Isolation and Characterization of Distinct Rotavirus A in Bat and Rodent Hosts.

Rotavirus A (RVA) causes diarrheal disease in humans and various animals. Recent studies have identified bat and rodent RVAs with evidence of zoonotic transmission and genome reassortment. However, the virological properties of bat and rodent RVAs with currently identified genotypes still need to be better clarified. Here, we performed virus isolation-based screening for RVA in animal specimens and isolated RVAs (representative strains: 16-06 and MpR12) from Egyptian fruit bat and Natal multimammate mouse collected in Zambia. Whole-genome sequencing and phylogenetic analysis revealed that the genotypes of bat RVA 16-06 were identical to that of RVA BATp39 strain from the Kenyan fruit bat, which has not yet been characterized. Moreover, all segments of rodent RVA MpR12 were highly divergent and assigned to novel genotypes, but RVA MpR12 was phylogenetically closer to bat RVAs than to other rodent RVAs, indicating a unique evolutionary history. We further investigated the virological properties of the isolated RVAs. In brief, we found that 16-06 entered cells by binding to sialic acids on the cell surface, while MpR12 entered in a sialic acid-independent manner. Experimental inoculation of suckling mice with 16-06 and MpR12 revealed that these RVAs are causative agents of diarrhea. Moreover, 16-06 and MpR12 demonstrated an ability to infect and replicate in a 3D-reconstructed primary human intestinal epithelium with comparable efficiency to the human RVA. Taken together, our results detail the unique genetic and virological features of bat and rodent RVAs and demonstrate the need for further investigation of their zoonotic potential. IMPORTANCE Recent advances in nucleotide sequence detection methods have enabled the detection of RVA genomes from various animals. These studies have discovered multiple divergent RVAs and have resulted in proposals for the genetic classification of novel genotypes. However, most of these RVAs have been identified via dsRNA viral genomes and not from infectious viruses, and their virological properties, such as cell/host tropisms, transmissibility, and pathogenicity, are unclear and remain to be clarified. Here, we successfully isolated RVAs with novel genome constellations from three bats and one rodent in Zambia. In addition to whole-genome sequencing, the isolated RVAs were characterized by glycan-binding affinity, pathogenicity in mice, and infectivity to the human gut using a 3D culture of primary intestinal epithelium. Our study reveals the first virological properties of bat and rodent RVAs with high genetic diversity and unique evolutional history and provides basic knowledge to begin estimating the potential of zoonotic transmission.

Human Borreliosis Caused by a New World Relapsing Fever Borrelia-like Organism in the Old World.

BACKGROUND: Relapsing fever is an infectious disease previously neglected in Africa, which imposes a large public health burden in the country. We aimed to investigate and report on a case of relapsing fever borreliosis in Zambia. METHODS: A previously unknown Borrelia species was isolated from the blood of a febrile patient. Investigations of the presumptive vector ticks and natural hosts for the Borrelia species were conducted by culture isolation and/or DNA detection by Borrelia-specific polymerase chain reaction. Using culture isolates from the patient and bat specimens, genetic characterization was performed by multilocus sequence analysis based on the draft genome sequences. RESULTS: The febrile patient was diagnosed with relapsing fever. The isolated Borrelia species was frequently detected in Ornithodoros faini (n = 20/50 [40%]) and bats (n = 64/237 [27%]). Multilocus sequence analysis based on a draft genome sequence revealed that the Borrelia species isolates from the patient and presumptive reservoir host (bats) formed a monophyletic lineage that clustered with relapsing fever borreliae found in the United States. CONCLUSIONS: A febrile illness caused by a Borrelia species that was treatable with erythromycin was identified in Zambia. This is the first study to report on relapsing fever Borrelia in Zambia and suggesting the likely natural reservoir hosts of the isolated Borrelia species. Interestingly, the isolated Borrelia species was more closely related to New World relapsing fever borreliae, despite being detected in the Afrotropic ecozone.

Marburgvirus in Egyptian Fruit Bats, Zambia.

We detected Marburg virus genome in Egyptian fruit bats (Rousettus aegyptiacus) captured in Zambia in September 2018. The virus was closely related phylogenetically to the viruses that previously caused Marburg outbreaks in the Democratic Republic of the Congo. This finding demonstrates that Zambia is at risk for Marburg virus disease.

Seroprevalence of Filovirus Infection of Rousettus aegyptiacus Bats in Zambia.

Bats are suspected to play important roles in the ecology of filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of filovirus infection in this bat species even in countries where filovirus diseases have not been reported.

Immunological priming requires regulatory T cells and IL-10-producing macrophages to accelerate resolution from severe lung inflammation.

Overwhelming lung inflammation frequently occurs following exposure to both direct infectious and noninfectious agents and is a leading cause of mortality worldwide. In that context, immunomodulatory strategies may be used to limit severity of impending organ damage. We sought to determine whether priming the lung by activating the immune system, or immunological priming, could accelerate resolution of severe lung inflammation. We assessed the importance of alveolar macrophages, regulatory T cells, and their potential interaction during immunological priming. We demonstrate that oropharyngeal delivery of low-dose LPS can immunologically prime the lung to augment alveolar macrophage production of IL-10 and enhance resolution of lung inflammation induced by a lethal dose of LPS or by Pseudomonas bacterial pneumonia. IL-10-deficient mice did not achieve priming and were unable to accelerate lung injury resolution. Depletion of lung macrophages or regulatory T cells during the priming response completely abrogated the positive effect of immunological priming on resolution of lung inflammation and significantly reduced alveolar macrophage IL-10 production. Finally, we demonstrated that oropharyngeal delivery of synthetic CpG-oligonucleotides elicited minimal lung inflammation compared with low-dose LPS but nonetheless primed the lung to accelerate resolution of lung injury following subsequent lethal LPS exposure. Immunological priming is a viable immunomodulatory strategy used to enhance resolution in an experimental acute lung injury model with the potential for therapeutic benefit against a wide array of injurious exposures.

Resolution of experimental lung injury by monocyte-derived inducible nitric oxide synthase.

Although early events in the pathogenesis of acute lung injury (ALI) have been defined, little is known about the mechanisms mediating resolution. To search for determinants of resolution, we exposed wild type (WT) mice to intratracheal LPS and assessed the response at intervals to day 10, when injury had resolved. Inducible NO synthase (iNOS) was significantly upregulated in the lung at day 4 after LPS. When iNOS-/- mice were exposed to intratracheal LPS, early lung injury was attenuated; however, recovery was markedly impaired compared with WT mice. iNOS-/- mice had increased mortality and sustained increases in markers of lung injury. Adoptive transfer of WT (iNOS+/+) bone marrow-derived monocytes or direct adenoviral gene delivery of iNOS into injured iNOS-/- mice restored resolution of ALI. Irradiated bone marrow chimeras confirmed the protective effects of myeloid-derived iNOS but not of epithelial iNOS. Alveolar macrophages exhibited sustained expression of cosignaling molecule CD86 in iNOS-/- mice compared with WT mice. Ab-mediated blockade of CD86 in iNOS-/- mice improved survival and enhanced resolution of lung inflammation. Our findings show that monocyte-derived iNOS plays a pivotal role in mediating resolution of ALI by modulating lung immune responses, thus facilitating clearance of alveolar inflammation and promoting lung repair.

Regulatory T cells reduce acute lung injury fibroproliferation by decreasing fibrocyte recruitment.

Acute lung injury (ALI) causes significant morbidity and mortality. Fibroproliferation in ALI results in worse outcomes, but the mechanisms governing fibroproliferation remain poorly understood. Regulatory T cells (Tregs) are important in lung injury resolution. Their role in fibroproliferation is unknown. We sought to identify the role of Tregs in ALI fibroproliferation, using a murine model of lung injury. Wild-type (WT) and lymphocyte-deficient Rag-1(-/-) mice received intratracheal LPS. Fibroproliferation was characterized by histology and the measurement of lung collagen. Lung fibrocytes were measured by flow cytometry. To dissect the role of Tregs in fibroproliferation, Rag-1(-/-) mice received CD4(+)CD25(+) (Tregs) or CD4(+)CD25(-) Tcells (non-Tregs) at the time of LPS injury. To define the role of the chemokine (C-X-C motif) ligand 12 (CXCL12)-CXCR4 pathway in ALI fibroproliferation, Rag-1(-/-) mice were treated with the CXCR4 antagonist AMD3100 to block fibrocyte recruitment. WT and Rag-1(-/-) mice demonstrated significant collagen deposition on Day 3 after LPS. WT mice exhibited the clearance of collagen, but Rag-1(-/-) mice developed persistent fibrosis. This fibrosis was mediated by the sustained epithelial expression of CXCL12 (or stromal cell-derived factor 1 [SDF-1]) that led to increased fibrocyte recruitment. The adoptive transfer of Tregs resolved fibroproliferation by decreasing CXCL12 expression and subsequent fibrocyte recruitment. Blockade of the CXCL12-CXCR4 axis with AMD3100 also decreased lung fibrocytes and fibroproliferation. These results indicate a central role for Tregs in the resolution of ALI fibroproliferation by reducing fibrocyte recruitment along the CXCL12-CXCR4 axis. A dissection of the role of Tregs in ALI fibroproliferation may inform the design of new therapeutic tools for patients with ALI.

Macrophage A2A adenosinergic receptor modulates oxygen-induced augmentation of murine lung injury.

Acute respiratory distress syndrome (ARDS) causes significant morbidity and mortality. Exacerbating factors increasing the risk of ARDS remain unknown. Supplemental oxygen is often necessary in both mild and severe lung disease. The potential effects of supplemental oxygen may include augmentation of lung inflammation by inhibiting anti-inflammatory pathways in alveolar macrophages. We sought to determine oxygen-derived effects on the anti-inflammatory A2A adenosinergic (ADORA2A) receptor in macrophages, and the role of the ADORA2A receptor in lung injury. Wild-type (WT) and ADORA2A(-/-) mice received intratracheal lipopolysaccharide (IT LPS), followed 12 hours later by continuous exposure to 21% oxygen (control mice) or 60% oxygen for 1 to 3 days. We measured the phenotypic endpoints of lung injury and the alveolar macrophage inflammatory state. We tested an ADORA2A-specific agonist, CGS-21680 hydrochloride, in LPS plus oxygen-exposed WT and ADORA2A(-/-) mice. We determined the specific effects of myeloid ADORA2A, using chimera experiments. Compared with WT mice, ADORA2A(-/-) mice exposed to IT LPS and 60% oxygen demonstrated significantly more histologic lung injury, alveolar neutrophils, and protein. Macrophages from ADORA2A(-/-) mice exposed to LPS plus oxygen expressed higher concentrations of proinflammatory cytokines and cosignaling molecules. CGS-21680 prevented the oxygen-induced augmentation of lung injury after LPS only in WT mice. Chimera experiments demonstrated that the transfer of WT but not ADORA2A(-/-) bone marrow cells into irradiated ADORA2A(-/-) mice reduced lung injury after LPS plus oxygen, demonstrating myeloid ADORA2A protection. ADORA2A is protective against lung injury after LPS and oxygen. Oxygen after LPS increases macrophage activation to augment lung injury by inhibiting the ADORA2A pathway.

Cryopreservation of zebrafish (Danio rerio) primordial germ cells by vitrification of yolk-intact and yolk-depleted embryos using various cryoprotectant solutions.

The aim of this study was to examine the effects of partial removal of yolk and cryoprotectant mixtures on the viability of cryopreserved primordial germ cells (PGCs) and elucidated the differentiation ability of cryopreserved PGCs in zebrafish. First, dechorionated yolk-intact and yolk-depleted (partially yolk removed) embryos, PGCs of which were labeled with green fluorescence protein (GFP), were vitrified after serial exposures to pretreatment solution (PS) and vitrification solution (VS) that contained ethylene glycol (EG), dimethyl sulfoxide (Me2SO) or propylene glycol at 3 and 5 M, respectively. Although partial removal of yolk improved the viability of cryopreserved PGCs, numbers of PGCs with pseudopodial movement were limited (0­2.6 cells/embryo). Next, yolk-depleted embryos were cryopreserved using mixtures of two types of cryoprotectants. The maximum survival rate of PGCs (81%; 9.6 cells/embryo) was obtained from the yolk-depleted embryos vitrified using PS containing 2 M EG + 1 M Me2SO and VS containing 3 M EG + 2 M Me2SO and 56% (5.3 cells/embryo) of PGCs showed pseudopodial movement. Finally, PGCs recovered from yolk-depleted embryos (wild-type) that were vitrified under the optimum condition were transplanted individually into 236 sterilized recipient blastulae (recessive light-colored). Seven recipients matured and generated progeny with characteristics inherited from the PGC donor. In conclusion, the authors confirmed the beneficial effects of partial removal of yolk on the viability of cryopreserved PGCs and that the viability of the PGCs was improved by using PS and VS that contained two types of cryoprotectants, especially PS containing 2 M EG + 1 M Me2SO and VS containing 3 M EG + 2 M Me2SO, and that recovered PGCs retained ability to differentiate into functional gametes.

Expression of Chimeric HPV-HIV Protein L1P18 in Pichia pastoris; Purification and Characterization of the Virus-like Particles.

Currently, three human papillomavirus (HPV) vaccines are already licensed and all of them are based on virus-like particles (VLPs) of HPV L1 capsid protein but not worldwide accessible. While about 38.0 million people were living with HIV in 2019, only 68% of HIV-infected individuals were accessing antiretroviral therapy as of the end of June 2020 and there is no HIV vaccine yet. Therefore, safe, effective, and affordable vaccines against those two viruses are immediately needed. Both HPV and HIV are sexually transmitted infections and one of the main access routes is the mucosal genital tract. Thus, the development of a combined vaccine that would protect against HPV and HIV infections is a logical effort in the fight against these two major global pathogens. In this study, a recombinant Pichia pastoris producing chimeric HPV-HIV L1P18 protein intracellularly was constructed. After cell disruption, the supernatant was collected, and the VLPs were purified by a combination of ammonium sulfate precipitation, size exclusion chromatography, ultracentrifugation, and ultrafiltration. At the end of purification process, the chimeric VLPs were recovered with 96% purity and 9.23% overall yield, and the morphology of VLPs were confirmed by transmission electron microscopy. This work contributes towards the development of an alternative platform for production of a bivalent vaccine against HPV and HIV in P. pastoris.

Screening of tick-borne pathogens in argasid ticks in Zambia: Expansion of the geographic distribution of Rickettsia lusitaniae and Rickettsia hoogstraalii and detection of putative novel Anaplasma species.

Ticks (Ixodidae and Argasidae) are important arthropod vectors of various pathogens that cause human and animal infectious diseases. Many previously published studies on tick-borne pathogens focused on those transmitted by ixodid ticks. Although there are increasing reports of viral pathogens associated with argasid ticks, information on bacterial pathogens they transmit is scarce. The aim of this molecular study was to detect and characterize Rickettsia and Anaplasmataceae in three different argasid tick species, Ornithodoros faini, Ornithodoros moubata, and Argas walkerae collected in Zambia. Rickettsia hoogstraalii and Rickettsia lusitaniae were detected in 77 % (77/100) of Ar. walkerae and 10 % (5/50) of O. faini, respectively. All O. moubata pool samples (n = 124) were negative for rickettsial infections. Anaplasmataceae were detected in 63 % (63/100) of Ar. walkerae and in 82.2 % (102/124) of O. moubata pools, but not in O. faini. Phylogenetic analysis based on the concatenated sequences of 16S rRNA and groEL genes revealed that Anaplasma spp. detected in the present study were distinct from previously validated Anaplasma species, indicating that the current knowledge on the diversity and vector range of Anaplasma spp. is incomplete. Our findings highlight new geographical records of R. lusitaniae and R. hoogstraalii and confirm that the wide geographic distribution of these species includes the African continent. The data presented here increase our knowledge on argasid tick-borne bacteria and contribute toward understanding their epidemiology.

Molecular Detection and Genotyping of Coxiella-Like Endosymbionts in Ticks Collected from Animals and Vegetation in Zambia.

Ticks are obligate ectoparasites as they require to feed on their host blood during some or all stages of their life cycle. In addition to the pathogens that ticks harbor and transmit to vertebrate hosts, they also harbor other seemingly nonpathogenic microorganisms including nutritional mutualistic symbionts. Tick nutritional mutualistic symbionts play important roles in the physiology of the host ticks as they are involved in tick reproduction and growth through the supply of B vitamins as well as in pathogen maintenance and propagation. Coxiella-like endosymbionts (CLEs) are the most widespread endosymbionts exclusively reported in ticks. Although CLEs have been investigated in ticks in other parts of the world, there is no report of their investigation in ticks in Zambia. To investigate the occurrence of CLEs, their maintenance, and association with host ticks in Zambia, 175 ticks belonging to six genera, namely Amblyomma, Argas, Haemaphysalis, Hyalomma, Ornithodoros, and Rhipicephalus, were screened for CLEs, followed by characterization of CLEs by multi-locus sequence typing of the five Coxiella housekeeping genes (dnaK, groEL, rpoB, 16S rRNA, and 23S rRNA). The results showed that 45.7% (n = 80) were positive for CLEs. The comparison of the tick 16S rDNA phylogenetic tree with that of the CLEs concatenated sequences showed that there was a strong correlation between the topology of the trees. The results suggest that most of the CLEs have evolved within tick species, supporting the vertical transmission phenomenon. However, the negative results for CLE in some ticks warrants further investigations of other endosymbionts that the ticks in Zambia may also harbor.

Attenuated infection by a Pteropine orthoreovirus isolated from an Egyptian fruit bat in Zambia.

BACKGROUND: Pteropine orthoreovirus (PRV) is an emerging bat-borne zoonotic virus that causes severe respiratory illness in humans. Although PRVs have been identified in fruit bats and humans in Australia and Asia, little is known about the prevalence of PRV infection in Africa. Therefore, this study performed an PRV surveillance in fruit bats in Zambia. METHODS: Egyptian fruit bats (Rousettus aegyptiacus, n = 47) and straw-colored fruit bats (Eidolon helvum, n = 33) captured in Zambia in 2017-2018 were screened for PRV infection using RT-PCR and serum neutralization tests. The complete genome sequence of an isolated PRV strain was determined by next generation sequencing and subjected to BLAST and phylogenetic analyses. Replication capacity and pathogenicity of the strain were investigated using Vero E6 cell cultures and BALB/c mice, respectively. RESULTS: An PRV strain, tentatively named Nachunsulwe-57, was isolated from one Egyptian fruit bat. Serological assays demonstrated that 98% of sera (69/70) collected from Egyptian fruit bats (n = 37) and straw-colored fruit bats (n = 33) had neutralizing antibodies against PRV. Genetic analyses revealed that all 10 genome segments of Nachunsulwe-57 were closely related to a bat-derived Kasama strain found in Uganda. Nachunsulwe-57 showed less efficiency in viral growth and lower pathogenicity in mice than another PRV strain, Miyazaki-Bali/2007, isolated from a patient. CONCLUSIONS: A high proportion of Egyptian fruit bats and straw-colored fruit bats were found to be seropositive to PRV in Zambia. Importantly, a new PRV strain (Nachunsulwe-57) was isolated from an Egyptian fruit bat in Zambia, which had relatively weak pathogenicity in mice. Taken together, our findings provide new epidemiological insights about PRV infection in bats and indicate the first isolation of an PRV strain that may have low pathogenicity to humans.

An African tick flavivirus forming an independent clade exhibits unique exoribonuclease-resistant RNA structures in the genomic 3'-untranslated region.

Tick-borne flaviviruses (TBFVs) infect mammalian hosts through tick bites and can cause various serious illnesses, such as encephalitis and hemorrhagic fevers, both in humans and animals. Despite their importance to public health, there is limited epidemiological information on TBFV infection in Africa. Herein, we report that a novel flavivirus, Mpulungu flavivirus (MPFV), was discovered in a Rhipicephalus muhsamae tick in Zambia. MPFV was found to be genetically related to Ngoye virus detected in ticks in Senegal, and these viruses formed a unique lineage in the genus Flavivirus. Analyses of dinucleotide contents of flaviviruses indicated that MPFV was similar to those of other TBFVs with a typical vertebrate genome signature, suggesting that MPFV may infect vertebrate hosts. Bioinformatic analyses of the secondary structures in the 3'-untranslated regions (UTRs) revealed that MPFV exhibited unique exoribonuclease-resistant RNA (xrRNA) structures. Utilizing biochemical approaches, we clarified that two xrRNA structures of MPFV in the 3'-UTR could prevent exoribonuclease activity. In summary, our findings provide new information regarding the geographical distribution of TBFV and xrRNA structures in the 3'-UTR of flaviviruses.

Serologic and molecular evidence for circulation of Crimean-Congo hemorrhagic fever virus in ticks and cattle in Zambia.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonosis with a high case fatality rate in humans. Although the disease is widely found in Africa, Europe, and Asia, the distribution and genetic diversity of CCHF virus (CCHFV) are poorly understood in African countries. To assess the risks of CCHF in Zambia, where CCHF has never been reported, epidemiologic studies in cattle and ticks were conducted. Through an indirect immunofluorescence assay, CCHFV nucleoprotein-specific serum IgG was detected in 8.4% (88/1,047) of cattle. Among 290 Hyalomma ticks, the principal vector of CCHFV, the viral genome was detected in 11 ticks. Phylogenetic analyses of the CCHFV S and M genome segments revealed that one of the detected viruses was a genetic reassortant between African and Asian strains. This study provides compelling evidence for the presence of CCHFV in Zambia and its transmission to vertebrate hosts.

Production of fertile zebrafish (Danio rerio) possessing germ cells (gametes) originated from primordial germ cells recovered from vitrified embryos.

This study aimed to produce fertile zebrafish (Danio rerio) possessing germ cells (gametes) that originated from cryopreserved primordial germ cells (PGCs). First, to improve the vitrification procedure of PGCs in segmentation stage embryos, dechorionated yolk-intact and yolk-removed embryos, the PGCs of which were labeled with green fluorescent protein, were cooled rapidly after serial exposures to equilibration solution (ES) and vitrification solution (VS), which contained ethylene glycol, DMSO, and sucrose. Yolk removal well prevented ice formation in the embryos during cooling and improved the viability of cryopreserved PGCs. The maximum recovery rate of live PGCs in the yolk-removed embryos vitrified after optimum exposure to ES and VS was estimated to be about 90%, and about 50% of the live PGCs showed pseudopodial movement. Next, to elucidate the ability of cryopreserved PGCs to differentiate into functional gametes, PGCs recovered from the yolk-removed embryos (striped-type) that were vitrified under the optimum exposure to ES and VS were transplanted individually into 218 sterilized recipient blastulae (golden-type). Two days after the transplantation, 7.5% (14/187) of morphologically normal embryos had PGC(s) in the genital ridges. Six (5 males and 1 female) of the 14 recipient embryos developed into mature fish and generated progeny with characteristics inherited from PGC donors. In conclusion, we demonstrated the successful cryopreservation of PGCs by vitrification of yolk-removed embryos and the production of fertile zebrafish possessing germ cells that originated from the PGCs in vitrified embryos.

Priming with Recombinant BCG Expressing HTI Enhances the Magnitude and Breadth of the T-Cell Immune Responses Elicited by MVA.HTI in BALB/c Mice.

The use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) as a live vaccine vehicle is a promising approach for HIV-1-specific T-cell induction. In this study, we used recombinant BCG expressing HIVACAT T-cell immunogen (HTI), BCG.HTI2auxo.int. BALB/c mice immunization with BCG.HTI2auxo.int prime and MVA.HTI boost was safe and induced HIV-1-specific T-cell responses. Two weeks after boost, T-cell responses were assessed by IFN-γ ELISpot. The highest total magnitude of IFN-γ spot-forming cells (SFC)/106 splenocytes was observed in BCG.HTI2auxo.int primed mice compared to mice receiving MVA.HTI alone or mice primed with BCGwt, although the differences between the vaccination regimens only reached trends. In order to evaluate the differences in the breadth of the T-cell immune responses, we examined the number of reactive peptide pools per mouse. Interestingly, both BCG.HTI2auxo.int and BCGwt primed mice recognized an average of four peptide pools per mouse. However, the variation was higher in BCG.HTI2auxo.int primed mice with one mouse recognizing 11 peptide pools and three mice recognizing few or no peptide pools. The recognition profile appeared to be more spread out for BCG.HTI2auxo.int primed mice and mice only receiving MVA.HTI. Here, we describe a useful vaccine platform for priming protective responses against HIV-1/TB and other prevalent infectious diseases.

Isolation of Candidatus Bartonella rousetti and Other Bat-associated Bartonellae from Bats and Their Flies in Zambia.

Bat-associated bartonellae, including Bartonella mayotimonensis and Candidatus Bartonella rousetti, were recently identified as emerging and potential zoonotic agents, respectively. However, there is no report of bat-associated bartonellae in Zambia. Thus, we aimed to isolate and characterize Bartonella spp. from bats and bat flies captured in Zambia by culturing and PCR. Overall, Bartonella spp. were isolated from six out of 36 bats (16.7%), while Bartonella DNA was detected in nine out of 19 bat flies (47.3%). Subsequent characterization using a sequence of five different genes revealed that three isolates obtained from Egyptian fruit bats (Rousettus aegyptiacus) were Ca. B. rousetti. The isolates obtained from insectivorous bats (Macronycteris vittatus) were divided into two previously unclassified bat-associated bartonellae. A phylogenetic analysis of the six genotypes of Bartonella gltA sequences from nine pathogen-positive bat flies revealed that three genotypes belonged to the same clades as bat-associated bartonellae, including Ca. B. rousetti. The other three genotypes represented arthropod-associated bartonellae, which have previously been isolated only from ectoparasites. We demonstrated that Ca. B. rousetti is maintained between bats (R. aegyptiacus) and bat flies in Zambia. Continuous surveillance of Bartonella spp. in bats and serological surveys in humans in Africa are warranted to evaluate the public health importance of bat-associated bartonellae.

Designing Chimeric Virus-like Particle-based Vaccines for Human Papillomavirus and HIV: Lessons Learned.

Virus-like particles (VLPs) are a type of subunit vaccine which resembles viruses but do not contain any genetic material so that they are not infectious. VLPs maintain the same antigenic conformation to the original virus, and they could be a better vaccine candidate than live-attenuated and inactivated vaccines. In addition, compared to other subunit vaccines such as soluble protein, VLPs can stimulate both innate and adaptive immune responses effectively and safely against several pathogens by the closer morphology to its native virus. They have already been licensed as vaccines against Hepatitis B virus, human papillomavirus (HPV), and several veterinary diseases. Moreover, it has been investigated to prevent other viral infections including HIV. While HIV VLP-based vaccines have been studied over 35 years, none of them has been successful enough to reach even Phase III clinical trials. In this review, we summarize: (i) general features of VLPs; (ii) epidemiological data and current status of vaccine research and development on HPV and HIV; and (iii) previous studies held on HPV VLPs, HIV VLPs, and chimeric HPV/HIV VLPs including production methods and different animal immunization assays. Furthermore, we review present state of human clinical trials with VLPs and consider the potential to develop a successful preventive HIV vaccine using HPV VLP models. Finally, we discuss the benefits, limitations, and challenges of developing chimeric VLP-based HPV/HIV vaccines with recent findings, critical issues to improve VLP-based vaccines, and hot topics for the next 5 years to join the global effort to fight against these two pathogens.