Distribution of infecting hepatitis C virus genotypes in end-stage liver disease patients at a large American transplantation center

The distribution of hepatitis C virus (HCV) genotypes was studied in 202 anti-HCV-positive liver transplant candidates with end-stage liver disease. HCV sequences were successfully amplified from 185 patients: In the first 100, the genotype was determined by direct sequencing in the NS5 region, and in the remaining 85, type-specific primers were used for genotyping. Eighty-five patients (46.0%) were infected with type 1a HCV strains, 52 (28.1%) with type 1b, 14 (7.6%) with type 2b, 13 (7.0%) with type 4, 5 (2.7%) with type 3a, 2 (1.1%) with type 2a, and 1 (0.5%) with type 2c. Thirteen HCV-positive patients (7.0%) could not be genotyped. The relatively low prevalence of genotype 1b in this population of end-stage liver disease patients speaks against postulated higher pathogenicity of this genotype.

Expression of the BE-20 epididymal protein gene: in situ hybridization

A protein designated as BE-20 was purified from cauda epididymal fluid of male rabbits and the amino acid sequence of the N-terminus was determined. A 23-mer oligonucleotide coding the N-terminal eight amino acids of the BE-20 protein was synthesized. The oligonucleotide was used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. Digoxigenin-labeled BE-20 cDNA was prepared and used as a hybridization probe to detect the specific mRNA. The probe interacted with a 1.2-kb mRNA prepared from rabbit epididymis; mRNAs prepared from rabbit testis gave negative reaction. Using tissue sections, the BE-20 mRNA was located in the epithelial cells of the cauda epididymis and proximal segment of the ductus deferens by in situ hybridization method. Sections of the corpus and caput epididymis, testis, and liver gave negative reaction. Polyclonal anti-BE-20 antibodies were raised and found to inhibit in vitro the capacity of human sperm to penetrate zona-free hamster ova. The results suggest that BE-20 protein may influence maturation of spermatozoa during its movement through the epididymis and/or the capacity of sperm to fertilize ova.

Identification of a rabbit epididymal protein gene

A protein designated as BE-20 was purified from cauda epididymal fluid of the rabbit by preparative polyacrylamide gel electrophoresis and HPLC on a mono Q HR5/5 anion exchange column. The purified protein migrated with an estimated Mt of 20,000 when analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The amino acid sequence of the N-terminus of the BE-20 protein was determined. The initial eight amino acid residues were His-Gly-Ala-Asp-Lys-Pro-Gly-Val. The corresponding 23 mer oligonucleotide (5'-CATGGCGCTGACAAGCCTGGGGT-3') was synthesized and used as sense primer with rabbit epididymal mRNA as template in the RT-PCR system. The purified BE-20 cDNA consisted of 499 bp with an open reading frame of 285 bp encoding a deduced polypeptide composed of 95 amino acids. The BE-20 cDNA had 78.5% identity in 479 bp overlap with human epididymis-specific HE4 cDNA. The amino acid sequences of the initial 30 amino acid residues of the N-terminus of the purified protein and the deduced polypeptides were as follows: N-His-Gly-Ala-Asp-Lys-Pro-Gly-Val-Cys-Pro-Gln-Leu-Ser-Ala-Asp-Leu-Asn-Cy s- Thr-Gln-Asp-Cys-Arg-Ala-Asp-Gln-Asp-Cys-Ala-Glu. The deduced polypeptide contained 16 cysteine residues and had partial sequence homology with proteins belonging to the four-disulfide core family of extracellular proteinase inhibitors. The BE-20 protein may play a role in sperm maturation and/or capacitation.

[Cholecystokinin-octapeptide (CCK-8) reverses experimental endotoxin shock]

The effects of CCK-8 on the mean arterial pressure (MAP), blood components and path-morphological changes during endotoxin shock (endotoxin, 8 mg/kg b.w.iv.) in rats, as well as on the 24 h mortality rate (MR) of the lead-sensitized rats in endotoxin shock (endotoxin 1 microgram/100 g b.w.iv.) were observed. The results showed that injection of CCK in ES rats led to an increase in MAP, and a reduction of hematocrit and platelet as well as white cell count; the mortality rate decreased and the lesion in main organs lessened. It is suggested that release of endogenous CCK has important protective action during endotoxin shock.

Fine mapping of a C-terminal linear epitope highly conserved among the major envelope glycoprotein E2 (gp51 to gp54) of different pestiviruses

Envelope glycoprotein E2 (gp51 to gp54) is the major neutralizing antigen of pestiviruses, which include classical swine fever virus (CSFV), bovine viral diarrhoea virus (BVDV), and border disease virus (BVD). Previous studies carried out using a panel of monoclonal antibodies raised against CSFV strain Brescia have revealed the existence of four antigenic domains, A to D, of the E2 protein, all of which are located at the N-terminal half of the molecule. Here we report the detailed mapping, using three complementary techniques, of a novel linear epitope located at the C-terminal part of the molecule, which reacted with a monoclonal antibody (4-9D4) as well as polyclonal animal sera. This epitope is highly conserved in the three different members of pestiviruses and hence can be used as a genus-specific diagnosis tool. The observation that this epitope is not accessible on the native virus surface, together with its C-terminal location, supports a recently proposed structural model, indicating that the C-terminal part of E2 is membrane-bound while the N-terminal half of the molecule is exposed on the virus surface.

Application of linker-ligation-PCR for construction of phage display epitope libraries

An efficient method for construction of random epitope libraries using filamentous phage is described. Random DNA fragments generated by DNase I digestion were blunt ended by T4 DNA polymerase and ligated with a 12-mer linker, followed by PCR amplification using the same oligonucleotide linker as primers. The results showed that only the ligated product containing linker sequences on both ends was specifically amplified. When the linker ligated-PCR (LL-PCR) product was used for the construction of phage display epitope libraries, the total number of independent clones in the libraries was increased by 100 to 1000 fold in comparison to that obtained for libraries constructed using other methods. In addition, the LL-PCR strategy also increased the probability of isolating recombined DNA fragments which are derived by random in-frame ligation of two or more discontinuous peptide-coding sequences before being inserted into the display vector. Such randomly recombined DNA fragments might be useful in defining conformational epitopes.

Dynamic behavior of hepatitis C virus in chronically infected patients receiving liver graft from infected donors

We studied the outcome of hepatitis C virus (HCV) infection in 14 patients with end-stage HCV-related liver disease who received HCV-positive liver allografts. Viral sequences specific for donor and recipient were established by direct sequencing of PCR products from the NS5 region and by single-strand conformation polymorphism. Within a few months after transplantation the donor strain took over the recipient strain in 8 patients while in 6 patients it was the recipient strain which ultimately prevailed. Donor and recipient were infected by identical genotypes in 6 donor/recipient pairs and by different genotypes in the remaining 8 pairs. Subtype 1b and type 1 (1a + 1b) became the predominant strains in all recipient/donor pairs in which they were present. Patients retaining their own strain were found to have significantly more active liver disease than those infected by the donor strain. We show that HCV superinfection and overtake phenomena occur in humans and suggest that genotypes 1b and 1 (1a + 1b) may possess replicative advantages over other genotypes. Furthermore, we provide evidence of the existence of interference preventing simultaneous continuous infection even by the same genotype strains. The development of active liver disease associated with recipient strain infection and mild or no disease associated with infection from the donor suggests various pathogenic abilities of different HCV strains.

Epicutaneous exposure of protein antigen induces a predominant Th2-like response with high IgE production in mice

Hapten-induced contact hypersensitivity has been well-characterized in humans as well as in animal models. However, it is not clear whether or not protein Ag can directly sensitize epicutaneously and induce a primary immune response. We demonstrated in this study, for the first time, that through epicutaneous exposure protein Ag in the absence of adjuvant sensitizes animals and induces a predominant Th2-like response. Furthermore, mice receiving repeated protein Ag sustained elevated levels of specific IgE. This animal model can be used to investigate the molecular mechanism controlling the differential Th1/Th2 development in skin diseases.

Epicutaneous exposure of protein antigen induces a predominant Th2-like response with high IgE production in mice

Hapten-induced contact hypersensitivity has been well-characterized in humans as well as in animal models. However, it is not clear whether or not protein Ag can directly sensitize epicutaneously and induce a primary immune response. We demonstrated in this study, for the first time, that through epicutaneous exposure protein Ag in the absence of adjuvant sensitizes animals and induces a predominant Th2-like response. Furthermore, mice receiving repeated protein Ag sustained elevated levels of specific IgE. This animal model can be used to investigate the molecular mechanism controlling the differential Th1/Th2 development in skin diseases.

The association between lung innate immunity and differential airway antigen-specific immune responses

The mechanisms involved in the differential regulation of airway immune responses in atopic versus non-atopic individuals are poorly understood. In this study, the association between non-specific immunity and the differential airway antigen-specific immune responses was examined in a murine model. The disparity in antigen-specific IgE and IgG2a productions between the two strains of mice was observed to be significant. C57BL/6J mice were much more efficient than BALB/cJ mice in making IgE antibody to inhaled ovalbumin (OVA) antigen. On the contrary, BALB/cJ mice did make more IgG2a antibodies than C57BL/6J mice to inhaled OVA. These findings suggest that in C57BL/6J mouse strain a predominant Th2 type of immune response develops in response to inhaled OVA antigen. In contrast, BALB/cJ mice mount a Th1 type of immune response to aerosolized OVA antigen. Furthermore, after lipopolysaccharide (LPS) stimulation, the IL-12 mRNA expression of lung-derived cells from BALB/cJ mice was higher than that from C57BL/6J cells. However, the lung-derived cells of C57BL/6J mice stimulated by LPS produced higher levels of IL-10 and prostaglandin E2 than BALB/cJ lung-derived cells did. Therefore, our study demonstrated that the difference of lung-derived cells in their ability to produce cytokine and prostaglandin between BALB/cJ and C57BL/6J mice correlates well with the type of the airway antigen-specific immune effector functions.

BTag: a novel six-residue epitope tag for surveillance and purification of recombinant proteins

Epitope tagging (Eta) is becoming an increasingly useful technique in molecular biology and biotechnology for the detection, characterisation and purification of recombinant proteins (re-proteins). Here we describe a novel Eta system composed of two different monoclonal antibodies (mAb; D11 and F10) and a 6-amino-acid Eta (Gln-Tyr-Pro-Ala-Leu-Thr or QYPALT). This Eta was derived from a highly conserved region of the major core protein, VP7, of bluetongue (BT) viruses, hence the name BTag. BTag is unique among current tagging systems in its lack of charge and the fact the tag sequence can be placed and detected in any region of a re-protein. Other useful features of BTag include its small size and its recognition by two different mAb. Using the BTag system, more than 30 re-proteins have been produced from a variety of host organisms, and the antigenicity of the tag sequence was maintained in all of the proteins tested to date. Our result demonstrated that BTag could be superior to other existing Eta systems for certain applications.

Expression and characterization of a novel human sperm membrane protein

A cDNA fragment (HSD-1) coding for part of a human sperm membrane protein (hSMP-1) was previously isolated from a human testis cDNA expression library, with the serum from an infertile patient used as a probe. By rescreening human testis cDNA libraries with the HSD-1 insert and using rapid amplification of cDNA ends, the complete cDNA of 2482 bp was identified and sequenced. An open reading frame of 1572 bp encodes 523 amino acid residues with a computed molecular mass of 55.08 kDa. This protein sequence does not match any other sequence in the databases, indicating that it represents a novel sperm antigen. Northern blot analysis of human and rat testis poly(A) mRNA detected a band of approximately 2.5 kb in both species. Reverse transcriptase polymerase chain reaction analysis showed that hSMP-1 mRNA was present in human testis but was not in either kidney or liver. When the cDNA was expressed in Escherichia coli under the control of the T7 promoter, the expressed protein accumulated to a level of about 50% of the total cellular protein. The expressed protein, which contained an N-terminal poly(his) sequence tag, was purified by chromatography on an nitrilo-tri-acetic acid affinity resin. Approximately 10 mg of pure protein was obtained from a 500-ml culture, purified, and used as antigen to generate a polyclonal antiserum in rabbits. Western blot analysis of human sperm extracts showed a single specific band at 55.5 kDa. Immunofluorescence data showed that hSMP-1 was localized to the head of human sperm. The fluorescent staining formed a cap-shaped pattern that was similar in morphology to the human sperm acrosome. The availability of large amounts of recombinant hSMP-1 and its antiserum will facilitate studies on the function and expression of the protein during spermatogenesis and the assessment of its potential value as a contraceptive immunogen.

Topography and immunogenicity of bluetongue virus VP7 epitopes

The core of bluetongue virus (BTV) consists of ten dsRNA viral genome segments and five proteins, including two major (VP7 and VP3) and three minor (VP1, VP4 and VP6) components. The major core protein VP7 is believed to be an important structural constituent because it interacts, not only with the underlying core protein VP3, but also with two outer capsid proteins (VP2 and VP5). In this communication we summarise data on the mapping of at least six different epitopes of VP7 distributed along the molecule. Two of the six epitopes have not been mapped previously. The accessibility of these epitopes in intact virions and core particles was analysed using immunoelectron microscopy. The epitope located near the N-terminus of VP7 was accessible at the surface of intact virions and core particles. Epitopes in other parts of the VP7 molecule were detected weakly in core particles but not in intact virions. These results support the proposal that VP7 molecules are orientated with their N-terminus accessible on the surface of either the particle or at least one of the three different channels observed by cryoelectron microscopy in the outer capsid layer. Analysis of the immune response to BTV-infected or -immunised sheep and rabbits to three selected epitopes, which are located in different regions of the VP7 molecule, demonstrated that all of them were recognised by the animals tested. These results provided further molecular evidence suggesting that VP7 is indeed a major immunogenic antigen ideal for BTV antibody detection.

A single amino-acid change between the antigenically different extracellular serine proteases V2 and B2 from Dichelobacter nodosus

Dichelobacter nodosus (Dn), the causative organism of ovine footrot, secrets three distinct types of extracellular serine proteases which have been implicated in virulence. Southern analyses have shown that the proteases are encoded by three separate genes, and the genes encoding an acidic protease V5 and a basic protease have already been characterised from virulent Dn strain 198. The gene encoding the third protease type, as represented by acidic protease V2, was isolated from an EcoRI-BamHI library of strain 198 genomic DNA by probing with a polymerase chain reaction (PCR) fragment generated with oligodeoxyribonucleotides based on protease V2 amino acid (aa) sequences. A further clone from an RsaI library was isolated to complete the 5' region of the gene to yield an ORF of 1803 bp encoding a protein precursor of 601 aa. The acidic protease V2 gene, aprV2, shows the same precursor structure as the bprV and aprV5 genes with 72% and 69% similarity at the nucleotide (nt) level and with 73% and 69% similarity at the aa level, respectively. As monoclonal antibodies consistently distinguish the virulent (V) and benign (B) forms of this protease, the gene encoding the acidic protease B2 from benign Dn strain 305 was isolated using the PCR and characterized to investigate the molecular basis for this difference in antigenicity. A 2-bp substitution in a single codon was identified which appeared to be responsible for a change of epitope.

Outline of control practice of endemic fluorosis in China

Endemic fluorosis is prevalent in China covering 29 provinces, municipalities and autonomous regions. The endemically affected areas can be divided, according to the sources of fluoride, into three types: high fluoride water, pollution from coal burning, and drinking brick tea in excess. Since the 1960's, several pilot surveys of the disease have been made and control programmes carried out in some of the areas. An Expert Consultation Committee on Endemic Fluorosis Control of the Ministry of Public Health was formally established in 1979. A national survey programme and series of working criteria for the disease were drawn up at the First National Congress of Endemic Fluorosis Control in 1981. Under the Central Government of China, administrative organizations and institutions concerned at all levels have been set up, forming a nation-wide network of control. Cooperation and coordination among such departments as health, water conservancy, geology and finance have been achieved in the planning and implementation of control programmes. Since 1980, many projects for improving drinking water quality through de-fluoridation have been completed. At the same time, new methods and technologies for improving stove and grain baking have become widely used in some of the areas where environmental fluoride pollution exists from burning coal. After all the control programmes had been introduced, the incidence of the illness was reduced with some patients making a complete recovery.

[Effects of long-term atenolol treatment on beta-adrenoceptor subtypes in rat heart]

The effects of long-term beta 1-AR selective antagonist atenolol treatment on beta-adrenoceptor subtypes were studied by radioligand binding assay, function determination and cAMP accumulation measerment in rat heart. The reasults showed that during long-term administration of atenolol: (1) The density of total beta-AR was increased by approximately 57%; the positive inotropic response and cAMP formation induced by activation of beta-AR were also enhanced. (2) The 125I-pindol competitive inhibition curve for CGP20712A showed that there were no significant difference in the percentage of beta 1- and beta 2-AR sites between the atenolol treated rats and the control rats; pA2 values for selective beta 1-AR antagonist CGP20712A and pKB values for selective beta 1-AR antagonist ICI 118, 551 were not significantly different in the two groups. The results suggested that beta 1- and beta 2-adrenoceptors were upregulated not only in density but also in positive inotropic effect to the same extent.

Self-assembly, antigenicity, and immunogenicity of the rabbit haemorrhagic disease virus (Czechoslovakian strain V-351) capsid protein expressed in baculovirus

Rabbit haemorrhagic disease virus (RHDV) capsid protein was expressed in a baculovirus system. Analysis of the expressed product showed that the recombinant protein, which is 60 kDa in size, was antigenic as revealed by its reactions in ELISA and Western blot with the antibodies raised against RHDV. Direct electron microscopy of the cell culture supernatant and the purified protein demonstrated that the capsid protein expressed in insect cells self-assembled to form empty virus-like particles (VLP) which are similar in size and morphology to that of native virus. These particles were immunoreactive with polyclonal anti-RHDV antibodies and with four monoclonal antibodies which recognise conformational epitopes of the virus. The results indicated that the VLPs were morphologically and antigenically indistinguishable from native virus. The recombinant VLPs induced high levels of RHDV-specific antibodies in rabbits and mice following immunisation. The immune response to the VLPs protected the rabbits following challenge with the virulent RHDV. In haemagglutination assays, the VLPs bound to human red blood cells similar to the native virus particles. The recombinant protein and or VLPs is suitable for the development of a rapid, sensitive and reliable test for detection of antibodies to RHDV and for use as a vaccine for domestic rabbits.

Differentiation of cognate dsRNA genome segments of bluetongue virus reassortants by temperature gradient gel electrophoresis

The analysis of reassortant viruses has been a valuable tool in the investigation of protein interaction and function in double-stranded (ds) RNA virus research. The differentiation of cognate dsRNA genome segments of reassortants is conventionally achieved by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). However, due to a high degree of sequence homology among different bluetongue virus (BTV) serotypes, it is not uncommon to find that certain cognate dsRNA segments cannot be differentiated by SDS-PAGE. Temperature gradient gel electrophoresis (TGGE) has been shown to be a much more sensitive method of differentiating RNA or DNA fragments of high sequence homology. Here we report the preliminary application of TGGE in analysis of genomic reassortants of two BTV serotypes, 1 and 23. While six out of ten genome segments between BTV-1 and BTV-23 could not be resolved by SDS-PAGE, all of them were differentiated by TGGE. The ability of TGGE to distinguish between dsRNA segments of high sequence homology may also make it useful in the search for BTV genes responsible for defined characteristics, such as virulence, by differentiating wild-type and mutated gene segments of viruses displaying altered phenotypes.

Use of a gene-targeted phage display random epitope library to map an antigenic determinant on the bluetongue virus outer capsid protein VP5

We describe the use of a gene-targeted random epitope library for the mapping of antigenic determinants. A DNA clone encoding the target antigen was digested randomly with DNase I to generate a population of DNA fragments of different sizes and sequences. After size fractionation, small DNA fragments (100-200 bp) were isolated and cloned into the phage expression vector fUSE2 to form an expression library displaying random polypeptide sequences as fusion proteins at the N terminus of the phage gene III protein. This library, termed a gene-targeted random epitope library to distinguish it from totally random synthetic epitope libraries, was then screened by affinity selection for recombinant phages which were specifically bound by the antibody of interest. Using this approach, we have mapped a monoclonal antibody (mAb)-defined epitope on the bluetongue virus outer capsid protein VP5. This epitope is not accessible on the intact virus surface, but is recognised by the immune system of sheep and cattle during virus infection. Although the example given here utilised a DNA fragment of known sequence and the library was screened for a mAb-defined epitope, the strategy described should be equally applicable to genes of unknown sequence and for screening of epitopes using polyclonal antibodies. The approach can also be extended to identify immunodominant epitope from much more complex genome-targeted random epitope library for virus, bacteria and eukaryotic organisms. Other applications of recombinant phages expressing defined immunodominant epitopes include serodiagnosis and vaccine development.

Expression of the calpastatin gene segment during spermiogenesis in human testis: an in situ hybridization study

Serum obtained from an infertile woman contained antibodies that agglutinate human sperm. The antibodies interacted with a sperm protein with an estimated M(r) of 17.5 kD. The cDNA coding the 17.5-kD protein was isolated from a human testis lambda gt11 expression library and identified as a segment of the calpastatin gene. Single-stranded 35S-labeled RNA probes were prepared from the calpastatin cDNA segment. Using the techniques of in situ hybridization, the calpastatin mRNA was located in spermatids of human testis. The results support a previous observation that the calpastatin segment is produced during spermiogenesis and suggest that transcription of the calpastatin gene occurred during the postmeiotic haploid stage of spermatogenesis.

Gene encoding a mammalian epididymal protein

Polyclonal antibodies raised against a 20 kD epididymal protein (EP20) were used to isolate the cDNA from a human testis lambda gt11 expression library. The nucleotide sequence of the cDNA consisted of 1908 base pairs (bp) containing an open reading frame composed of 1479 bp encoding a polypeptide of 493 amino acid residues. The nucleotide sequence of EP-20 cDNA had 97% identities (282/288) with ESTO 0991 Homo Sapiens cDNA clone HHC M14 in the reverse orientation. The HHC M14 sequence corresponded to a segment in the non-translatable 3'end of EP-20 cDNA. The amino acid sequence of the deduced polypeptide showed no homology with reported polypeptides. The epididymal protein may be involved in sperm maturation and/or capacitation.

Fine mapping of a surface-accessible, immunodominant site on the bluetongue virus major core protein VP7

The 349-amino-acid major core protein VP7 of bluetongue virus (BTV) is both the most abundant viral structural protein and the major immunogenic serogroup-reactive viral antigen. Previous studies indicated that a conformation-dependent antigenic site, defined by the VP7-specific monoclonal antibody 20E9/B7/G2(20E9), was accessible from the virus surface and that the binding of the monoclonal antibody to this epitope could be blocked specifically by antisera raised against different serotypes of bluetongue virus, suggesting it is a serogroup-specific immunodominant epitope. Using a combination of three different mapping strategies, we have located the 20E9 binding site at the N-terminus of the molecule, between amino acids 30 and 48. The fine mapping of the 20E9 immunodominant epitope will facilitate structure-function analyses of the major core protein and provide new opportunities to improve existing BTV serodiagnosis methods based on this immunogenic site.

Major core protein VP7 of Australian bluetongue virus serotype 15: sequence and antigenicity divergence from other BTV serotypes

Full-length cDNA of the RNA genome segment coding for the major core protein VP7 of Australian bluetongue virus serotype 15 (BTV-15) has been isolated by reverse transcription-PCR cloning. Comparative analysis indicated that the BTV-15 VP7 sequence had diverged significantly from that of other members of the BTV serogroup. At the amino acid level, BTV-15 VP7 exhibited sequence identities of 80 to 84% with VP7 molecules of other serotypes, significantly lower than the sequence identities of between 93 and 100% observed among other serotypes characterized to date. This was consistent with previous observations that there were significant immunological differences between BTV-15 and other BTV serotypes and that monoclonal antibodies raised against BTV-1 VP7 failed to react with BTV-15 VP7. Recombinant BTV-15 VP7 protein produced from Escherichia coli was largely insoluble, but maintained its immunogenicity. Polyclonal mouse sera raised against the recombinant VP7 protein reacted strongly with VP7 of BTV-15, but weakly with that of BTV-1.

Expression in Escherichia coli of the extracellular basic protease from Dichelobacter nodosus

Dichelobacter nodosus, a Gram-negative obligate anaerobe and the causative agent of ovine footrot, secretes a number of extracellular proteases, one of which is highly basic in nature. The gene (bprV) encoding this basic protease, from virulent strain 198, has been cloned and sequenced. Clone pBR3KB contained the complete bprV gene which constitutively expressed an active protease using its own promoter, when cloned in Escherichia coli. However, levels of protease expression were low and unstable when the clone was expressed in liquid culture. A range of E. coli strains were examined for stable expression; strains NH274 and SURE were found to be better hosts for stable expression than other commonly used E. coli host strains. Stabilization and enhancement of expression was achieved by deletion of the native promoter region and expression from plasmid promoter or promoters, and by modification of culture conditions. The recombinant protease obtained from E. coli was indistinguishable from the native enzyme in size, activity, isoelectric point and immunological properties.

[Reversal of malignant phenotype of human hepatoma cells by antisense c-ets-2, c-myc and N-ras]

A recombinant retroviral vector was constructed which expressed antisense RNA of c-ets-2, c-myc and N-ras. The pseudotype virus was packaged and rescued by transfection in PA317 cells and used to infect human hepatoma cell line SMMC-7721. After selection with G418, resistant colonies were obtained. Stable integration of retrovirus in infectants was shown by Southern hybridization of genomic DNA and the presence of antisense RNA was detected by RNA dot blot hybridization. It was demonstrated that the antisense RNAs did inhibit the growth of human SMMC-7721 hepatoma cells. The ability to form colony in soft agar and tumorigenicity in nude mice of SMMC-7721 were significantly suppressed by the antisense RNAs. The result implicates the potential value in future cancer gene therapy.

The treatment of autoimmune disease in (NZB/NZW)F1 mice with syngeneic photomodulated splenocytes

(NZB x NZW)F1 (B/W) mice spontaneously develop a disease which is remarkably similar to systemic lupus erythematosus (SLE) in humans. This disease is characterized by the appearance of autoantibodies to double-stranded (ds)DNA and the subsequent development of fatal glomerulonephritis. The prophylactic treatment of B/W mice with syngeneic photomodulated autoimmune spleen cells was found to significantly improve survival, and to inhibit the outgrowth of autoreactive B cells and the production of high-titre IgG anti-dsDNA antibodies. The function of the autoreactive T cells in vivo, however, did not change significantly. Our findings suggested a novel treatment for spontaneously occurring autoantibody-related autoimmune diseases.

Calpastatin gene in human testis

Antibodies present in a serum obtained from an infertile woman interacted with a 17.5 kD glycoprotein (BS-17 component) extracted from human sperm by Western blot. Polyclonal antibodies were raised against the BS-17 component and used to identify positive staining clones from a human testis lambda gt11 expression library. The cDNA encoding the BS-17 component was isolated and its nucleotide sequence determined. The BS-17 cDNA contained 758 nucleotides with an open reading frame of 558 nucleotides encoding a polypeptide consisting of 186 amino acids. The BS-17 cDNA showed 99.7% homology in 758 nucleotides overlap with the 3' terminus of the gene coding calpastatin and 99.5% identity in 186 amino acid overlap with the carboxyl terminus of calpastatin. The BS-17 component of human sperm corresponds to the carboxyl terminus of calpastatin. This conclusion is supported by the finding that the polyclonal antibodies also interacted with a 84 kD protein corresponding to the M(r) of calpastatin.

Fertility studies with antisperm antibodies

Serum obtained from an infertile subject possessed antibodies that interacted with a human sperm glycoprotein with an estimated M(r) of 17,550 and pI of 5.65 containing 17.7% neutral hexoses and designated as the BS-17 component. Polyclonal antibodies raised against the BS-17 antigen blocked the capacity of human sperm to fertilize zona-free hamster ova in vitro; however, the antibodies did not influence the binding of human sperm to zone-free ova or alter the motility of human sperm. The antibodies inhibited the capacity of mouse sperm to fertilize ova upon in vivo insemination. The BS-17 antigen was detected in human, rat, mouse, rabbit, and hamster sperm by an immunocytochemical method, using polyclonal anti-BS-17 antibodies. Intense staining occurred over the surface of the acrosomal region of all mammalian sperm. The results suggest that the production of anti-BS-17 antibodies contribute to infertility by preventing the capacitation of sperm and/or by blocking the ability of capacitated sperm to fertilize the egg.

Immunization with synthetic peptide segments of a sperm protein impair fertility in rats

The nucleotide sequence of the cDNA encoding a sperm protein (rSMP-B) was determined in a previous study. Two peptide segments corresponding to the extracellular domain of the deduced sperm polypeptide were synthesized as multiple antigen peptide (MAP) and designated as rSMP-229 and rSMP-230. Polyclonal antibodies were raised against the two MAPs. Sera obtained from rabbits immunized with rSMP-230 interacted with human and rabbit sperm membrane proteins with estimated molecular sizes of 72 and 20.1 kD, respectively. Adult female and male rats were immunized with the MAPs and their fertilities determined. Immunization of female rats with rSMP-229 and rSMP-230 induced infertility in 25% and 83% of the treated animals, respectively. All male rats immunized with rSMP-229 remained fertile; whereas animals immunized with rSMP-230 did not mate with normal cycling female rats. Three impotent male rats were found to regain their mating potency 45 days after the last booster injection. These findings demonstrated that immunization with rSMP-230 induced a reversible impotency in male rats. Serum testosterone and LH levels were reduced in rSMP-230-immunized male rats and were elevated in rSMP-229-immunized animals. Histopathological examination of sections of testes from male rats immunized with rSMP-230 showed impairment of spermatogenesis and sloughing of germ cells into the lumen of the seminiferous tubules. The testes of male rats immunized with rSMP-229 showed normal morphology and active spermatogenesis with scattered foci of nodular hyperplasia of Leydig cells in the interstitial areas. In conclusion, immunization with synthetic peptide segments corresponding to different domains of a deduced sperm protein induced infertility in a significant number of female rats and transient impotency in male rats.

Fine mapping of a continuous epitope on VP7 of bluetongue virus using overlapping synthetic peptides and a random epitope library

Two complementary techniques have been used to delineate an epitope on VP7 of bluetongue virus. Two MAbs (F10 and D11), both of which bound within a region spanning amino acids 255 to 274 in the 349 amino acid protein, were used to probe overlapping synthetic peptides covering this region. A pentapeptide, QYPAL, and a hexapeptide, QY-PALT (amino acids 259-264), preferentially bound both MAbs. MAb F10 also reacted with a heptapeptide (TAEIFNV) immediately adjacent to QYPALT. The MAbs were also used to affinity-purify fusion phages from a random hexapeptide library. All phage peptides selected were similar to QYPALT. Comparison of the peptides suggested that residues Q and P at positions 1 and 3 were critical for recognition. Some affinity-purified phages displayed the hexapeptide QYPSLL, which is similar to a sequence in VP7 of another orbivirus, epizootic hemorrhagic disease virus. This finding allowed a potentially cross-reactive site to be identified.

Use of a gram- signal peptide for protein secretion by gram+ hosts: basic protease of Dichelobacter nodosus is produced and secreted by Bacillus subtilis

The bprV gene, encoding the extracellular basic protease of the Gram- anaerobic bacterium Dichelobacter nodosus, was expressed and the protein secreted in Bacillus subtilis using the novel cloning/expression vector pNC3 [Wu et al., Gene 106 (1991) 103-107]. The pre- and pro-peptides were processed correctly in this heterologous system, and the 127-amino acid C-terminal extension region was also removed. The recombinant gene product was indistinguishable biochemically or immunochemically from the authentic protease and was able to form crystals upon dialysis, as was found for the authentic protease. This is the first example of the direct secretion of a Gram- extracellular enzyme in B. subtilis via its own signal peptide. The fact that this gene can be expressed and its product secreted in both Escherichia coli and B. subtilis provides a unique opportunity to study and compare the similarities and differences in protein secretion between Gram- and Gram+ organisms.

Early detection of de novo hepatitis C infection in patients after liver transplantation by reverse transcriptase polymerase chain reaction

BACKGROUND

Reverse transcriptase polymerase chain reaction (RT-PCR) can detect the viral genome and show hepatitis C recurrence in patients who undergo transplantation for chronic hepatitis C viral (HCV) infection. We investigated the utility of an RT-PCR-based HCV assay for early detection of viral RNA in de novo HCV infection after liver transplantation.

METHODS

Pretransplantation antibodies and explanation HCV viral RNA status were obtained from 117 patients. Follow-up liver biopsy specimens were examined for evidence of hepatitis activity. Plasma samples during the period of time of the biopsy were assayed for HCV antibody and viral RNA. RNA was extracted from samples and reverse transcribed to cDNA. cDNA was amplified by PCR, and products were detected by liquid hybridization.

RESULTS

Clinical hepatitis developed in seventeen of 117 patients who, before transplantation, were HCV antibody negative and explant viral RNA negative. Ten patients were plasma PCR negative and had known non-hepatitis C causes for the biopsy findings. Of the remaining seven patients, five (70%) were plasma RT-PCR positive before seroconversion in matched plasma samples.

CONCLUSIONS

In liver transplant patients, the incidence of de novo clinical hepatitis is low, and HCV viral RNA in de novo clinical hepatitis C infection can be detected in the absence of HCV antibodies.

Expression of Bacillus subtilis neutral protease gene (nprE) in Saccharomyces cerevisiae

Expression in the yeast Saccharomyces cerevisiae of the intact nprE gene of Bacillus subtilis, which encodes the pre-pro-NprE neutral protease precursor, resulted in intracellular accumulation of unprocessed precursor without detectable secretion or processing of the expressed gene product. When sequences specifying the signal peptide of yeast invertase were fused upstream of sequences encoding the mature NprE enzyme, nprE gene products were secreted into the culture medium. The secreted protein products were, however, highly, glycosylated and biologically inactive.

[Photodegradation assay method of nifedipine and its application to studies on percutaneous absorption]

A new method of analysis for low concentrations nifedipine was developed according to the principle of a photodegradation analytical method that has been reported by the authors previously, and was used to study percutaneous absorption. The absorbance of sample solution was measured before and after light irradiation at 237 nm for 2 h. In this method, calibration graph was linear in the range of 1-20 micrograms/ml for delta A237. The average recovery for nifedipine was 98.80%. No interference from propylene glycol, azone, m-nifedipine, nitrendipine, verapamil and propranolol was observed. It is shown that azone can promote markedly percutaneous absorption of nifedipine.

Isolation and sequencing of the cDNA encoding the 75-kD human sperm protein related to infertility

Serum was obtained from an infertile woman (IS) inducing head-to-head agglutination of human sperm and was used to screen a human testis lambda gt11 cDNA library. A plaque producing the interacting antigen was located. The recombinant lambda gt11 was isolated and cut with EcoRI releasing a 0.7-kb cDNA. Using the 0.7-kb cDNA as a probe, a larger cDNA of 2.4 kb was isolated and its nucleotide sequence determined. It was composed of 2 427 nucleotides with an open reading frame of 1584 nucleotides encoding 528 amino acid residues. The specific antisperm antibody was isolated from IS by epitope selection, using positive plaques of E. coli Y1090. The epitope-selected antibodies interacted with a 75-kD human sperm protein and with a polypeptide in the form of a beta-galactosidase fusion protein in the recombinant lysate of E. coli Y1089, determined by immunoblot. The fusion protein was purified by affinity chromatography on an anti-beta-galactosidase-Sepharose column. It is proposed that production of anti-75-kD antibodies may be the underlying cause of the infertility.

Nucleolar organizer regions in aspirates of malignant lymphomas and benign disorders of the lymph nodes

Silver staining of nucleolar organizer regions (AgNOR) was used to differentiate malignant lymphoma and chronic lymphadenitis. Aspiration smear samples from lymph nodes of 120 cases, including 43 non-Hodgkin's lymphoma, 3 Hodgkin's disease, 56 chronic lymphadenitis, 7 tuberculosis, 6 reactive hyperplasia and 5 samples from other diseases (epidermoid cyst, branchial cyst, mixed tumor, lymphoepithelioma and nodulous disease), were investigated. The number of AgNORs in 200 cells in each sample was counted, and the mean +/- SD in each disease was calculated: non-Hodgkin's lymphoma, 6.58 +/- 2.37; Hodgkin's disease, 4.22 +/- 0.5; chronic lymphadenitis, 1.16 +/- 0.1; tuberculosis, 1.13 +/- 0.14; reactive hyperplasia, 1.48 +/- 0.25; other diseases, 1.47 +/- 0.31. The results indicate that the AgNOR count in malignant lymphoma differed highly significantly from that in benign disease (P less than .001). The size of AgNORs in malignant lymphoma and chronic lymphadenitis was measured, and the maximum diameter and area of lymphocyte and lymphoma cell were: lymphocyte, 0.93 +/- 0.12 microns, 0.61 +/- 0.13 microns 2; lymphoma cell, 0.83 +/- 0.22 microns, 0.50 +/- 0.25 microns 2. The AgNOR sizes in malignant lymphoma were significantly smaller than in chronic lymphadenitis (P less than .001).

[Determination of m-nifedipine and its pharmacokinetic study in rabbits by high-pressure liquid chromatography]

A high-pressure liquid chromatographic method was developed for determination of m-nifedipine in plasma using a chemical bonded C-18 phase column (YWG-C18 10 microns, made in China) with nitrendipine as internal standard. To increase life of the YWG-C18 column a mixture of methanol and 5 mmol.L-1 phosphate buffer (70:30 vol/vol) was selected as mobile phase with a flow rate of 0.8 ml.min-1. The method was sensitive to m-nifedipine 3 ng.ml-1 plasma and the standard curve was linear from 10 to 1000 ng.ml-1 with correlation coefficient of 0.99. The within-day and day-to-day precisions (CV) of this method were 4.5% and 7.0%, respectively, with recoveries of 95-102% (10-1000 ng.ml-1). There was no interference with nifedipine, amiodarone, propranol, and verapamil. A pharmacokinetic study on m-nifedipine was carried out in 8 rabbits. A better computer fitted to a two-compartment model was observed using 3P87 program. The parameters obtained were as follow: Vc 6.3 L.kg-1, Cl 0.021 L.kg-1.min-1, T1/2 alpha 30 min, T1/2 beta 230 min, AUC 102 micrograms.min.ml-1.

Expression of a gene encoding a specific human sperm protein in Chinese hamster ovarian cells

The cDNA (RSD-2) encoding a human sperm protein (YWK-II) was isolated from a rat testis lambda gt11 expression library. Its nucleotide sequence was determined. The deduced polypeptide showed high identity with the transmembrane-cytoplasmic domains of A4 amyloid precursor protein of Alzheimer's disease. The RSD-2 was inserted into the EcoRI site of the pSV2-EP vector to construct the pSVRS-2 vector. Chinese hamster ovarian (CHO-dhfr) cells were cotransformed with pSV2-neo and pSVRS-2. mRNA and chromosomal DNA prepared from the transformed cells interacted with [32P]RSD-2 as probe by dot hybridization. The production of the YWK-II protein was determined by staining with the YWK-II mAb by an indirect immunofluorescence technique. There was marked staining of the cytoplasm. The RSD-2 cDNA encoding the YWK-II sperm was expressed in the transformed CHO cells. The pSV2-EP vector and the CHO cell expression system can be utilized to produce sperm proteins for antifertility studies.

Gene expression of human sperm component related to A4 amyloid precursor protein

Monoclonal antibodies were raised against a specific human sperm protein and designated as the YWK-II mAb. The partial cDNA encoding the protein was isolated from a rat testis lambda gt11 expression library and the amino acid sequence of the protein was deduced. The cytoplasmic-transmembrane domains of the deduced protein had high homology with the A4 amyloid precursor protein of Alzheimer's disease. To evaluate the stage of spermatogenesis when the gene was expressed, single-stranded 35S-labeled RNA probes were prepared from the cDNA. By an in situ hybridization technique the mRNA for the antigen was detected in germ cells at all stages of spermatogenesis. The finding that the gene is expressed in spermatogonia suggests possible involvement in the initiation of germ cell differentiation or in the detachment of spermatogonia from the basement membrane.

[Clinicopathological study of osteosarcoma of the jaw]

Eighty-five cases of osteosarcoma of the jaw were analyzed for clinical and histologic characters. According to the predominant histologic differentiation of the tumor, it was divided into osteoblastic, chondroblastic and fibroblastic type. Chondroblastic osteosarcoma was associated with the worst survival rate. The histologic grade was closely related to the prognosis of tumor.

Expression of a gene encoding a rabbit sperm membrane protein in mammalian cells

A general mammalian expression vector designated pSV2-EP was reconstructed by inserting an oligonucleotide fragment into pSV2-dhfr. This vector allowed insertion of cDNAs with EcoRI cohesive ends. The pSV2-EP contains a simian virus 40 (SV40) early promoter, origin for DNA replication, SV40 poly-A site, splicing site, an initiator ATG downstream from the promoter and an EcoRI site for the insertion of cDNA fragment screened from lambda gt11 expression libraries. A recombinant plasmid (pS-VRS-1) was constructed by inserting RSD-1, a cDNA encoding a rabbit sperm tail protein, into the EcoRI site of the pSV2-EP vector. Chinese hamster ovarian (CHO) dhfr-negative cells were cotransformed with pSV2-dhfr and pSVRS-1 by the calcium phosphate method. In selective culture medium without thymidine and hypoxanthine, several cell lines were obtained containing mRNA and DNA that hybridized with RSD-1. One of these transformed cell lines stained intensely with anti-rSMP-B antibodies, demonstrating that the RSD-1 was expressed in the transformed CHO cells.

Expression of a full-length nonstructural protein NS1 of bluetongue virus serotype 17 in Escherichia coli

The relative abundance of the nonstructural protein NS1 in bluetongue virus (BTV)-infected cells, the existence of NS1 in the BTV particles and the highly conserved NS1 gene among BTV serotypes indicate the diagnostic potential of using NS1 in detecting BTV infections. In this study a NS1 gene was expressed with the T7 RNA polymerase expression system to produce a full-length NS1 protein. Sheep anti-NS1 antibodies were raised with the E. coli-produced NS1 and used to show that the NS1 proteins of the five BTV serotypes in the Unites States were immunologically indistinguishable.

Development of a novel Bacillus subtilis cloning system employing its neutral protease as screen marker

Part of the pUC19 polylinker sequence (33 bp) was inserted into the pro-peptide-coding region of the Bacillus subtilis neutral protease-encoding gene to replace a 93-bp FspI-HindIII fragment. This in-frame sequence replacement had little effect on the expression and secretion of the neutral protease. This plasmid can therefore be used as a cloning vector, and recombinant clones can be directly identified on skim milk indicator plates by the loss of a clear ring (or halo) around the colonies. This novel cloning system offers several advantages over existing B. subtilis cloning vectors: (i) convenient direct screening of recombinants; (ii) the use of inexpensive indicator; (iii) no restriction on the use of host strains; and (iv) the availability of seven frequently used unique cloning sites: BamHI, XbaI, SalI, PstI, SphI, HindIII, and EcoRI. This system also has the potential to be used as an expression/secretion vector.

[Study on T-lymphocyte culture and function of T-lymphocyte subsets in patients with aplastic anemia]

T-lymphocytes form the peripheral blood of 12 patients with aplastic anemia (AA) and 4 patients with aplastic anaemia-paroxysmal hemoglobinuria syndrome (AA-PNH) were cultivated and their subsets were measured by monoclonal antibodies CD4, CD8, CD25 with indirect immunofluorescence technique. Change of the proportion of T-lymphocyte subsets was observed in 5 patients with AA after the mononuclear cells were activated with phytohemagglutinin (PHA). Its was shown that the number of CFU-T of the patients with AA was apparently decreased in comparison with that of normal controls (P less than 0.05). Disorder of T-lymphocyte subsets took place in patients with AA. The percentages of CD8 and CD25 lymphocytes were increased. The helper: suppressor T-lymphocytes (CD4:CD8) ratio was significantly increased (P less than 0.01). In the cases of AA-PNH, the number of CFU-T was significantly increased (P less than 0.01) and that of T-lymphocyte subsets did not change. The ratio of CD4/CD8 in 5 patients with AA was further decreased after activating mononuclear cells with PHA. These results showed that the increase of T-lymphocytes in patients with AA may account for the low level of CFU-T; the high level of CFU-T in patients with AA-PNH may be related to the multiplication of bone marrow cells. However, there may be a potential disorder of immune system on patients with AA at the same time.

A seral epidemiological study of HIV transmitted through human seral gamma-globulin preparations

In order to study the potential risk of transferring HIV through human seral gamma-globulin preparations (immunoglobulin), indirect immunofluorescent antibody test (IFA) and Western Blot (WB) assay were applied to 343 random samples (sera) with previous injection of imported human seral gamma-globulins (Ig) positive for Human Immunodeficiency Virus (HIV) antibodies between 1981-1987 for the detection of HIV antibodies. All results were negative and tests on all 23 controls who had previously received Ig made in China also gave negative results. However all 12 batches of imported Ig collected from the above-mentioned users, were positive for HIV antibodies when tested by WB and IFA. This study shows that under normal conditions, human seral gamma-globulin does not transmit HIV.

Expression in Escherichia coli of the Bacillus subtilis neutral protease gene (NPRE) lacking its ribosome binding site

Bacillus subtilis neutral protease (NprE) is first produced as a precursor, pre-pro-NprE, which consists of a signal peptide or prepeptide for secretion (27 amino acid residues) and a pro-peptide (194 amino acid residues) between the signal peptide and the mature protease. While the wildtype nprE gene could not be maintained in Escherichia coli, we have been able to show that expression and secretion of the neutral protease can be achieved from the nprE gene when its ribosome binding site (RBS) is removed. The results suggest that the failure to observe expression of the wildtype nprE gene is due to the lytic effect of the nprE gene product on E. coli host cells and that translation initiation in E. coli can be achieved even in the absence of a classical ribosome binding site.

Inhibition of leukocyte chemotaxis by immunosuppressive agents. Specific inhibition of lymphocyte chemotaxis by cyclosporine

Since chemotaxis is an important mechanism by which leukocytes are recruited to allografts during rejection, the effect of immunosuppressant agents on in vitro chemotactic responses of neutrophils, monocytes, and lymphocytes was studied. Cyclosporine caused profound inhibition of lymphocyte chemotaxis to three different chemotactic factors at pharmacologic levels but had no effect on neutrophil or monocyte chemotaxis. Methylprednisolone and azathioprine both inhibited chemotactic responses of neutrophils and monocytes as well as lymphocytes. These data suggest that immunosuppressant agents are potent inhibitors of leukocyte chemotaxis and that drugs differ as to which leukocyte cell type they inhibit. The selective action of cyclosporine might explain why this drug is ineffective in reversing established rejection episodes in which monocytes and neutrophils are also involved. Inhibition of leukocyte chemotaxis may be an important mode of action of immunosuppressant drugs, and drug regimes might be adjusted to cause selective inhibition of particular cell types.