Potent CTLs can be induced against tumor cells in an environment of lower levels of systemic MFG-E8

The direction and magnitude of immune responses are critically affected when dead cells are disposed of. Milk fat globule-epidermal growth factor-factor 8 (MFG-E8) promotes the engulfment of apoptotic normal and cancerous cells without inducing inflammation. We have previously reported that a certain proportion of the cancer cells express abundant MFG-E8, and that such expression is associated with the shorter survival of patients with esophageal cancer who had received chemotherapy before surgery. However, the influence of tumor-derived and systemically existing MFG-E8 on antitumor immune responses has not yet been fully investigated. Herein, we showed that CTL-dependent antitumor immune responses were observed in mice with no or decreased levels of systemic MFG-E8, and that such responses were enhanced further with the administration of anti-PD-1 antibody. In mice with decreased levels of systemic MFG-E8, the dominance of regulatory T cells in tumor-infiltrating lymphocytes was inverted to CD8+ T cell dominance. MFG-E8 expression by tumor cells appears to affect antitumor immune responses only when the level of systemic MFG-E8 is lower than the physiological status. We have also demonstrated in the clinical setting that lower levels of plasma MFG-E8, but not MFG-E8 expression in tumor cells, before the treatment was associated with objective responses to anti-PD-1 therapy in patients with non-small cell lung cancer. These results suggest that systemic MFG-E8 plays a critical role during the immunological initiation process of antigen-presenting cells to increase tumor-specific CTLs. Regulation of the systemic level of MFG-E8 might induce efficient antitumor immune responses and enhance the potency of anti-PD-1 therapy.

Prediction for oxaliplatin-induced liver injury using patient-derived liver organoids

BACKGROUND

Liver injury associated with oxaliplatin (L-OHP)-based chemotherapy can significantly impact the treatment outcomes of patients with colorectal cancer liver metastases, especially when combined with surgery. To date, no definitive biomarker that can predict the risk of liver injury has been identified. This study aimed to investigate whether organoids can be used as tools to predict the risk of liver injury.

METHODS

We examined the relationship between the clinical signs of L-OHP-induced liver injury and the responses of patient-derived liver organoids in vitro. Organoids were established from noncancerous liver tissues obtained from 10 patients who underwent L-OHP-based chemotherapy and hepatectomy for colorectal cancer.

RESULTS

Organoids cultured in a galactose differentiation medium, which can activate the mitochondria of organoids, showed sensitivity to L-OHP cytotoxicity, which was significantly related to clinical liver toxicity induced by L-OHP treatment. Organoids from patients who presented with a high-grade liver injury to the L-OHP regimen showed an obvious increase in mitochondrial superoxide levels and a significant decrease in mitochondrial membrane potential with L-OHP exposure. L-OHP-induced mitochondrial oxidative stress was not observed in the organoids from patients with low-grade liver injury.

CONCLUSIONS

These results suggested that L-OHP-induced liver injury may be caused by mitochondrial oxidative damage. Furthermore, patient-derived liver organoids may be used to assess susceptibility to L-OHP-induced liver injury in individual patients.

Establishment of organoids using residual samples from saline flushes during endoscopic ultrasound-guided fine-needle aspiration in patients with pancreatic cancer

Background and study aims  In patients with pancreatic cancer (PC), patient-derived organoid cultures can be useful tools for personalized drug selection and preclinical evaluation of novel therapies. To establish a less invasive method of creating organoids from a patient's tumor, we examined whether PC organoids can be established using residual samples from saline flushes (RSSFs) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Methods  Five patients with PC who underwent EUS-FNA were enrolled in a prospective study conducted at our institution. RSSFs obtained during EUS-FNA procedures were collected. An organoid culture was considered as established when ≥ 5 passages were successful. Organoid-derived xenografts were created using established organoids. Results  EUS-FNA was performed using a 22- or 25-gauge lancet needle without complications. Patient-derived organoids were successfully established in four patients (80.0 %) with the complete medium and medium for the selection of KRAS mutants. Organoid-derived xenografts were successfully created and histologically similar to EUS-FNA samples. Conclusions  Patient-derived PC organoids were successfully established using EUS-FNA RSSFs, which are produced as a byproduct of standard manipulations, but are usually not used for diagnosis. This method can be applied to all patients with PC, without additional invasive procedures, and can contribute to the development of personalized medicine and molecular research.

High-throughput screening in colorectal cancer tissue-originated spheroids

Patient‐derived cancer organoid culture is an important live material that reflects clinical heterogeneity. However, the limited amount of organoids available for each case as well as the considerable amount of time and cost to expand in vitro makes it impractical to perform high‐throughput drug screening using organoid cultures from multiple patients. Here, we report an advanced system for the high‐throughput screening of 2427 drugs using the cancer tissue‐originated spheroid (CTOS) method. In this system, we apply the CTOS method in an ex vivo platform from xenograft tumors, using machines to handle CTOS and reagents, and testing a CTOS reference panel of multiple CTOS lines for the hit drugs. CTOS passages in xenograft tumors resulted in minimal changes of morphological and genomic status, and xenograft tumor generation efficiently expanded the number of CTOS to evaluate multiple drugs. Our panel of colorectal cancer CTOS lines exhibited diverse sensitivities to the hit compounds, demonstrating the usefulness of this system for investigating highly heterogeneous disease.

Evaluation of the culture method NIHSJ-02 alternative to ISO 10272-1:2006 for the detection of campylobacter jejuni and campylobacter coli in chicken: collaborative study

For the surveillance of the prevalence of Campylobacter jejuni and Campylobacter coli in raw chicken products in Japan, a qualitative method, National Institute of Health Sciences Japan (NIHSJ)-02, was developed as an alternative to International Organization for Standardization (ISO) 10272-1:2006. In the NIHSJ-02 culture method, the enrichment step is carried out in a reduced volume of Preston broth at 42 +/- 1 degrees C to reduce cost and space, and to prevent the overgrowth of background bacteria. To evaluate the performance of NIHSJ-02, a collaborative study was conducted, and the results obtained by NIHSJ-02 were compared with those obtained using the reference method, ISO 10272-1:2006. Fifteen laboratories participated; each examined 48 minced chicken samples consisting of test samples uninoculated, inoculated with C. jejuni at a low or high level, and inoculated with C. coli at a low level. The average probabilities of detection by NIHSJ-02 across laboratories were 0.033, 0.222, 0.678, and 0.267 in samples uninoculated, inoculated with C. jejuni at a low and high level, and with C. coli at a low level, respectively. Those by ISO 10272-1:2006 were 0.051, 0.128, 0.551, and 0.090. Significantly higher probabilities of detection were determined by NIHSJ-02 compared to ISO 10272-1:2006, except for uninoculated samples. On the other hand, significantly lower frequency of occurrence of background bacteria was observed by NIHSJ-02 (43.1%) compared with ISO 10272-1:2006 (92.6%). NIHSJ-02 showed better performance than ISO 10272-1:2006 with regard to the selective detection of C. jejuni and C. coli in chicken.

Molecular evidence for the thriving of Campylobacter jejuni ST-4526 in Japan

Campylobacter jejuni is a leading cause of human gastroenteritis worldwide. This study aimed at a better understanding of the genetic diversity of this pathogen disseminated in Japan. We performed multilocus sequence typing (MLST) of Campylobacter jejuni isolated from different sources (100 human, 61 poultry, and 51 cattle isolates) in Japan between 2005 and 2006. This approach identified 62 sequence types (STs) and 19 clonal complexes (CCs), including 11 novel STs. These 62 STs were phylogenetically divided into 6 clusters, partially exhibiting host association. We identified a novel ST (ST-4526) that has never been reported in other countries; a phylogenetic analysis showed that ST-4526 and related STs showed distant lineage from the founder ST, ST-21 within CC-21. Comparative genome analysis was performed to investigate which properties could be responsible for the successful dissemination of ST-4526 in Japan. Results revealed that three representative ST-4526 isolates contained a putative island comprising the region from Cj0737 to Cj0744, which differed between the ST-4526 isolates and the reference strain NCTC11168 (ST-43/CC-21). Amino acid sequence alignment analyses showed that two of three ST-4526 isolates expressed 693aa- filamentous hemagglutination domain protein (FHA), while most of other C. jejuni strains whose genome were sequenced exhibited its truncation. Correspondingly, host cell binding of FHA-positive C. jejuni was greater than that of FHA-truncated strains, and exogenous administration of rFHA protein reduced cell adhesion of FHA-positive bacteria. Biochemical assays showed that this putative protein exhibited a dose-dependent binding affinity to heparan sulfate, indicating its adhesin activity. Moreover, ST-4526 showed increased antibiotic-resistance (nalidixic acid and fluoroquinolones) and a reduced ability for DNA uptake. Taken together, our data suggested that these combined features contributed to the clonal thriving of ST-4526 in Japan.

Importance of subunit vaccine antigen of major Fli C antigenic site of Salmonella enteritidis II: a challenge trial

Salmonella enterica subsp. enterica serovar Enteritidis (SE) infection in chickens shows a mild pathogenicity except for young ages, compared with other animals, and laying hens sometimes produce SE-contaminated eggs leading to public health concerns. To reduce the problem, SE bacterin in poultry farms has been applied. We previously demonstrated that a subunit antigen, g.m. part polypeptide in SE-Fli C (SEp 9), could be a candidate subunit antigen of SE vaccine which may show less side effects in chickens. In this study, we used SEp 9 along with an adjuvant to inoculate chickens, then the chickens were orally challenged with SE, and suppression of the SE count in the cecum was investigated. Chickens inoculated with a commercial SE vaccine were prepared as positive controls (vaccine group), and those with physiological saline (control group) for comparison of the bacterial count after challenge. Employing two types of antibody-detection ELISA coated with either de-flagellated SE or SEp 9, specific antibody levels in blood and the intestine were determined. The bacterial count was significantly lower 1 and 3 weeks after challenge in the SEp 9 than in the control group. Specific antibody only against SEp 9 in blood but not the intestine of these birds in the SEp 9 group was detected. This study confirmed that SEp 9 antigen is a major effective antigen in SE inactivated vaccine, and it is suggested that only the subunit vaccine antigen SEp 9 is needed to effectively suppress colonization in the chicken intestine, without the need for other SE component antigens.

Importance of the major Fli C antigenic site of Salmonella enteritidis as a subunit vaccine antigen

Our previous study indicated that the antibody against the major antigenic site of SE Fli C (g.m. region) is characteristically produced after the application of SE bacterin, however, the antibody is not produced in chickens after SE infection. In the present study, we determined histologically if the major antigenic site could be a candidate antigen for SE subunit vaccine. When Layermune SE, a commercial SE bacterin, was injected subcutaneously into the shoulder region as a positive control, the following histological changes were observed: formation of epithelioid granuloma with epithelioid cells and multinuclear giant cells surrounding necrotic sites and oil cysts (Indicator 1); a perivascular accumulation of lymphocytes near the granulation tissue (Indicator 2); peripheral fibroplasia encapsulating the granulation tissue (Indicator 3). On the other hand, at the injection site from the incomplete Freund adjuvant as a negative control antigen, there was only hyperplasia of the connective tissues around oil cysts. By using these indicators, the histological changes induced by injection of major antigenic site (SEp9) of Fli C, Fli C, and SE somatic antigen were evaluated. Histological changes after the injection with SEp9 demonstrated Indicators 2 and 3. The injection with SE Fli C demonstrated all three indicators. Contrarily, de-flagellated SE antigen injection induced only Indicator 3. The present results suggest that the antigen g.m. site of SE Fli C (SEp9) may play an important role as a subunit vaccine not only for including continuous immunological reaction in SE infection in chickens but also for antigen presentation.

Survey of Japanese layer farms for Salmonella enteritidis with vaccination- and infection-specific antigens for egg yolk antibodies

Japanese layer farms were surveyed for Salmonella Enteritidis vaccination and infection with specific antigens for egg yolk antibodies with the use of vaccination-specific antigen Salmonella Enteritidis FliC-specific 9-kDa polypeptide (SEP9) and infection-specific antigen deflagellated Salmonella Enteritidis whole cell (DEWC). The specific antibodies in eggs from 201 commercial layer farms throughout Japan were surveyed. The percentages of farm flocks with a mean enzyme-linked immunosorbent assay (ELISA) titer of over 0.1 were 56.2% (113 of 201) in DEWC-ELISA and 22.3% (45 of 201) in SEP9-ELISA. Flocks indicating high titers in SEP9-ELISA always showed high titers in DEWC-ELISA. Because both specific antibody titers of the vaccinated flocks monitored long term remained high throughout life, flocks with high titers of both ELISAs in this survey must be vaccinated. On the other hand, 34.3% (69 of 201) of flocks had high titers of DEWC-specific antibody alone. Because Salmonella Enteritidis infection induces the DEWC-specific antibody but not the SEP9-specific antibody, detecting only high ELISA titers of DEWC-specific antibody can be an effective monitoring tool for Salmonella Enteritidis exposure rather than vaccination. These results suggest that vaccination programs in Japanese layer farms would be insufficient to control Salmonella Enteritidis infection, and egg screening to detect specific antibodies would be valuable in obtaining the necessary information to control Salmonella Enteritidis infection.

Detection of specific antibodies against deflagellated Salmonella Enteritidis and S. Enteritidis FliC-specific 9kDa polypeptide

Specific antibody levels of laying hens and young chickens experimentally infected with Salmonella Enteritidis and vaccinated farm flocks were evaluated by enzyme-linked immunosorbent assays (ELISAs) with two different antigens, deflagellated S. Enteritidis whole cell (DEWC) and S. Enteritidis FliC-specific 9kDa polypeptide (SEP9). Infected laying hens excreted S. Enteritidis throughout the experimental period, and the specific antibody titers in DEWC-ELISA, were significantly higher than the uninfected group. It suggests that this DEWC-specific antibody will serve as an effective indicator of S. Enteritidis infection, especially for non-vaccinated laying flocks. SEP9-specific antibodies were detected in spray-inoculated young chickens but not in oral-inoculated young chickens. Compared with greatly high SEP9-specific antibody levels of vaccinated farm flocks, no response was observed in orally infected hens. These results indicate that S. Enteritidis discontinues expressing SEP9 once it has crossed the intestinal barrier, and that SEP9-ELISA will serve as a valuable monitoring tool for the status of S. Enteritidis vaccination on a flockwide basis, independent of stable S. Enteritidis infections.