Intranasal oxytocin suppresses seizure-like behaviors in a mouse model of NGLY1 deficiency

NGLY1 deficiency is a genetic disease caused by biallelic mutations of the Ngly1 gene. Although epileptic seizure is one of the most severe symptoms in patients with NGLY1 deficiency, preclinical studies have not been conducted due to the lack of animal models for epileptic seizures in NGLY1 deficiency. Here, we observed the behaviors of male and female Ngly1-/- mice by video monitoring and found that these mice exhibit spontaneous seizure-like behaviors. Gene expression analyses and enzyme immunoassay revealed significant decreases in oxytocin, a well-known neuropeptide, in the hypothalamus of Ngly1-/- mice. Seizure-like behaviors in Ngly1-/- mice were transiently suppressed by a single intranasal administration of oxytocin. These findings suggest the therapeutic potential of oxytocin for epileptic seizure in patients with NGLY1 deficiency and contribute to the clarification of the disease mechanism.

Orexin 2 receptor-selective agonist danavorexton (TAK-925) promotes wakefulness in non-human primates and healthy individuals

The orexin 2 receptor-selective agonist danavorexton (TAK-925) has been shown to produce wake-promoting effects in wild-type mice, narcolepsy-model mice, and individuals with narcolepsy type 1 and type 2. Here, we report wake-promoting effects of danavorexton in non-human primates and healthy men during their sleep phase. Electroencephalogram analyses revealed that subcutaneous administration of danavorexton significantly increased wakefulness in common marmosets (p < 0.05 at 0.1 mg kg-1 , and p < 0.001 at 1 mg kg-1 and 10 mg kg-1 ) and cynomolgus monkeys (p ≤ 0.05 at 1 mg kg-1 and 3 mg kg-1 ). In a phase 1b crossover, randomized, double-blind, placebo-controlled and active-controlled study in sleep-deprived healthy participants (ClinicalTrials.gov identifier: NCT03522506), modafinil 300 mg (used to demonstrate assay sensitivity) and continuous infusion of danavorexton 44 mg and danavorexton 112 mg showed statistically superior wake-promoting effects to placebo (n = 18). Measured using the Maintenance of Wakefulness Test, mean (standard deviation) sleep latencies during infusion of danavorexton 44 mg, danavorexton 112 mg and placebo were 21.4 (8.9), 31.8 (3.2) and 9.2 (6.4) min, respectively. Least-squares mean difference from placebo in average sleep latency was 16.8 min with danavorexton 44 mg and 30.2 min with danavorexton 112 mg (both p < 0.001). Karolinska Sleepiness Scale scores were statistically significantly lower (indicating decreased sleepiness) for participants receiving danavorexton than for those receiving placebo during infusion (danavorexton 44 mg, p = 0.010; danavorexton 112 mg, p < 0.001). Together, these results indicate that an orexin 2 receptor agonist increases wakefulness in non-human primates and healthy individuals during their sleep phase.

The miR-124-AMPAR pathway connects polygenic risks with behavioral changes shared between schizophrenia and bipolar disorder

Schizophrenia (SZ) and bipolar disorder (BP) are highly heritable major psychiatric disorders that share a substantial portion of genetic risk as well as their clinical manifestations. This raises a fundamental question of whether, and how, common neurobiological pathways translate their shared polygenic risks into shared clinical manifestations. This study shows the miR-124-3p-AMPAR pathway as a key common neurobiological mediator that connects polygenic risks with behavioral changes shared between these two psychotic disorders. We discovered the upregulation of miR-124-3p in neuronal cells and the postmortem prefrontal cortex from both SZ and BP patients. Intriguingly, the upregulation is associated with the polygenic risks shared between these two disorders. Seeking mechanistic dissection, we generated a mouse model that upregulates miR-124-3p in the medial prefrontal cortex. We demonstrated that the upregulation of miR-124-3p increases GRIA2-lacking calcium-permeable AMPARs and perturbs AMPAR-mediated excitatory synaptic transmission, leading to deficits in the behavioral dimensions shared between SZ and BP.

Discovery of TAK-925 as a Potent, Selective, and Brain-Penetrant Orexin 2 Receptor Agonist

TAK-925, a potent, selective, and brain-penetrant orexin 2 receptor (OX2R) agonist, [methyl (2R,3S)-3-((methylsulfonyl)amino)-2-(((cis-4-phenylcyclohexyl)oxy)methyl)piperidine-1-carboxylate, 16], was identified through the optimization of compound 2, which was discovered by a high throughput screening (HTS) campaign. Subcutaneous administration of compound 16 produced wake-promoting effects in mice during the sleep phase. Compound 16 (TAK-925) is being developed for the treatment of narcolepsy and other related disorders.

From population to neuron: exploring common mediators for metabolic problems and mental illnesses

Major mental illnesses such as schizophrenia (SZ) and bipolar disorder (BP) frequently accompany metabolic conditions, but their relationship is still unclear, in particular at the mechanistic level. We implemented an approach of "from population to neuron", combining population-based epidemiological analysis with neurobiological experiments using cell and animal models based on a hypothesis built from the epidemiological study. We characterized high-quality population data, olfactory neuronal cells biopsied from patients with SZ or BP, and healthy subjects, as well as mice genetically modified for insulin signaling. We accessed the Danish Registry and observed (1) a higher incidence of diabetes in people with SZ or BP and (2) higher incidence of major mental illnesses in people with diabetes in the same large cohort. These epidemiological data suggest the existence of common pathophysiological mediators in both diabetes and major mental illnesses. We hypothesized that molecules associated with insulin resistance might be such common mediators, and then validated the hypothesis by using two independent sets of olfactory neuronal cells biopsied from patients and healthy controls. In the first set, we confirmed an enrichment of insulin signaling-associated molecules among the genes that were significantly different between SZ patients and controls in unbiased expression profiling data. In the second set, olfactory neuronal cells from SZ and BP patients who were not pre-diabetic or diabetic showed reduced IRS2 tyrosine phosphorylation upon insulin stimulation, indicative of insulin resistance. These cells also displayed an upregulation of IRS1 protein phosphorylation at serine-312 at baseline (without insulin stimulation), further supporting the concept of insulin resistance in olfactory neuronal cells from SZ patients. Finally, Irs2 knockout mice showed an aberrant response to amphetamine, which is also observed in some patients with major mental illnesses. The bi-directional relationships between major mental illnesses and diabetes suggest that there may be common pathophysiological mediators associated with insulin resistance underlying these mental and physical conditions.

Ulk2 controls cortical excitatory-inhibitory balance via autophagic regulation of p62 and GABAA receptor trafficking in pyramidal neurons

Autophagy plays an essential role in intracellular degradation and maintenance of cellular homeostasis in all cells, including neurons. Although a recent study reported a copy number variation of Ulk2, a gene essential for initiating autophagy, associated with a case of schizophrenia (SZ), it remains to be studied whether Ulk2 dysfunction could underlie the pathophysiology of the disease. Here we show that Ulk2 heterozygous (Ulk2+/-) mice have upregulated expression of sequestosome-1/p62, an autophagy-associated stress response protein, predominantly in pyramidal neurons of the prefrontal cortex (PFC), and exhibit behavioral deficits associated with the PFC functions, including attenuated sensorimotor gating and impaired cognition. Ulk2+/- neurons showed imbalanced excitatory-inhibitory neurotransmission, due in part to selective down-modulation of gamma-aminobutyric acid (GABA)A receptor surface expression in pyramidal neurons. Genetically reducing p62 gene dosage or suppressing p62 protein levels with an autophagy-inducing agent restored the GABAA receptor surface expression and rescued the behavioral deficits in Ulk2+/- mice. Moreover, expressing a short peptide that specifically interferes with the interaction of p62 and GABAA receptor-associated protein, a protein that regulates endocytic trafficking of GABAA receptors, also restored the GABAA receptor surface expression and rescued the behavioral deficits in Ulk2+/- mice. Thus, the current study reveals a novel mechanism linking deregulated autophagy to functional disturbances of the nervous system relevant to SZ, through regulation of GABAA receptor surface presentation in pyramidal neurons.

BTZO-2, an antioxidant response element-activator, provides protection against lethal endotoxic shock in mice

We recently reported a unique antioxidant response element (ARE)-activator, BTZO-1, which induced expression of cytoprotective proteins such as heme oxygenase-1 (HO-1) and suppressed oxidative stress-induced cardiomyocyte apoptosis via binding to macrophage migration inhibitory factor (MIF). HO-1 induction and apoptosis inhibition have been reported to improve the outcomes following experimental sepsis by protecting the organs. Therefore, we investigated the potential of BTZO-2, an active BTZO-1 derivative, as a drug for sepsis. BTZO-2 significantly protected mice from the endotoxic shock induced by 5mg/kg lipopolysaccharide (LPS); survival rates increased from 42% to 100%. In contrast, BTZO-2 did not provide significant protection to mice from the shock induced by 10 μg/kg LPS together with d-galactosamine (d-GalN, hepatocyte-specific transcription inhibitor) (LPS/d-GalN). Hepatic HO-1 protein was up-regulated by BTZO-2 in mice injected with 5mg/kg LPS, but not in those injected with 10 μg/kg LPS/d-GalN. Interestingly, BTZO-2 showed little or no effect on LPS-induced up-regulation of plasma cytokine levels in mice. Thus, the organ protection mediated by HO-1 may have a pivotal role in the pharmacological effect of BTZO-2. These results suggest that BTZO-2 is a promising compound for a novel drug for sepsis.

BTZO-15, an ARE-activator, ameliorates DSS- and TNBS-induced colitis in rats

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders that are primarily represented by ulcerative colitis and Crohn's disease. The etiology of IBD is not well understood; however, oxidative stress is considered a potential etiological and/or triggering factor for IBD. We have recently reported the identification of BTZO-1, an activator of antioxidant response element (ARE)-mediated gene expression, which protects cardiomyocytes from oxidative stress-induced insults. Here we describe the potential of BTZO-15, an active BTZO-1 derivative for ARE-activation with a favorable ADME-Tox profile, for the treatment of IBD. BTZO-15 induced expression of heme oxygenase-1 (HO-1), an ARE-regulated cytoprotective protein, and inhibited NO-induced cell death in IEC-18 cells. Large intestine shortening, rectum weight gain, diarrhea, intestinal bleeding, and an increase in rectal myeloperoxidase (MPO) activity were observed in a dextran sulfate sodium (DSS)-induced colitis rat model. Oral administration of BTZO-15 induced HO-1 expression in the rectum and attenuated DSS-induced changes. Furthermore BTZO-15 reduced the ulcerated area and rectal MPO activity in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rats without affecting rectal TNF-α levels. These results suggest that BTZO-15 is a promising compound for a novel IBD therapeutic drug with ARE activation properties.

BTZO-1, a cardioprotective agent, reveals that macrophage migration inhibitory factor regulates ARE-mediated gene expression

In a screening program to discover therapeutic drugs for heart diseases, we identified BTZO-1, a 1,3-benzothiazin-4-one derivative, which activated antioxidant response element (ARE)-mediated gene expression and suppressed oxidative stress-induced cardiomyocyte apoptosis in vitro. An active BTZO-1 derivative for ARE-activation protected heart tissue during ischemia/reperfusion injury in rats. Macrophage migration inhibitory factor (MIF), which is known to protect cells from oxidative insult, was identified as a specific BTZO-1-binding protein. BTZO-1 binds to MIF with a K(d) of 68.6 nM, and its binding required the intact N-terminal Pro1. MIF, in the presence of BTZO-1, activated the glutathione S-transferase Ya subunit (GST Ya) gene ARE, whereas reduction of cellular MIF protein levels by siRNA suppressed BTZO-1-induced GST Ya expression. These results suggest that BTZO-1 activates the GST Ya gene ARE by interacting with MIF.

ITZ-1, a client-selective Hsp90 inhibitor, efficiently induces heat shock factor 1 activation

ITZ-1 is a chondroprotective agent that inhibits interleukin-1beta-induced matrix metalloproteinase-13 (MMP-13) production and suppresses nitric oxide-induced chondrocyte death. Here we describe its mechanisms of action. Heat shock protein 90 (Hsp90) was identified as a specific ITZ-1-binding protein. Almost all known Hsp90 inhibitors have been reported to bind to the Hsp90 N-terminal ATP-binding site and to simultaneously induce degradation and activation of its multiple client proteins. However, within the Hsp90 client proteins, ITZ-1 strongly induces heat shock factor-1 (HSF1) activation and causes mild Raf-1 degradation, but scarcely induces degradation of a broad range of Hsp90 client proteins by binding to the Hsp90 C terminus. These results may explain ITZ-1's inhibition of MMP-13 production, its cytoprotective effect, and its lower cytotoxicity. These results suggest that ITZ-1 is a client-selective Hsp90 inhibitor.

The chondroprotective agent ITZ-1 inhibits interleukin-1beta-induced matrix metalloproteinase-13 production and suppresses nitric oxide-induced chondrocyte death

In a screening program aimed at discovering anti-osteoarthritis (OA) drugs, we identified an imidazo[5,1-c][1,4]thiazine derivative, ITZ-1, that suppressed both interleukin-1beta (IL-1beta)-induced proteoglycan and collagen release from bovine nasal cartilage in vitro and suppressed intra-articular infusion of IL-1beta-induced cartilage proteoglycan degradation in rat knee joints. ITZ-1 did not inhibit enzyme activities of various matrix metalloproteinases (MMPs), which have pivotal roles in cartilage degradation, while it selectively inhibited IL-1beta-induced production of MMP-13 in human articular chondrocytes (HAC). IL-1beta-induced MMP production has been shown to be mediated by extracellular signal-regulated protein kinase (ERK), p38 kinase, and c-Jun N-terminal kinase (JNK) of the mitogen-activated protein kinase (MAPK) family signal transduction molecules. An ERK-MAPK pathway inhibitor (U0126), but not a p38 kinase inhibitor (SB203580) or a JNK inhibitor (SP600125), also selectively inhibited IL-1beta-induced MMP-13 production in HAC. Furthermore, ITZ-1 selectively inhibited IL-1beta-induced ERK activation without affecting p38 kinase and JNK activation, which may account for its selective inhibition of MMP-13 production. Inhibition of nitric oxide (NO)-induced chondrocyte apoptosis has been another area of interest as a therapeutic strategy for OA, and ITZ-1 also suppressed NO-induced death in HAC. These results suggest that ITZ-1 is a promising lead compound for a disease modifying anti-OA drug program.

AAT-1, a novel testis-specific AMY-1-binding protein, forms a quaternary complex with AMY-1, A-kinase anchor protein 84, and a regulatory subunit of cAMP-dependent protein kinase and is phosphorylated by its kinase

AMY-1 has been identified by us as a c-Myc-binding protein and was found to stimulate c-Myc transcription activity. AMY-1 was also found to be associated with protein kinase A anchor protein 84/149 (S-AKAP84/AKAP149) in the mitochondria in somatic cells and sperm, suggesting that it plays a role in spermatogenesis. To determine the molecular function of AMY-1, a two-hybrid screening of cDNAs encoding AMY-1-binding proteins was carried out with AMY-1 as a bait using a human testis cDNA library, and a clone encoding a novel protein, AAT-1, was obtained. Three isoforms of AAT-1, AAT-1alpha, -beta, and -gamma, were found to be derived from an alternative splicing of the transcripts of the aat-1 gene, which was mapped at human chromosome 3q13-3q21. AAT-1 was found to be specifically expressed in the testis during the course of spermatogenesis and also to be present in the spermatid and mature sperm, as was AMY-1. AAT-1alpha was found to bind to and be colocalized in mitochondria with AMY-1 in human HeLa and mouse GC-1 cells. Furthermore, AAT-1alpha was found to bind to the N-terminal half of S-AKAP84/AKAP149 in a quaternary complex with AMY-1 and a regulatory subunit (RII) of cAMP-dependent kinase (PKA), in which AAT-1alpha was associated with RII via S-AKAP84/AKAP149, in rat testis and HeLa cells. It was then found that AAT-1alpha weakly stimulated a phosphorylation activity of PKA and also that AAT-1 itself was phosphorylated by PKA in vivo and in vitro. These results suggest that both AAT-1 and AMY-1 play roles in spermatogenesis.

AMAP-1, a novel testis-specific AMY-1-binding protein, is differentially expressed during the course of spermatogenesis

AMY-1 has been identified by us as a c-Myc-binding protein and was found to stimulate c-Myc transcription activity. AMY-1 was also found to be associated with AKAP84/149 in the mitochondria in somatic cells and sperm, suggesting that it plays a role in spermatogenesis. To access the molecular function of AMY-1, a two-hybrid screening of cDNAs encoding AMY-1-binding proteins was carried out with AMY-1 as a bait using a human testis cDNA library, and a clone encoding a novel protein, AMAP-1, was obtained. The amap-1 gene was mapped at human chromosome 17q21. AMY-1 was found to bind to and be colocalized with AMAP-1 in human 293T and HeLa cells. AMAP-1 was found to be specifically expressed in the testis and expressed post-meiotically in the testis, as was AMY-1. These results suggest that both AMAP-1 and AMY-1 play roles in spermatogenesis.

Mycobacterium bovis bacillus calmette-guérin induces protective immunity against infection by Plasmodium yoelii at blood-stage depending on shifting immunity toward Th1 type and inducing protective IgG2a after the parasite infection

Bacillus calmette-guérin (BCG)-vaccination raised dramatically the survival rates of A/J mice from infection by Plasmodium yoelii 17XL at blood-stage. The analysis of the immune response of spleen cells indicated that BCG vaccination biased the immune response toward Th1 type. Neutralization of IFN-gamma and nitric oxide abrogated the protection. The kinetics of Ab production in the course of P. yoelii 17XL infection was monitored. Surprisingly, larger amounts of parasite-specific Abs were produced in BCG-vaccinated mice than in the placebo control. The vast majority of the produced IgG against parasites in BCG-vaccinated mice was IgG2a, which was observed hardly in placebo controls. The peak of IgG2a production coincided with the clearance of infection. The naive mice transferred adoptively with IgG2a from self-cured mice survived the lethal challenge from the parasite. These data indicated that BCG vaccination protected A/J mouse from P. yoelii 17XL infection by biasing immunity toward Th1-type after parasite infection and enhancing production of IgG2a, which ultimately played a major role in protection.

The gene encoding mycobacterial DNA-binding protein I (MDPI) transformed rapidly growing bacteria to slowly growing bacteria

Pathogenic species of Mycobacterium are slowly growing intracellular bacteria. Slow growth is important for the parasitism of these organisms and chronicity of the disease, but its precise mechanism has not been elucidated. Recently, we found that a novel DNA-binding protein (MDPI) was expressed (7-10% in total protein) in mycobacteria, such as Mycobacterium bovis bacillus Calmette-Guérin, Mycobacterium tuberculosis, and Mycobacterium leprae. In this study, we observed that MDPI interfered with replication, transcription, and translation in the analysis in in vitro E. coli cell-free macromolecular biosynthesizing systems. Furthermore, MDPI inhibited the rapid growth of both Escherichia coli and Mycobacterium smegmatis, and NH(2)-terminal second amino acid, asparagine, was observed to be important in terms of this function. These data suggest an important role of MDPI for suppression of growth rates of mycobacteria.

Identification of a novel DNA-binding protein from Mycobacterium bovis bacillus Calmette-Guérin

A novel DNA-binding protein expressed (8-10% in total protein) in Mycobacterium bovis bacillus Calmette-Guérin was observed. This protein was designated mycobacterial DNA-binding protein 1 (MDP1). MDP1 recognized bases, sugar moieties, phosphate-backbone on DNA and preferentially bound to DNA guanine and cytosine. In the gel retardation assay, MDP1 preferentially bound to closed circular plasmid DNA than open circular and linear form plasmid DNA and also bound to RNA. MDP1 formed a highly polymerized structure and localized not only in the nucleoid but also at the 50S ribosomal subunits and cell surface. MDP1 was conserved in Mycobacterium thus far examined and the expression was enhanced in stationary growth phases. These results will provide a reasonable basis for further study of the function of MDP1 in living mycobacteria.

Long-lasting protective immunity against rodent malaria parasite infection at the blood stage by recombinant BCG secreting merozoite surface protein-1

Previously, we constructed a recombinant live BCG (rBCG) secreting a 15 kDa C-terminal region of MSP-1 from Plasmodium yoelii (MSP-1(15)) and succeeded in the induction of more efficient protective immunity against parasite infection than observed with artificial adjuvants (Matsumoto S, Yukitake H, Kanbara H, Yamada T. Recombinant Mycobacterium bovis bacillus Calmette-Guerin secreting merozoite surface protein 1 (MSP-1) induces protection against rodent malaria parasite infection depending on MSP-1-stimulated interferon gamma and parasite-specific antibodies. J Exp Med 1998;188:845-54 [1]). In this study, we examined the endurance of the protective effects. The protective effect generated by rBCGMSP-1(15) was observed even 9 months after final immunization, whereas the effects of immunization by MSP-1(15) together with incomplete Freund adjuvant (IFA) were found to last only 4 months.

Host immune responses to ribosome, ribosomal proteins, and RNA from Mycobacterium bovis bacille de Calmette-Gúerin

The ribosomes from BCG strongly induced delayed type hypersensitivity (DTH) skin reactions in guinea pigs immunized with live BCG or heat killed Mycobacterium tuberculosis H37Rv, and also induced lymphocyte proliferative response in mice immunized with ribosomes. In contrast, neither ribosomal proteins nor RNA alone induced both DTH skin reactions and lymphocyte proliferative responses. Particle form consisted of ribosomal proteins and RNAs might be absolutely required for the activation of immune responses.

Recombinant Mycobacterium bovis bacillus Calmette-Guérin secreting merozoite surface protein 1 (MSP1) induces protection against rodent malaria parasite infection depending on MSP1-stimulated interferon gamma and parasite-specific antibodies

The merozoite surface protein 1 (MSP1) has emerged as a leading malaria vaccine candidate at the erythrocytic stage. Recombinant bacillus Calmette-Guérin (rBCG), which expressed a COOH-terminal 15-kD fragment of MSP1 of Plasmodium yoelii (MSP1-15) as a fusion protein with a secretory protein of Mycobacterium kansasii, was constructed. Immunization of mice with this rBCG induced a higher degree of protection against blood-stage parasite infection than with recombinant MSP1-15 in the RIBI adjuvant (RIBI ImmunoChem Research, Inc., Hamilton, MT) or incomplete Freund's adjuvant systems. We studied the mechanism of protection induced by MSP1-15, and found that interferon (IFN)-gamma had a major role in protection in all adjuvant systems we examined. Mice that produced low amounts of MSP1-15 stimulated IFN-gamma and could not control parasite infection. The antibody against MSP1-15 did not play a major role in protection in this system. After parasite infection, immunoglobulin G2a antibodies, which had been produced by IFN-gamma stimulation, were induced and subsequently played an important role in eradicating parasites. Thus, both cellular and humoral immune responses were essential for protection from malaria disease. These data revealed that BCG is a powerful adjuvant to induce such a protective immune response against malaria parasites.

Shotgun cloning and characterization of the thymidylate synthase-encoding gene from Mycobacterium bovis BCG

The shotgun cloning of a Mycobacterium bovis BCG (BCG) genome into pBluescript SK (+) successfully yielded a 0.9 kbp fragment, confirming the ability of Escherichia coli thyA mutant MH2702 to grow in a thymine-depleted medium. This DNA fragment contained a gene homologous to the thymidylate synthase (TS)-encoding genes (thyA) of other organisms. An inverted repeat sequence and open reading frame (ORF) were observed at the upstream region of the thyA. A computer analysis revealed that the protein encoded by this ORF possessed a structure unique for a DNA binding protein.

Inhibition of multiplication of Mycobacterium leprae in mouse foot pads by immunization with ribosomal fraction and culture filtrate from Mycobacterium bovis BCG

Immunization of mice with the ribosomal fraction from ruptured Mycobacterium bovis Bacillus Calmette-Guérin (BCG) and the culture filtrate reduced remarkably the multiplication of Mycobacterium leprae in the foot pads of mice. This is the first reported case of the protective activity against M. leprae multiplication in mice of the BCG ribosomal fraction and culture filtrate. The inhibition was more evident with the culture filtrate than with the ribosomal fraction. When the ribosomal proteins separated from ribosomal RNA were injected into mice, only slight inhibition was observed. Ribosomal RNA alone did not inhibit at all, in contrast to the conclusion reported by Youmans and Youmans.

Long-lasting immune response induced by recombinant bacillus Calmette-Guérin (BCG) secretion system

The recombinant bacillus Calmette-Guérin (rBCG) secretion system utilizing an extracellular alpha antigen of Mycobacterium kansasii (alpha-K) was characterized biochemically and immunologically. The human immunodeficiency virus type 1 (HIV-1) p17gag B cell epitope fused to alpha-K was secreted in extremely large amounts. At least three mice out of seven inoculated with rBCG generated high titres of antibody to the epitope. The long-lasting antibody production persisted more than 14 months.

A stable Escherichia coli-mycobacteria shuttle vector 'pSO246' in Mycobacterium bovis BCG

The most widely used plasmid vector system in mycobacteria is based on pAL5000 from Mycobacterium fortuitum. The derivatives of the pAL5000-based shuttle vectors between Escherichia coli and mycobacteria, which we have utilized to secrete recombinant antigens, were generated. The stability of the vectors was assessed in Mycobacterium bovis BCG (BCG). The plasmid vector pSO246 was stable in BCG for at least 50 generations.

[The role of some cellular components of bacterial parasites in determining the incidence of tuberculosis: studies on mycobacterial antigens, with special reference to mycobacterial immunoreactive ribosomal and secreted proteins]

Tuberculosis remains as major disease, affecting more than 20 million people. The elimination of the disease with vaccination, rapid diagnosis, and and efficient therapy is an important objective of our study. To realize the objective, the characterization of antigens is essential. We have chosen two kinds of antigens for our study, the ribosomal antigens and and an antigenic proteins secreted by mycobacteria. The biochemical and immunological characterization of ribosomal fraction was carried out. Ribosomal proteins were purified and assessed for DTH reaction. The N-terminal amino acids sequences were determined. Total structures of S19, S7 and S12 in 30S and L7/L12 in 50S subunits were elucidated. L7/L12 had 66% homology with analogue from S. griseus which showed GTPase activity in protein synthesis. This protein was secreted in culture medium and induced strong DTH. Secreted antigenic proteins are of great interest for us. Secreted antigens may be recognized rapidly by immune system and therefore may induce rapid and high level immune response. It is also expected that it may contain protective antigens, since live BCG protect disease more efficiently than heat killed BCG. We have determined and published the total structure of four proteins (MPB64, MPB70, MPB57 and alpha antigen). We attempted to utilize this antigen for the diagnosis and the design of vaccine. The structures of alpha antigens from M. avium, M. intracellulare, M. scrofulaceum, M. kansasii and BCG were determined and its potential for application to diagnosis was presented. Using the operon of M. kansasii, alpha antigen and V3 region of HIV-1 were expressed by recombinant BCG which induced CTL in mice.

[Study on recombinant BCG]

For the purpose to establish the system to express foreign antigen from Mycobacterium bovis BCG. We have cloned, sequenced and expressed genes for secreting proteins, alpha antigen, MPB64, MPB57 and MPB70 from M. bovis BCG. The upstreams and structural genes were characterized. The gene for alpha antigen of Mycobacterium kansasii was also characterized. The gene for alpha antigen of M. kansasii (k-alpha) was chosen for the further study at first. This gene was fused with shuttle plasmid PIJ666-PAL5000 obtained from T. Kisser and transfected to M. bovis BCG (Tokyo). Transformant was obtained by a selection with kanamycin. It was able to secrete k-alpha antigen. DNA-containing a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 P17 gag was fused to this vector at C terminal of k-alpha. Using this vector, we have succeeded to express foreign antigen in M. bovis BCG. The products were analyzed in one or two dimensional electro-phoresis. The results thus obtained will be reported elsewhere.

Establishment of a foreign antigen secretion system in mycobacteria

In order to develop recombinant Mycobacterium bovis BCG into a useful multivaccine vehicle, we established a foreign antigen secretion system in mycobacteria in which an extracellular alpha antigen of Mycobacterium kansasii was utilized as a carrier. By using this system, a B-cell epitope (Glu-12-Leu-Asp-Arg-Trp-Glu-Lys-Ile-19) of human immunodeficiency virus type 1 p17gag, which was identified by a fusion protein-based method, has been successfully obtained from BCG along with the alpha antigen. This is the first report of expression and secretion of a foreign viral antigen from BCG. It is possible that the system can become a universal vaccination vehicle applicable to protection against various infectious diseases.

Attachment of Mycoplasma salivarium and Mycoplasma orale to glass surfaces

Mycoplasma salivarium ATCC 23064 and 24 other oral strains, and Mycoplasma orale ATCC 15539 and 22 other oral strains were examined quantitatively for attachment to glass surfaces by using ELISA method. Although all of the tested strains attached to glass surfaces, M. salivarium attached far more readily than M. orale. The results suggested that electrostatic bonds were involved in the attachment and that bivalent metal ions also played a role.

Hemagglutinating activity of Mycoplasma salivarium and its attachment to sheep red blood cells

Mycoplasma salivarium (ATCC 23064) and 10 other strains isolated from human saliva agglutinated red blood cells of rabbits and human types A and O weakly, and those of sheep (SRBC) and human type B strongly. Glycoproteins on the surface of the organism cells and N-acetylneuraminic acid residues and some sugars on SRBC were suggested to be involved in agglutination of SRBC. Protein A-like activity was detected in the organism cells. The organism cells were also shown to attach to SRBC in PPLO broth (Difco) supplemented with 10% horse serum, and bivalent metal ions were suggested to be involved in the attachment. The organism cells attaching to SRBC activated complement through the alternative pathway and lyzed the SRBC.