigens. In addition, PS demonstrated the stimulatory capacity of peptide-specific helper T cells in vivo.

Conclusions/Significance

This work indicates that PS is the easily preparable efficient carrier with a simple structure that delivers antigen to professional APCs effectively and induce both helper and cytotoxic T cell responses in vivo. Therefore, PS is a promising novel adjuvant for T cell-inducing peptide vaccines.

Whole-genome sequencing of Theileria parva strains provides insight into parasite migration and diversification in the African continent

The disease caused by the apicomplexan protozoan parasite Theileria parva, known as East Coast fever or Corridor disease, is one of the most serious cattle diseases in Eastern, Central, and Southern Africa. We performed whole-genome sequencing of nine T. parva strains, including one of the vaccine strains (Kiambu 5), field isolates from Zambia, Uganda, Tanzania, or Rwanda, and two buffalo-derived strains. Comparison with the reference Muguga genome sequence revealed 34 814–121 545 single nucleotide polymorphisms (SNPs) that were more abundant in buffalo-derived strains. High-resolution phylogenetic trees were constructed with selected informative SNPs that allowed the investigation of possible complex recombination events among ancestors of the extant strains. We further analysed the dN/dS ratio (non-synonymous substitutions per non-synonymous site divided by synonymous substitutions per synonymous site) for 4011 coding genes to estimate potential selective pressure. Genes under possible positive selection were identified that may, in turn, assist in the identification of immunogenic proteins or vaccine candidates. This study elucidated the phylogeny of T. parva strains based on genome-wide SNPs analysis with prediction of possible past recombination events, providing insight into the migration, diversification, and evolution of this parasite species in the African continent.

The use of Loop-mediated Isothermal Amplification (LAMP) to detect the re-emerging Human African Trypanosomiasis (HAT) in the Luangwa and Zambezi valleys

Background

Loop-mediated isothermal amplification (LAMP) is a novel strategy which amplifies DNA with high sensitivity and rapidity under isothermal conditions. In the present study, the performance of the repetitive insertion mobile element (RIME)-LAMP and human serum resistance-associated gene (SRA)-LAMP assays were evaluated using clinical specimens obtained from four male patients from Luangwa and Zambezi valleys in Zambia and Zimbabwe, respectively.

Findings

The cases reported in this preliminary communication were all first diagnosed by microscopy, through passive surveillance, and confirmed by both RIME-LAMP and SRA-LAMP. A good correlation between microscopy and LAMP was observed and contributed to staging and successful treatment of patient. RIME-LAMP and SRA-LAMP complimented each other well in all the cases.

Conclusions

Both RIME-LAMP and SRA-LAMP were able to detect Trypanosoma brucei rhodesiense DNA in patient blood and CSF and hence confirmed HAT in the parasitaemic patients. Our study indicates that the LAMP technique is a potential tool for HAT diagnosis, staging and may be useful for making therapeutic decisions. However, no statistically significant conclusion may be drawn due to the limited sample size used in the present study. It is thus imperative to conduct a detailed study to further evaluate the potential of LAMP as a bedside diagnostic test for HAT.

MDM2 regulates a novel form of incomplete neoplastic transformation of Theileria parva infected lymphocytes

Our efforts are concerned with identifying features of incomplete malignant transformation caused by non viral pathogens. Theileria parva (T. parva) is a tick-transmitted protozoan parasite that can cause a fatal lymphoproliferative disease in cattle. The T. parva-infected lymphocytes display a transformed phenotype and proliferate in culture media like the other tumor cells, however those cells will return to normal after antiprotozoal treatment reflecting the incomplete nature of transformation. To identify signaling pathways involved in this form of transformation of T. parva-infected cells, we screened a library of anticancer compounds. Among these, TIBC, a specific inhibitor of MDM2, markedly inhibited proliferation of T. parva-infected lymphocytes and promoted apoptosis. Therefore we analyzed MDM2 function in T. parva-infected cells. Several T. parva-infected cell lines showed increased expression level of MDM2 with alternatively spliced isoforms compared to the lymphoma cells or ConA blasts. In addition, buparvaquone affected MDM2 expression in T. parva transformed cells. Moreover, p53 protein accumulation and function were impaired in T. parva-infected cells after cisplatin induced DNA damage despite the increased p53 transcription level. Finally, the treatment of T. parva-infected cells with boronic-chalcone derivatives TIBC restored p53 protein accumulation and induced Bax expression. These results suggest that the overexpression of MDM2 is closely linked to the inhibition of p53-dependent apoptosis of T. parva-infected lymphocytes. Aberrant expression of host lymphocyte MDM2 induced by cytoplasmic existence of T. parva, directly and/or indirectly, is associated with aspects of this type of transformation of T. parva-infected lymphocytes. This form of transformation shares features of oncogene induced malignant phenotype acquisition.

The role of splenic CD103+CD8α+cDCs in the induction of CTL responses during respiratory virus infection (168.11)

We have previously reported that large numbers of virus-specific CD8+ T cells were detected in the spleen following intranasal influenza virus infection. This finding does not seem simply due to the migration of cells from the draining mediastinal lymph nodes (mLN), but rather indicates that spleen can be a site for the induction of primary CTL responses. Although the integrin αEβ7 (CD103)+ migratory DCs have been known as a major DC subset which prime naïve influenza virus-specific CD8+ T cells in the mLN, what kind of DC subset is responsible for the induction of CTL responses in the spleen remains unclear. In this study, we found that increased numbers of CD103+DCs were detectable in the spleen following influenza virus infection, and the majority of CD103+DCs expressed CD8α. Although both CD103+CD11chi DCs (CD103+DCs) and CD103-CD11chi DCs (CD103-DCs) showed activated phenotype evidenced by the expression of co-stimulatory molecules at 9 days post infection, PDL-1 expression pattern was different between these two subsets. Immunohistochemical analysis showed that CD103+DCs localized in the T cell area (also in the B cell area) and purified CD103+DCs produced large amounts of IL-12p40 compared with CD103-DCs. These data suggest that splenic CD103+DCs may play a critical role in the development of CTL responses during influenza virus infection. We are currently investigating how efficiently splenic CD103+DCs act as antigen presenting cells.

A pilot study on developing mucosal vaccine against alveolar echinococcosis (AE) using recombinant tetraspanin 3: Vaccine efficacy and immunology

Background

We have previously evaluated the vaccine efficacies of seven tetraspanins of Echinococcus multilocularis (Em-TSP1–7) against alveolar echinococcosis (AE) by subcutaneous (s.c.) administration with Freund's adjuvant. Over 85% of liver cyst lesion number reductions (CLNR) were achieved by recombinant Em-TSP1 (rEm-TSP1) and -TSP3 (rEm-TSP3). However, to develop an efficient and safe human vaccine, the efficacy of TSP mucosal vaccines must be thoroughly evaluated.

Methodology/Principal Findings

rEm-TSP1 and -TSP3 along with nontoxic CpG ODN (CpG oligodeoxynucleotides) adjuvant were intranasally (i.n.) immunized to BALB/c mice and their vaccine efficacies were evaluated by counting liver CLNR (experiment I). 37.1% (p<0.05) and 62.1% (p<0.001) of CLNR were achieved by these two proteins, respectively. To study the protection-associated immune responses induced by rEm-TSP3 via different immunization routes (i.n. administration with CpG or s.c. immunization with Freund's adjuvant), the systemic and mucosal antibody responses were detected by ELISA (experiment II). S.c. and i.n. administration of rEm-TSP3 achieved 81.9% (p<0.001) and 62.8% (p<0.01) CLNR in the liver, respectively. Both the immunization routes evoked strong serum IgG, IgG1 and IgG2α responses; i.n. immunization induced significantly higher IgA responses in nasal cavity and intestine compared with s.c. immunization (p<0.001). Both immunization routes induced extremely strong liver IgA antibody responses (p<0.001). The Th1 and Th2 cell responses were assessed by examining the IgG1/IgG2α ratio at two and three weeks post-immunization. S.c. immunization resulted in a reduction in the IgG1/IgG2α ratio (Th1 tendency), whereas i.n. immunization caused a shift from Th1 to Th2. Moreover, immunohistochemistry showed that Em-TSP1 and -TSP3 were extensively located on the surface of E. multilocularis cysts, protoscoleces and adult worms with additional expression of Em-TSP3 in the inner part of protoscoleces and oncospheres.

Conclusions

Our study indicated that i.n. administration of rEm-TSP3 with CpG is able to induce both systemic and local immune responses and thus provides significant protection against AE.

Humans and rodents become infected with E. multilocularis by oral ingesting of the eggs, which then develop into cysts in the liver and progress an endless proliferation. Untreated AE has a fatality rate of >90% in humans. Tetraspanins have been identified in Schistosoma and showed potential as the prospective vaccine candidates. In our recent study, we first identified seven tetraspanins in E. multilocularis and evaluated their protective efficacies as vaccines against AE when subcutaneously administered to BALB/c mice. Mucosal immunization of protective proteins is able to induce strong local and systemic immune responses, which might play a crucial role in protecting humans against E. multilocularis infection via the intestine, blood and liver. We focused on Em-TSP3, which achieved significant vaccine efficacy via both s.c. and i.n. routes. The adjuvanticity of nontoxic CpG OND as i.n. vaccine adjuvant was evaluated. The widespread expression of Em-TSP3 in all the developmental stages of E. multilocularis, and the strong local and systemic immune responses evoked by i.n. administration of rEm-TSP3 with CpG OND adjuvant suggest that this study might open the way for developing efficient, nontoxic human mucosal vaccines against AE.

Osteopontin modulates the generation of memory CD8+ T cells during influenza virus infection

The adaptive immune system generates memory cells, which induce a rapid and robust immune response following secondary Ag encounter. Memory CD8(+) T cells are a critical component of protective immunity against infections and cancers. Therefore, understanding the mechanism whereby memory CD8(+) T cells are generated and maintained is important for inducing effective memory CD8(+) T cell response. Recent studies have demonstrated that the inflammatory cytokine IL-12 favors the generation of terminal effector CD8(+) T cells rather than memory precursor effector CD8(+) T cells by regulating the expression of the transcription factor T-bet. In this study, we report that the inflammatory cytokine osteopontin (Opn) modulates memory CD8(+) T cell generation during influenza virus infection. Although Opn wild-type and Opn knockout (KO) mice had similar numbers of virus-specific effector CD8(+) T cells, virus-specific effector CD8(+) T cells generated in Opn KO mice showed low levels of T-bet expression and an increased memory precursor cell population compared with cells generated in Opn wild-type mice. This resulted in the persistently increased number of memory CD8(+) T cells in Opn KO mice. Studies with bone marrow-derived dendritic cells demonstrated that Opn deficiency in bone marrow-derived dendritic cells results in low levels of IL-12 production in response to the stimulation with influenza virus. Thus, we hypothesize that Opn modulates the generation of memory precursor effector CD8(+) T cells by regulating cytokine milieu during the acute phase of virus infection. This finding may provide new insight into the role of Opn in adaptive immune response.

Cross-protective peptide vaccine against influenza A viruses developed in HLA-A*2402 human immunity model

Background

The virus-specific cytotoxic T lymphocyte (CTL) induction is an important target for the development of a broadly protective human influenza vaccine, since most CTL epitopes are found on internal viral proteins and relatively conserved. In this study, the possibility of developing a strain/subtype-independent human influenza vaccine was explored by taking a bioinformatics approach to establish an immunogenic HLA-A24 restricted CTL epitope screening system in HLA-transgenic mice.

Methodology/Principal Findings

HLA-A24 restricted CTL epitope peptides derived from internal proteins of the H5N1 highly pathogenic avian influenza A virus were predicted by CTL epitope peptide prediction programs. Of 35 predicted peptides, six peptides exhibited remarkable cytotoxic activity in vivo. More than half of the mice which were subcutaneously vaccinated with the three most immunogenic and highly conserved epitopes among three different influenza A virus subtypes (H1N1, H3N2 and H5N1) survived lethal influenza virus challenge during both effector and memory CTL phases. Furthermore, mice that were intranasally vaccinated with these peptides remained free of clinical signs after lethal virus challenge during the effector phase.

Conclusions/Significance

This CTL epitope peptide selection system can be used as an effective tool for the development of a cross-protective human influenza vaccine. Furthermore this vaccine strategy can be applicable to the development of all intracellular pathogens vaccines to induce epitope-specific CTL that effectively eliminate infected cells.

Development of loop-mediated isothermal amplification (LAMP) assays for rapid detection of Ehrlichia ruminantium

Background

The rickettsial bacterium Ehrlichia ruminantium is the causative agent of heartwater, a potential zoonotic disease of ruminants transmitted by ticks of the genus Amblyomma. The disease is distributed in nearly all of sub-Saharan Africa and some islands of the Caribbean, from where it threatens the American mainland. This report describes the development of two different loop-mediated isothermal amplification (LAMP) assays for sensitive and specific detection of E. ruminantium.

Results

Two sets of LAMP primers were designed from the pCS20 and sodB genes. The detection limits for each assay were 10 copies for pCS20 and 5 copies for sodB, which is at least 10 times higher than that of the conventional pCS20 PCR assay. DNA amplification was completed within 60 min. The assays detected 16 different isolates of E. ruminantium from geographically distinct countries as well as two attenuated vaccine isolates. No cross-reaction was observed with genetically related Rickettsiales, including zoonotic Ehrlichia species from the USA. LAMP detected more positive samples than conventional PCR but less than real-time PCR, when tested with field samples collected in sub-Saharan countries.

Conclusions

Due to its simplicity and specificity, LAMP has the potential for use in resource-poor settings and also for active screening of E. ruminantium in both heartwater-endemic areas and regions that are at risk of contracting the disease.

Molecular cloning and characterization of a T24-like protein in Echinococcus multilocularis

One tetraspanin, designated as E24, was cloned from a full-length enriched vector-capping cDNA library of Echinococcus multilocularis metacestode. The amino acid sequence and phylogenetic analysis suggested that E24 is a T24-like protein. The crucial, functional large extracellular loop (LEL) domain of E24 was expressed and characterized using a polyclonal antiserum by Western blot and immunohistochemistry. The results showed that anti-recombinant-E24 (anti-recE24) antibody can specifically recognize approximately 25 kDa recombinant protein and 25 kDa cyst-extracted antigen; the germinal layer of both the protoscolex-free and protoscolex-formed cysts were intensely labeled by immunofluorescent antibody. This study revealed that E24 is an antigenic, germinal layer-located protein of E. multilocularis metacestode, implying for its potential in diagnostic and vaccine development.

Treatment of asystole and PEA

Recent reports consistently point to a substantial decline in the incidence of ventricular fibrillation (VF) as the initial rhythm observed by Emergency Medical Service (EMS) responders and a complementary increase in pulseless electrical activity (PEA) and asystole. Historically, efforts at improving survival have focused primarily on patients found in VF. Consequently, the approach for other patients has included frequent pauses in cardiopulmonary resuscitation (CPR) to check for VF followed by shock when VF is observed. However, the "yield" of survivors comes largely from the non-shocked patients. Therefore, it is critical that we start evaluating treatments specifically for the PEA and asystole groups.

Analysis of the immune response of Hantaan virus nucleocapsid protein-specific CD8+ T cells in mice

The major histocompatibility complex (MHC) class-I restricted epitope of Hantaan virus nucleocapsid protein (N) was identified using overlapping peptides and BALB/c mice. Using the MHC tetramer derived from the epitope, we found that the level of N-specific CD8(+) T cells increased to approximately 20% of all antigen-specific CD8(+) T cells in a mouse model of transient infection. However, N-specific CD8(+) T cells were undetectable in a mouse model of persistent infection, both in the persistently infected phase and in the convalescent phase. Levels of CD8(+) T cells producing interferon-gamma were weak in both the acute and convalescent phases in the persistently infected model. These results indicate that hantavirus strongly suppresses the production of N-specific CD8(+) T cells throughout the course of infection in persistently infected mice. Moreover, N-specific CD8(+) T cells were not effective in recovering persistently infected mice, despite the existence of abundant N antigen in vivo.

Peptides coupled to the surface of a kind of liposome protect infection of influenza viruses

In our previous study, OVA conjugated on the surface of a liposome, we termed Oleoyl liposome, which consisted of dioleoyl phosphatidyl choline, dioleoyl phosphatidyl ethanolamine, dioleoyl phosphatidyl glycerol acid and cholesterol in a 4:3:7:2 molar ratio, induced OVA-specific IgG antibody production but not OVA-specific IgE antibody production that is detrimental to the host. Furthermore, OVA(257-264)-Oleoyl liposome elicited CTL responses in the presence of CpG and rejected E.G7 tumors in mice. In this study we tested whether a peptide-Oleoyl liposome conjugates are capable of inducing protection against viral growth. Subcutaneous inoculation of NP(366-374)-Oleoyl liposome with CpG inhibited growth of influenza viruses in lungs of mice. Thus, surface-linked liposomal peptide might serve as an effective vaccine without detrimental effects in the presence of immune potentiators.

Preparation of fully activated dendritic cells capable of priming tumor-specific cytotoxic T lymphocytes in patients with metastatic cancer using penicillin-killed streptococcus pyogenes (OK432) and anti-CD40 antibody

In order to achieve sufficient therapeutic potency, it has been proposed that vaccine therapy with dendritic cells needs to be combined with manipulation of immunological checkpoints, such as inhibition of regulatory T cells and blockade of negative signals, and enhancement of T cell trafficking to tumor sites. In the combinatorial cancer immunotherapy, use of matured/activated dendritic cells (DCs) with more potent antigen presenting capacity seems to be essential for eliciting anti-tumor immune responses. We herein established an ex vivo induction strategy for activated DCs capable of eliciting efficient tumor antigen-specific cytotoxic T lymphocytes (CTLs) from patients with metastatic cancer as well as healthy donors. Immature DCs were matured by 48-h culture in the presence of anti-CD40 antibody and penicillin-killed streptococcus pyogenes (OK432). Supplementation with both anti-CD40 and OK432 resulted in induction of activated DCs with higher surface expression of CD80, CD83, CD86 and major histocompatibility complex class II antigens, compared with other mature DCs that were induced by the combination of anti-CD40 with tumor necrosis factor-alpha or lipopolysaccharide. In analysis of the produced cytokine profiles, the activated DCs produced the highest T-helper 1-type cytokines for at least 72 h. Furthermore, the activated DCs, pulsed with tumor-associated antigen peptide, elicited in vitro tumor-specific CTLs, but DCs activated with other combinations did not in cancer patients. Therefore, we suggest that the activated DCs studied here might be used as a basic element for the combinatorial cancer immunotherapy.

Involvement of IL-10 in exhaustion of myeloid dendritic cells and rescue by CD40 stimulation

It has recently been shown that immature dendritic cells (DCs) stimulated by a danger signal undergo transient maturation followed by exhaustion. However, the exact mechanism for this has not been elucidated. In this study, we show that interleukin-10 (IL-10) secreted from transiently matured DCs stimulated by danger signals is responsible for this rapid DC exhaustion. Blocking of the autocrine IL-10 enabled transient mature DCs to maintain the mature phenotype for several days. However, these DCs remained phenotypically unstable because the addition of IL-10 altered the transient mature DCs to exhausted DCs. More importantly, stimulation of DCs by CD40 protected transient mature DCs from IL-10-dependent exhaustion, with the result that mature DCs remained stable in the presence of IL-10. Furthermore, in vivo administration of stable mature DCs pulsed with ovalbumin protein induced antigen-specific cytotoxic T lymphocytes (CTLs) effectively, whereas neither exhausted DCs nor transient mature DCs were able to prime a strong antigen-specific CTL response. These results indicate that DC-T cell engagement via CD40-CD154 is required for stable DC maturation leading to effective CTL induction. Otherwise, DCs stimulated solely by a danger signal are temporarily activated, but then rapidly lose their immune-activating capacity under the influence of autocrine IL-10.

Antigen Chemically Coupled to the Surface of Liposomes Are Cross-Presented to CD8+ T Cells and Induce Potent Antitumor Immunity

We have previously demonstrated that liposomes with differential lipid components display differential adjuvant effects when Ags are chemically coupled to their surfaces. In the present study, Ag presentation of liposome-coupled OVA was investigated in vitro, and it was found that OVA coupled to liposomes made using unsaturated fatty acid was presented to both CD4+ and CD8+ T cells, whereas OVA coupled to liposomes made using saturated fatty acid was presented only to CD4+ T cells. Confocal laser scanning microscopic analysis demonstrated that a portion of the OVA coupled to liposomes made using unsaturated, but not saturated fatty acid, received processing beyond the MHC class II compartment, suggesting that the degradation of OVA might occur in the cytosol, and that the peptides generated in this manner would be presented to CD8+ T cells via MHC class I. The ability to induce cross-presentation of an Ag coupled to liposomes consisting of unsaturated fatty acid was further confirmed by in vivo induction of CTL and by the induction of tumor eradication in mice; E.G7 tumors in mice that received combined inoculation with OVA(257-264)-liposome conjugates, CpG, and anti-IL-10 mAbs were completely eradicated. In those mice, the frequency of CD8+ T cells reactive with OVA(257-264) peptides in the context of H-2K(b) was significantly increased. These results suggested that, by choosing lipid components for liposomes, surface-coupled liposomal Ags might be applicable for the development of tumor vaccines to present tumor Ags to APCs and induce antitumor responses.

Spontaneous elicitation of potent antitumor immunity and eradication of established tumors by administration of DNA encoding soluble transforming growth factor-beta II receptor without active antigen-sensitization

Since immunity is generally suppressed by immunoregulatory factors, such as transforming growth factor-beta (TGF-beta), interleukin (IL)-10, and vascular endothelial growth factor (VEGF), produced by tumor cells or stromal cells surrounding tumor cells, various kinds of cancer immunotherapy mostly fail to elicit potent antitumor immunity. Herein, we tested whether neutralization of TGF-beta can elicit strong antitumor immune responses and tumor regression in tumor-bearing mice. A plasmid DNA, pcDNA-sTGFbetaR/huIg, encoding a fusion protein consisting of the extracellular domain of TGF-beta type II receptor (TGFbetaRII) and the Fc portion of human IgG heavy chain, was injected through different routes into B6 mice carrying established tumors of E.G7 cells, which consist of the poorly immunogenic tumor cells EL4, transfected with the ovalbumin (OVA) gene. The frequency of OVA-specific cytotoxic T lymphocytes (CTL), in the treated mice. increased resulting in the tumor eradication and relapse-free survival in around 70% of the E.G7-bearing mice. In contrast, administration of mock DNA into E.G7-bearing mice did not elicit tumor-specific immune responses. Therefore, administration of DNA encoding TGFbetaRII allowed tumor-bearing hosts to elicit sufficiently potent antitumor immune responses without requirement of further active antigen-immunization. This strategy seems to be applicable to clinical therapy against cancer, because it is low-cost, safe, and easy to manipulate.

B1-B cells are the main antigen presenting cells in CpG-ODN-stimulated peritoneal exudate cells

Peritoneal exudate cells (PEC) have long been used as antigen presenting cells (APC), because they have been considered to contain mainly macrophages. However, it is still unclear specifically which cells of the peritoneal exudate function as APC. Herein, we focused on macrophages and B1-B cells of the PEC and examined their APC function and cytokine production. B1-B cells purified from PEC functioned effectively as APC after CpG-stimulation and mainly produced IL-10. In contrast, macrophages purified from PEC were not able to present incorporated antigens to T cells, despite the production of IL-12 and expression of co-stimulatory molecules after CpG stimulation. These results suggest that previously held ideas regarding the functions of the mixture of cells in the PEC need to re-evaluated. In summary, the antigen presenting function of PEC was mainly attributed to B1-B cells and immunoenhancing cytokine production was dominantly derived from peritoneal macrophages.

Fas-disabling small exocyclic peptide mimetics limit apoptosis by an unexpected mechanism

Fas ligand- (FasL) mediated apoptosis is an important element of tissue-specific organ damage. We have developed biologically active small exocyclic peptide mimetics that disable apoptotic functions of Fas. The most effective mimetic binds to both its receptor and FasL with comparable affinity. In vitro, the most effective antagonist blocked FasL-induced cytotoxicity completely and specifically. In vivo, the antagonistic mimetic also prevented Concanavilin A (Con A) induced hepatitis, a CD4(+) T cell-mediated animal model of liver injury. Although current approaches prevent Fas receptor signaling by excluding FasL binding to Fas, the small molecule mimetics reported here disable Fas by promoting a defective Fas-FasL receptor complex. This event desensitizes FasL-mediated apoptosis by inhibiting extracellular signal regulated kinase activity and up-regulating NF-kappaB.

Study of disabling T-cell activation and inhibiting T-cell-mediated immunopathology reveals a possible inverse agonist activity of CD4 peptidomimetics

We designed a new class of aromatically modified exocyclic peptides based on the structure of CD4 by engineering one of the cysteine residues in a peptidomimetic derived from the CDR3 region of the CD4 molecule. All three species mediate inhibition of T-cell proliferation at concentrations ranging from 10 to 100 microM. The mimetics CD4-Cys and CD4-Met bind to sCD4 with affinities ranging from 1 to 2 microM, while CD4-Ser shows poor binding in radioisotope assay. Though these mimetics have similar structures, they exhibit different biochemical and biological functions. Activation of T-cells as measured by thymidine incorporation or IL-2 production revealed that CD4-Cys and CD4-Ser mimetics behave as classical antagonists. On the other hand, the CD4-Met species inhibited T-cell proliferation with an IC(50) of 30 microM but unexpectedly increased IL-2 secretion modestly at a less than 3 microM concentration. In experimental autoimmune encephalitis (EAE), CD4-Ser and CD4-Cys mimetics reduced the severity of EAE symptoms while the CD4-Met mimetic exacerbated the conditions. We propose that CD4-Cys and CD4-Ser are classical antagonists, but CD4-Met may possess properties of an inverse agonist. The structure-activity relationship of mimetics reveals that a minor change in the net hydropathic value is enough to alter the dynamic nature of the receptor-ligand complex.

Intranasal administration of a synthetic peptide vaccine encapsulated in liposome together with an anti-CD40 antibody induces protective immunity against influenza A virus in mice

Mucosal immunity is critical for protection from viral infections. We attempted to activate mucosal cytotoxic T lymphocytes (CTLs) specific for influenza A virus nucleoprotein (NP) which play an important role in protective immunity. It has been shown that dendritic cells (DCs) activated by signaling via CD40-CD40 ligand (CD40L) interaction are required for the differentiation of naive CD8(+) T cells into antigen-specific CTLs in a non-mucosal environment. We herein inoculated mice intranasally with an anti-CD40 monoclonal antibody (anti-CD40 mAb) and NP366-374 peptide, corresponding to a CTL epitope on NP, encapsulated in liposome (liposomal NP366-374) to induce protective CTL responses against influenza A virus. Intranasal but not subcutaneous immunization with liposomal NP366-374 effectively induced mucosal immunity to reduce virus replication in the lung, suggesting that anti-CD40 mAb also functioned as a mucosal adjuvant. Interestingly, neither MHC class I- nor class II-deficient mice immunized intranasally with these materials were resistant to the infection. Since anti-CD40 mAb was considered to help replace CD4(+) T cells, another help of CD4(+) T cells are presumably required for the induction of CTL activity in the lung. This approach may prove promising for developing vaccines to induce mucosal CTL responses, and seems to highlight differences between mucosal and non-mucosal immunity.

Recombination hot spot of hepatitis B virus genome binds to members of the HMG domain protein family and the Y box binding protein family; implication of these proteins in genomic instability

OBJECTIVE

Previously we hypothesized that the occurrence of hepatocellular carcinoma (HCC) is enhanced by genomic instability induced by the integrated hepatitis B virus (HBV) DNA. Using an in vitro recombination assay, we showed that a subgenomic fragment of HBV DNA designated 15AB (nt1855-1914) is indispensable for in vitro recombination, and also showed the existence of 15AB binding protein. On the assumption that the 15AB binding protein may be a candidate cellular recombinogenic protein which accelerates genomic instability and hepatocarcinogenesis, we tried to isolate it by southwestern screening.

RESULTS AND CONCLUSION

We obtained several positive clones including mouse upstream binding factor (UBF) and DNA binding protein A (dbpA). UBF belongs to an HMG domain protein family and dbpA belongs to a Y box binding protein family. 15AB binding seemed to be mediated by the conserved DNA binding domains in these families, because other members in the families such as HMG1 and YB-1 also bound to 15AB. We report them here because several documents have already suggested the possible association of these families and DNA recombination.

Hepatoprotective drugs for the treatment of virus-induced chronic hepatitis: from hypercarcinogenic state to hypocarcinogenic state

Interferon (IFN)-based therapy is a standard treatment for chronic hepatitis caused by hepatitis C virus (HCV) infection. This treatment is effective in approximately 30-40% of the patients and using ribavirin in combination with IFN increases the rate of sustained virologic clearance. For the remaining patients, glycyrrhizin is often used. Glycyrrhizin is known to prevent the development of hepatocellular carcinoma (HCC), but glycyrrhizin is usually administered intravenously. Drugs that are effective by oral administration are convenient for patients for long-term administration, and development of more effective drugs than glycyrrhizin is preferable. However, studies on drugs for the treatment of hepatitis are not actively conducted, and promotion of the study of drugs in this area is encouraging. For that reason, we show our approach to study drugs for the treatment of hepatitis. We analyzed the effect of glycyrrhizin on hepatitis as a standard chemical using the mouse liver injury model. Based on this, we screened drugs and found that a coumarin derivative seems to be one of model chemicals for the treatment of hepatitis.

Hepatitis C virus core protein activates the MAPK/ERK cascade synergistically with tumor promoter TPA, but not with epidermal growth factor or transforming growth factor alpha

Persistent hepatitis C virus (HCV) infection is associated with the development of human hepatocellular carcinoma (HCC), although the mechanism of HCV-related hepatocarcinogenesis remains unclear. Recently, however, the close relationships between the development of HCC and the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) cascade have been described. In the present study, we investigated the effects of HCV core protein on this MAPK/ERK cascade. HCV core protein significantly activated the MAPK/ERK cascade, including Elk1. We also examined whether HCV core protein acted synergistically along with hepatocyte mitogen-mediated MAPK/ERK activation. Interestingly, Elk-1 activities were further enhanced by the tumor promoter, 12-O-tetradecanoyl phorbol 13-acetate (TPA), but not by hepatocyte mitogens (epidermal growth factor [EGF] and transforming growth factor alpha [TGF-alpha]) in NIH3T3 cells and HepG2 cells expressing HCV core protein. Moreover, the MAPK/ERK activation by HCV core protein was blocked in the presence of the specific MEK1 inhibitor, PD98059. These results indicate that ERK activation by HCV core protein may be independent of hepatocyte mitogen-mediated signaling but synergistic with TPA, and HCV core protein may function at MEK1 or farther upstream of that component.

A novel gene "Niban" upregulated in renal carcinogenesis: cloning by the cDNA-amplified fragment length polymorphism approach

A modified AFLP (amplified fragment length polymorphism) method was employed to isolate genes differentially expressed in renal carcinogenesis of Tsc2 gene mutant (Eker) rats. One gene, selected for further investigation, was named "Niban" "second" in Japanese), because it is the second new gene to be found after Erc (expressed in renal carcinoma) in our laboratory. Importantly, "Niban" is well expressed even in small primary rat Eker renal tumors, more than in progressed cell lines, and is also expressed in human renal carcinoma cells, but not in normal human or rat kidneys. Chromosome assignment was to RNO 13 in the rat, and HSA 1. This "Niban" gene is a candidate as a marker for renal tumor, especially early-stage renal carcinogenesis.

beta-catenin mutations are absent in hepatocellular carcinomas of SV40 T-antigen transgenic mice

beta-catenin mutations have been found not only in melanoma and prostatic carcinoma but also in hepatocellular carcinomas in human, c-myc, H-ras genes transgenic mice and chemically-induced models. We investigated beta-catenin mutations in human hepatocellular carcinomas (HCCs), Hep G2 cell line and HCCs in SV40 T-antigen transgenic mice, in order to examine whether beta-catenin mutations are frequently observed in HCC in general. We found a point mutation of beta-catenin in one of nine HCCs in human and a deletion of it in Hep G2 cell line. However, we found no mutation in HCC in SV40 TG mice liver.

VCP, a weak ATPase involved in multiple cellular events, interacts physically with BRCA1 in the nucleus of living cells

BRCA1, a breast/ovarian cancer susceptibility gene, undergoes mutations in as many as 50% of familial breast tumors. Recent studies indicate that BRCA1 may be involved in DNA damage repair. Here, we demonstrate that the BRCA1 protein physically associates with valosin-containing protein (VCP), a member of the ATPases associated with a variety of cellular activities (AAA) superfamily. In vitro studies revealed that VCP, via its N- terminal region, binds to amino acid residues 303-625 in the BRCA1 protein. Although found predominantly in the cytoplasm and, less abundantly, in the nucleus, VCP can be translocated from the nucleus after stimulation with epidermal growth factor. Collectively, our results suggest that VCP, by binding to BRCA1, participates in the DNA damage-repair function as an ATP transporter, possibly facilitating the transcription-coupled repair.

Cloning of differentially expressed genes in highly and low metastatic rat osteosarcomas by a modified cDNA-AFLP method

To identify differentially expressed genes between highly and low metastatic rat transplantable osteosarcomas, we applied a modified AFLP (amplified fragment length polymorphisms) method for cDNA subtraction. The specific point of our modification is selective amplification using suppression PCR technique after restriction enzyme cutting. Our cDNA-AFLP gave high reproducibility (about 95%) in mRNA patterns and enabled us to clone four dominantly expressed genes in a highly metastatic tumor line. Three showed homology with known genes, encoding Ki-67, a proliferation-associated effective marker of malignancy, type IV collagen alpha-3, a major component of basement membrane, and KIAA77 for which the function is unknown. Although one fragment showed no database homology, we revealed a derivation from the rat homologue of the Drosophila melanogaster diaphanous gene (Dia) by cloning of longer cDNA. Dia genes, known to affect actin filament formation, are downstream effectors of Rho small GTPase. The results suggest that alterations in the expression of cytoskeletal protein, basement membrane elements, and proliferative markers may be important for metastasis of osteosarcomas.

Unique features of dendritic cells in IFN-gamma transgenic mice: relevance to cancer development and therapeutic implications

Although induction of interferon gamma (IFN-gamma) and activation of antigen presenting dendritic cells (DCs) are two vital events during an immune response, the impact of endogenous IFN-gamma on DC function has yet to be clarified. The phenotype and function of DCs isolated from mice with high (IFN-gamma-transgenic mouse [Tg]) and undetectable levels of circulating IFN-gamma (normal mice [NM]) were therefore compared. The capacity to stimulate allogenic (p < 0.05) and antigen-specific T lymphocytes (p < 0.05), as well as the ability to produce IL-12 (p < 0.05) and to process soluble protein antigens (p < 0.05) was found to be significantly higher in DCs from the Tg mice compared to the NM case. The presence of activated DCs in a microenvironment of endogenous IFN-gamma suggests that the IFN-gamma-Tg mouse is a suitable animal model to study cancer immunotherapy in vivo.

[Prevalence of TT virus infection and viral integration in human hepatocellular carcinoma]

In 1997, Nishizawa et al cloned a novel DNA virus designated as TT virus (TTV) from a patient with post-transfusion hepatitis and this virus is being thought to be a new hepatitis virus. Approximately 5 to 10% of hepatocellular carcinomas (HCCs) in Japan occurs in hepatitis B virus-negative and hepatitis C virus-negative (NBNC) patients. In order to study the possible role of TTV in hepatocarcinogenesis, we studied the prevalence of the TTV DNA in liver tissue of HCC patients. As a result, TTV was shown not to be specific for NBNC HCC and TTV integration into host DNA was not detected in any HCC patient by Southern blotting.

Determination of the clonal origin of multiple human hepatocellular carcinomas by cloning and polymerase chain reaction of the integrated hepatitis B virus DNA

The poor prognosis of hepatocellular carcinoma (HCC) is partly the result of the high rate of recurrence that is caused either by intrahepatic metastasis (IM) or independent multicentric occurrence (MO). For convenience, discrimination of IM and MO is based on pathological findings, but reliable parameters are not sufficiently established. In the case of hepatitis B virus (HBV)-associated HCC, molecular discrimination of IM from MO can be achieved by comparison of integrated HBV DNAs. However, Southern blotting cannot be used for this purpose when one tumor is saved in frozen form and the other is in paraffin-embedded form. To solve this problem, we employed polymerase chain reaction (PCR) assays to confirm the clonality of primary and recurrent tumors. From the frozen tissue, we determined the junction between the integrated HBV and flanking genomic DNA by molecular cloning, and checked the existence of an identical junction in the DNA of paraffin-embedded tissue by PCR. Using this method, as well as Southern blotting, we proved in 6 of 8 patients that two nodular HCC lesions resected metachronously or simultaneously were caused by MO, while the remaining 2 cases were caused by IM. In 1 IM case, band patterns between two HCCs detected by Southern blotting were not identical.

Induction of endometriosis and adenomyosis by transvaginal pituitary transplantation in mice with and without natural killer cell activity

PROBLEM

The aims of this study were to establish a mouse model of endometriosis and adenomyosis and to elucidate the necessity of reduced natural killer (NK)-cell and T-cell activities in the establishment of endometriosis and adenomyosis.

METHOD OF STUDY

Pituitary glands, submandibular glands, a hypothalami were transvaginally inoculated into the uteri of syngeneic female mice. Twenty weeks later, the recipient mice were sacrificed and examined.

RESULTS

Cysts, adhesion of the uteri to surrounding tissues, and adenomyosis had formed in the uteri of 7 (29.2%), 14 (58.3%), and 22 (91.7%) mice, respectively, out of 24 BALB/c mice after the transplantation of pituitary glands. Similar findings were obtained by experiments with C3H/He and C57BL/6 mice. In NK-cell-deficient C57BL/6-bgJ and T-cell-deficient BALB/c nu/nu mice, an increase in the formation of cysts, adhesion, and adenomyosis was not observed.

CONCLUSIONS

These findings indicate that transvaginal pituitary transplantation specifically induces cysts, adhesion, and adenomyosis. Reduced NK-cell activities may not be necessary in the primary development of endometriosis and adenomyosis.

BRCA1 binds c-Myc and inhibits its transcriptional and transforming activity in cells

c-Myc, a proto-oncogene that is implicated in tumorigenesis, embryonic development and apoptosis, can physically associate with BRCA1. We have found that BRCA1 interacts with c-Myc in yeast, in in vitro assays and in mammalian cells. Endogenous interactions between BRCA1 and c-Myc were also observed. Efficient BRCA1-Myc association requires the intact helix-loop-helix region of c-Myc, a motif involved in Myc-Max dimerization. BRCA1 does not however bind to Max. Our studies revealed that BRCA1 represses Myc-mediated transcription while having no effect on some other transcriptional activities. Furthermore, BRCA1 reverses the phenotype of embryonic fibroblasts transformed by the activation of Myc and Ras, but only minimally affects the transformed phenotype induced by SV40 virus. These data indicate that BRCA1 may function as a tumor suppressor by regulating the behavior of c-Myc and provide a molecular explanation for some of the effects of the BRCA1 gene product.