Biology subjects

He, R.

Publications and source records attributed to He, R..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

Genome-wide Mapping Eukaryotic Open Chromatin Regions with Double-Stranded DNA Deaminase

A variety of methods such as ATAC-seq and CUT&Tag have been developed for probing chromatin states. However, enzymatic cleavage of DNA in these methods hinders their multi-omics integration with other DNA profiling techniques. Here, by extending our use of dsDNA deaminase (FOOtprinting with DeamInasE, FOODIE), we introduce two new methods for mapping Chromatin Open region by DeamInasE (ChrODIE) and histone modification by ANtibody-associated DeamInasE (ANDIE), respectively. Unlike cleavage-based methods, both ChrODIE and ANDIE leave genomic DNA after deamination unfragmented and amplifiable. This offers the potential for simultaneous or downstream integration with other genomic profiling methods, such as mapping 3D genome interactions.

genomics↗

bioRxiv2024

Exploring phenotype-related single-cells through attention-enhanced representation learning

The scope of atlas-level single-cell investigations reveals the pathogenesis and progression of various diseases. Accurate interpretation of phenotype-related single-cell data necessitates the pre-definition of single-cell subtypes and the identification of their abundance variations for downstream analysis. In this context, biases from batch correlation and the selection of clustering resolutions can significantly impact single-cell data analysis and result interpretation. To strengthen the associations across single cells in each sample and their clinical phenotype, and to enhance single-cell exploration by integrating cell and gene-level information. This study proposes a method to learn phenotype-related sample representations from single cells via the attention-based multiple instance learning (AMIL) mechanism. This approach incorporates gene expression profiles from each single cell for sample-level clinical phenotype prediction. By integrating deep learning interpretation methods and phenotype-specific single-cell attention weights across sample groups, this method highlights critical gene programs and cell subtypes that mostly contribute to the sample-level clinical phenotype, and facilitate mechanistic exploration. Using single-cell atlases from COVID-19 infected patients and age-related healthy human blood, we demonstrate that this method can accurately predict disease severity and age-related phenotypes. Additionally, variations in cellular attention reflect the underlying biological mechanisms associated with these phenotypes. This method proposes a supervised framework for single-cell data interpretation and can be further adapted for other atlas-level clinical phenotype analyses.

bioinformatics↗

bioRxiv2024

Precise amplification-free detection of highly structured RNA with an enhanced SCas12a assay

The CRISPR/Cas12a system has revolutionized molecular diagnostics; however, its application in directly detecting complex structured RNA remains challenging. Recently, we have developed a RNA detection method called SCas12a, which exhibits high sensitivity and efficiency in detecting RNA molecules devoid of intricate secondary structures. Here, we present an enhanced SCas12a assay (SCas12aV2) that facilitates precise amplification-free detection of highly structured RNA molecules. Our approach reengineers the split Cas12a system by optimizing the scaffold RNA length and targeting asymmetric RNA structures, thereby minimizing steric hindrance. We observe that utilization of a dsDNA-ssDNA hybrid DNA activator significantly enhances both the sensitivity and kinetics compared to those achieved using traditional ssDNA or dsDNA activators. The SCas12aV2 assay demonstrates exceptional sensitivity, with a limit of detection reaching 246 aM for pooled activators and 10 pM for single-site targeting. It also exhibits high specificity for single nucleotide polymorphisms (SNPs) and successfully identifies viable bacterial populations and SARS-CoV-2 infections from clinical samples. The assays versatility is further highlighted by its applicability to various Cas12a orthologs, including the thermostable CtCas12a. This work offers a significant advance in molecular diagnostics, enhancing the potential for accurate and efficient RNA detection.

molecular biology↗

bioRxiv2024

Human transcription factor combinations mapped by genome-wide footprinting with deaminase

An individuals somatic cells have the same genome but exhibit cell-type-specific transcriptome regulated by a combination of transcription factors (TFs) for each gene. Mapping of TF sites on the human genome is critically important for understanding functional genomics. Here we report a novel technique to measure human TFs binding sites genome-wide with single-base resolution by footprinting with deaminase (FOODIE). Single-molecule sequencing reads from thousands of cells after in situ deamination yielded site-specific TF binding fractions and the cooperativity among adjacent TFs. In a human lymphoblastoid cell line, we found that genes in a correlated gene module (CGM) share TF(s) in their cis-regulatory elements to participate a particular biological function. Finally, single-cell resolved experiments (scFOODIE) allow cell-type-specific TF footprinting in heterogeneous brain tissues.

genomics↗

bioRxiv2024

Knowledge Graph-based Thought: a knowledge graph enhanced LLMs framework for pan-cancer question answering

BackgroundIn recent years, Large Language Models (LLMs) have shown promise in various domains, notably in biomedical sciences. However, their real-world application is often limited by issues like erroneous outputs and hallucinatory responses. ResultsWe developed the Knowledge Graph-based Thought (KGT) framework, an innovative solution that integrates LLMs with Knowledge Graphs (KGs) to improve their initial responses by utilizing verifiable information from KGs, thus significantly reducing factual errors in reasoning. The KGT framework demonstrates strong adaptability and performs well across various open-source LLMs. Notably, KGT can facilitate the discovery of new uses for existing drugs through potential drug-cancer associations, and can assist in predicting resistance by analyzing relevant biomarkers and genetic mechanisms. To evaluate the Knowledge Graph Question Answering (KGQA) task within biomedicine, we utilize a pan-cancer knowledge graph to develop a pan-cancer question answering benchmark, named the Pan-cancer Question Answering (PcQA). ConclusionsThe KGT framework substantially improves the accuracy and utility of LLMs in the biomedical field. This study serves as a proof-of-concept, demonstrating its exceptional performance in biomedical question answering. Key PointsO_LIWe introduce a framework combining LLMs with KGs to improve factual accuracy in LLM reasoning. C_LIO_LIOur system is a flexible architecture that seamlessly integrates various LLMs. C_LIO_LIUtilizing a pan-cancer knowledge graph, we have proposed the first KGQA benchmark in the field of biomedicine. C_LIO_LICase studies reveal our method enhanced LLMs in addressing biomedical challenges such as drug repositioning, resistance research, individualized treatment, and biomarker analysis. C_LIO_LIThe method performs favorably in comparison to existing methods. C_LI

bioinformatics↗

bioRxiv2024

Transcription factor dynamics, oscillation, and functions in human enteroendocrine cell differentiation

Enteroendocrine cells (EECs), which secrete serotonin (enterochromaffin cells, EC) or a dominant peptide hormone, serve vital physiologic functions. As with any adult human lineage, the basis for terminal cell diversity remains obscure. We replicated human EEC differentiation in vitro, mapped transcriptional and chromatin dynamics that culminate in discrete cell types, and studied abundant EEC precursors expressing selected transcription factors (TFs) and gene programs. Before expressing the pre-terminal factor NEUROD1, non-replicating precursors oscillated between epigenetically similar but transcriptionally distinct ASCL1+ and HES6hi cell states. Loss of either factor substantially accelerated EEC differentiation and disrupted EEC individuality; ASCL1 or NEUROD1 deficiency had opposing consequences on EC and hormone-producing cell features. Expressed late in EEC differentiation, the latter TFs mainly bind cis-elements that are accessible in undifferentiated stem cells and tailor the subsequent expression of TF combinations that specify EEC types. Thus, TF oscillations retard EEC maturation to enable accurate EEC diversification.

molecular biology↗

bioRxiv2023

Changes in the structure of spontaneous speech predict the disruption of hierarchical brain organization in first-episode psychosis

Psychosis implicates changes across a broad range of cognitive functions. These functions are cortically organized in the form of a hierarchy ranging from primary sensorimotor (unimodal) to higher-order association cortices, which involve functions such as language (transmodal). Language has long been documented as undergoing structural changes in psychosis. We hypothesized that these changes as revealed in spontaneous speech patterns may act as readouts of alterations in the configuration of this unimodal-to-transmodal axis of cortical organization in psychosis. Results from 29 patients with first-episodic psychosis (FEP) and 29 controls scanned with 7T resting-state fMRI confirmed a compression of the cortical hierarchy in FEP, which affected metrics of the hierarchical distance between the sensorimotor and default mode networks, and of the hierarchical organization within the semantic network. These organizational changes were predicted by graphs representing semantic and syntactic associations between meaningful units in speech produced during picture descriptions. These findings unite psychosis, language, and the cortical hierarchy in a single conceptual scheme, which helps to situate language within the neurocognition of psychosis and opens the clinical prospect for mental dysfunction to become computationally measurable in spontaneous speech.

neuroscience↗

bioRxiv2023

From sequence to ecology: siderophore-receptor coevolution algorithm predicts bacterial interactions in complex communities

Predicting bacterial social interactions from genome sequences is notoriously difficult. Here, we developed bioinformatic tools to predict whether secreted iron-scavenging siderophores stimulate or inhibit the growth of community members. Siderophores are chemically diverse and can be stimulatory or inhibitory depending on whether bacteria possess or lack corresponding uptake receptors. We focused on 1928 representative Pseudomonas genomes and developed a co-evolution algorithm to match all encoded siderophore synthetases to corresponding receptor gene groups with >90% accuracy based on experimental validation. We derived community-level iron interaction networks to show that selection for siderophore-mediated interactions differs across habitats and lifestyles. Specifically, dense networks of siderophore sharing and competition were observed among environmental (soil/water/plant) strains and non-pathogenic species, while only fragmented networks occurred among human-derived strains and pathogenic species. Altogether, our sequence-to-ecology approach empowers the analyses of social interactions among thousands of bacterial strains and uncovers ways for targeted intervention to microbial communities. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=87 SRC="FIGDIR/small/565711v3_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@60d907org.highwire.dtl.DTLVardef@48756eorg.highwire.dtl.DTLVardef@115aac1org.highwire.dtl.DTLVardef@17d76e5_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2023

From sequence to molecules: Feature sequence-based genome mining uncovers the hidden diversity of bacterial siderophore pathways

Microbial secondary metabolites are a rich source for pharmaceutical discoveries and play crucial ecological functions. While tools exist to identify secondary metabolite clusters in genomes, precise sequence-to-function mapping remains challenging because neither function nor substrate specificity of biosynthesis enzymes can accurately be predicted. Here we developed a knowledge-guided bioinformatic pipeline to solve these issues. We analyzed 1928 genomes of Pseudomonas bacteria and focused on iron-scavenging pyoverdines as model metabolites. Our pipeline predicted 188 chemically different pyoverdines with nearly 100% structural accuracy and the presence of 94 distinct receptor groups required for the uptake of iron-loaded pyoverdines. Our pipeline unveils an enormous yet overlooked diversity of siderophores (151 new structures) and receptors (91 new groups). Our approach, combining feature sequence with phylogenetic approaches, is extendable to other metabolites and microbial genera, and thus emerges as powerful tool to reconstruct bacterial secondary metabolism pathways based on sequence data. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/564663v5_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1dedad4org.highwire.dtl.DTLVardef@1f0a39eorg.highwire.dtl.DTLVardef@185e345org.highwire.dtl.DTLVardef@10beec6_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2023

IL-23 receptor signaling licenses group 3-like innate lymphoid cells to restrict a live-attenuated oral Chlamydia vaccine in the gut

An IFN{gamma}-susceptible mutant of Chlamydia muridarum is attenuated in pathogenicity in the genital tract and recently licensed as an intracellular Oral vaccine vector or intrOv. Oral delivery of intrOv induces transmucosal protection in the genital tract but intrOv itself is cleared from the gut (without shedding any infectious particles externally) by IFN{gamma} from group 3-like innate lymphoid cells (ILC3s). We further characterized the intrOv interactions with ILC3s in the current study since the interactions may impact both the safety and efficacy of intrOv as an oral Chlamydia vaccine. Intracolonic inoculation with intrOv induced IFN{gamma} that in return inhibited intrOv. The intrOv-IFN{gamma} interactions were dependent on ROR{gamma}t, a signature transcriptional factor of ILC3s. Consistently, transfer of oral intrOv-induced ILC3s from ROR{gamma}t-GFP reporter mice to IFN{gamma}-deficient mice rescued the inhibition of intrOv. Thus, IFN{gamma} produced by intrOv-induced ILC3s is likely responsible for inhibiting intrOv, which is further supported by the observation that oral intrOv did induce significant levels of IFN{gamma}-producing LC3s (IFN{gamma}+ILC3s). Interestingly, IL-23 receptor knockout (IL-23R-/-) mice no longer inhibited intrOv, which was accompanied with reduced colonic IFN{gamma}. Transfer of oral intrOv-induced ILC3s rescued the IL-23R-/- mice to inhibit intrOv, validating the dependence of ILC3s on IL-23R signaling for inhibiting intrOv. Clearly, intrOv induces intestinal IFN{gamma}+ILC3s for its own inhibition in the gut, which is facilitated by IL-23R signaling. These findings have provided a mechanism for ensuring the safety of intrOv as an oral Chlamydia vaccine and a platform for investigating how oral intrOv induces transmucosal protection in the genital tract. SignificanceDespite the extensive efforts, no subunit vaccine is available for protecting humans against C. trachomatis infection and pathogenicity. Recent studies have led to a licensed live-attenuated oral vaccine (intrOv) that is both effective in inducing transmucosal protection in the genital tract and safe due to its susceptibility to IFN{gamma} delivered by ILC3s. Characterization of the intrOv interactions with IFN{gamma}-producing ILC3s in the current study has revealed a critical role of IL-23 receptor signaling in facilitating ILC3s to clear intrOv from the gut, which has provided a mechanism for ensuring the safety of intrOv and laid a foundation for further revealing the mechanisms by which oral intrOv induces transmucosal immunity in the genital tract since ILC3s can also function as antigen presenting cells.

immunology↗

bioRxiv2023

SIDERITE: Unveiling Hidden Siderophore Diversity in the Chemical Space Through Digital Exploration

Siderophores, a highly diverse family of secondary metabolites, play a crucial role in facilitating the acquisition of the essential iron. However, the current discovery of siderophore relies largely on manual approaches. In this work, we introduced SIDERTE, a digitized siderophore information database containing 872 siderophore records with 649 unique structures. Leveraging this digitalized dataset, we gained a systematic overview of siderophores by their clustering patterns in the chemical space. Building upon this, we developed a functional group-based method for predicting new iron-binding molecules. Applying this method to 4,314 natural product molecules from TargetMols Natural Product Library for high throughput screening, we experimentally confirmed that 40 out of the 48 molecules predicted as siderophore candidates possessed iron-binding abilities. Expanding our approach to the COCONUT natural product database, we predicted a staggering 3,199 siderophore candidates, showcasing remarkable structure diversity that are largely unexplored. Our study provides a valuable resource for accelerating the discovery of novel iron-binding molecules and advancing our understanding towards siderophores.

biochemistry↗

bioRxiv2023

A computational pipeline for spatial mechano-transcriptomics

Advances in spatial profiling technologies are providing insights into how molecular programs are influenced by local signaling and environmental cues. However, cell fate specification and tissue patterning involve the interplay of biochemical and mechanical feedback. Here, we develop a computational framework that enables the joint statistical analysis of transcriptional and mechanical signals in the context of spatial transcriptomics. To illustrate the application and utility of the approach, we use spatial transcriptomics data from the developing mouse embryo to infer the forces acting on individual cells, and use these results to identify mechanical, morphometric, and gene expression signatures that are predictive of tissue compartment boundaries. In addition, we use geoadditive structural equation modeling to identify gene modules that predict the mechanical behavior of cells in an unbiased manner. This computational framework is easily generalized to other spatial profiling contexts, providing a generic scheme for exploring the interplay of biomolecular and mechanical cues in tissues.

genomics↗

bioRxiv2023

Multimodal engineering of extracellular vesicles for efficient intracellular protein delivery

Extracellular vesicles (EVs) are promising tools to transfer macromolecular therapeutic molecules to recipient cells, however, efficient functional intracellular protein delivery by EVs remains challenging. Here, we have developed novel and versatile systems that leverage selected molecular tools to engineer EVs for robust cytosolic protein delivery both in vitro and in vivo. These systems, termed VSV-G plus EV-sorting Domain-Intein-Cargo (VEDIC) and VSV-G-Foldon-Intein-Cargo (VFIC), exploit an engineered mini-intein (intein) protein with self-cleavage activity to link cargo to an EV-sorting domain and release it from the EV membrane inside the EV lumen. In addition, we utilize the fusogenic protein VSV-G to facilitate endosomal escape and cargo release from the endosomal system to the cytosol of recipient cells. Importantly, we demonstrate that the combination of the self-cleavage intein, fusogenic protein and EV-sorting domain are indispensable for efficient functional intracellular delivery of cargo proteins by engineered EVs. As such, nearly 100% recombination and close to 80% genome editing efficiency in reporter cells were observed by EV-transferred Cre recombinase and Cas9/sgRNA RNPs, respectively. Moreover, EV-mediated Cre delivery by VEDIC or VFIC engineered EVs resulted in significant in vivo recombination in Cre-LoxP R26-LSL-tdTomato reporter mice following both local and systemic injections. Finally, we applied these systems for improved treatment of LPS-induced systemic inflammation by delivering a super-repressor of NF-B activity. Altogether, this study describes a platform by which EVs can be utilized as a vehicle for the efficient intracellular delivery of macromolecular therapeutics for treatments of disease. Graphic summary: Development of VEDIC and VFIC systems for high-efficiency intracellular protein delivery in vitro and in vivo.Intein in tripartite fusion protein (EV-sorting Domain-Intein-Cargo) performs C-terminal cleavage during the process of EV-biogenesis, resulting in enriched free cargo proteins inside of vesicles. Together with fusogenic protein, VSV-G, these engineered EVs achieve high-efficiency intracellular delivery of cargo protein (Cre and super repressor of NF-B) or protein complex (Cas9/sgRNA RNPs) both in reporter cells and in mice models. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/535834v4_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@d0da37org.highwire.dtl.DTLVardef@1a6514corg.highwire.dtl.DTLVardef@235c9aorg.highwire.dtl.DTLVardef@194bbfa_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Learning virus genotype-fitness landscape in embedding space

The relationship between genotype and fitness is fundamental to evolution, but quantitatively mapping genotypes to fitness has remained challenging. We propose the Phenotypic-Embedding theorem (P-E theorem) that bridges genotype-phenotype through an encoder-decoder deep learning framework. Inspired by this, we proposed a more general first principle for correlating genotype-phenotype, and the Phenotypic-Embedding theorem provides a computable basis for the application of first principle. As an application example of the P-E theorem, we developed the Co-attention based Transformer model to bridge Genotype and Fitness (CoT2G-F) model, a Transformer-based pre-train foundation model with downstream supervised fine-tuning (SFT) that can accurately simulate the neutral evolution of viruses and predict immune escape mutations. Accordingly, following the calculation path of the P-E theorem, we accurately obtained the basic reproduction number (R0) of SARS-CoV-2 from first principles, quantitatively linked immune escape to viral fitness, and plotted the genotype-fitness landscape. The theoretical system we established provides a general and interpretable method to construct genotype-phenotype landscapes, providing a new paradigm for studying theoretical and computational biology.

evolutionary biology↗

bioRxiv2023

Omics Analysis Unveils the Pathway Involved in the Purple Coloration in Tomato Seedling and Fruits

The purple tomato variety Indigo Rose(InR) is favored due to its bright appearance and abundant anthocyanins. SlHY5 is associated with anthocyanin biosynthesis in Indigo Rose plants. However, residual anthocyanins still present in Slhy5 seedlings and fruit peel indicated there was an anthocyanin induction pathway that is independent of HY5 in plants. The molecular mechanism of color formation in Indigo Rose and Slhy5 mutants is unclear. In this study, we performed omics analysis to clarify the regulatory network underlying coloration in seedling and fruit peel of Indigo Rose and Slhy5 mutant. Results showed that the total amount of anthocyanins in both seedling and fruit of InR were significantly higher than those in Slhy5 mutant and most genes associated with anthocyanin biosynthesis exhibited higher expression levels in InR, suggesting that SlHY5 play pivotal roles in flavonoid biosynthesis both in tomato seedlings and fruit. Yeast two-hybrid (Y2H) results revealed that SlBBX24 physically interacts with SlAN2-like and SlAN2, while SlWRKY44 could interact with SlAN11 protein. Unexpectedly, both SlPIF1 and SlPIF3 were found to interact with SlBBX24, SlAN1 and SlJAF13 by yeast two-hybrid assay. Suppression of SlBBX24 by virus-induced gene silencing (VIGS) retarded the purple coloration of the fruit peel, indicating an important role of SlBBX24 in the regulation of anthocyanin accumulation. These results deepen the understanding of purple color formation in tomato seedling and fruits in an HY5-dependent or independent manner via excavating the genes involved in anthocyanin biosynthesis based on omics analysis.

molecular biology↗

bioRxiv2023

Ferroptosis is determined by chloride ions

Ferroptosis has emerged as a deliberate type of programmed cell death that manifests marked importance ubiquitously in health and diseases. However, after a decade of research, the mechanisms of ferroptosis execution remain unclear. Here we identify chloride ions (Cl-) as essential determinants of ferroptosis. Water homeostasis manipulated by extracellular solute concentration disrupts ferroptotic cell death. Hyperosmotic stress attenuates ferroptosis and endues cells with high lipid peroxidation. Analyses of a fluorescent chloride probe show that Cl- fluxes into the cytoplasm during ferroptosis, substantiating a role for Cl- to drive water flow. Depletion of extracellular chloride ions ([Cl-]o) from culture media congruously confers resistance to ferroptosis. The [Cl-]o-depleted ferroptotic cells fall into two populations: cells with low lipid peroxidation; cells with high lipid peroxidation but not cell swelling or cell rupture. Contrarily, solitary [Cl-]o overload is sufficient to elicit ferroptosis without canonical ferroptosis inducers. Further experiments show that ferroptotic cells depolarize and [Cl-]o is positively correlated with this process. Membrane depolarization upregulates the level of lipid peroxidation, suggesting that membrane potential may be a universal mechanism governing ferroptosis. Together, our findings reveal that ferroptosis is determined by chloride ions.

cell biology↗

bioRxiv2023

Multi-species polyploidization, chromosome shuffling, and genome extraction in Zea/Tripsacum hybrids

By hybridization and special sexual reproduction, we sequentially aggregated Zea mays, Zea perennis, and Tripsacum dactyloides in an allohexaploid, backcrossed it with maize, derived self-fertile allotetraploids of maize and Z. perennis by natural genome extraction, extended their first six selfed generations, and finally constructed amphitetraploid maize using nascent allotetraploids as a genetic bridge. Transgenerational chromosome inheritance, subgenomes stability, chromosome pairings and rearrangements, and their impacts on an organisms fitness were investigated by fertility phenotyping and molecular cytogenetics techniques GISH and FISH. Results showed that diversified sexual reproductive methods produced highly differentiated progenies (2n=35-84) with varying proportions of subgenomic chromosomes, of which one individual (2n=54, MMMPT) overcame self-incompatibility barriers and produced self-fertile nascent near-allotetraploid by preferentially eliminating Tripsacum chromosomes. Nascent near-allotetraploid progenies showed persistent chromosome changes, intergenomic translocations, and rDNA variations for at least up to the first six selfed generations; however, ploidy tended to stabilize at near-tetraploid level (2n=40) with full integrity of 45SrDNA pairs, and a trend of decreasing variations by advancing generations with an average of 25.53, 14.14, and 0.37 maize, Z. perennis, and T. dactyloides chromosomes, respectively. The mechanisms for three genome stabilities and karyotype evolution for formatting new polyploid species were discussed.

genetics↗

bioRxiv2023

Induction of transmucosal protection by oral vaccination with an attenuated Chlamydia

Chlamydia muridarum has been used to study chlamydial pathogenesis since it induces mice to develop hydrosalpinx, a pathology observed in C. trachomatis-infected women. We identified a C. muridarum mutant that is no longer able to induce hydrosalpinx. In the current study, we evaluated the mutant as an attenuated vaccine. Following an intravaginal immunization with the mutant, mice were protected from hydrosalpinx induced by wild type C. muridarum. However, the mutant itself productively colonized the mouse genital tract and produced infectious organisms in vaginal swabs. Nevertheless, the mutant failed to produce infectious shedding in the rectal swabs following an oral inoculation. Importantly, mice orally inoculated with the mutant mounted transmucosal immunity against challenge infection of wild type C. muridarum in the genital tract. The protection was detected as early as day 3 following the challenge infection and the immunized mice were protected from any significant pathology in the upper genital tract. However, the same orally immunized mice failed to prevent the colonization of wild type C. muridarum in the gastrointestinal tract. The transmucosal immunity induced by the oral mutant was further validated in the airway. The orally vaccinated mice were protected from both lung infection and systemic toxicity caused by intranasally inoculated wild type C. muridarum although the same mice still permitted the gastrointestinal colonization by the wild type C. muridarum. These observations suggest that the mutant C. muridarum may be developed into an intracellular oral vaccine vector (or IntrOv) for selectively inducing transmucosal immunity in extra-gut tissues.

immunology↗