A trypanosome species isolated from naturally infected Haemaphysalis hystricis ticks in Kagoshima Prefecture, Japan

Common arthropod vectors for trypanosomes are flies, fleas and bugs. This study reports on an unknown trypanosome species isolated from naturally infected Haemaphysalis hystricis ticks, hereby, referred to as Trypanosoma KG1 isolate. The parasite has been successfully cultured in vitro with L929 or HEK 293T cell line as feeder cells. This trypanosome cannot survive in vitro without feeder cells. Following experimental infections of ticks, the trypomastigote-like and the epimastigote-like forms of this trypanosome could be detected by Giemsa-stained smears of the midgut and salivary glands of Ornithodoros moubata ticks which were made to feed on a culturing medium containing Trypanosoma KG1 isolate through an artificial membrane. Trypanosoma KG1 isolate could also be detected from Giemsa-stained smears of the haemolymph up to 30 days post-inoculation into the O. moubata haemocoel. Trypanosoma KG1 isolate cannot be propagated in laboratory animals including mice, rats, rabbits and sheep. A phylogenetic tree constructed with the 18S rRNA gene indicates that Trypanosoma KG1 is a member of the stercorarian trypanosomes.

[Radiological findings in initial pulmonary alveolar proteinosis detected in the post-treatment course of nocardiosis]

Chest CT detected a small localized ground glass opacity in the right upper lung in a 52-year-old woman being treated for nocardiosis. A PAS-stain positive material and elevated surfactant level were confirmed in bronchoalveolar lavage fluid, then a diagnosis of pulmonary alveolar proteinosis was established. In early pulmonary alveolar proteinosis with focal opacity, HRCT can demonstrate the substantial findings of alveolar proteinosis such as a crazy-paving appearance or geographic distribution. We should note that alveolar proteinosis in the early stage is easily overlooked and, in addition, nocardiosis might overlap with alveolar proteinosis.

Acute fibrinous and organizing pneumonia: initial presentation as a solitary nodule

A 55-year-old man complained of cough and dyspnea. His chest radiograph and CT scan revealed a solitary nodule with a diameter of 2 cm, which showed an air bronchogram and had a hazy contour. After 3 weeks, the radiologic findings changed to diffuse infiltration with small centrilobular nodules, alveolar consolidation, and bronchial wall thickening. The alveoli contained numerous fibrin balls and organizing tissue, which are typical pathologic features of acute fibrinous and organizing pneumonia (AFOP), on histologic examination. We report the initial radiologic features of AFOP and suggest that there are some radiologic similarities between this condition and cryptogenic organizing pneumonia.

[BALF lymphocyte CD 4/8 ratio in a case of sarcoidosis with radiological resolution]

A 60-year-old man was given a diagnosis of pulmonary and ocular sarcoidosis. His radiological abnormalities and visual disturbance resolved after two years. Ten years later, at age 70, squamous cell carcinoma was detected in the right lower lobe of the lung. Lymphocyte CD4/8 ratio in bronchoalveolar lavage fluid has remained at a high level for the previous 10 years and was 7.41 immediately before the operation. Chest CT and gallium scintigram could not detect abnormalities in mediastinal or hilar nodes. The tumor and right lower lobe were resected with hilar and mediastinal lymph nodes. Histological examination revealed that there were numerous epithelioid cell granulomas in mediastinal and hilar lymph nodes. BALF analysis reflects residual granulomatous inflammation, even if the radiological findings do not show any abnormalities.

IL-15 is superior to IL-2 in the generation of long-lived antigen specific memory CD4 and CD8 T cells in rhesus macaques

Using tetanus toxoid (TT) and influenza (Flu) immunization of rhesus macaques as a model, the effect of IL-2 and IL-15 on the generation and maintenance of antigen specific memory T cells was evaluated following primary and secondary immunization. Daily cytokine administration expanded primarily effector but not memory cells, while spacing cytokine administration to q3-7 days markedly enhanced TT and Flu specific memory responses. Following primary immunization, TT specific CD4 and influenza matrix protein (Flu-MP) specific CD8 effector responses were enhanced by IL-2 administration but CD8 specific memory responses were no different from cytokine non-treated monkeys. In contrast, expansion of Flu specific CD8 cells with IL-15 was only modest but resulted in significantly elevated levels of memory cells at 6 months. IL-15 also significantly enhanced early and late TT specific CD4 responses. The highest levels of primary effector and memory T cells were observed following alternate administration of both IL-2 and IL-15. Following booster immunization, however, only IL-15 appeared able to enhance CD8 T cell responses while IL-2 or IL2/IL-15 administration were less effective.

Four serine proteinase inhibitors (serpin) from the brown ear tick, Rhiphicephalus appendiculatus; cDNA cloning and preliminary characterization

While development of an anti-Boophilus microplus vaccine is advanced and practical, work on other economically important ticks such as Rhipicephalus appendiculatus is still in its infancy. Guess PCR primers, designed from a consensus amino acid sequence (NAVYKFG) motif were used with rapid amplification of cDNA ends (RACE) to clone four cDNAs encoding serine proteinase inhibitors (serpin) from the brown ear tick Rhipicephalus appendiculatus. The four genes designated as R. appendiculatus serpin (RAS) -1 to -4 encode polypeptides of 378, 380, 398 and 486 amino acids long, respectively. Sequence comparison of RAS-1 to -4 predicted amino acid sequences to the serpin-like hypothetical protein from Ixodes ricinus (Leboulle et al., 2002) revealed closer structural similarities among tick serpins. Expression analysis by RT-PCR showed that RAS-1 to -4 are expressed in other tick organs in addition to salivary glands and midguts. Except for RAS-3 whose expression level appears to be equivalent in all tick organs, RAS-1, -2 and -4 are predominantly expressed in the salivary glands. We have discussed our findings with reference to development of vaccines against R. appendiculatus.

Three serine proteinases from midguts of the hard tick Rhipicephalus appendiculatus; cDNA cloning and preliminary characterization

Rhipicephalus appendiculatus is one of the most economically important ticks distributed in south central and eastern Africa where little or no progress has been made on attempts to develop a vaccine. We have used a combination of RT-PCR, the 3' and 5'rapid amplification of cDNA ends (RACE) to clone and sequence three cDNAs encoding full-length R. appendiculatus midgut serine proteinases (RAMSP). RT-PCR degenerate primers were designed from amino acid sequences surrounding active sites, His57 and Ser195 conserved among most known serine proteinase-like genes (Mulenga et al. 2001). Northern blotting analysis of total RNA extracted from unfed and partially fed adult ticks revealed that mRNAs for RAMSP-1 and -2 were expressed only in partially fed ticks, while RAMSP-3 mRNA was not only expressed in both unfed and partially fed ticks, it was also up-regulated as tick feeding progressed. Expression analysis by RT-PCR revealed that RAMSP-3 was predominantly expressed in midguts when compared to salivary glands. For RAMSP-1 and -2, they were expressed at equivalent levels in both midguts and salivary glands. Based on key amino acid sequence features as well as similarity comparisons from the database, we speculated that polypeptides encoded by RAMPSP-1 to -3 are structurally more closely related to chymotrypsin- than trypsin-like serine proteinases. We have based our comments on the potential of serine proteinases as candidates for tick vaccines.

Development and evaluation of an enzyme-linked immunosorbent assay with recombinant SAG2 for diagnosis of Toxoplasma gondii infection in cats

Cats are pivotal in the transmission of Toxoplasma gondii. To develop a sensitive and specific serodiagnostic method for feline toxoplasmosis, surface antigen 2 (SAG2) of T. gondii was expressed in Escherichia coli and its diagnostic potential evaluated in an enzyme-linked immunosorbent assay (ELISA). The ELISA with recombinant SAG2 (rSAG2) was able to differentiate very clearly between sera from cats experimentally infected with T. gondii and sera from normal cats. Serum samples collected from domestic cats in Japan were investigated by the ELISA, and the results were compared with those of a commercially available latex agglutination test (LAT) kit. Of the 192 samples screened, 42 (21.9%) were positive by ELISA. Among the 42 ELISA-positive samples, 39 were positive by LAT. There was a significant correlation between ELISA and LAT titers. All the 150 ELISA-negative samples were negative by LAT. These results indicate that the ELISA with rSAG2 expressed in E. coli should be a useful method for detection of T. gondii infection in cats.

JC virus genotyping offers a new means of tracing the origins of unidentified cadavers

There has been no reliable means of tracing the origins of unidentified cadavers but the recent finding that JC virus (JCV) can serve as a means of elucidating human migrations suggested that this virus may also be useful to trace the origins of unidentified cadavers. DNA samples extracted from renal tissue and urine were used as the template for PCR amplification of a 610 bp region (IG region) of the viral genome. We detected JCV DNA in 45% of the renal samples and in 33% of the urine samples and was detectable even 10 days after death. The sequences of the amplified IG regions could be used to determine the genotypes. We conclude that the JC virus genotype is a new marker useful for tracing the origins of unidentified cadavers.

Asian domains of four major genotypes of JC virus, Af2, B1-b, CY and SC

JC virus (JCV) strains worldwide can be classified into various genotypes based on DNA sequence variations. To define the domains of the four major JCV genotypes in Asia, we collected urine samples at six unstudied sites: three in southeastern Asia, two in the central highlands and one in central Asia. DNA was extracted from urine samples, and used to amplify a 610-bp region of the viral genome. For each geographical site, we determined 16 to 31 sequences, from which a phylogenetic tree was constructed to unambiguously classify detected JCV isolates into distinct genotypes. From JCV genotype profiles at the sites studied here and elsewhere, the following conclusions were drawn. Although Af2 is the major genotype in Africa, this genotype also occurs in western and central Asia. B1-b mainly occurs in western and central Asia, including the central highlands. CY occurs in northeastern Asia with the southern boundary between China and southeast Asian countries. Although SC predominates in southeastern Asia, it also occurs in northern and central Asia at lower frequencies. In addition, a few minor JCV genotypes (B1-a, B2 and B3) occur at many sites. We discuss here the anthropological and medical significance of the present findings.

Serodiagnosis of Toxoplasma gondii infection in cats by enzyme-linked immunosorbent assay using recombinant SAG1

The gene encoding surface antigen 1 (SAG1, P30) of Toxoplasma gondii (T. gondii) was cloned into the plasmid pGEX-4T-3 and subsequently expressed in Escherichia coli (E. coli) as a glutathione-S-transferase (GST) fusion protein. The recombinant SAG1 (rSAG1) was refolded using 8M urea solution followed by dialysis and thereafter evaluated in an enzyme-linked immunosorbent assay (ELISA) for serological diagnosis of toxoplasmosis. The test sera were adsorbed with GST to block non-specific reactivity to the GST-SAG1 fusion protein. The ELISA with rSAG1 was able to differentiate very clearly between sera from cats or mice experimentally infected with T. gondii and sera from normal cats or mice. The ELISA detected no cross-reactivity with sera from mice experimentally infected with the closely related parasite Neospora caninum (N. caninum). Some 193 cat sera were tested for antibodies to T. gondii, out of which 40 (20.7%) reacted positively by ELISA with the rSAG1 while another 79.3% cats reacted negative to the assay. Both positive and negative sera were confirmed by Western blot analysis. The results of ELISA were in agreement with those of a commercially available latex agglutination test (LAT) kit, although the former had higher titers than the latter.

Survey of Theileria parasite infection in cattle in Cambodia and Vietnam using piroplasm surface protein gene-specific polymerase chain reaction

A survey of Theileria parasite infection in cattle in Cambodia and Vietnam was carried out by using allele-specific polymerase chain reaction. A total of 137 blood samples from draught animals in Cambodia and 40 blood samples from dairy cattle in Vietnam were analyzed. In Cambodia, 69 out of 137(50.4%) samples were PCR-positive containing mainly the Thai and the C type parasites. In Vietnam, 11 (27.5%) samples were positive and all were of the Thai type parasite.

Tick-Encoded serine proteinase inhibitors (serpins); potential target antigens for tick vaccine development

Immunological protection of hosts against tick infestation is at present the most practically sustainable alternative tick control method to the current use of acaricides that is riddled with serious limitations. The current focus of tick vaccine research is the identification, cloning and in vitro production of recombinant tick vaccine candidate antigens. We have examined a selected number of reports on the roles of parasite-encoded members of the serine proteinase inhibitor (serpin) superfamily in modulation of mammalian anti-parasite defense and developed some food for thought commentaries on the possibility of targeting this class of proteins for anti-tick vaccine development.

JC virus regulatory region rearrangements in the brain of a long surviving patient with progressive multifocal leukoencephalopathy

JC virus (JCV) infection of oligodendrocytes causes demyelination in brains of patients with with progressive multifocal leukoencephalopathy (PML). Expansion of demyelination throughout the brain is not fully understood. The opportunity was taken to investigate the postmortem brain of a long surviving patient with PML for whom diagnosis was made 4 years before death based on pathological and virological findings of a brain biopsy. Four distinct regulatory sequences in the JCV genome were detected (designated as JW-1 to 4) from various regions of the necropsied brain. All regulatory sequences were rearranged forms that could be produced from the archetype by deletions and duplications. JW-1 and 2 shared some structural features not present in JW-3 and 4 and vice versa. JW-1 was distributed throughout the brain, whereas JW-2, 3, and 4 were restricted to only part of the brain. JW-1 and 2 had been detected in the initial brain biopsy 4 years earlier. These findings suggested that brain lesions in advanced stages were generated not only by expansion of the original variant (JW-1) of JCV but also by delayed growth of two other variants (JW-3 and 4).

Tumor necrosis factor alpha and its receptors in experimentally bovine leukemia virus-infected sheep

To examine whether tumor necrosis factor alpha (TNF alpha) contributes to the pathogenesis of bovine leukemia virus (BLV) infection, the mRNA expression patterns of TNF alpha and its receptors, type 1 (TNF R1) and type 2 (TNF R2) were investigated. Sheep inoculated with BLV were divided into two groups; one was BLV-positive and the other BLV-negative based on the detection in peripheral blood mononuclear cells (PBMC). Expression of TNF R1 mRNA was down-regulated in PBMC from the BLV-positive compared to BLV-negative sheep. No difference was shown in the expression levels of TNF R2 mRNA between the two groups. Furthermore, proliferative responses of PBMC in the presence of TNF alpha were observed from the BLV-positive, but not BLV-negative sheep. Membrane-bound TNF alpha (mTNF alpha) is thought to be one of the ligands, inducing B-cell activation. Flow cytometric analysis demonstrated that the number of PBMC, that were positive for mTNF alpha expression, was increased in the BLV-positive sheep. Thus, the expression of TNF alpha and its receptors may be closely associated with lymphocytosis induced by BLV.

Phylogenetic relationships of bovine immunodeficiency virus in cattle and buffaloes based on surface envelope gene sequences. Brief report

Isolates of bovine immunodeficiency virus (BIV) exhibit a striking genomic diversity, most of which are located in the viral envelope gene. Since this property of the BIV group of viruses may play an important role in the pathobiology of the virus, the surface envelope gene, particularly the conserved (C) 2, hypervariable (V) 1, V2 and C3 regions, of eleven different isolates from different environments with different bovine breeds naturally infected with BIV, including dairy cows in Japan, buffaloes in Pakistan and draught animals in Cambodia, were sequenced. When compared to the nucleotide sequence of American BIV isolates, all Asian BIV field isolates seem to be smaller, several base substitutions were observed in the V1 region, and deletions were also found in the V2 region of env gene in these samples. However, deduced amino acid sequences were not so different among isolates from different bovine breeds, suggesting that bovine susceptibility to BIV infection may not depend upon bovine breed or buffaloes. Moreover, phylogenetic analysis revealed that genotypes were distinct between Asian and American BIV isolates and these results also provide an information on the molecular epidemiology of naturally occurring BIV infection in cattle and buffaloes.

Expression of two subtypes of human IFN-alpha in transgenic potato plants

Plant expression systems have advantages over other in vitro expression systems in terms of low production costs and low risk of contamination by animal viruses or bacterial endotoxins. In this study, cDNA encoding two subtypes of human interferon-alpha2b and 8 (HuIFN-alpha2b and HuIFN-alpha8) were introduced into potato plants (Solanum tuberosum) using Agrobacterium-mediated transformation. Transcription and translation of the inserted HuIFN-alpha cDNA were confirmed by Northern blot analysis and ELISA, respectively. Bioactivity of the products was assayed by inhibition of vesicular stomatitis virus (VSV) replication on a human amniotic cell line. However, because of the presence of substances in potato tissue extracts that were toxic to animal cells, successful demonstration of IFN bioactivity in the transformants was achieved only after removal of such substances by dialysis. The maximum level of IFN activity in plant extracts was 560 IU/g of tissue. These results indicated that the HuIFN-alpha gene introduced into the potato plant was correctly translated and transcribed in plant cells. This report for the first time shows that biologically active animal cytokines with potential pharmaceutical applications could be expressed in transgenic potato plants.

Epitope-Mapping of antigen-specific T lymphocyte in cattle immunized with recombinant major piroplasm surface protein of Theileria sergenti

The cellular immune responses against major piroplasm surface protein (MPSP) of Theileria sergenti were characterized. Three cattle were immunized with recombinant MPSP (C type) encapsulated by mannan-coated liposome. The proliferative responses of peripheral blood mononuclear cells (PBMC) against MPSP were detected in all immunized animals. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that T cell lines derived from each animal expressed relatively high levels of interferon (IFN)-gamma mRNA, low levels of interleukin (IL)-2, IL-10, and tumor necrosis factor (TNF)-alpha mRNAs, but no detectable level of IL-4 mRNA. From the results of T cell epitope-mapping, T-cell lines from two animals responded to DTSKFTPTVAHRLKHAEDLF (residues 61 to 80), while other animal responded to GTGKVYDFVGNFKVTKVKFE (residues 141 to 160). The MPSP-type specific response of a T-cell line was observed in the latter region of MPSP. These data suggest that immunization with cocktail vaccine consisting of different types of MPSP may be necessary in the field trial.

cDNA cloning, characterization and vaccine effect analysis of Haemaphysalis longicornis tick saliva proteins

Immunological control of ticks is currently the only sustainable and practical alternative method to the current use of acaricides which has serious limitations. The success of this method is dependent upon identification and cloning of potential tick vaccine antigens. We used a combination of immuno-screening of an adult tick cDNA library as well as the 3 and 5 rapid amplification of cDNA ends to clone two cDNAs, encoding tick saliva proteins from Haemaphysalis longicornis. The two cDNAs herein named HL 34 and 35 are 1000 bp each and encode polypeptides with 292 and 321 amino acid residues respectively. Northern blotting analysis of total RNA from ticks at different feeding stages revealed that expression of both HL 34 and HL35 mRNAs is induced during the slow feeding phase. We speculate that the functions of both genes are closely associated with blood feeding. Expression analysis by RT-PCR showed that both genes are expressed in other tick organs in addition to salivary glands. Recombinant HL 34 was successfully expressed in Escherichia coli and its suitability as a tick vaccine antigen was analyzed in rabbits. We propose that rHL34 could be a useful component of a cocktail tick vaccine.

Granulocyte colony-stimulating factor (G-CSF)-mediated signaling regulates type IV collagenase activity in head and neck cancer cells

Granulocyte colony-stimulating factor (G-CSF), a hematopoietic cytokine, regulates the proliferation and differentiation of granulocytic progenitor cells and functionally activated mature neutrophils. G-CSF also affects nonhematopoietic tumor cells through its binding to the specific receptor (G-CSFR) on the cells. The type IV collagenase [matrix metalloproteinase 2 (MMP-2)] is known to play a main role in the process of invasion and metastasis, but its regulation, for example, in expression or in activation, is not clearly understood. In this study, we investigated the role of G-CSF in the regulation of tumor cell invasion and the synthesis of MMP-2. G-CSFs producing the head and neck carcinoma cell line T3M-1 cells with metastatic ability and no G-CSF receptor (G-CSFR) expression were transfected with G-CSFR expression vector. In vitro treatment of G-CSFR-transfectant T3M-1 cells with recombinant G-CSF (rG-CSF) significantly augmented their invasive potential in a reconstituted basement membrane (Matrigel) system compared with that of parental cells. Moreover, MMP-2 activity of G-CSFR-transfectant T3M-1 cells was enhanced by the stimulation with rG-CSF, as assessed by gelatin zymography. These results identify G-CSF as a regulator of MMP-2 and cellular invasion.

Phylogenetic analysis of dengue-3 viruses prevalent in Guatemala during 1996-1998

Dengue is an acute viral disease transmitted by the Aedes aegypti mosquito which is present in most tropical urban areas of the world. There are four antigenically distinct serotypes, designated dengue-1 (DEN-1), dengue-2 (DEN-2), dengue-3 (DEN-3) and dengue-4 virus (DEN-4). In this study, we determined the serotypes of dengue viruses isolated in Guatemala in 1995-1998, and found that DEN-3 viruses appeared in 1995 and became predominant in the following three years. We then sequenced cDNAs from fifteen DEN-3 isolates recovered during 1996-1998. From the nucleic acid sequences and previously determined DEN-3 sequences, a phylogenetic tree was constructed using the neighbor joining method. The tree indicated that all fifteen isolates and other DEN-3 viruses isolated in Sri Lanka, India, Samoa and Mozambique formed subtype III. More than two decades ago, DEN-3 virus was prevalent in the Caribbean, but the isolates obtained at that time belonged to subtype IV. Therefore, we concluded that the 1996-1998 dengue epidemic in Guatemala was caused by DEN-3 strains, imported from a tropical area of Asia or Africa or from a Pacific island.

Characterization of two cDNAs encoding serine proteinases from the hard tick Haemaphysalis longicornis

Host vaccination against tick infestation is at present the most practical and sustainable alternative tick control method to the current acaricide use which has serious limitations. However the success of this approach to control ticks depends upon the identification of target vaccine antigens. Members of the serine proteinase gene family may represent an interesting group of proteins to target as candidate antigens because of their involvement in regulation of many physiological functions and development processes in a wide range of organisms. We used RT-PCR with the 3' and 5' RACE to clone two cDNAs encoding full-length serine proteinases from the hard tick, Haemaphysalis longicornis. RT-PCR degenerate primers were designed from amino acid sequences surrounding active sites, His(57) and Ser(195) conserved among most known serine proteinase. Gene specific primers designed from nucleotide sequences of the RT-PCR products were used to prime the 3' and 5' RACE. Southern blotting analysis showed that both HLSG-1 and -2 are single copy. The 2 cDNAs, HLSG-1 and -2 are 1.2 and 1.0 kb long in size with open reading frames encoding polypeptides with 37.7 and 31.2 kDa predicted molecular mass respectively. Northern blotting analysis of total RNA from unfed and partially fed whole ticks showed that the expression of mRNAs for both HLSG-1 and -2 was induced by blood feeding. Expression analysis by RT-PCR showed that both HLSG-1 and -2 are expressed in other tick organs in addition to salivary glands and midguts. The 6 serine proteinase consensus cyteine residues are well conserved in both HLSG-1 and -2. We have discussed our findings with respect to tick vaccine development research.

Prevalence of virulent Rhodococcus equi in isolates from soil collected from two horse farms in South Africa and restriction fragment length polymorphisms of virulence plasmids in the isolates from infected foals, a dog and a monkey

The prevalence of virulent Rhodococcus equi in soil isolates from two horse farms in South Africa and nine clinical isolates from six foals, a foal foetus, a dog, and a monkey was investigated. The isolates were tested for the presence of virulence plasmid DNA and 15- to 17-kDa antigens by immunoblotting. Rhodococcus equi was isolated from almost all of the soil samples obtained from the two farms with 5.0 x 10(1) to 3.3 x 10(4) colony forming units per gram of soil. Virulent R. equi was isolated from three soil samples from one of the farms and appeared in 3.8% (three of 80 isolates), but not in any of the 182 isolates from the other farm. Of the three virulent R. equi isolates, one contained an 85-kb type I plasmid and two an 87-kb type I plasmid. Of nine clinical isolates from the foals, foal foetus, dog and monkey, five from the foals were virulent R. equi which expressed the virulence-associated antigens and contained a virulence plasmid 85-kb type I, and were all isolated from cases of pneumonia typical of that induced by R. equi in young foals living in widely separated areas in South Africa. The isolates from the other four foals, the dog and the monkey were avirulent R. equi.