Phase I and II randomized clinical trial of an oral therapeutic vaccine targeting human papillomavirus for treatment of cervical intraepithelial neoplasia 2 and 3.

BACKGROUND: Although many human papillomavirus (HPV)-targeted therapeutic vaccines have been examined for efficacy in clinical trials, none have been translated into clinical use. These previous agents were mostly administered by intramuscular or subcutaneous injection to induce systemic immunity. We investigated the safety and therapeutic efficacy of an HPV-16 E7-expressing lacticaseibacillus-based oral vaccine. METHODS: In a double-blind, placebo-controlled, randomized trial, a total of 165 patients with HPV-16-positive high-grade cervical intraepithelial neoplasia 2 and 3 were assigned to orally administered placebo or low, intermediate, or high doses of IGMKK16E7 (lacticaseibacillus paracasei expressing cell surface, full-length HPV-16 E7). In the 4 groups, IGMKK16E7 or placebo was administered orally at weeks 1, 2, 4, and 8 postenrollment. The primary outcomes included histopathological regression and IGMKK16E7 safety. RESULTS: In per-protocol analyses, histopathological regression to normal (complete response) occurred in 13 (31.7%) of 41 high-dose recipients and in 5 (12.5%) of 40 placebo recipients (rate difference = 19.2, 95% confidence interval [CI] = 0.5 to 37.8). In patients positive for HPV-16 only, the clinical response rate was 40.0% (12 of 30) in high-dose recipients and 11.5% (3 of 26) in recipients of placebo (rate difference = 28.5, 95% CI = 4.3 to 50.0). There was no difference in adverse events that occurred in the high-dose and placebo groups (P = .83). The number of HPV-16 E7-specific interferon-γ producing cells within peripheral blood increased with level of response (stable disease, partial, and complete responses; P = .004). The regression to normal (complete response) rates among recipients with high levels of immune response were increased in a dose-dependent manner. CONCLUSION: This trial demonstrates safety of IGMKK16E7 and its efficacy against HPV-16-positive cervical intraepithelial neoplasia 2 and 3. IGMKK16E7 is the first oral immunotherapeutic vaccine to show antineoplastic effects. TRIAL REGISTRATION: jRCT2031190034.

Negative chemotaxis of Ligilactobacillus agilis BKN88 against gut-derived substances.

Ligilactobacillus agilis is a motile lactic acid bacterium found in the gastrointestinal tracts of animals. The findings of our previous study suggest that the motility of L. agilis BKN88 enables gut colonization in murine models. However, the chemotactic abilities of motile lactobacilli remain unknown. This study aimed to identify the gut-derived chemoeffectors and their corresponding chemoreceptors in L. agilis BKN88. Chemotaxis assays with chemotactic and non-chemotactic (ΔcheA) L. agilis strains revealed that low pH, organic acids, and bile salts served as repellents. L. agilis BKN88 was more sensitive to bile and acid than the gut-derived non-motile lactobacilli, implying that L. agilis might utilize motility and chemotaxis instead of exhibiting stress tolerance/resistance. L. agilis BKN88 contains five putative chemoreceptor genes (mcp1-mcp5). Chemotaxis assays using a series of chemoreceptor mutants revealed that each of the five chemoreceptors could sense multiple chemoeffectors and that these chemoreceptors were functionally redundant. Mcp2 and Mcp3 sensed all tested chemoeffectors. This study provides further insights into the interactions between chemoreceptors and ligands of motile lactobacilli and the unique ecological and evolutionary features of motile lactobacilli, which may be distinct from those of non-motile lactobacilli.

Campylobacter spp. prevalence and fluoroquinolone resistance in chicken layer farms.

Chicken is a major source of human campylobacteriosis. Chicken meat originates not only from broilers but also from spent layers; however, few reports have documented the prevalence and antimicrobial resistance of Campylobacter spp. in layers in Japan. Therefore, we investigated the prevalence and antimicrobial susceptibility of Campylobacter spp. in 47 layer farms in Japan. Fecal samples were collected from the youngest and oldest flocks on the farm, and Campylobacter spp. was isolated from 46/47 (97.9%) farms. Among the C. jejuni isolates, the resistance rates to ampicillin, tetracycline, and ciprofloxacin were 29.6%, 22.2%, and 19.8%, respectively. The ciprofloxacin resistance rate (7.3%) in C. jejuni isolated from old flocks was significantly (P<0.01) lower than that in young flocks (32.5%).

A Placebo-Controlled, Double-Blind Randomized (Phase IIB) Trial of Oral Administration with HPV16 E7-Expressing Lactobacillus, GLBL101c, for the Treatment of Cervical Intraepithelial Neoplasia Grade 2 (CIN2).

Cervical intraepithelial neoplasia (CIN), a precursor lesion to cervical cancer, is caused by high-risk human papillomavirus (HPV); high-grade CIN lesions (CIN2-3) are precancerous and require treatment. No globally approved therapy is available for CIN2-3 treatment. This study is a placebo-controlled randomized clinical trial of GLBL101c treatment for CIN2 in 40 patients with HPV16-positive CIN2 who were 1:1 randomized to receive GLBL101c (1 g/daily) or placebo for 5 days at 1, 2, 4, and 8 weeks. No differences were noted between the GLBL101c and placebo groups for patient background and adverse events. Moreover, no statistically significant difference was noted between the two groups at the primary endpoint, pathological regression after 16 weeks of the first oral dose; however, only in the GLBL101c group, two patients had complete regression (CR; regression to normal within 16 weeks). IFNγ production was significantly correlated with the number of spots identified by the interferon gamma enzyme-linked immunospot (IFNγ-ELISPOT) assay using cervical lymphocytes (CxLs) or peripheral blood mononuclear cells. In the two cases of CR, E7-specific Th1 immune responses were observed at week 16. Therefore, we concluded as a novel Lactobacillus-based vaccine with stronger immunogenicity than GLBL101c should be developed.

Ligilactobacillus agilis BKN88 possesses thermo-/acid-stable heteropolymeric flagellar filaments.

Many flagellated bacteria possess multiple flagellins, but the roles and the compositions of each flagellin are diverse and poorly understood. In Ligilactobacillus agilis BKN88, there are two active flagellin gene paralogues but their function and composition in its flagellar filaments have not been described. The aim of this study is to find the function and composition of the flagellins by employing mutant strains each of which expresses a single flagellin or a modified flagellin. Two single flagellin-expressing strains were both flagellated while the number of flagella per cell in the single flagellin-expressing derivatives was lower than that in the wild type. Nonetheless, these derivative strains were apparently equally motile as the wild type. This indicates that either flagellin is sufficient for cell motility. The immunological activity via Toll-like receptor 5 of the single flagellin-expressing strains or purified single flagellins was readily detectable but mostly variably weaker than that of the wild type. The flagellar filaments of wild type L. agilis BKN88 were more acid-/thermo-stable than those of single flagellin-expressing derivatives. Using a combination of immunoprecipitation and flagellin-specific staining, wild type BKN88 appeared to possess heteropolymeric flagellar filaments consisting of both flagellins and each flagellin appeared to be equally distributed throughout the filaments. The results of this study suggest that the two flagellins together form a more robust filament than either alone and are thus functionally complementary.

Draft Genome Sequences of Non-H2S-Producing Strains of Salmonella enterica Serovars Infantis, Enteritidis, Berta, and Kiambu in Japan.

We report the draft genome sequences of six strains of Salmonella enterica serovars Berta, Enteritidis, Infantis, and Kiambu, isolated from humans or chicken meats in Osaka, Japan, that were negative for hydrogen sulfide production. Their genome sizes ranged from 4,460,389 to 4,933,483 bp, with 3 to 9 rRNAs and 64 to 73 tRNAs and with coverages of 95× to 159×.

PCR-based screening, isolation, and partial characterization of motile lactobacilli from various animal feces.

BACKGROUND: Most lactobacilli found in animal intestines are generally non-motile, but there are few exceptions. Our previous work showed that Lactobacillus agilis BKN88, which is a highly motile strain originating from a chicken, takes advantage of motility in gut colonization in murine models, and thus motile lactobacilli likely have unique ecological characteristics conferred by motility. However, the ecology and habitat of gut-derived motile lactobacilli are still rarely understood. In addition, the limited availability of motile Lactobacillus isolates is one of the major obstacles for further studies. To gain insight into the ecology and habitat of the motile lactobacilli, we established a routinely applicable detection method for motile lactobacilli using PCR and subsequent selective isolation in semi-solid MRS medium for the collection of additional motile lactobacilli from animal feces. RESULTS: We applied the PCR detection using motile lactobacilli-specific primers, based on the motor switch protein gene (fliG) of flagella, to 120 animal feces, followed by selective isolation performed using 45 animal feces. As a result, motile lactobacilli were detected in 44 animal feces. In the selective isolation, 29 isolates of L. agilis and 2 isolates of L. ruminis were obtained from 8 animal species. CONCLUSIONS: These results indicated that motile lactobacilli are distributed in different animal species. Moreover, phylogenetic analysis of the L. agilis isolates suggests co-evolution with the host, and adaptation to a particular environmental niche.

NADH peroxidase plays a crucial role in consuming H2O2 in Lactobacillus casei IGM394.

The facultative anaerobic bacterium Lactobacillus casei IGM394 is used as a host for drug delivery systems, and it exhibits the same growth rate under aerobic and anaerobic conditions. L. casei strains carry several genes that facilitate oxygen and reactive oxygen species (ROS) tolerance in their genomes, but their complete functions have not been uncovered. To clarify the oxygen and ROS tolerance mechanisms of L. casei IGM394, we constructed 23 deficient mutants targeting genes that confer oxidative stress resistance. Significantly decreased growth and high H2O2 accumulation were observed in the NADH peroxidase gene-mutated strain (Δnpr) compared with the findings in the wild type. The H2O2 degradation capacity of Δnpr revealed that NADH peroxidase is a major H2O2-degrading enzyme in L. casei IGM394. Interestingly, ΔohrR, a mutant deficient in the organic hydroperoxide (OhrA) repressor, exhibited higher H2O2 resistance than the wild-type strain. Increased Npr expression and H2O2 degradation ability were observed in ΔohrR, further supporting the importance of OhrA to ROS tolerance mechanisms. The other mutants did not exhibit altered growth rates, although some mutants had higher growth in the presence of oxygen. From these results, it is presumed that L. casei IGM394 has multiple oxygen tolerance mechanisms and that the loss of a single gene does not alter the growth rate because of the presence of complementary mechanisms. Contrarily, the H2O2 tolerance mechanism is solely dependent on NADH peroxidase in L. casei IGM394.

Adsorption of Tolaasins, the Toxins Behind Mushroom Bacterial Blotch, by Microbacterium spp. is Insufficient for Its Detoxification.

Tolaasins are lipodepsipeptides secreted by Pseudomonas tolaasii, the causal agent of bacterial blotch on several kinds of cultivated mushrooms. Our previous study reported on tolaasin detoxification by Microbacterium sp. K3-5 as a potential biocontrol of the disease. In this study, the tolaasin-detoxifying activities of various type strains of Microbacterium spp. were evaluated through chemical and biological assays. The bacterial cells of all tested strains of Microbacterium spp. showed tolaasin I-elimination from liquid phase. However, the toxin activities of tolaasins were still retained on the tolaasin-treated bacterial cells of all Microbacterium strains except M. foliorum NBRC 103072T. Furthermore, intact tolaasin I was recovered from the tolaasin-treated bacterial cells of all tested strains except M. foliorum NBRC 103072T. Our data reveal that Microbacterium spp. can be characterized as effective tolaasin I-eliminating bacteria through cell adsorption, but that this adsorption alone is insufficient for actual tolaasin detoxification. The biological degradation process must be needed to carry out the detoxification.

Comparative analysis of immunological properties of S-layer proteins isolated from Lactobacillus strains.

Previous studies have suggested that some Lactobacillus S-layer proteins could modulate immune responses. Primary structures of the S-layer proteins are variable, and their immunological differences are poorly understood. In this study, we evaluated the immunological properties of eight distinct S-layer proteins from different Lactobacillus species. We found that removal of the S-layer proteins from the cell surface reduced the immunological activities of Lactobacillus cells in THP-1 cells. Furthermore, the purified S-layer proteins induced the production of IL-12 p40, although their immunological activities varied between the different S-layer proteins. The production of IL-12 p40 was notably induced by the S-layer protein SLP(aly) from Lactobacillus amylolyticus NRIC 0558T. Multiple sequence alignment revealed that the percent identity of the S-layer proteins of the eight strains vary from 10 to 90 %. In particular, N-terminal regions showed high levels of diversity. To obtain more information about their structure and the immunogenicity, truncated and chimeric S-layer proteins were constructed in recombinant E. coli. Profiling of cytokine production in THP-1 cells by truncated and chimeric S-layer proteins suggested that the intact conformation of the N-terminal region of SLP(aly) contributes to high immunogenicity.

Identification of the novel hcbB operon catalyzing the dechlorination of pentachlorophenol in the Gram-positive bacterium Nocardioides sp. strain PD653.

While pcp genes are well known in Gram-negative bacteria to code for the enzymes responsible for pentachlorophenol (C6HCl5O; PCP) degradation, little is known about PCP-degrading genes in Gram-positive bacteria. Here we describe a novel gene operon possibly responsible for catalyzing the degradation of PCP in the Gram-positive bacterium Nocardioides sp. strain PD653, which is capable of mineralizing hexachlorobenzene (C6Cl6; HCB) via PCP. Transcriptome analysis based on RNA-Seq revealed overexpressed genes in strain PD653 following exposure to HCB. Based on in silico annotation, three open reading frames (ORFs) were selected as biodegrading enzyme candidates. Recombinant E. coli cells expressing candidate genes degraded approximately 9.4 µmol L-1 PCP in 2 hr. Therefore, we designated these genes as hcbB1, hcbB2, and hcbB3. Interestingly, PCP-degrading activity was recorded when hcbB3 was coexpressed with hcbB1 or hcbB2, and the function of HcbB3 was expected to be similar to chlorophenol 4-monooxygenase (TftD).

Treatment with Lactobacillus Retards the Tumor Growth of Head and Neck Squamous Cell Carcinoma Cells Inoculated in Mice.

Bacteria have been used for more than a century to treat solid tumors. Because solid tumors generate an anaerobic environment, we evaluated the anti-tumor effect of the obligate anaerobe strain KK378, derived from Lactobacillus casei (L. casei), using mice bearing head and neck cancer. Wild-type L. casei is a nonpathogenic bacterium that is commonly used in foods. Moreover, patients with head and neck squamous cell carcinoma often have multiple cancers and cervical lymph node metastasis that can be directly sensed beneath the skin. To establish the animal model bearing head and neck cancer, we inoculated each of human squamous cell carcinoma cell lines, SAS, HSQ89, and HSC2, on the back skin of BALB/cSlc-nu/nu mice. After tumor formation, L. casei KK378 was administered directly into the tumor, and tumor size and serum cytokine levels were analyzed. Mice injected with 108 cfu of L. casei KK378 showed reduction in tumor growth compared with PBS control; especially, the SAS tumor was significantly reduced (p = 0.008). Administered L. casei KK378 was detected in tumor tissues but not in normal tissues (liver, kidney, and lung) of SAS tumor-bearing mice, which was associated with increased blood cytokines (TNF-α, IFN-γ, IL-5, IL-10, and IL-12). Among these cytokines, the serum levels of IFN-γ and TNF-α were significantly increased (p < 0.05). In conclusion, L. casei KK378 infection may suppress tumor growth by inducing the host immune response. Direct injection of Lactobacillus into the tumor could be a potential strategy to treat head and neck squamous cell carcinoma.

The impact of motility on the localization of Lactobacillus agilis in the murine gastrointestinal tract.

BACKGROUND: While the overall composition of the mammalian gut microbiota has been intensively studied, the characteristics and ecologies of individual gut species are incompletely understood. Lactobacilli are considered beneficial commensals in the gastrointestinal mucosa and are relatively well-studied except for the uncommon species which exhibit motility. In this study, we evaluate the importance of motility on gut colonization by comparing motile and non-motile strains of Lactobacillus agilis in mice models. RESULTS: A flagellated but non-motile L. agilis strain was constructed by mutation of the motB gene. Colonization of the wild type and the mutant strain was assessed in both antibiotic-treated female Balb/c mice and gnotobiotic mice. The results suggest that the motile strain is better able to persist and/or localize in the gut mucosa. Chemotaxis assays indicated that the motile L. agilis strain is attracted by mucin, which is a major component of the intestinal mucus layer in animal guts. CONCLUSIONS: Motility and chemotactic ability likely confer advantages in gut colonization to L. agilis. These findings suggest that the motile lactobacilli have unique ecologies compared to non-motile commensals of the lactic acid bacteria.

Optimization of human papillomavirus (HPV) type 16 E7-expressing lactobacillus-based vaccine for induction of mucosal E7-specific IFNγ-producing cells.

Therapeutic HPV vaccine is an agent to induce E7-specific Th1 immune responses to treat cervical neoplasia (CIN2-3). Our previous clinical trial has demonstrated that oral administration of HPV16 E7-expressing Lactobacillus casei (L. casei), GLBL101c, resulted in the regression of HPV16-related CIN3. Here we examined optimization of the E7-expressing L. casei for induction of the mucosal immune responses to E7. Various doses of HPV16 E7 molecule were displayed on the L. casei. Immunization with E7-bound L. casei showed the induction of E7-specific mucosal IFNγ-producing cells was dependent on displayed E7-doses but saturated beyond 0.3 µg/108 cells. A new agent, L. casei with endogenous expression of E7 (IGMKK16E7), showed the optimal amount of displayed-E7. Immunization with IGMKK16E7 demonstrated 4-fold higher induction of E7-specific mucosal IFNγ-producing cells when compared with the former one. Our new system provided the optimal E7-expressing L. casei for displayed-E7 amount and induction of mucosal Th1 immune response.

Detoxification process of tolaasins, lipodepsipeptides, by Microbacterium sp. K3-5.

Tolaasins are antimicrobial lipodepsipeptides. Here, we report the tolaasins-detoxifying properties of Microbacterium sp. K3-5 (K3-5). The detoxification of tolaasins by K3-5 was performed by hydrolyzation of cyclic structure of tolaasins depending on the tolaasin-K3-5 cell interaction. Our data suggest that the cyclic structure of tolaasins is critical for its interaction to target cells.

Microbiological Quality Assessment of Game Meats at Retail in Japan.

In this study, we examined the prevalence of Shiga toxin-producing Escherichia coli and Salmonella spp. and the distribution of indicator bacteria in 248 samples of game meats (120 venison and 128 wild boar) retailed between November 2015 and March 2016 in Japan. No Salmonella spp. were detected in any of the samples, whereas Shiga toxin-producing Escherichia coli serotype OUT:H25 (stx2d+, eae-) was isolated from one deer meat sample, suggesting a possible source for human infection. Plate count assays indicated greater prevalence of coliforms and E. coli in wild boar meat than in venison, whereas their prevalence in processing facilities showed greater variation than in animal species. The 16S rRNA ion semiconductor sequencing analysis of 24 representative samples revealed that the abundances of Acinetobacter and Arthrobacter spp. significantly correlated with the prevalence of E. coli, and quantitative PCR analyses in combination with selective plate count assay verified these correlations. To our knowledge, this is the first report to characterize the diversity of microorganisms of game meats at retail in Japan, together with identification of dominant microbiota. Our data suggest the necessity of bottom-up hygienic assessment in areas of slaughtering and processing facilities to improve microbiological safety.

Identification of the hcb Gene Operon Involved in Catalyzing Aerobic Hexachlorobenzene Dechlorination in Nocardioides sp. Strain PD653.

Nocardioides sp. strain PD653 was the first identified aerobic bacterium capable of mineralizing hexachlorobenzene (HCB). In this study, strain PD653-B2, which was unexpectedly isolated from a subculture of strain PD653, was found to lack the ability to transform HCB or pentachloronitrobenzene into pentachlorophenol. Comparative genome analysis of the two strains revealed that genetic rearrangement had occurred in strain PD653-B2, with a genomic region present in strain PD653 being deleted. In silico analysis allowed three open reading frames within this region to be identified as candidate genes involved in HCB dechlorination. Assays using recombinant Escherichia coli cells revealed that an operon is responsible for both oxidative HCB dechlorination and pentachloronitrobenzene denitration. The metabolite pentachlorophenol was detected in the cultures produced in the E. coli assays. Significantly less HCB-degrading activity occurred in assays under oxygen-limited conditions ([O2] < 0.5 mg liter-1) than under aerobic assays, suggesting that monooxygenase is involved in the reaction. In this operon, hcbA1 was found to encode a monooxygenase involved in HCB dechlorination. This monooxygenase may form a complex with the flavin reductase encoded by hcbA3, increasing the HCB-degrading activity of PD653.IMPORTANCE The organochlorine fungicide HCB is widely distributed in the environment. Bioremediation can effectively remove HCB from contaminated sites, but HCB-degrading microorganisms have been isolated in few studies and the genes involved in HCB degradation have not been identified. In this study, possible genes involved in the initial step of the mineralization of HCB by Nocardioides sp. strain PD653 were identified. The results improve our understanding of the protein families involved in the dechlorination of HCB to give pentachlorophenol.

Characterization of flagellins isolated from a highly motile strain of Lactobacillus agilis.

BACKGROUND: Most lactic acid bacteria are non-motile but some of them are flagellated and exhibit motility. So far, motile lactobacilli have rarely been studied, and characteristics of their flagellins are poorly understood. In this study, a highly motile strain of Lactobacillus agilis was recruited for transcriptional analysis and characterization of its flagellins. RESULTS: Unlike another motile lactic acid bacteria of intestinal isolate, Lactobacillus ruminis, flagellar filaments of the L. agilis strain probably consist of two homologous but distinct flagellins. Glycosylation of the flagellar filaments and their resistance to heat, acid and SDS were also observed. The immunological activity of the flagellins was evaluated through the stimulation of Caco-2 cells. The results show that TLR5-stimulating activity of the protein is attenuated, likely due to an incomplete TLR5-recognition site. CONCLUSIONS: The flagella filaments of L. agilis BKN88 consist of two homologous glycosylated flagellins, which likely have an incomplete TLR5-recognition site. The characteristics of the flagellin are presumably a consequence of adaptation as a commensal microbe in the gastrointestinal tract.