Near-infrared Photoimmunotherapy Targeting Cancer-Associated Fibroblasts in Patient-Derived Xenografts using a Humanized anti-Fibroblast Activation Protein Antibody.

Esophageal cancer remains a highly aggressive malignancy with a poor prognosis, despite ongoing advancements in treatments such as immunotherapy. The tumor microenvironment, particularly cancer-associated fibroblasts (CAFs), plays a crucial role in driving the aggressiveness of esophageal cancer. In a previous study utilizing human-derived xenograft models, we successfully developed a novel cancer treatment that targeted CAFs with near-infrared photoimmunotherapy (NIR-PIT), as an adjuvant therapy. In this study, we sought to translate our findings toward clinical practice by employing patient-derived xenograft (PDX) models and utilizing humanized monoclonal antibodies, specifically Sibrotuzumab, which is anti-human fibroblast activation protein (FAP) antibody and already being investigated in clinical trials as monotherapy. PDX models derived from esophageal cancer patients were effectively established, preserving the expression of key biomarkers such as EGFR and FAP, as observed in primary tumors. The application of FAP-targeted NIR-PIT using Sibrotuzumab, conjugated with the photosensitizer IR700DX, exhibited precise binding and selective elimination of FAP-expressing fibroblasts in vitro. Notably, in our in vivo investigations using both cell line-derived xenograft and PDX models, FAP-targeted NIR-PIT led to significant inhibition of tumor progression compared to control groups, all without inducing adverse events such as weight loss. Immunohistological assessments revealed a substantial reduction in CAFs exclusively within the tumor microenvironment of both models, further supporting the efficacy of our approach. Thus, our study demonstrates the potential of CAF-targeted NIR-PIT employing Sibrotuzumab as a promising therapeutic avenue for clinical treatment of esophageal cancer patients.

Molecular Evolution of GII.P31/GII.4_Sydney_2012 Norovirus over a Decade in a Clinic in Japan.

Norovirus (NoV) genogroup II, polymerase type P31, capsid genotype 4, Sydney_2012 variant (GII.P31/GII.4_Sydney_2012) has been circulating at high levels for over a decade, raising the question of whether this strain is undergoing molecular alterations without demonstrating a substantial phylogenetic difference. Here, we applied next-generation sequencing to learn more about the genetic diversity of 14 GII.P31/GII.4_Sydney_2012 strains that caused epidemics in a specific region of Japan, with 12 from Kyoto and 2 from Shizuoka, between 2012 and 2022, with an emphasis on amino acid (aa) differences in all three ORFs. We found numerous notable aa alterations in antigenic locations in the capsid region (ORF2) as well as in other ORFs. In all three ORFs, earlier strains (2013-2016) remained phylogenetically distinct from later strains (2019-2022). This research is expected to shed light on the evolutionary properties of dominating GII.P31/GII.4_Sydney_2012 strains, which could provide useful information for viral diarrhea prevention and treatment.

Development of recombinant rotavirus carrying herpes simplex virus 2 glycoprotein D gene based on reverse genetics technology.

Vaccine development for herpes simplex virus 2 (HSV-2) has been attempted, but no vaccines are yet available. A plasmid-based reverse genetics system for Rotavirus (RV), which can cause gastroenteritis, allows the generation of recombinant RV containing foreign genes. In this study, we sought to develop simian RV (SA11) as a vector to express HSV-2 glycoprotein D (gD2) and evaluated its immunogenicity in mice. We generated the recombinant SA11-gD2 virus (rSA11-gD2) and confirmed its ability to express gD2 in vitro. The virus was orally inoculated into suckling BALB/c mice and into 8-week-old mice. Serum IgG and IgA titers against RV and gD2 were measured by ELISA. In the 8-week-old mice inoculated with rSA11-gD2, significant increases in not only antibodies against RV but also IgG against gD2 were demonstrated. In the suckling mice, antibodies against RV were induced, but gD2 antibody was not detected. Diarrhea observed after the first inoculation of rSA11-gD2 in suckling mice was similar to that induced by the parent virus. A gD2 expressing simian RV recombinant, which was orally inoculated, induced IgG against gD2. This strategy holds possibility for genital herpes vaccine development.

Rotavirus circumvents the antiviral effects of protein ISGylation via proteasomal degradation of Ube1L.

Among the ramified cellular responses elicited in response to pathogenic stimuli, upregulation and covalent conjugation of an Ubiquitin-like modifier ISG15 to lysine residues of target proteins (ISGylation) through sequential action of three enzymes E1 (Ube1L), E2 (Ube2L6) and E3 (Herc5) have emerged as an important regulatory facet governing innate immunity against numerous viral infections. In the present study, we investigated the interplay between host ISGylation system and Rotavirus (RV). We observed that RV infection upregulates the expression of free ISG15 but prevents protein ISGylation. Analysing the expression of ISGylation machinery components revealed that RV infection results in steady depletion of Ube1L protein with the progression of infection. Indeed, restoration of Ube1L expression caused induction in protein ISGylation during RV infection. Subsequent investigation revealed that ectopic expression of RV non-structural protein 5 (NSP5) fosters proteolytic ubiquitylation of Ube1L, thereby depleting it in an ubiquitin-proteasome-dependent manner. Moreover, pan-Cullin inhibition also abrogates proteolytic ubiquitylation and rescued depleted Ube1L in RV-NSP5 expressing cells, suggesting the involvement of host cellular Cullin RING Ligases (CRLs) in proteasomal degradation of Ube1L during RV-SA11 infection. Reciprocal co-immunoprecipitation analyses substantiated a molecular association between Ube1L and RV-NSP5 during infection scenario and also under ectopically overexpressed condition independent of intermediate RNA scaffold and RV-NSP5 hyperphosphorylation. Interestingly, clonal overexpression of Ube1L reduced expression of RV proteins and RV infectivity, which are restored in ISG15 silenced cells, suggesting that Ube1L is a crucial anti-viral host cellular determinant that inhibits RV infection by promoting the formation of ISG15 conjugates.

Full genome-based characterization of an Asian G3P[6] human rotavirus strain found in a diarrheic child in Japan: Evidence for porcine-to-human zoonotic transmission.

Human rotavirus strains having the unconventional G3P[6] genotype have been sporadically detected in diarrheic patients in different parts of the world. However, the full genomes of only three human G3P[6] strains from Asian countries (China, Indonesia, and Vietnam) have been sequenced and characterized, and thus the exact origin and evolution of G3P[6] strains in Asia remain to be elucidated. Here, we sequenced and characterized the full genome of a G3P[6] strain (RVA/Human-wt/JPN/SO1199/2020/G3P[6]) found in a stool sample from a 3-month-old infant admitted with acute gastroenteritis in Japan. On full genomic analysis, strain SO1199 was revealed to have a unique Wa-like genogroup configuration: G3-P[6]-I5-R1-C1-M1-A8-N1-T1-E1-H1. VP6 genotype I5 and NSP1 genotype A8 are commonly found in porcine rotavirus strains. Furthermore, phylogenetic analysis demonstrated that all 11 genes of strain SO1199 were closely related to those of porcine and/or porcine-like human rotaviruses and thus appeared to be of porcine origin. Thus, strain SO1199 was shown to possess a porcine-like genomic backbone and thus is likely to be the result of interspecies transmission of a porcine rotavirus strain. Of note is that all 11 genes of strain SO1199 were phylogenetically located in clusters, distinct from those of the previously identified porcine-like human G3P[6] strains from around the world including Asia, suggesting the occurrence of independent porcine-to-human zoonotic transmission events. To our knowledge, this is the first report on full genome-based characterization of a human G3P[6] strain that has emerged in Japan. Our findings revealed the diversity of unconventional human G3P[6] strains in Asia, and provide important insights into the origin and evolution of G3P[6] strains.

Similarities in rotavirus vaccine viral shedding and immune responses in pairs of twins.

Objectives: Intestinal rotavirus (RV) vaccine replication and host immune response are suggested to be affected by several factors, including maternal antibodies, breastfeeding history, and gut microbiome, which are thought to be similar in pairs of twins. The aim of this study was to determine whether viral shedding from the fecal RV vaccine strain Rotarix® (RV1) and IgG and IgA responses to RV show similarity in pairs of twins. Methods: Quantitative reverse transcription polymerase chain reaction specific to RV vaccine strain RV1 was used to monitor fecal RV1 viral shedding. RV IgG and IgA titers were measured using an in-house enzyme-linked immunosorbent assay. Fecal RV1 viral shedding and immune responses were compared between twins and singletons with mixed effects and fixed effects models. Results: A total of 347 stool and 54 blood samples were collected from four pairs of twins and twelve singletons during the observation period. Although the kinetics of fecal RV1 viral shedding and immune responses differed among vaccinated individuals, they appeared to be similar within twin pairs. RV shedding after the first dose (P=0.049) and RV IgG titers during the entire observation period (P=0.015) had a significantly better fit in the fixed effect model that assumed that twins have the same response versus the model that assumed that twins have a different response. Conclusions: The similarity of RV vaccine viral replication in intestine and host immune responses in twin pairs was demonstrated using statistical analysis.

Whole genome sequencing and genomic characterization of a DS-1-like G2P[4] group A rotavirus in Japan.

After rotavirus was discovered in 1973, it became the leading pathogen in causing acute gastroenteritis in humans worldwide. In this study, we performed whole genome sequencing and genomic characterization of a DS-1-like G2P[4] group A rotavirus in feces of a Japanese child with acute gastroenteritis who was fully Rotarix® vaccinated. The genomic investigation determined a genomic constellation G2-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2 of this rotavirus strain. Its antigenic epitopes of the VP7 and VP4 proteins had significant mismatches compared with the vaccine strains. Our study is the latest attempt to investigate the evolution of the VP7 and VP4 genes of emerging G2P[4] rotavirus in Japan.

Conventional Cancer Therapies Can Accelerate Malignant Potential of Cancer Cells by Activating Cancer-Associated Fibroblasts in Esophageal Cancer Models.

Esophageal cancer is one of the most aggressive tumors, and the outcome remains poor. One contributing factor is the presence of tumors that are less responsive or have increased malignancy when treated with conventional chemotherapy, radiotherapy, or a combination of these. Cancer-associated fibroblasts (CAFs) play an important role in the tumor microenvironment. Focusing on conventional cancer therapies, we investigated how CAFs acquire therapeutic resistance and how they affect tumor malignancy. In this study, low-dose chemotherapy or radiotherapy-induced normal fibroblasts showed enhanced activation of CAFs markers, fibroblast activation protein, and α-smooth muscle actin, indicating the acquisition of malignancy in fibroblasts. Furthermore, CAFs activated by radiotherapy induce phenotypic changes in cancer cells, increasing their proliferation, migration, and invasion abilities. In in vivo peritoneal dissemination models, the total number of tumor nodules in the abdominal cavity was significantly increased in the co-inoculation group of cancer cells and resistant fibroblasts compared to that in the co-inoculation group of cancer cells and normal fibroblasts. In conclusion, we demonstrated that conventional cancer therapy causes anti-therapeutic effects via the activation of fibroblasts, resulting in CAFs. It is important to select or combine modalities of esophageal cancer treatment, recognizing that inappropriate radiotherapy and chemotherapy can lead to resistance in CAF-rich tumors.

Overcoming cancer-associated fibroblast-induced immunosuppression by anti-interleukin-6 receptor antibody.

Cancer-associated fibroblasts (CAFs) are a critical component of the tumor microenvironment and play a central role in tumor progression. Previously, we reported that CAFs might induce tumor immunosuppression via interleukin-6 (IL-6) and promote tumor progression by blocking local IL-6 in the tumor microenvironment with neutralizing antibody. Here, we explore whether an anti-IL-6 receptor antibody could be used as systemic therapy to treat cancer, and further investigate the mechanisms by which IL-6 induces tumor immunosuppression. In clinical samples, IL-6 expression was significantly correlated with α-smooth muscle actin expression, and high IL-6 cases showed tumor immunosuppression. Multivariate analysis showed that IL-6 expression was an independent prognostic factor. In vitro, IL-6 contributed to cell proliferation and differentiation into CAFs. Moreover, IL-6 increased hypoxia-inducible factor 1α (HIF1α) expression and induced tumor immunosuppression by enhancing glucose uptake by cancer cells and competing for glucose with immune cells. MR16-1, a rodent analog of anti-IL-6 receptor antibody, overcame CAF-induced immunosuppression and suppressed tumor progression in immunocompetent murine cancer models by regulating HIF1α activation in vivo. The anti-IL-6 receptor antibody could be systemically employed to overcome tumor immunosuppression and improve patient survival with various cancers. Furthermore, the tumor immunosuppression was suggested to be induced by IL-6 via HIF1α activation.

Dual-targeted near-infrared photoimmunotherapy for esophageal cancer and cancer-associated fibroblasts in the tumor microenvironment.

Cancer-associated fibroblasts (CAFs) play a significant role in tumor progression within the tumor microenvironment. Previously, we used near-infrared photoimmunotherapy (NIR-PIT), a next-generation cancer cell-targeted phototherapy, to establish CAF-targeted NIR-PIT. In this study, we investigated whether dual-targeted NIR-PIT, targeting cancer cells and CAFs, could be a therapeutic strategy. A total of 132 cases of esophageal cancer were analyzed for epidermal growth factor receptor (EGFR), human epidermal growth factor 2 (HER2), and fibroblast activation protein (FAP) expression using immunohistochemistry. Human esophageal cancer cells and CAFs were co-cultured and treated with single- or dual-targeted NIR-PIT in vitro. These cells were co-inoculated into BALB/c-nu/nu mice and the tumors were treated with single-targeted NIR-PIT or dual-targeted NIR-PIT in vivo. Survival analysis showed FAP- or EGFR-high patients had worse survival than patients with low expression of FAP or EGFR (log-rank, P < 0.001 and P = 0.074, respectively), while no difference was observed in HER2 status. In vitro, dual (EGFR/FAP)-targeted NIR-PIT induced specific therapeutic effects in cancer cells and CAFs along with suppressing tumor growth in vivo, whereas single-targeted NIR-PIT did not show any significance. Moreover, these experiments demonstrated that dual-targeted NIR-PIT could treat cancer cells and CAFs simultaneously with a single NIR light irradiation. We demonstrated the relationship between EGFR/FAP expression and prognosis of patients with esophageal cancer and the stronger therapeutic effect of dual-targeted NIR-PIT than single-targeted NIR-PIT in experimental models. Thus, dual-targeted NIR-PIT might be a promising therapeutic strategy for cancer treatment.

Suppression of classical nuclear import pathway by importazole and ivermectin inhibits rotavirus replication.

BACKGROUND: Rotavirus is the foremost cause of acute gastroenteritis among infants in resource-poor countries, causing severe morbidity and mortality. The currently available rotavirus vaccines are effective in reducing severity of the disease but not the infection rates, thus antivirals as an adjunct therapy are needed to reduce the morbidity in children. Viruses rely on host cellular machinery for nearly every step of the replication cycle. Therefore, targeting host factors that are indispensable for virus replication could be a promising strategy. OBJECTIVES: To assess the therapeutic potential of ivermectin and importazole against rotaviruses. METHODS: Antirotaviral activity of importazole and ivermectin was measured against various rotavirus strains (RV-SA11, RV-Wa, RV-A5-13, RV-EW) in vitro and in vivo by quantifying viral protein expression by western blot, analysing viroplasm formation by confocal microscopy, and measuring virus yield by plaque assay. RESULTS: Importin-ß1 and Ran were found to be induced during rotavirus infection. Knocking down importin-ß1 severely impaired rotavirus replication, suggesting a critical role for importin-ß1 in the rotavirus life cycle. In vitro studies revealed that treatment of ivermectin and importazole resulted in reduced synthesis of viral proteins, diminished production of infectious virus particles, and decrease in viroplasm-positive cells. Mechanistic study proved that both drugs perform antirotavirus activity by inhibiting the function of importin-ß1. In vivo investigations in mice also confirmed the antirotavirus potential of importazole and ivermectin at non-toxic doses. Treatments of rotavirus-infected mice with either drug resulted in diminished shedding of viral particles in the stool sample, reduced expression of viral protein in the small intestine and restoration of damaged intestinal villi comapared to untreated infected mice. CONCLUSIONS: The study highlights the potential of importazole and ivermectin as antirotavirus therapeutics.

Whole genome sequencing and evolutionary analysis of G8P [8] rotaviruses emerging in Japan.

Unusual DS-1-like intergenogroup reassortant rotaviruses with a bovine-like G8 genotype (DS-1-like G8P [8] rotaviruses) have emerged and rapidly spread in several countries. In this study, the nucleotide sequences of seven human rotavirus G8P [8] strains in 2017 and 2019 in Japan were determined using viral metagenomics. Its genomic constellation (VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes) was defined as G8-P [8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Our genetic analysis revealed that the Japanese G8P [8] rotavirus strains in 2017 and 2019 were classified into the same lineages G8-5 and P [8]-3, but they were phylogenetically located on separate branches and belonged to distinct clusters. Our study is the first attempt to investigate the evolution of emerging rotavirus G8P [8] in Japan.

Establishment of a reverse genetics system for avian rotavirus A strain PO-13.

Avian rotavirus A (RVA) is one of major enteric pathogens that cause diarrhoea in young avian individuals. Importantly, some of the avian RVA strains of G18P[17] genotype are naturally transmitted to and cause clinical diseases in mammalian species, indicating their potential risks to animal health. Although molecular information on the pathogenesis by avian RVA strains will be useful for estimating their risks, the absence of a reverse genetics (RG) system for these strains has hindered the elucidation of their pathogenic mechanisms. In this study, we aimed to establish an RG system for the avian G18P[17] prototype strain PO-13, which was isolated from a pigeon in Japan in 1983 and was experimentally shown to be pathogenic in suckling mice. Transfection with plasmids expressing 11 genomic RNA segments of the strain resulted in rescue of the infectious virus with an artificially introduced genetic marker on its genome, indicating that an RG system for the PO-13 strain was successfully established. The rescued recombinant strain rPO-13 had biological properties almost identical to those of its wild-type strain (wtPO-13). Notably, both rPO-13 and wtPO-13 induced diarrhoea in suckling mice with similar efficiencies. It was thus demonstrated that the RG system will be useful for elucidating the pathogenic mechanisms of the PO-13 strain at the molecular level. This is the first report of the establishment of an RG system for an avian RVA strain.

Rapid Spread in Japan of Unusual G9P[8] Human Rotavirus Strains Possessing NSP4 Genes of E2 Genotype.

The emergence of unusual G9P[8]-E2 human rotaviruses in the Tokyo metropolitan area, Japan, in 2018 has been reported. During rotavirus strain surveillance in different regions of Japan (Mie, Okayama, and Chiba prefectures), G9P[8]-E2 strains were detected in children with diarrhea from all three prefectures. Here, we characterized the whole genome of seven representative G9P[8]-E2 strains. In the full-genome-based analysis, the seven study strains exhibited a unique genotype configuration with the NSP4 gene of genogroup 2 in a genogroup 1 genomic backbone: G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1. This genotype constellation was shared by the Tokyo G9P[8]-E2 strains. Phylogenetic analysis showed that all 11 genes, except NSP4, of the seven study strains appeared to have originated from co-circulating Wa-like G9P[8]-E1 strains. In contrast, NSP4 appeared to have originated from the co-circulating DS-1-like G2P[4]-E2 strains. Thus, G9P[8]-E2 strains appear to be derived through reassortment between G9P[8]-E1 and G2P[4]-E2 strains in Japan. Notably, the seven study G9P[8]-E2 strains and Tokyo G9P[8]-E2 strains were revealed to have 11-segment genomes almost indistinguishable from one another in their sequences (99.3-100%), indicating all these G9P[8]-E2 strains had a common origin. To our knowledge, this is the first description of the rapid spread of G9P[8]-E2 strains across a country.

Whole genome sequence of an uncommon G9P[4] species A rotavirus containing DS-1-like (genotype 2) genes in Japan.

Species A rotaviruses (RVAs) have been recognized as one of the leading causes of acute gastroenteritis in humans worldwide. Here, the complete coding sequences of 11 RNA segments of an uncommon G9P[4] RVA strain, which was detected in feces of a diarrheal child in Japan, were determined by next-generation sequencing technology. Its genomic constellation, VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5, was determined as G9-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2. This work reports the complete coding sequences of a G9P[4] RVA strain containing DS-1-like (genotype 2) genes that was isolated in Japan in 2013.

Rotavirus incapable of NSP6 expression can cause diarrhea in suckling mice.

The group A rotavirus (RVA) genome comprising 11 double-stranded RNAs encodes six structural proteins (VP1-VP4, VP6, and VP7) and six non-structural proteins (NSP1-NSP6). Among these 12 rotaviral proteins, NSP6 has been less studied as to its function. We previously prepared a recombinant NSP6-deficient RVA derived from simian strain SA11-L2 by reverse genetics, and found that the NSP6-deficient virus grew well in cell culture, although its growth was less abundant than that of the parental SA11-L2 strain. In this study, we examined the potency of a recombinant RVA incapable of NSP6 expression to cause diarrhoea in suckling mice. The suckling mice infected with the NSP6-deficient virus apparently experienced diarrhoea, although the symptom was milder and the duration of diarrhoea was shorter than in the mice infected with the authentic SA11-L2 strain. Thus, together with the results obtained for cultured cells in the previous study, it can be concluded that NSP6 is not necessarily required for replication and pathogenicity in vitro and in vivo.

Rotavirus genotypes and clinical outcome of natural infection based on vaccination status in the post-vaccine era.

Rotavirus (RV) is a leading cause of gastroenteritis in children. In Japan, Rotarix (RV1; GlaxoSmithKline), which is a monovalent vaccine derived from human RV (G1P[8]), has been introduced since November 2011, and RotaTeq (RV5; MSD) which is an pentavalent, human-bovine mono-reassortant vaccine (G1, G2, G3, G4, and P1A[8]), has been introduced since July 2012. Long-term follow-up on vaccine efficacy and RV genotypical change should be carried out in order to control RV infection. The RV gastroenteritis (RVGE) outbreak occurred during the 2018/2019 season in Aichi prefecture, Japan. Therefore, the molecular epidemiology of RV among three different groups of RVGE, which were outpatients who received RV1, those who received RV5, and those without vaccination, was explored. Clinical features of RVGE patients were compared among the three patient groups. Children less than 15 years of age with gastroenteritis who visited any of seven pediatric practices between January and June 2019 were enrolled in the study. G, P, and E genotypes were determined by direct sequencing of reverse transcription-polymerase chain reaction products amplified from stool samples. Among 110 patients, there were 27, 28, and 55 in the RV1-vaccinated, RV5-vaccinated, and unvaccinated groups, respectively. The most frequent genotype was G8P[8] (92/110 patients, 83.6%). Genotype distributions did not significantly differ among the three patient groups (P = .125). Mean Vesikari score was significantly lower among RV1-vaccinated (7.1) and RV5-vaccinated patients (6.4) than among unvaccinated patients (10.2) (P < .001). Even in RVGE patients treated in an outpatient clinic, RV vaccine reduced the severity of the disease in this cohort.

[Traumatic Neuroma Mimicking Lymph Node Metastasis of Pancreatic Neuroendocrine Neoplasms Developed after Pancreatoduodenectomy-A Case Report].

A traumatic neuroma is a benign tumor consisting of a non-neoplastic growth of injured nerves as a result of trauma or surgery. It is rarely found in an abdominal cavity, but some reports showed that it occurred around the bile duct. We report a case of a 72-year-old man who underwent subtotal stomach-preserving pancreatoduodenectomy for pancreatic neuroendocrine neoplasms 4 years ago. An abdominal contrast-enhanced CT follow-up examination revealed a growing nodule on the dorsal surface of the portal vein. The lesion showed a mild increase in fluorodeoxyglucose uptake in FDG-PET⊘CT. A lymph node metastasis of pancreatic neuroendocrine neoplasms was suspected. Nodule resection was performed for purpose of diagnosis and treatment. The final pathological diagnosis was traumatic neuroma with no evidence of recurrence. Traumatic neuromas developed after pancreatoduodenectomy have not been reported. Postoperative masses around the bile ducts should also be considered traumatic neuromas.

Genomic characterization of an African G4P[6] human rotavirus strain identified in a diarrheic child in Kenya: Evidence for porcine-to-human interspecies transmission and reassortment.

Human rotavirus strains having the unconventional G4P[6] genotype have been sporadically identified in diarrheic patients in different parts of the world. However, the whole genome of only one human G4P[6] strain from Africa (central Africa) has been sequenced and analyzed, and thus the exact origin and evolutionary pattern of African G4P[6] strains remain to be elucidated. In this study, we characterized the full genome of an African G4P[6] strain (RVA/Human-wt/KEN/KCH148/2019/G4P[6]) identified in a stool specimen from a diarrheic child in Kenya. Full genome analysis of strain KCH148 revealed a unique Wa-like genogroup constellation: G4-P[6]-I1-R1-C1-M1-A1-N1-T7-E1-H1. NSP3 genotype T7 is commonly found in porcine rotavirus strains. Furthermore, phylogenetic analysis showed that 10 of the 11 genes of strain KCH148 (VP7, VP4, VP6, VP1-VP3, NSP1, and NSP3-NSP5) appeared to be of porcine origin, the remaining NSP2 gene appearing to be of human origin. Therefore, strain KCH148 was found to have a porcine rotavirus backbone and thus is likely to be of porcine origin. Furthermore, strain KCH148 is assumed to have been derived through interspecies transmission and reassortment events involving porcine and human rotavirus strains. To our knowledge, this is the first report on full genome-based characterization of a human G4P[6] strain from east Africa. Our observations demonstrated the diversity of human G4P[6] strains in Africa, and provide important insights into the origin and evolutionary pattern of zoonotic G4P[6] strains on the African continent.