Tick-borne Rickettsia, Anaplasma, Theileria, and enzootic nasal tumor virus in ruminant, PET, and poultry animals in Pakistan.

Introduction: Pakistan is an agricultural country; most of its income is based on livestock rearing. The increasing prevalence of tick-borne pathogens among animals may affect the animal production and livelihood of owners, which eventually derange the economy of a country. Methodology: To further comprehend TBPs, 213 ticks were collected from different animals, including ruminants, pets, and poultry. After molecular and phylogenetic analysis identification, ticks were managed into different pools based on their species level (Hyalomma anatolicum = 80, Rhipicephalus microplus = 35, Hyalomma scupense = 23, Rhipicephalus turanicus = 70, and Rhipicephalus sanguineus = 5). Results and discussion: After tick species identification, further molecular PCR amplification was carried out to screen out the pathogens for the presence of Theileria, Rickettsia, Anaplasma, and enzootic nasal tumor virus (ENTV). The following pathogens were detected: 11 (5.16%) for Anaplasma, 1 (0.47%) for Rickettsia, and 9 (4.23%) for Theileria. Nevertheless, other TBPs that had not been reported so far in Pakistan 3 (1.41%), were positive for enzootic nasal tumor virus (ENTV). Besides, phylogenetic analysis of the enzootic nasal tumor virus (ENTV) strain confirmed its resemblance to the Chinese strain, while Anaplasma has comparability with Pakistan and China, Rickettsia with Pakistan, China, and Iran, and Theileria with India, South Africa, United States, Japan, and Spain. Conclusion: This study reveals that there is a considerably wider range of TBPs held in Pakistan that take in various contagious zoonotic pathogens than was previously thought. This information advances TBP epidemiology and will contribute to upgrade future control measure.

A rapid and sensitive fluorescent chromatography with cloud system for MPXV point-of-care diagnosis.

Monkeypox (mpox) is spreading around the world, and its rapid diagnosis is of great significance. In the present study, a rapid and sensitive fluorescent chromatography assisted with cloud system was developed for point-of-care diagnosis of mpox. To screen high affinity antibodies, nanoparticle antigen AaLS-A29 was generated by conjugating A29 onto scaffold AaLS. Immunization with AaLS-A29 induced significantly higher antibody titers and monoclonal antibodies were generated with the immunized mice. A pair of monoclonal antibodies, MXV 14 and MXV 15, were selected for fluorescence chromatography development. The Time-Resolved Fluorescence Immunoassay (TRFIA) was used to develop the chromatography assay. After optimization of the label and concentration of antibodies, a sensitive TRFIA assay with detection limit of 20 pg/mL and good repeatability was developed. The detection of the surrogate Vaccinia virus (VACA) strain Tian Tan showed that the TRFIA assay was more sensitive than the SYBR green I based quantitative PCR. In real samples, the detection result of this assay were highly consistent with the judgement of Quantitative Real-Time PCR (Concordance Rate = 90.48%) as well as the clinical diagnosis (Kappa Value = 0.844, P < 0.001). By combining the portable detection and online cloud system, the detection results could be uploaded and shared, making this detection system an ideal system for point-of-care diagnosis of mpox both in field laboratory and outbreak investigation.

Effects of dietary supplementation of postbiotic derived from Bacillus subtilis ACCC 11025 on growth performance, meat yield, meat quality, excreta bacteria, and excreta ammonia emission of broiler chicks.

The primary aim of this study was to explore the impact of dietary supplementation with a postbiotic derived from Bacillus subtilis ACCC 11025 on growth performance, meat yield, meat quality, excreta bacterial populations, and excreta ammonia emissions of broiler chicks. A total of 480 day-old Arbor Acre broiler chicks, initially weighing 52.83 ± 1.38 g, were randomly allocated into 4 distinct groups. Each group was housed in 6 separate cages, each containing 20 birds. The experimental phase spanned 42 d, divided into 2 periods (d 1-21 and d 22-42). Dietary interventions were based on a basal diet, with postbiotic supplementation at levels of 0.000, 0.015, 0.030, or 0.045%. Our findings indicate that dietary supplementation with postbiotic had a positive influence on body weight gain (BWG) and feed efficiency. The most substantial improvements in BWG and feed efficiency were observed in the group of broiler chicks fed a diet containing 0.015% postbiotic. Furthermore, the inclusion of postbiotic in the diet led to an increase in the yield of breast and leg muscles, with a significant difference in meat yields observed between the control group and the group receiving 0.015% postbiotic supplementation. It's noteworthy that dietary manipulation did not exert any discernible impact on the quality of breast and leg muscle samples. Concurrently, we observed an elevation in serum albumin and total protein contents corresponding to the increasing postbiotic dosage in the diet. Additionally, dietary supplementation with postbiotic effectively controlled the emission of ammonia from excreta and reduced the abundance of Salmonella in excreta while enhancing the presence of Lactobacillus bacteria. The group receiving 0.015% postbiotic supplementation displayed the lowest levels of ammonia emission and the highest counts of Lactobacillus bacteria in excreta. In light of these results, we conclude that dietary supplementation with 0.015% postbiotic represents an efficacious strategy for increasing BWG and meat yield of broiler chicks by enhancing feed efficiency as well as mitigating ammonia emissions from excreta by modulating the composition of excreta bacterial communities.

Rapid and highly potent humoral responses to mpox nanovaccine candidates adjuvanted by thermostable scaffolds.

Monkeypox (mpox) is a zoonotic disease caused by monkeypox virus (MPXV) of the orthopoxvirus genus. The emergence and global spread of mpox in 2022 was declared as a public health emergency by World Health Organization. This mpox pandemic alarmed us that mpox still threaten global public health. Live vaccines could be used for immunization for this disease with side effects. New alternative vaccines are urgently needed for this re-emerging disease. Specific antibody responses play key roles for protection against MPXV, therefore, vaccines that induce high humoral immunity will be ideal candidates. In the present study, we developed thermostable nanovaccine candidates for mpox by conjugating MPXV antigens with thermostable nanoscafolds. Three MPXV protective antigens, L1, A29, and A33, and the thermostable Aquafex aeolicus lumazine synthase (AaLS), were expressed in E. coli and purified by Ni-NTA methods. The nanovaccines were generated by conjugation of the antigens with AaLS. Thermal stability test results showed that the nanovaccines remained unchanged after one week storage under 37℃ and only partial degradation under 60℃, indicating high thermostability. Very interesting, one dose immunization with the nanovaccine could induce high potent antibody responses, and two dose induced 2-month high titers of antibodes. In vitro virus neutralization test showed that nanovaccine candidates induced significantly higher levels of neutralization antibodies than monomers. These results indicated that the AaLS conjugation nanovaccines of MPXV antigens are highly thermostable in terms of storage and antigenic, being good alternative vaccine candidates for this re-emerging disease.

A Divalent Chikungunya and Zika Nanovaccine with Thermostable Self-Assembly Multivalent Scaffold LS-SUMO.

The convergence strategies of antigenic subunits and synthetic nanoparticle scaffold platform improve the vaccine production efficiency and enhance vaccine-induced immunogenicity. Selecting the appropriate nanoparticle scaffold is crucial to controlling target antigens immunologically. Lumazine synthase (LS) is an attractive candidate for a vaccine display system due to its thermostability, modification tolerance, and morphological plasticity. Here, the first development of a multivalent thermostable scaffold, LS-SUMO (SUMO, small ubiquitin-likemodifier), and a divalent nanovaccine covalently conjugated with Chikungunya virus E2 and Zika virus EDIII antigens, is reported. Compared with antigen monomers, LS-SUMO nanoparticle vaccines elicit a higher humoral response and neutralizing antibodies against both antigen targets in mouse sera. Mice immunized with LS-SUMO conjugates produce CD4+ T cell-mediated Th2-biased responses and promote humoral immunity. Importantly, LS-SUMO conjugates possess equivalent humoral immunogenicity after heat treatment. Taken together, LS-SUMO is a powerful biotargeting nanoplatform with high-yield production, thermal stability and opens a new avenue for multivalent presentation of various antigens.

Development and Immunological Evaluation of a Multiantigen Thermostable Nanovaccine Adjuvanted with T-Cell-Activating Scaffold for African Swine Fever.

African swine fever is an acute and highly contagious infectious disease with a mortality rate of up to 100%. The lack of commercial vaccines and drugs is a serious economic threat to the global pig industry. Cell-mediated immunity plays an essential role in protection against viral infection. We previously reported the rational design of a T-cell-activating thermostable scaffold (RPT) for antigen delivery and improved cellular immunity. We conjugated antigens P30, P54, P72, CD2 V, and CP312R to RPT, using a SpyCatcher/SpyTag covalent attachment strategy to construct nanovaccines (multiantigens-RPT). Multiantigens-RPT exhibited significantly higher thermal, storage, and freeze-thaw stability. The specific antibodies IgG and IgG2a of the multiantigen-RPT-immunized were higher than the antigens cocktail-immunized by approximately 10-100 times. ELISpot demonstrated that more IFN-γ-secreting cells were produced by the multiantigen-RPT-immunized than by the antigens cocktail-immunized. Delivery of the multiantigen nanovaccine by a T-cell-activating scaffold induced strong humoral and cellular immune responses in mice and pigs and is a potentially useful candidate vaccine for the African swine fever virus.

A genome-wide CRISPR screen identified host genes essential for intracellular Brucella survival.

Brucella is a zoonotic intracellular bacterium that poses threats to human health and economic security. Intracellular infection is a hallmark of the agent Brucella and a primary cause of distress, through which the bacterium regulates the host intracellular environment to promote its own colonization and replication, evading host immunity and pharmaceutical killing. Current studies of Brucella intracellular processes are typically premised on bacterial phenotype such as intracellular bacterial survival, followed by biochemical or molecular biological approaches to reveal detailed mechanisms. While such processes can deepen the understanding of Brucella-host interaction, the insights into host alterations in infection would be easily restricted to known pathways. In the current study, we applied CRISPR Cas9 screen to identify host genes that are most affected by Brucella infection on cell viability at the genomic level. As a result of CRISPR screening, we firstly identified that knockout of the negatively selected genes GOLGA6L6, DEFB103B, OR4F29, and ERCC6 attenuate the viability of both the host cells and intracellular Brucella, suggesting these genes to be potential therapeutic targets for Brucella control. In particular, knockout of DEFB103B diminished Brucella intracellular survival by altering host cell autophagy. Conversely, knockout of positive screening genes promoted intracellular proliferation of Brucella. In summary, we screened host genes at the genomic level throughout Brucella infection, identified host genes that are previously not recognized to be involved in Brucella infection, and provided targets for intracellular infection control.IMPORTANCEBrucella is a Gram-negative bacterium that infects common mammals causing arthritis, myalgia, neuritis, orchitis, or miscarriage and is difficult to cure with antibiotics due to its intracellular parasitism. Therefore, unraveling the mechanism of Brucella-host interactions will help controlling Brucella infections. CRISPR-Cas9 is a gene editing technology that directs knockout of individual target genes by guided RNA, from which genome-wide gene-knockout cell libraries can be constructed. Upon infection with Brucella, the cell library would show differences in viability as a result of the knockout and specific genes could be revealed by genomic DNA sequencing. As a result, genes affecting cell viability during Brucella infection were identified. Further testing of gene function may reveal the mechanisms of Brucella-host interactions, thereby contributing to clinical therapy.

Spatial risk of Haemaphysalis longicornis borne Dabieshan tick virus (DBTV) in China.

The uncertainty and unknowability of emerging infectious diseases have caused many major public health and security incidents in recent years. As a new tick-borne disease, Dabieshan tick virus (DBTV) necessitate systematic epidemiological and spatial distribution analysis. In this study, tick samples from Liaoning Province were collected and used to evaluate distribution of DBTV in ticks. Outbreak points of DBTV and the records of the vector Haemaphysalis longicornis in China were collected and used to establish a prediction model using niche model combined with environmental factors. We found that H. longicornis and DBTV were widely distributed in Liaoning Province. The risk analysis results showed that the DBTV in the eastern provinces of China has a high risk, and the risk is greatly influenced by elevation, land cover, and meteorological factors. The risk geographical area predicted by the model is significantly larger than the detected positive areas, indicating that the etiological survey is seriously insufficient. This study provided molecular and important epidemiological evidence for etiological ecology of DBTV. The predicted high-risk areas indicated the insufficient monitoring and risk evaluation and the necessity of future monitoring and control work.

Potent immune responses against thermostable Foot-and-Mouth disease virus VP1 nanovaccine adjuvanted with polymeric thermostable scaffold.

Foot-and-mouth disease (FMD) is an acute zoonosis causes significant economic losses. Vaccines able to stimulate efficient protective immune responses are urgently needed. In this study, Escherichia coli-derived recombinant VP1 of serotype A and O FMD virus (FMDV) was conjugated to thermostable scaffold lumazine synthase (LS) or Quasibacillus thermotolerans encapsulin (QtEnc) using a robust plug-and-display SpyTag/SpyCatcher system to generate multimeric nanovaccines. These nanovaccines induced highly potent antibody responses in vaccinated mice. On day 14 after the first immunisation, antibody titres were approximately 100 times higher than those of monomer antigens. Both vaccines induced high and long-term IgG antibody production. Moreover, the QtEnc-VP1 nanovaccine induced higher antibody titres than the LS-VP1 nanovaccine. The nanovaccines also induced Th1-biased immune responses and higher levels of neutralising antibodies. These data indicated that FMDV nanovaccines generated by conjugating VP1 with a thermostable scaffold are highly immunogenic and ideal candidates for FMDV control in low-resource areas.

Green synthesis and characterization of an orally bioactive artemisinin-zinc nanoparticle with enhanced bactericidal activity.

The occurrence of multidrug-resistant bacteria necessitates the development of new antibacterial agents. This study synthesized artemisinin-zinc nanoparticles (AZ NPs) using a simple green method and investigated their physicochemical properties, antibacterial activity, and oral biological activity. A spherical shape morphology of AZ NPs was observed by scanning and transmission electron microscopy, with a particle size of 73 ± 2.604 nm. Energy dispersive spectrometry analysis showed that the AZ NPs consisted mainly of Zn, C, N, and O elements. According to differential scanning calorimeter analysis, the AZ NPs were stable up to 450 °C. Fourier-transform infrared spectroscopy revealed that artemisinin successfully bound to zinc acetate. The AZ NPs showed antibacterial activity against Salmonella and Escherichia coli, with a minimum inhibitory concentration of 0.056 mg/mL for both and minimum bactericidal concentrations of 0.21 and 0.11 mg/mL, respectively. The mechanisms by which AZ NPs mediate membrane damage were revealed by the downregulation of gene expression, and potassium ion and protein leakage. In vivo safety trials of these drugs revealed low toxicity. After AZ NPs were administered to infected mice, the intestinal bacteria decreased significantly, liver and kidney function were restored, histopathological damage to the liver and spleen were reduced, and the expression of inflammatory cytokines decreased. Therefore, AZ NPs have the potential as an oral antibacterial agent and can be used in antibiotic development and in the pharmaceutical industry.

Driving effect of multiplex factors on Mpox in global high-risk region, implication for Mpox based on one health concept.

Mpox is an ongoing viral zoonotic disease epidemic worldwide. Being different from conventional animal-to-human transmission, the present outbreak is mainly caused by human-to-human transmission of Mpox virus, putting forward the risk of worldwide epidemic. The current spatial distribution characteristics and risk area prediction are urgently needed for preparedness for prevention and control of the disease based on the One Health strategy. In the present study, the global outbreak point of Mpox virus were collected and used to predict potential global risk of Mpox virus with ecological niche model constructed with a combination of eco-geographical, anthropoid, meteorological, and host variables. The results showed that human factors are the key to the risk and prevalence of Mpox. The risk map indicated that Mpox may affect extensive areas worldwide. Europe and North America have the highest risk of Mpox. Although most areas have never recorded Mpox before, there are some high-risk areas in Asia. Our findings highlight population density is the most important contributing factor for high-risk area. Many large cities with dense populations, developed transportation, and high migration rate in the world, are in high risks. At present, the spread of Mpox is highly valued in the world and strict prevention and control measures have been taken. However, under the influence of human factors, Mpox has the potential of a global pandemic. The risk area prediction and main risk factors provide key information for targeted preparedness for prevention and control of Mpox outbreak and avoiding potential global epidemic through the One Health approach.

CRISPR-Cas12a test strip (CRISPR/CAST) package: In-situ detection of Brucella from infected livestock.

BACKGROUND: Brucellosis is a common zoonotic disease caused by Brucella, which causes enormous economic losses and public burden to epidemic areas. Early and precise diagnosis and timely culling of infected animals are crucial to prevent the infection and spread of Brucella. In recent years, RNA-guided CRISPR/Cas12a(Clustered Regularly Interspaced Short Palindromic Repeats and its associated protein 12a) nucleases have shown great promise in nucleic acid detection. This research aims to develop a CRISPR/CAST (CRISPR/Cas12a Test strip) package that can rapidly detect Brucella nucleic acid during on-site screening, especially on remote family pastures. The CRISPR/Cas12a system combined with recombinase polymerase amplification (RPA), and lateral flow read-out. RESULTS: We selected the conserved gene bp26, which commonly used in Brucella infection detection and compared on Genbank with other Brucella species. The genomes of Brucella abortus 2308, Brucella suis S2, Brucella melitansis 16 M, and Brucella suis 1330, et al. were aligned, and the sequences were found to be consistent. Therefore, the experiments were only performed on B. melitensis. With the CRISPR/CAST package, the assay of Brucella nucleic acid can be completed within 30 min under isothermal temperature conditions, with a sensitivity of 10 copies/µl. Additionally, no antigen cross-reaction was observed against Yersinia enterocolitica O:9, Escherichia coli O157, Salmonella enterica serovar Urbana O:30, and Francisella tularensis. The serum samples of 398 sheep and 100 cattle were tested by the CRISPR/CAST package, of which 31 sheep and 8 cattle were Brucella DNA positive. The detection rate was consistent with the qPCR results and higher than that of the Rose Bengal Test (RBT, 19 sheep and 5 cattle were serum positive). CONCLUSIONS: The CRISPR/CAST package can accurately detect Brucella DNA in infected livestock within 30 min and exhibits several advantages, including simplicity, speed, high sensitivity, and strong specificity with no window period. In addition, no expensive equipment, standard laboratory, or professional operators are needed for the package. It is an effective tool for screening in the field and obtaining early, rapid diagnoses of Brucella infection. The package is an efficient tool for preventing and controlling epidemics.

Regulating effects of chlorinated drinking water on cecal microbiota of broiler chicks.

In this study, 2 types of drinking water were provided to broiler chicks to evaluate the relationship between the bacterial load of drinking water and cecal microbiota. One type of drinking water was untreated, while the other type was daily treated with sodium dichlorocyanurate (50 mg/L). A total of 240 broiler chicks were divided into 2 groups based on their initial body weight. There were 6 replicates in each group, and each replicate cage contained 20 birds. Each cage was assigned to a different floor of the battery cage. On the final day, water samples were collected from each replicate cage at the opening of the drinking cup height, and one bird was selected from each replicate cage to obtain cecal content samples for measuring microbiota composition using the 16S rRNA technique. We found that drinking water treated with sodium dichlorocyanurate significantly reduced the richness and diversity of microbiota and diminished/disappeared most gram-negative bacteria. Broiler chicks that consumed chlorinated drinking water exhibited changes in the composition of cecal microbiota, with Alistipes serving as the marker species in the cecal content of broiler chicks that consumed untreated water, whereas AF12 served as the marker species in the cecal content of broiler chicks that consumed chlorinated drinking water. Functional prediction using the MetaCyc database and species composition analysis of metabolic pathways showed that changes in 7 metabolic pathways were related to the abundance of Providencia. Therefore, we concluded that chlorinated drinking water reduced the bacterial load in drinking water, thereby altering the cecal microbiota composition and regulating the metabolic activity of broiler chicks.

Thermostable T Cell Multiepitope Nanoparticle Antigens Inducing Potent Immune Responses against the Swine Fever Virus.

African swine fever (ASF) is caused by the African swine fever virus (ASFV) and is a highly contagious, acute, febrile disease that has high morbidity and mortality rates in domestic and wild swine. However, a safe and effective vaccine against ASF remains unavailable as single antigens fail to provide sufficient protection. Therefore, a combination of multiple antigens with an efficient delivery system might be an alternative strategy. Herein, a de novo-designed antigen with multiple T-cell epitopes (TEPs) of ASFV was conjugated for surface display on self-assembled nanoparticles (NPs) of Aquifex aeolicus lumazine synthase (AaLS) and Quasibacillus thermotolerans encapsulin (QT) through the SpyCatcher/SpyTag system to construct nanovaccines (TEP-Spy-NPs). TEP-Spy-NPs exhibited significantly more thermal, storage, and freeze-thaw stability in comparison to TEP monomers. TEP-Spy-NPs were highly immunogenic and induced strong polyclonal antibody responses in mice and pigs. The specific antibody titers against the TEP of the TEP-Spy-AaLS and TEP-Spy-QT groups were significantly higher than those of the TEP monomer immune group after the second booster immunization. The antibody titer against TEP of the TEP-Spy-QT group was approximately twice that of the TEP-Spy-AaLS group in mice. ELISpot analysis demonstrated that more IFN-γ- and IL-2-secreting splenic lymphocytes were produced by TEP-Spy-AaLS- and TEP-Spy-QT-immunized mice than by TEP monomer-immunized mice. TEP-Spy-NPs elicited stronger cellular immunity and in vivo immunity in immunized pigs than did TEP monomers. Thus, the TEP nanovaccine successfully induced strong humoral and cellular immune responses in mice and pigs, and TEP-Spy-NPs have the potential as candidate vaccines for ASFV.

Risk transboundary transmission areas and driving factors of brucellosis along the borders between China and Mongolia.

OBJECTIVE: Brucellosis is a common and neglected zoonotic infectious disease worldwide caused by Brucella. However, transboundary transmissions among countries, particularly those with high incidences, are seldom investigated. In the present study, by taking China and Mongolia as examples, we aim to identify transboundary transmission risk and driving factors of brucellosis along borders. METHODS: 167 brucellosis outbreak locations along the border between China and Mongolia were collected. Wildlife distribution and cross-border activities were mapped. Maximum entropy approach modeling was conducted to predict the potential risk of prevalence of brucellosis with meteorological factors, geographical environment, economic development, living habits et al. The accuracy of the models was assessed by the area under the receiver operating characteristic (ROC) curve (AUC), Kappa test, and correctly classified instances (CCI). RESULTS: The spatial model performed excellent predictive performance with the predictor variables of soils, pastures, goat density, mean precipitation of the wettest month, temperature seasonality, and population density, which with the contribution and permutation important in 27.2 %, 31.9; 23.3 %, 6.8; 18.0 %, 17.2; 11.2 %, 18.1; 10. 3 %, 15.2; 10.0 %, 10.8. The calculated AUC, SD, Kappa, and CCI are 0.870, 0.001, 0.882, and 0.883, respectively. The distribution map of brucellosis showed high-risk areas along the borders. CONCLUSIONS: Our study identified high-risk areas and the driving effect of brucellosis along the borders between China and Mongolia. Moreover, there is the possibility of cross-border wildlife activities in high-risk areas, which increases the risk of cross-border brucellosis transmission. The funding provides clues for cooperative prevention and control of brucellosis by reducing transboundary transmission.

Comparative application of droplet-based digital and quantitative real-time PCR for human brucellosis detection.

We evaluated the diagnostic value of droplet-based digital PCR (dd-PCR) by comparing it with the quantitative real-time PCR (RT-qPCR) for detecting Brucella DNA, 487 whole blood and serum samples collected from suspected human brucellosis, respectively. Sensitivity and specificity were 88.14% and 100% for RT-qPCR; 97.12% and 100% for dd-PCR. The positive rate detected by RT-qPCR and dd-PCR based on the nucleic acid extracted by simultaneous extraction method in serum and blood cells were 56.49% and 62.22%, respectively, which is higher than the commercial kit in 47.74% and 52.77%. Additionally, 32 false-negative samples of chronic patients analyzed by serological tests were positive in the detection from the blood cell nucleic acid. dd-PCR could be considered a valuable tool for detecting Brucella DNA, particularly in false-negative test results. The simultaneous extraction method is complementary to dd-PCR in diagnosing human brucellosis cases at different disease stages, especially in chronic and relapsed stages.

The Brucella Effector Protein BspF Regulates Apoptosis through the Crotonylation of p53.

The Brucella type IV secretion system (T4SS) can promote the intracellular survival and reproduction of Brucella. T4SS secretes effector proteins to act on cellular signaling pathways to inhibit the host's innate immune response and cause a chronic, persistent Brucella infection. Brucella can survive in host cells for a long time by inhibiting macrophage apoptosis and avoiding immune recognition. The effector protein, BspF, secreted by T4SS, can regulate host secretory transport and accelerate the intracellular replication of Brucella. BspF has an acetyltransferase domain of the GNAT (GCN5-related N-acetyltransferases) family, and in our previous crotonylation proteomics data, we have found that BspF has crotonyl transferase activity and crotonylation regulation of host cell protein in the proteomics data. Here, we found that BspF attenuates the crotonylation modification of the interacting protein p53, which reduces the p53 expression through the GNAT domain. BspF can inhibit the transcription and protein expression of downstream apoptotic genes, thereby inhibiting host cell apoptosis. Additionally, the Brucella ΔbspF mutant stain promotes apoptosis and reduces the survival rate of Brucella in the cells. In conclusion, we identified that the T4SS effector protein BspF can regulate host cell apoptosis to assist Brucella in its long-term survival by attenuating crotonylation modification of p53 and decreasing p53 expression. Our findings reveal a unique mechanism of elucidating how Brucella regulates host cell apoptosis and promotes its proliferation through the secretion of effector proteins.

T Cell Activating Thermostable Self-Assembly Nanoscaffold Tailored for Cellular Immunity Antigen Delivery.

Antigen delivery based on non-virus-like particle self-associating protein nanoscffolds, such as Aquifex aeolicus lumazine synthase (AaLS), is limited due to the immunotoxicity and/or premature clearance of antigen-scaffold complex resulted from triggering unregulated innate immune responses. Here, using rational immunoinformatics prediction and computational modeling, we screen the T epitope peptides from thermophilic nanoproteins with the same spatial structure as hyperthermophilic icosahedral AaLS, and reassemble them into a novel thermostable self-assembling nanoscaffold RPT that can specifically activate T cell-mediated immunity. Tumor model antigen ovalbumin T epitopes and the severe acute respiratory syndrome coronavirus 2 receptor-binding domain are loaded onto the scaffold surface through the SpyCather/SpyTag system to construct nanovaccines. Compared to AaLS, RPT -constructed nanovaccines elicit more potent cytotoxic T cell and CD4+ T helper 1 (Th1)-biased immune responses, and generate less anti-scaffold antibody. Moreover, RPT significantly upregulate the expression of transcription factors and cytokines related to the differentiation of type-1 conventional dendritic cells, promoting the cross-presentation of antigens to CD8+ T cells and Th1 polarization of CD4+ T cells. RPT confers antigens with increased stability against heating, freeze-thawing, and lyophilization with almost no antigenicity loss. This novel nanoscaffold offers a simple, safe, and robust strategy for boosting T-cell immunity-dependent vaccine development.

Asymmetric Assembly and Self-Adjuvanted Antigen Delivery Platform for Improved Antigen Uptake and Antitumor Effect.

The development of effective tumor vaccines is an important direction in the field of cancer prevention/immunotherapy. Efficient antigen delivery is essential for inducing effective antitumor responses for tumor vaccines. Lumazine synthase (BLS) from Brucella spp. is a decameric protein with delivery and adjuvant properties, but its application in tumor vaccines is limited. Here, we developed an antigen delivery platform by combining a BLS asymmetric assembly and the Plug-and-Display system of SpyCatcher/SpyTag. An asymmetric assembly system consisting of BLSke and BLSdr was developed to equally assemble two molecules. Then, the MHC-I-restricted ovalbumin peptide (OVA(257-264) SIINFEKL) was conjugated with BLSke, and a cell-penetrating peptide (CPP) KALA was conjugated with BLSdr using the SpyCatcher/SpyTag system. KALA modification enhanced internalization of OVA peptides by DCs as well as promoted the maturation of DCs and the cross-presentation of SIINFEKL. Moreover, the immunotherapy of a KALA-modified vaccine suppressed tumor growth and enhanced CD8+ T cell responses in E.G7-OVA tumor-bearing mice. In the prophylactic model, KALA-modified vaccination showed the most significant protective effect and significantly prolonged the survival period of tumor challenged mice. In conclusion, the asymmetric assembly platform equally assembles two proteins or peptides, avoiding their spatial or functional interference. This asymmetric assembly and Plug-and-Display technology provide a universal platform for rapid development of personalized tumor vaccines.