Whole-cell Vaccine Research Articles

Adjuvant Effect of Whole-Cell Pertussis Component on Tetanus Toxoid Potency in Murine Model.

There is currently an increasing interest in the development of new-generation purified antigen-based vaccines with a higher safety profile compared to conventional inactivated vaccines. The main problem of subunit vaccines is their lower immunogenicity compared to whole-cell vaccines and inducing weaker and shorter-lasting immune responses. In this paper, the results of the assay of the potency of the tetanus component combined with the diphtheria component and whole-cell pertussis vaccine (DTwP), diphtheria and tetanus vaccine (DT), and in monovalent tetanus vaccine (T) are presented. In the mice model, an adjuvant impact of the whole-cell pertussis component on the immune response against tetanus was observed. It was noticed that the potency of tetanus component in the DTwP vaccine was significantly higher than tetanus potency in DT and T vaccines, despite the same bounding ability unit of the tetanus toxoid in the vaccine formulations. The levels of induction of tetanus antibodies by the tested vaccines were also examined. There were no differences in the induction of humoral responses against tetanus by tested vaccines. This publication discusses the possible mechanisms of impact of the whole-cell pertussis component on the other vaccine antigens and the positive and negative aspects of using the whole-cell pertussis component as an adjuvant.

Conformational comparisons of Pasteurella multocida types B and E and structurally related capsular polysaccharides.

Pasteurella multocida, an encapsulated gram-negative bacterium, is a significant veterinary pathogen. P. multocida is classified into five serogroups (A, B, D, E, and F) based on the bacterial capsular polysaccharide (CPS), which is important for virulence. Serogroups B and E are the primary causative agents of bovine hemorrhagic septicemia that is associated with significant yearly losses of livestock worldwide, primarily in low- and middle-income countries. P. multocida disease is currently managed by whole-cell vaccination, albeit with limited efficacy. CPS is an attractive antigen target for an improved vaccine: CPS-based vaccines have proven highly effective against human bacterial diseases and could provide longer-term protection against P. multocida. The recently elucidated CPS repeat units of serogroups B and E both comprise a ManNAcA/GlcNAc disaccharide backbone with Fruf side chain, but differ in their glycosidic linkages, and a glycine side chain in serogroup B. Interestingly, the Haemophilus influenzae types e and d CPS have the same backbone residues. Here comparative modeling of P. multocida serogroups B and E and H. influenzae types e and d CPS identifies a significant impact of small structural differences on both the chain conformation and the exposed potential antibody-binding epitopes. Further, Fruf and/or glycine side chains shield the immunogenic amino-sugar CPS backbone-a possible common strategy for immune evasion in both P. multocida and H. influenzae. As the lack of common epitopes suggests limited potential for cross-reactivity, a bivalent CPS-based vaccine may be necessary to provide adequate protection against P. multocida types B and E.

Vaccines against Tuberculosis: Where Are We Now?

Tuberculosis (TB) is among the top 10 leading causes of death in low-income countries. Statistically, TB kills more than 30,000 people each week and leads to more deaths than any other infectious disease, such as acquired immunodeficiency syndrome (AIDS) and malaria. TB treatment is largely dependent on BCG vaccination and impacted by the inefficacy of drugs, absence of advanced vaccines, misdiagnosis improper treatment, and social stigma. The BCG vaccine provides partial effectiveness in demographically distinct populations and the prevalence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB incidences demands the design of novel TB vaccines. Various strategies have been employed to design vaccines against TB, such as: (a) The protein subunit vaccine; (b) The viral vector vaccine; (c) The inactivation of whole-cell vaccine, using related mycobacteria, (d) Recombinant BCG (rBCG) expressing Mycobacterium tuberculosis (M.tb) protein or some non-essential gene deleted BCG. There are, approximately, 19 vaccine candidates in different phases of clinical trials. In this article, we review the development of TB vaccines, their status and potential in the treatment of TB. Heterologous immune responses generated by advanced vaccines will contribute to long-lasting immunity and might protect us from both drug-sensitive and drug-resistant TB. Therefore, advanced vaccine candidates need to be identified and developed to boost the human immune system against TB.

The Comparison of the Duration of Immunity Induced by Pertussis Vaccines and Infection in a Baboon Model

Abstract Whooping cough is a highly contagious, acute respiratory illness caused by the Gram-negative bacteria, Bordetella pertussis. Disease is often mild in older children and adults but can be severe or fatal in young children and infants. It is endemic worldwide and a major cause of vaccine-preventable deaths despite high vaccine coverage rate. A steady increase in the number of reported pertussis cases has been evident over the last 20 years. The apparent correlation of this resurgence and the replacement of whole-cell (wP) vaccines with acellular (aP) vaccines suggests the current aP vaccines may not control pertussis as well as the wP vaccines they replaced. Some evidence indicates the aP vaccines may induce protection with shorter duration of immunity relative to wP vaccines. There is increased interest in developing next-generation vaccines that induce longer lasting protection. However, immunological correlates predicting durable and protective immunity remain unknown. Studying duration of immunity in a human population is problematic due to potential asymptomatic exposures and the difficulty in sample accessibility. In an ongoing, long-term study, using a baboon model we are comparing the duration of immunity and immunological correlates of protection in a controlled population comparing aP, wP vaccines and natural infection. Extensive sampling was undertaken around the vaccinations to characterize the vaccine-mediated immune responses. Animals enrolled in the study will be followed for years with sampling twice yearly. With strict control of Bordetella exposure, the data generated from the study will provide a clearer understanding and a basis of comparison for the duration of aP, wP, and infection-induced immunity.

Development of a Serum-Free Medium To Aid Large-Scale Production of Mycoplasma-Based Therapies.

To assist in the advancement of the large-scale production of safe Mycoplasma vaccines and other Mycoplasma-based therapies, we developed a culture medium free of animal serum and other animal components for Mycoplasma pneumoniae growth. By establishing a workflow method to systematically test different compounds and concentrations, we provide optimized formulations capable of supporting serial passaging and robust growth reaching 60 to 70% of the biomass obtained in rich medium. Global transcriptomic and proteomic analysis showed minor physiological changes upon cell culture in the animal component-free medium, supporting its suitability for the production of M. pneumoniae-based therapies. The major contributors to growth performance were found to be glucose as a carbon source, glycerol, cholesterol, and phospholipids as a source of fatty acids. Bovine serum albumin or cyclodextrin (in the animal component-free medium) were required as lipid carriers to prevent lipid toxicity. Connaught Medical Research Laboratories medium (CMRL) used to simplify medium preparation as a source of amino acids, nucleotide precursors, vitamins, and other cofactors could be substituted by cysteine. In fact, the presence of protein hydrolysates such as yeastolate or peptones was found to be essential and preferred over free amino acids, except for the cysteine. Supplementation of nucleotide precursors and vitamins is not strictly necessary in the presence of yeastolate, suggesting that this animal origin-free hydrolysate serves as an efficient source for these compounds. Finally, we adapted the serum-free medium formulation to support growth of Mycoplasma hyopneumoniae, a swine pathogen for which inactivated whole-cell vaccines are available. IMPORTANCE Mycoplasma infections have a significant negative impact on both livestock production and human health. Vaccination is often the first option to control disease and alleviate the economic impact that some Mycoplasma infections cause on milk production, weight gain, and animal health. The fastidious nutrient requirements of these bacteria, however, challenges the industrial production of attenuated or inactivated whole-cell vaccines, which depends on the use of animal serum and other animal raw materials. Apart from their clinical relevance, some Mycoplasma species have become cellular models for systems and synthetic biology, owing to the small size of their genomes and the absence of a cell wall, which offers unique opportunities for the secretion and delivery of biotherapeutics. This study proposes medium formulations free of serum and animal components with the potential of supporting large-scale production upon industrial optimization, thus contributing to the development of safe vaccines and other Mycoplasma-based therapies.

RAD51–WSS1-dependent genetic pathways are essential for DNA–protein crosslink repair and pathogenesis in Candida albicans

Genetic analyses in Saccharomyces cerevisiae suggest that nucleotide excision repair (NER), homologous recombination (HR), and proteases-dependent repair (PDR) pathways coordinately function to remove DNA-protein crosslinks (DPCs) from the genome. DPCs are genomic cytotoxic lesions generated due to the covalent linkage of proteins with DNA. Although NER and HR processes have been studied in pathogenic Candida albicans, their roles in DPCs repair (DPCR) are yet to be explored. Proteases like Wss1 and Tdp1 are known to be involved in DPCR, however, Tdp1 that selectively removes topoisomerase-DNA complexes is intrinsically absent in C. albicans. Therefore, the mechanism of DPCR might have evolved differently in C. albicans. Herein, we investigated the interplay of three genetic pathways and found that RAD51-WSS1 dependent HR and PDR pathways are essential for DPCs removal, and their absence caused an increased rate of loss of heterozygosity in C. albicans. RAD1 but not RAD2 of NER is critical for DPCR. Additionally, we observed truncation of chromosome#6 in the cells defective in both RAD51 and WSS1 genes. While the protease and DNA binding activities are essential, a direct interaction of Wss1 with the eukaryotic DNA clamp PCNA is not a requisite for Wss1's function. DPCR-defective C. albicans cells exhibited filamentous morphology, reduced immune cell evasion, and attenuation in virulence. Thus, we concluded that RAD51-WSS1-dependent DPCR pathways are essential for genome stability and candidiasis development. Since no vaccine against candidiasis is available for human use yet, we propose to explore DPCR defective attenuated strains (rad51ΔΔwss1ΔΔ and rad2ΔΔrad51ΔΔwss1ΔΔ) for whole-cell vaccine development.

Using an Aluminum Hydroxide-Chitosan Matrix Increased the Vaccine Potential and Immune Response of Mice against Multi-Drug-Resistant Acinetobacter baumannii.

Acinetobacter baumannii is a Gram-negative, immobile, aerobic nosocomial opportunistic coccobacillus that causes pneumonia, septicemia, and urinary tract infections in immunosuppressed patients. There are no commercially available alternative antimicrobials, and multi-drug resistance is an urgent concern that requires emergency measures and new therapeutic strategies. This study evaluated a multi-drug-resistant A. baumannii whole-cell vaccine, inactivated and adsorbed on an aluminum hydroxide-chitosan (mAhC) matrix, in an A. baumannii sepsis model in immunosuppressed mice by cyclophosphamide (CY). CY-treated mice were divided into immunized, non-immunized, and adjuvant-inoculated groups. Three vaccine doses were given at 0D, 14D, and 28D, followed by a lethal dose of 4.0 × 108 CFU/mL of A. baumannii. Immunized CY-treated mice underwent a significant humoral response, with the highest IgG levels and a higher survival rate (85%); this differed from the non-immunized CY-treated mice, none of whom survived (p < 0.001), and from the adjuvant group, with 45% survival (p < 0.05). Histological data revealed the evident expansion of white spleen pulp from immunized CY-treated mice, whereas, in non-immunized and adjuvanted CY-treated mice, there was more significant organ tissue damage. Our results confirmed the proof-of-concept of the immune response and vaccine protection in a sepsis model in CY-treated mice, contributing to the advancement of new alternatives for protection against A. baumannii infections.

Promising whole-cell vaccines against cryptococcosis.

Cryptococcosis is a mycosis caused by Cryptococcus neoformans and C. gattii species complexes. Although this infection is potentially lethal, no prophylactic vaccine is yet commercially available, and the immune memory that enables prevention is still under investigation. These pathogens have a capsule layer for immune evasion and a sophisticated mechanism to advance the infection, and it is expected that these characteristics will make it difficult to develop prophylactic vaccines and to decipher the protective immunity. The current vaccine studies are focused on subunit, mRNA, DNA, and viral vector vaccines, with whole-cell vaccines also proving successful against cryptococcal infections. Cryptococcal whole-cell vaccines have been composed of highly immunostimulating strains with low-pathogenicity that are modified by genetic recombination technology. Examples include the whole-cell vaccines H99γ, sgl1∆, fbp1∆, znf2oe , cda1/2/3∆, cap59∆, and cap60∆. Some of these whole-cell vaccines were found to be highly effective in prolonging life and suppressing the fungal burden after an infection challenge in mice, and to be cross-reactive to C. neoformans, C. gattii, and other fungal pathogens. Furthermore, for some vaccines, the protective effect can be retained even in an immunocompromised host depleted of CD4+ T cells. These findings have provided new insights into protective immunity that should aid in vaccine development. In this review, we highlight the upsides and downsides of whole-cell vaccines against cryptococcosis.

Bystander activation of Bordetella pertussis-induced nasal tissue-resident memory CD4 T cells confers heterologous immunity to Klebsiella pneumoniae.

Tissue-resident memory CD4 T (TRM ) cells induced by infection with Bordetella pertussis persist in respiratory tissues and confer long-term protective immunity against reinfection. However, it is not clear how they are maintained in respiratory tissues. Here, we demonstrate that B. pertussis-specific CD4 TRM cells produce IL-17A in response to in vitro stimulation with LPS or heat-killed Klebsiella pneumoniae (HKKP) in the presence of dendritic cells. Furthermore, IL-17A-secreting CD4 TRM cells expand in the lung and nasal tissue of B. pertussis convalescent mice following in vivo administration of LPS or HKKP. Bystander activation of CD4 TRM cells was suppressed by anti-IL-12p40 but not by anti-MHCII antibodies. Furthermore, purified respiratory tissue-resident, but not circulating, CD4 T cells from convalescent mice produced IL-17A following direct stimulation with IL-23 and IL-1β or IL-18. Intranasal immunization of mice with a whole-cell pertussis vaccine induced respiratory CD4 TRM cells that were reactivated following stimulation with K. pneumoniae. Furthermore, the nasal pertussis vaccine conferred protective immunity against B. pertussis but also attenuated infection with K. pneumoniae. Our findings demonstrate that CD4 TRM cells induced by respiratory infection or vaccination can undergo bystander activation and confer heterologous immunity to an unrelated respiratory pathogen.

Tumor cell vaccine combined with Newcastle disease virus promote immunotherapy of lung cancer.

Lung cancer is a fatal disease with the highest worldwide morbidity and mortality rates. Despite recent advances in targeted therapy and immune checkpoint inhibitors for cancer, their efficacy remained limited. Therefore, we designed a Newcastle disease virus (NDV)-modified tumor whole-cell vaccine as a therapeutic vaccine and identified its antigen presentation level to develop effective immunotherapy. Then, we calculated the therapeutic and immune-stimulating effects of NDV-modified lung cancer cell vaccine and intratumoral NDV injection combination on tumor-bearing mice. The results showed that the immunogenic cell death (ICD) expression in NDV-modified lung cancer cell vaccine stimulates dendritic cell maturation and T cell activation in vivo and in vitro. Moreover, NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could significantly inhibit tumor growth and enhance the differentiation of Th1 cells and Inflammatory cell infiltration in vivo, leading to an excellent immunotherapeutic effect. Therefore, our results revealed that NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could promote antigen presentation and induce a strong antitumor immune response, which provided a promising combined therapy strategy for tumor immunotherapy.

Pol32, an accessory subunit of DNA polymerase delta, plays an essential role in genome stability and pathogenesis of Candida albicans

ABSTRACT Candida albicans is a pathobiont that inflicts serious bloodstream fungal infections in individuals with compromised immunity and gut dysbiosis. Genomic diversity in the form of copy number alteration, ploidy variation, and loss of heterozygosity as an adaptive mechanism to adverse environments is frequently observed in C. albicans. Such genomic variations also confer a varied degree of fungal virulence and drug resistance, yet the factors propelling these are not completely understood. DNA polymerase delta (Polδ) is an essential replicative DNA polymerase in the eukaryotic cell and is yet to be characterized in C. albicans. Therefore, this study was designed to gain insights into the role of Polδ, especially its non-essential subunit Pol32, in the genome plasticity and life cycle of C. albicans. PCNA, the DNA clamp, recruits Polδ to the replication fork for processive DNA replication. Unlike in Saccharomyces cerevisiae, the PCNA interaction protein (PIP) motif of CaPol32 is critical for Polδ’s activity during DNA replication. Our comparative genetic analyses and whole-genome sequencing of POL32 proficient and deficient C. albicans cells revealed a critical role of Pol32 in DNA replication, cell cycle progression, and genome stability as SNPs, indels, and repeat variations were largely accumulated in pol32 null strain. The loss of pol32 in C. albicans conferred cell wall deformity; Hsp90 mediated azoles resistance, biofilm development, and a complete attenuation of virulence in an animal model of systemic candidiasis. Thus, although Pol32 is dispensable for cell survival, its function is essential for C. albicans pathogenesis; and we discuss its translational implications in antifungal drugs and whole-cell vaccine development.

Manganese-mineralized cancer cells as immunogenic cancer vaccines for tumor immunotherapy.

The strategy of using tumor cells to construct whole-cell cancer vaccines has received widespread attention. However, the limited immunogenicity of inactivated tumor cells and the challenge of overcoming immune suppression in solid tumors have hindered the application of whole-cell-based cancer immune therapy. Inspired by the regulatory effects of MnO2 and spatiotemporal control capability of material layers in cell surface engineering, we developed a manganese (Mn)-mineralized tumor cell, B16F10@MnO2, by inactivating B16F10 melanoma cells with KMnO4 to generate manganese-mineralized tumor cells. The cell-based composite was formed by combining amorphous MnO2 with the membrane structure of cells based on the redox reaction between KMnO4 and tumor cells. The MnO2 layer induced a stronger phagocytosis of ovalbumin (OVA)-expressing tumor cells by antigen presenting cells than formaldehyde-fixed cells did, resulting in specific antigen-presentation in vitro and in vivo and subsequent immune responses. Intratumoral therapy with B16F10@MnO2 inhibited B16F10 tumor growth. Moreover, the infiltration of CD8+ T cells within B16F10 solid tumors and the proportion of central memory T cells both increased in B16F10@MnO2 treated tumor-bearing mice, indicating enhanced adaptive immunity. This study provides a convenient and effective method to improve whole-cell-based anti-tumor therapy.

Evaluation of Whole-Cell and Acellular Pertussis Vaccines in the Context of Long-Term Herd Immunity.

After the pertussis vaccine had been introduced in the 1940s and was shown to be very successful in reducing the morbidity and mortality associated with the disease, the possibility of improving both vaccine composition and vaccination schedules has become the subject of continuous interest. As a result, we are witnessing a considerable heterogeneity in pertussis vaccination policies, which remains beyond universal consensus. Many pertussis-related deaths still occur in low- and middle-income countries; however, these deaths are attributable to gaps in vaccination coverage and limited access to healthcare in these countries, rather than to the poor efficacy of the first generation of pertussis vaccine consisting in inactivated and detoxified whole cell pathogen (wP). In many, particularly high-income countries, a switch was made in the 1990s to the use of acellular pertussis (aP) vaccine, to reduce the rate of post-vaccination adverse events and thereby achieve a higher percentage of children vaccinated. However the epidemiological data collected over the past few decades, even in those high-income countries, show an increase in pertussis prevalence and morbidity rates, triggering a wide-ranging debate on the causes of pertussis resurgence and the effectiveness of current pertussis prevention strategies, as well as on the efficacy of available pertussis vaccines and immunization schedules. The current article presents a systematic review of scientific reports on the evaluation of the use of whole-cell and acellular pertussis vaccines, in the context of long-term immunity and vaccines efficacy.

Pertussis in India: Past, Present, and Future.

While vaccines have markedly reduced the incidence of pertussis, a resurgence has occurred in many countries. Until recently, pertussis has not been recognized as an important public health challenge in India due to its successful infant immunization program. However, India still accounts for a large proportion of the world's cases, and increasing reports of pertussis in other countries and in neonates have regenerated interest in pertussis among Indian authorities. The Global Pertussis Initiative (GPI) Annual Meeting was held virtually in October 2020, in part, to gain a better understanding of the epidemiology and disease burden of pertussis and to explore opportunities to improve its prevention in India. There was a consensus that pertussis cases are being underestimated in India due to multiple factors, such as a reliance on passive surveillance and diagnostic challenges. India offers both whole-cell pertussis and acellular pertussis vaccines, but vaccine coverage is inconsistent across regions due to differences in vaccine availability, access to health care, and regional administrative challenges. This report summarizes the outcomes and considers the key clinical implications of this meeting. The GPI agreed that active surveillance of pertussis in India would be optimal and recommended several studies, including serosurveillance among women of reproductive age to assess the prevalence of recent pertussis infection and to enable policy changes that will enhance the rational use of acellular and whole-cell vaccines. It also recommended engagement with nongovernmental organizations in order to encourage pregnancy immunization in the public sector. To achieve effective control of pertussis in the future, the GPI recognizes there are opportunities to characterize the burden of pertussis in India appropriately and increase vaccination coverage in multiple age groups.

Arsenic trioxide elicits prophylactic and therapeutic immune responses against solid tumors by inducing necroptosis and ferroptosis.

Boosting tumor immunosurveillance with vaccines has been proven to be a feasible and cost-effective strategy to fight cancer. Although major breakthroughs have been achieved in preventative tumor vaccines targeting oncogenic viruses, limited advances have been made in curative vaccines for virus-irrelevant malignancies. Accumulating evidence suggests that preconditioning tumor cells with certain cytotoxic drugs can generate whole-cell tumor vaccines with strong prophylactic activities. However, the immunogenicity of these vaccines is not sufficient to restrain the outgrowth of existing tumors. In this study, we identified arsenic trioxide (ATO) as a wide-spectrum cytotoxic and highly immunogenic drug through multiparameter screening. ATO preconditioning could generate whole-cell tumor vaccines with potent antineoplastic effects in both prophylactic and therapeutic settings. The tumor-preventive or tumor-suppressive benefits of these vaccines relied on CD8+ T cells and type I and II interferon signaling and could be linked to the release of immunostimulatory danger molecules. Unexpectedly, following ATO-induced oxidative stress, multiple cell death pathways were activated, including autophagy, apoptosis, necroptosis, and ferroptosis. CRISPR‒Cas9-mediated knockout of cell death executors revealed that the absence of Rip3, Mlkl, or Acsl4 largely abolished the efficacy of ATO-based prophylactic and therapeutic cancer vaccines. This therapeutic failure could be rescued by coadministration of danger molecule analogs. In addition, PD-1 blockade synergistically improved the therapeutic efficacy of ATO-based cancer vaccines by augmenting local IFN-γ production.

Single-cell analyses reveal the therapeutic effects of ATHENA and its mechanism in a rhabdomyosarcoma patient.

Whole-cell tumor vaccines tend to suffer from low immunogenicity. Our previous study showed that irradiated lung cancer cell vaccines in mouse models enhance antitumor efficacy by eliciting an intensive T cells response and improving immunogenicity. Based on these findings, we developed an improved whole-cell tumor vaccine, Autologous Tumor Holo antigEn immuNe Activation (ATHENA). In this study, we report the successful treatment of a 6-year-old male diagnosed with meningeal rhabdomyosarcoma with pulmonary and liver metastases using ATHENA. After 6 cycles of therapy, PET/CT showed the therapeutic efficacy of ATHENA. We profiled the immune response by single-cell RNA sequencing (scRNA-seq). Flow cytometry analysis was implemented to validate the status transitions of CD8+ T cells. In CD8+ T cells, the exhausted status was weakened after treatment. The exhausted CD4+ T cells shifted towards the central memory phenotype after the treatment. Breg cells were converted to Plasma or Follicular B cells. Survival analysis for pan-cancer and transcription factor analysis indicated that such T cell and B cell transitions represent the recovery of antitumoral adaptive immune response. We validated that the proportion of CD279+CD8+ T cells were reduced and the expression of CD44 molecule was upregulated by flow cytometry assay. Such studies not only show that ATHENA therapy may be a promising alternative treatment for tumor patients but provide a novel idea to analyses the mechanisms of rare cases or personalized cancer treatment.

Comparative Efficacy in Challenge Dose Models of a Toxin Expressing Whole-Cell Vaccine against Eight Serovars of Actinobacillus pleuropneumoniae in Pigs.

Actinobacillus pleuropneumoniae is a major economically significant bacterial respiratory pig pathogen, and whole cell vaccines are used to prevent disease. However, there is little data available on multi-serovar whole cell vaccine protection. Therefore, we determined the protective efficacies of a whole-cell A. pleuropneumoniae serovar 1 and 2 vaccine comprising ApxI-III toxins (C-vaccine, Coglapix®, Ceva, France) against serovars 1, 2, 4, 5, 6, 7, 9/11, and 13. The infection doses used induced disease representative of endemic field conditions, and standard protocols were used for all studies. Protection against homologous serovars 1 and 2 significantly reduced lung lesion scores (LLS) compared to positive controls: p = 0.00007 and p = 0.00124, respectively. The protection against heterologous serovars 4, 5, 6, 7, 9/11, and 13 also significantly reduced LLS: range p = 2.9 × 10-10 to p = 0.00953. As adjudged by the estimated random effect, reproducibility between studies was high. A highly significant serovar-independent reduction of pathological lung lesions by the C-vaccine was found for all the serovars tested (1, 2, 4, 5, 6, 7, 9/11, and 13). We conclude that the C-vaccine gives high serovar-independent protection against disease and is suitable for this use in the field.

Characterization of Coxiella burnetii Dugway Strain Host-Pathogen Interactions In Vivo.

Coxiella burnetii is a Gram-negative, intracellular bacterium that causes the zoonosis Q fever. Among the many natural isolates of C. burnetii recovered from various sources, the Dugway group exhibits unique genetic characteristics, including the largest C. burnetii genomes. These strains were isolated during 1954-1958 from wild rodents from the Utah, USA desert. Despite retaining phase I lipopolysaccharide and the type 4B secretion system, two critical virulence factors, avirulence has been reported in a guinea pig infection model. Using guinea pig models, we evaluated the virulence, whole-cell vaccine (WCV) efficacy, and post-vaccination hypersensitivity (PVH) potential of a representative Dugway strain. Consistent with prior reports, Dugway appeared to be highly attenuated compared to a virulent strain. Indeed, Dugway-infected animals showed similarly low levels of fever, body weight loss, and splenomegaly like Nine Mile II-infected animals. When compared to a human Q fever vaccine, QVax®, Dugway WCV exhibited analogous protection against a heterologous Nine Mile I challenge. PVH was investigated in a skin-testing model which revealed significantly decreased maximum erythema in Dugway Δdot/icm WCV-skin-tested animals compared to that of QVax®. These data provide insight into this unique bacterial strain and implicate its potential use as a mutated WCV candidate.

The whole-cell pertussis vaccine imposes a broad effector B cell response in mouse heterologous prime-boost settings.

ÍSince the introduction of new generation pertussis vaccines, resurgence of pertussis has been observed in many developed countries. Former whole-cell pertussis (wP) vaccines are able to protect against disease and transmission but have been replaced in several industrialized countries because of their reactogenicity and adverse effects. Current acellular pertussis (aP) vaccines, made of purified proteins of Bordetella pertussis, are efficient at preventing disease but fail to induce long-term protection from infection. While the systemic and mucosal T cell immunity induced by the 2 types of vaccines has been well described, much less is known concerning B cell responses. Taking advantage of an inducible activation-induced cytidine deaminase fate-mapping mouse model, we compared effector and memory B cells induced by the 2 classes of vaccines and showed that a stronger and broader memory B cell and plasma cell response was achieved by a wP prime. We also observed that homologous or heterologous vaccine combinations that include at least 1 wP administration, even as a booster dose, were sufficient to induce this broad effector response, thus highlighting its dominant imprint on the B cell profile. Finally, we describe the settlement of memory B cell populations in the lung following subcutaneous wP prime vaccination.

Whole-cell tumor vaccines desialylated to uncover tumor antigenic Gal/GalNAc epitopes elicit anti-tumor immunity

BackgroundAberrant sialoglycans on the surface of tumor cells shield potential tumor antigen epitopes, escape recognition, and suppress activation of immunocytes. α2,3/α2,6Gal- and α2,6GalNAc (Gal/GalNAc)-linked sialic acid residues of sialoglycans could affect macrophage galactose-type lectins (MGL) mediated-antigen uptake and presentation and promote sialic acid-binding immunoglobulin-like lectins (Siglecs) mediated-immunosuppression. Desialylating sialoglycans on tumor cells could present tumor antigens with Gal/GalNAc residues and overcome glyco-immune checkpoints. Thus, we explored whether vaccination with desialylated whole-cell tumor vaccines (DWCTVs) triggers anti-tumor immunity in ovarian cancer (OC).MethodsSialic acid (Sia) and Gal/GalNAc residues on OC A2780, OVCAR3, and ID8 cells treated with α2-3 neuraminidase (α2-3NA) and α2-6NA, and Sigec-9 or Siglec-E and MGL on DCs pulsed with desialylated OC cells were identified using flow cytometry (FCM); RT-qPCR determined IFNG expression of T cells, TRBV was sequenced using Sanger sequencing and cytotoxicity of αβ T cells was measured with LDH assay; Anti-tumor immunity in vivo was validated via vaccination with desialylated whole-cell ID8 vaccine (ID8 DWCTVs).ResultsGal/GalNAc but not Sia residues were significantly increased in the desialylated OC cells. α2-3NA-modified DWCTV increased MGL but decreased Siglec-9 or Siglec E expression on DCs. MGLbright/Siglec-9dim DCs significantly up-regulated IFNG expression and CD4/CD8 ratio of T cells and diversified the TCR repertoire of αβ T-cells that showed enhanced cytotoxic activity. Vaccination with α2-3NA-modified ID8 DWCTVs increased MGLbright/Siglec-Edim DCs in draining lymph nodes, limited tumor growth, and extended survival in tumor-challenged mice.ConclusionDesialylated tumor cell vaccine could promote anti-tumor immunity and provide a strategy for OC immunotherapy in a clinical setting.