Immunoproteomic discovery of Mycobacterium bovis antigens, including the surface lipoprotein Mpt83 as a T cell antigen useful for vaccine development.

Tuberculosis (TB) is one of the leading causes of death from infectious diseases, killing approximately 1.3 million people worldwide in 2022 alone. The current vaccine for TB contains a live attenuated bacterium, Mycobacterium bovis BCG (Bacille Calmette-Guérin). The BCG vaccine is highly effective in preventing severe forms of childhood TB but does not protect against latent infection or disease in older age groups. A new or improved BCG vaccine for prevention of pulmonary TB is urgently needed. In this study, we infected murine bone marrow derived dendritic cells from C57BL/6 mice with M. bovis BCG followed by elution and identification of BCG-derived MHC class I and class II-bound peptides using tandem mass spectrometry. We identified 1436 MHC-bound peptides of which 94 were derived from BCG. Fifty-five peptides were derived from MHC class I molecules and 39 from class II molecules. We tested the 94 peptides for their immunogenicity using IFN- γ ELISPOT assay with splenocytes purified from BCG immunized mice and 10 showed positive responses. Seven peptides were derived from MHC II and three from MHC class I. In particular, MHC class II binding peptides derived from the mycobacterial surface lipoprotein Mpt83 were highly antigenic. Further evaluations of these immunogenic BCG peptides may identify proteins useful as new TB vaccine candidates.

Vaccination to Prevent Lyme Disease: A Movement Towards Anti-Tick Approaches.

Lyme disease is caused by the spirochete, Borrelia burgdorferi, which is transmitted by Ixodes spp ticks. The rise in Lyme disease cases since its discovery in the 1970s has reinforced the need for a vaccine. A vaccine based on B burgdorferi outer surface protein A (OspA) was approved by the Food and Drug Administration (FDA) several decades ago, but was pulled from the market a few years later, reportedly due to poor sales, despite multiple organizations concluding that it was safe and effective. Newer OspA-based vaccines are being developed and are likely to be available in the coming years. More recently, there has been a push to develop vaccines that target the tick vector instead of the pathogen to inhibit tick feeding and thus prevent transmission of tick-borne pathogens to humans and wildlife reservoirs. This review outlines the history of Lyme disease vaccines and this movement to anti-tick vaccine approaches.

Chimeric lipoproteins for leptospirosis vaccine: immunogenicity and protective potential.

Leptospirosis, a neglected zoonotic disease, is caused by pathogenic spirochetes belonging to the genus Leptospira and has one of the highest morbidity and mortality rates worldwide. Vaccination stands out as one of the most effective preventive measures for susceptible populations. Within the outer membrane of Leptospira spp., we find the LIC12287, LIC11711, and LIC13259 lipoproteins. These are of interest due to their surface location and potential immunogenicity. Thorough examination revealed the conservation of these proteins among pathogenic Leptospira spp.; we mapped the distribution of T- and B-cell epitopes along their sequences and assessed the 3D structures of each protein. This information aided in selecting immunodominant regions for the development of a chimeric protein. Through gene synthesis, we successfully constructed a chimeric protein, which was subsequently expressed, purified, and characterized. Hamsters were immunized with the chimeric lipoprotein, formulated with adjuvants aluminum hydroxide, EMULSIGEN®-D, Sigma Adjuvant System®, and Montanide™ ISA206VG. Another group was vaccinated with an inactivated Escherichia coli bacterin expressing the chimeric protein. Following vaccination, hamsters were challenged with a virulent L. interrogans strain. Our evaluation of the humoral immune response revealed the production of IgG antibodies, detectable 28 days after the second dose, in contrast to pre-immune samples and control groups. This demonstrates the potential of the chimeric protein to elicit a robust humoral immune response; however, no protection against challenge was achieved. While this study provides valuable insights into the subject, further research is warranted to identify protective antigens that could be utilized in the development of a leptospirosis vaccine. KEY POINTS: • Several T- and B-cell epitopes were identified in all the three proteins. • Four different adjuvants were used in vaccine formulations. • Immunization stimulated significant levels of IgG2/3 in vaccinated animals.

A novel syphilis Treponema pallidum lipoprotein peptide antigen diagnostic assay using red cell kodecytes in routine blood centre column agglutination testing platforms.

BACKGROUND AND OBJECTIVES: The detection of treponemal antibodies, which are used to make a diagnosis of syphilis, is important both for diagnostic purposes and as a mandatory blood donor test in most countries. We evaluated the feasibility of using Kode Technology to make syphilis peptide red cell kodecytes for use in column agglutination serologic platforms. MATERIALS AND METHODS: Candidate Kode Technology function-spacer-lipid (FSL) constructs were made for the Treponema pallidum lipoprotein (TmpA) of T. pallidum, using the peptide and FSL selection algorithms, and then used to make kodecytes. Developmental kodecytes were evaluated against a large range of syphilis antibody reactive and non-reactive samples in column agglutination platforms and compared against established methodologies. Overall, 150 reactive and 2072 non-reactive Syphicheck assay (a modified T. pallidum particle agglutination) blood donor samples were used to evaluate the agreement rate of the developed kodecyte assay. RESULTS: From three FSL-peptide candidate constructs, one was found to be the most suitable for diagnostics. Of 150 Syphicheck assay reactive samples, 146 were TmpA-kodecyte reactive (97.3% agreement), compared with 58.0% with the rapid plasmin reagin (RPR) assay for the same samples. Against the 2072 expected syphilis non-reactive samples the agreement rate for TmpA-kodecytes was 98.8%. CONCLUSION: TmpA-kodecytes are viable for use as cost-effective serologic reagent red cells for the detection of treponemal antibodies to diagnose syphilis with a high level of specificity in blood centres. This kodecyte methodology also potentially allows for introduction of the reverse-algorithm testing into low-volume laboratories, by utilizing existing transfusion laboratory infrastructure.

Antibody-mediated immunological memory correlates with long-term Lyme veterinary vaccine protection in mice.

Lyme disease, caused by the bacterium Borrelia burgdorferi, is the most common tick-borne illness in the United States. Despite the rise in Lyme disease incidence, there is no vaccine against B. burgdorferi approved for human use. Little is known about the immune correlates of protection needed to prevent Lyme disease. In this work, a mouse model was used to characterize the immune response and compare the protection provided by two USDA-approved vaccines for use in canines: Duramune (bacterin vaccine) and Vanguard crLyme (subunit vaccine composed of two outer surface proteins, OspA and OspC). C3H/HeNCrl mice were immunized with two doses of either Duramune or Vanguard, and immune responses and protection against B. burgdorferi were assessed in short (35 days) and long-term (120 days) studies. Flow cytometry, ELISPOT detection of antibody-producing cells, and antibody affinity studies were performed to identify correlates of vaccine-mediated protection. Both vaccines induced humoral responses, with high IgG titers against B. burgdorferi. However, the levels of anti-B. burgdorferi antibodies decayed over time in Vanguard-vaccinated mice. While both vaccines triggered the production of antibodies against both OspA and OspC, antibody levels against these proteins were also lower in Vanguard-vaccinated mice 120 days post-vaccination. Both vaccines only provided partial protection against B. burgdorferi at the dose used in this model. The protection provided by Duramune was superior to Vanguard 120 days post-vaccination, and was characterized by higher antibody titers, higher abundance of long-lived plasma cells, and higher avidity antibodies than Vanguard. Overall, these studies provide insights into the importance of the humoral memory response to veterinary vaccines against Lyme disease and will help inform the development of future human vaccines.

Monoclonal Antibody chP3R99 Reduces Subendothelial Retention of Atherogenic Lipoproteins in Insulin-Resistant Rats: Acute Treatment Versus Long-Term Protection as an Idiotypic Vaccine for Atherosclerosis.

BACKGROUND: Atherosclerosis is triggered by the retention of apolipoprotein B-containing lipoproteins by proteoglycans. In addition to low-density lipoprotein, remnant lipoproteins have emerged as pivotal contributors to this pathology, particularly in the context of insulin resistance and diabetes. We have previously reported antiatherogenic properties of a monoclonal antibody (chP3R99) that recognizes sulfated glycosaminoglycans on arterial proteoglycans. METHODS AND RESULTS: Solid-phase assays demonstrated that chP3R99 effectively blocked >50% lipoprotein binding to chondroitin sulfate and vascular extracellular matrix in vitro. The preperfusion of chP3R99 (competitive effect) resulted in specific antibody-arterial accumulation and reduced fluorescent lipoprotein retention by ~60% in insulin resistant JCR:LA-cp rats. This competitive reduction was dose dependent (25-250 µg/mL), effectively decreasing deposition of cholesterol associated with lipoproteins. In a 5-week vaccination study in insulin resistant rats with (200 µg subcutaneously, once a week), chP3R99 reduced arterial lipoprotein retention, and was associated with the production of antichondroitin sulfate antibodies (Ab3) able to accumulate in the arteries (dot-blot). Neither the intravenous inoculation of chP3R99 (4.5 mg/kg), nor the immunization with this antibody displayed adverse effects on lipid or glucose metabolism, insulin resistance, liver function, blood cell indices, or inflammation pathways in JCR:LA-cp rats. CONCLUSIONS: Both acute (passive) and long-term administration (idiotypic cascade) of chP3R99 antibody reduced low-density lipoprotein and remnant lipoprotein interaction with proteoglycans in an insulin-resistant setting. These findings support the innovative approach of targeting proatherogenic lipoprotein retention by chP3R99 as a passive therapy or as an idiotypic vaccine for atherosclerosis.

Optimisation of dose level and vaccination schedule for the VLA15 Lyme borreliosis vaccine candidate among healthy adults: two randomised, observer-blind, placebo-controlled, multicentre, phase 2 studies.

BACKGROUND: Rising Lyme borreliosis incidence rates, potential for severe outcomes, and limitations in accurate and timely diagnosis for treatment initiation suggest the need for a preventive vaccine; however, no vaccine is currently available for human use. We performed two studies in adults to optimise the dose level and vaccination schedule for VLA15, an investigational Lyme borreliosis vaccine targeting outer surface protein A (OspA) serotypes 1-6, which are associated with the most common pathogenic Borrelia species in Europe and North America. METHODS: Both randomised, observer-blind, placebo-controlled, multicentre phase 2 studies included participants aged 18-65 years without recent history of Lyme borreliosis or tick bites. Study one was conducted at nine clinical research and study centre sites in the USA (n=6), Germany (n=2), and Belgium (n=1); study two was conducted at five of the study one US sites. Based on a randomisation list created by an unmasked statistician for each study, participants were randomly assigned via an electronic case report form randomisation module to receive 90 µg (study one only), 135 µg, or 180 µg VLA15 or placebo by intramuscular injection at months 0, 1, and 2 (study one) or 0, 2, and 6 (study two). Study one began with a run-in phase to confirm safety, after which the Data Safety Monitoring Board recommended the removal of the 90 µg group and continuation of the study. In the study one run-in phase, randomisation was stratified by study site, whereas in the study one main phase and in study two, randomisation was stratified by study site, age group, and baseline B burgdorferi (sensu lato) serostatus. All individuals were masked, other than staff involved in randomisation, vaccine preparation or administration, or safety data monitoring. The primary endpoint for both studies was OspA-specific IgG geometric mean titres (GMTs) at 1 month after the third vaccination and was evaluated in the per-protocol population. Safety endpoints were evaluated in the safety population: all participants who received at least one vaccination. Both studies are registered at ClinicalTrials.gov (study one NCT03769194 and study two NCT03970733) and are completed. FINDINGS: For study one, 573 participants were screened and randomly assigned to treatment groups between Dec 21, 2018, and Sept, 26, 2019. For study two, 248 participants were screened and randomly assigned between June 26 and Sept 3, 2019. In study one, 29 participants were assigned to receive 90 µg VLA15, 215 to 135 µg, 205 to 180 µg, and 124 to placebo. In study two, 97 participants were assigned to receive 135 µg VLA15, 100 to 180 µg, and 51 to placebo. At 1 month after the third vaccination (ie, month 3), OspA-specific IgG GMTs in study one ranged from 74·3 (serotype 1; 95% CI 46·4-119·0) to 267·4 units per mL (serotype 3; 194·8-367·1) for 90 µg VLA15, 101·9 (serotype 1; 87·1-119·4) to 283·2 units per mL (serotype 3; 248·2-323·1) for 135 µg, and 115·8 (serotype 1; 98·8-135·7) to 308·6 units per mL (serotype 3; 266·8-356·8) for 180 µg. In study two, ranges at 1 month after the third vaccination (ie, month 7) were 278·5 (serotype 1; 214·9-361·0) to 545·2 units per mL (serotype 2; 431·8-688·4) for 135 µg VLA15 and 274·7 (serotype 1; 209·4-360·4) to 596·8 units per mL (serotype 3; 471·9-754·8) for 180 µg. Relative to placebo, the VLA15 groups had more frequent reports of solicited local adverse events (study one: 94%, 95% CI 91-96 vs 26%, 19-34; study two: 96%, 93-98 vs 35%, 24-49 after any vaccination) and solicited systemic adverse events (study one: 69%, 65-73 vs 43%, 34-52; study two: 74%, 67-80 vs 51%, 38-64); most were mild or moderate. In study one, unsolicited adverse events were reported by 52% (48-57) of participants in the VLA15 groups and 52% (43-60) of those in the placebo groups; for study two these were 65% (58-71) and 69% (55-80), respectively. Percentages of participants reporting serious unsolicited adverse events (study one: 2%, 1-4; study two: 4%, 2-7) and adverse events of special interest (study one: 1%, 0-2; study two: 1%, 0-3) were low across all groups. A single severe, possibly related unsolicited adverse event was reported (worsening of pre-existing ventricular extrasystoles, which resolved after change of relevant concomitant medication); no related serious adverse events or deaths were reported. INTERPRETATION: VLA15 was safe, well tolerated, and elicited robust antibody responses to all six OspA serotypes. These findings support further clinical development of VLA15 using the 180 µg dose and 0-2-6-month schedule, which was associated with the greatest immune responses. FUNDING: Valneva.

Differential antigenicity of individual Mycoplasma hyorhinis variable lipoproteins.

The Mycoplasma hyorhinis (Mhr) variable lipoprotein (Vlp) family, comprising Vlps A, B, C, D, E, F, and G, are highly variable in expression, size, and cytoadhesion capabilities across Mhr strains. The 'Vlp system' plays a crucial role in cytoadhesion, immune evasion, and in eliciting a host immunologic response. This pilot study described the development of Vlp peptide-based ELISAs to evaluate the antigenic reactivity of individual Vlps against Mhr antisera collected throughout a longitudinal study focused on Mhr strain 38983, reproducing Mhr-associated disease under experimental conditions. Specifically, serum samples were collected at day post-inoculation 0, 7, 10, 14, 17, 21, 24, 28, 35, 42, 49, and 56 from Mhr- and mock (Friis medium)-inoculated cesarean-derived, colostrum-deprived pigs. Significant Mhr-specific IgG responses were detected at specific time points throughout the infection, with some variations for each Vlp. Overall, individual Vlp ELISAs showed consistently high accuracy rates, except for VlpD, which would likely be associated with its expression levels or the anti-Vlp humoral immune response specific to the Mhr strain used in this study. This study provides the basis and tools for a more refined understanding of these Vlp- and Mhr strain-specific variations, which is foundational in understanding the host immune response to Mhr.

Lipidation of pneumococcal proteins enables activation of human antigen-presenting cells and initiation of an adaptive immune response.

Streptococcus pneumoniae remains a significant global threat, with existing vaccines having important limitations such as restricted serotype coverage and high manufacturing costs. Pneumococcal lipoproteins are emerging as promising vaccine candidates due to their surface exposure and conservation across various serotypes. While prior studies have explored their potential in mice, data in a human context and insights into the impact of the lipid moiety remain limited. In the present study, we examined the immunogenicity of two pneumococcal lipoproteins, DacB and MetQ, both in lipidated and non-lipidated versions, by stimulation of primary human immune cells. Immune responses were assessed by the expression of common surface markers for activation and maturation as well as cytokines released into the supernatant. Our findings indicate that in the case of MetQ lipidation was crucial for activation of human antigen-presenting cells such as dendritic cells and macrophages, while non-lipidated DacB demonstrated an intrinsic potential to induce an innate immune response. Nevertheless, immune responses to both proteins were enhanced by lipidation. Interestingly, following stimulation of dendritic cells with DacB, LipDacB and LipMetQ, cytokine levels of IL-6 and IL-23 were significantly increased, which are implicated in triggering potentially important Th17 cell responses. Furthermore, LipDacB and LipMetQ were able to induce proliferation of CD4+ T cells indicating their potential to induce an adaptive immune response. These findings contribute valuable insights into the immunogenic properties of pneumococcal lipoproteins, emphasizing their potential role in vaccine development against pneumococcal infections.

Bacterial surface lipoproteins mediate epithelial microinvasion by Streptococcus pneumoniae.

Streptococcus pneumoniae, a common colonizer of the upper respiratory tract, invades nasopharyngeal epithelial cells without causing disease in healthy participants of controlled human infection studies. We hypothesized that surface expression of pneumococcal lipoproteins, recognized by the innate immune receptor TLR2, mediates epithelial microinvasion. Mutation of lgt in serotype 4 (TIGR4) and serotype 6B (BHN418) pneumococcal strains abolishes the ability of the mutants to activate TLR2 signaling. Loss of lgt also led to the concomitant decrease in interferon signaling triggered by the bacterium. However, only BHN418 lgt::cm but not TIGR4 lgt::cm was significantly attenuated in epithelial adherence and microinvasion compared to their respective wild-type strains. To test the hypothesis that differential lipoprotein repertoires in TIGR4 and BHN418 lead to the intraspecies variation in epithelial microinvasion, we employed a motif-based genome analysis and identified an additional 525 a.a. lipoprotein (pneumococcal accessory lipoprotein A; palA) encoded by BHN418 that is absent in TIGR4. The gene encoding palA sits within a putative genetic island present in ~10% of global pneumococcal isolates. While palA was enriched in the carriage and otitis media pneumococcal strains, neither mutation nor overexpression of the gene encoding this lipoprotein significantly changed microinvasion patterns. In conclusion, mutation of lgt attenuates epithelial inflammatory responses during pneumococcal-epithelial interactions, with intraspecies variation in the effect on microinvasion. Differential lipoprotein repertoires encoded by the different strains do not explain these differences in microinvasion. Rather, we postulate that post-translational modifications of lipoproteins may account for the differences in microinvasion.IMPORTANCEStreptococcus pneumoniae (pneumococcus) is an important mucosal pathogen, estimated to cause over 500,000 deaths annually. Nasopharyngeal colonization is considered a necessary prerequisite for disease, yet many people are transiently and asymptomatically colonized by pneumococci without becoming unwell. It is therefore important to better understand how the colonization process is controlled at the epithelial surface. Controlled human infection studies revealed the presence of pneumococci within the epithelium of healthy volunteers (microinvasion). In this study, we focused on the regulation of epithelial microinvasion by pneumococcal lipoproteins. We found that pneumococcal lipoproteins induce epithelial inflammation but that differing lipoprotein repertoires do not significantly impact the magnitude of microinvasion. Targeting mucosal innate immunity and epithelial microinvasion alongside the induction of an adaptive immune response may be effective in preventing pneumococcal colonization and disease.

The molecular determinants of classical pathway complement inhibition by OspEF-related proteins of Borrelia burgdorferi.

The complement system serves as the first line of defense against invading pathogens by promoting opsonophagocytosis and bacteriolysis. Antibody-dependent activation of complement occurs through the classical pathway and relies on the activity of initiating complement proteases of the C1 complex, C1r and C1s. The causative agent of Lyme disease, Borrelia burgdorferi, expresses two paralogous outer surface lipoproteins of the OspEF-related protein family, ElpB and ElpQ, that act as specific inhibitors of classical pathway activation. We have previously shown that ElpB and ElpQ bind directly to C1r and C1s with high affinity and specifically inhibit C2 and C4 cleavage by C1s. To further understand how these novel protease inhibitors function, we carried out a series of hydrogen-deuterium exchange mass spectrometry (HDX-MS) experiments using ElpQ and full-length activated C1s as a model of Elp-protease interaction. Comparison of HDX-MS profiles between unbound ElpQ and the ElpQ/C1s complex revealed a putative C1s-binding site on ElpQ. HDX-MS-guided, site-directed ElpQ mutants were generated and tested for direct binding to C1r and C1s using surface plasmon resonance. Several residues within the C-terminal region of ElpQ were identified as important for protease binding, including a single conserved tyrosine residue that was required for ElpQ- and ElpB-mediated complement inhibition. Collectively, our study identifies key molecular determinants for classical pathway protease recognition by Elp proteins. This investigation improves our understanding of the unique complement inhibitory mechanism employed by Elp proteins which serve as part of a sophisticated complement evasion system present in Lyme disease spirochetes.

Outer surface protein E (OspE) mediates Borrelia burgdorferi sensu stricto strain-specific complement evasion in the eastern fence lizard, Sceloporus undulatus.

In North America, Lyme disease is primarily caused by the spirochetal bacterium Borrelia burgdorferi sensu stricto (Bb), which is transmitted between multiple vertebrate hosts and ixodid ticks, and is a model commonly used to study host-pathogen interactions. While Bb is consistently observed in its mammalian and avian reservoirs, the bacterium is rarely isolated from North American reptiles. Two closely related lizard species, the eastern fence lizard (Sceloporus undulatus) and the western fence lizard (Sceloporus occidentalis), are examples of reptiles parasitized by Ixodes ticks. Vertebrates are known to generate complement as an innate defense mechanism, which can be activated before Bb disseminate to distal tissues. Complement from western fence lizards has proven lethal against one Bb strain, implying the role of complement in making those lizards unable to serve as hosts to Bb. However, Bb DNA is occasionally identified in distal tissues of field-collected eastern fence lizards, suggesting some Bb strains may overcome complement-mediated clearance in these lizards. These findings raise questions regarding the role of complement and its impact on Bb interactions with North American lizards. In this study, we found Bb seropositivity in a small population of wild-caught eastern fence lizards and observed Bb strain-specific survivability in lizard sera. We also found that a Bb outer surface protein, OspE, from Bb strains viable in sera, promotes lizard serum survivability and binds to a complement inhibitor, factor H, from eastern fence lizards. Our data thus identify bacterial and host determinants of eastern fence lizard complement evasion, providing insights into the role of complement influencing Bb interactions with North American lizards.

Membrane particles evoke a serotype-independent cross-protection against pneumococcal infection that is dependent on the conserved lipoproteins MalX and PrsA.

Pneumococcal conjugate vaccines (PCVs) used in childhood vaccination programs have resulted in replacement of vaccine-type with nonvaccine-type pneumococci in carriage and invasive pneumococcal disease (IPD). A vaccine based on highly conserved and protective pneumococcal antigens is urgently needed. Here, we performed intranasal immunization of mice with pneumococcal membrane particles (MPs) to mimic natural nasopharyngeal immunization. MP immunization gave excellent serotype-independent protection against IPD that was antibody dependent but independent of the cytotoxin pneumolysin. Using Western blotting, immunoprecipitation, mass spectrometry, and different bacterial mutants, we identified the conserved lipoproteins MalX and PrsA as the main antigens responsible for cross-protection. Additionally, we found that omitting the variable surface protein and vaccine candidate PspA from MPs enhanced protective immune responses to the conserved proteins. Our findings suggest that MPs containing MalX and PrsA could serve as a platform for pneumococcal vaccine development targeting the elderly and immunocompromised.

VlsE, the nexus for antigenic variation of the Lyme disease spirochete, also mediates early bacterial attachment to the host microvasculature under shear force.

Hematogenous dissemination is a critical step in the evolution of local infection to systemic disease. The Lyme disease (LD) spirochete, which efficiently disseminates to multiple tissues, has provided a model for this process, in particular for the key early event of pathogen adhesion to the host vasculature. This occurs under shear force mediated by interactions between bacterial adhesins and mammalian cell-surface proteins or extracellular matrix (ECM). Using real-time intravital imaging of the Lyme spirochete in living mice, we previously identified BBK32 as the first LD spirochetal adhesin demonstrated to mediate early vascular adhesion in a living mouse; however, deletion of bbk32 resulted in loss of only about half of the early interactions, suggesting the existence of at least one other adhesin (adhesin-X) that promotes early vascular interactions. VlsE, a surface lipoprotein, was identified long ago by its capacity to undergo rapid antigenic variation, is upregulated in the mammalian host and required for persistent infection in immunocompetent mice. In immunodeficient mice, VlsE shares functional overlap with OspC, a multi-functional protein that displays dermatan sulfate-binding activity and is required for joint invasion and colonization. In this research, using biochemical and genetic approaches as well as intravital imaging, we have identified VlsE as adhesin-X; it is a dermatan sulfate (DS) adhesin that efficiently promotes transient adhesion to the microvasculature under shear force via its DS binding pocket. Intravenous inoculation of mice with a low-passage infectious B. burgdorferi strain lacking both bbk32 and vlsE almost completely eliminated transient microvascular interactions. Comparative analysis of binding parameters of VlsE, BBK32 and OspC provides a possible explanation why these three DS adhesins display different functionality in terms of their ability to promote early microvascular interactions.

Lipoproteome screening of the Lyme disease agent identifies inhibitors of antibody-mediated complement killing.

Spirochetal pathogens, such as the causative agent of Lyme disease, Borrelia burgdorferi sensu lato, encode an abundance of lipoproteins; however, due in part to their evolutionary distance from more well-studied bacteria, such as Proteobacteria and Firmicutes, few spirochetal lipoproteins have assigned functions. Indeed, B. burgdorferi devotes almost 8% of its genome to lipoprotein genes and interacts with its environment primarily through the production of at least 80 surface-exposed lipoproteins throughout its tick vector­vertebrate host lifecycle. Several B. burgdorferi lipoproteins have been shown to serve roles in cellular adherence or immune evasion, but the functions for most B. burgdorferi surface lipoproteins remain unknown. In this study, we developed a B. burgdorferi lipoproteome screening platform utilizing intact spirochetes that enables the identification of previously unrecognized host interactions. As spirochetal survival in the bloodstream is essential for dissemination, we targeted our screen to C1, the first component of the classical (antibody-initiated) complement pathway. We identified two high-affinity C1 interactions by the paralogous lipoproteins, ElpB and ElpQ (also termed ErpB and ErpQ, respectively). Using biochemical, microbiological, and biophysical approaches, we demonstrate that ElpB and ElpQ bind the activated forms of the C1 proteases, C1r and C1s, and represent a distinct mechanistic class of C1 inhibitors that protect the spirochete from antibody-mediated complement killing. In addition to identifying a mode of complement inhibition, our study establishes a lipoproteome screening methodology as a discovery platform for identifying direct host­pathogen interactions that are central to the pathogenesis of spirochetes, such as the Lyme disease agent.

Evaluation of the indirect impact of the 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine in a cluster-randomised trial.

BACKGROUND: In the nation-wide double-blind cluster-randomised Finnish Invasive Pneumococcal disease trial (FinIP, ClinicalTrials.gov NCT00861380, NCT00839254), we assessed the indirect impact of the 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) against five pneumococcal disease syndromes. METHODS: Children 6 weeks to 18 months received PHiD-CV10 in 48 clusters or hepatitis B/A-vaccine as control in 24 clusters according to infant 3+1/2+1 or catch-up schedules in years 2009-2011. Outcome data were collected from national health registers and included laboratory-confirmed and clinically suspected invasive pneumococcal disease (IPD), hospital-diagnosed pneumonia, tympanostomy tube placements (TTP) and outpatient antimicrobial prescriptions. Incidence rates in the unvaccinated population in years 2010-2015 were compared between PHiD-CV10 and control clusters in age groups <5 and ≥5 years (5-7 years for TTP and outpatient antimicrobial prescriptions), and in infants <3 months. PHiD-CV10 was introduced into the Finnish National Vaccination Programme (PCV-NVP) for 3-month-old infants without catch-up in 9/2010. RESULTS: From 2/2009 to 10/2010, 45398 children were enrolled. Vaccination coverage varied from 29 to 61% in PHiD-CV10 clusters. We detected no clear differences in the incidence rates between the unvaccinated cohorts of the treatment arms, except in single years. For example, the rates of vaccine-type IPD, non-laboratory-confirmed IPD and empyema were lower in PHiD-CV10 clusters compared to control clusters in 2012, 2015 and 2011, respectively, in the age-group ≥5 years. CONCLUSIONS: This is the first report from a clinical trial evaluating the indirect impact of a PCV against clinical outcomes in an unvaccinated population. We did not observe consistent indirect effects in the PHiD-CV10 clusters compared to the control clusters. We consider that the sub-optimal trial vaccination coverage did not allow the development of detectable indirect effects and that the supervening PCV-NVP significantly diminished the differences in PHiD-CV10 vaccination coverage between the treatment arms.

The beneficial effects of virgin olive oil against oxidative stress induced by hypercholesterolemia in rats

Cardiovascular disease(CVD) remains the major cause of mortality in the world, typically claiming a third of all deaths. The primary cause of CVD is atherosclerosis. Therefore, timely prevention and therapy of atherosclerosis are able to reduce the risk of the development of its clinical manifestations. Anti-atherosclerotic activity of medicinal plants mainly appears in their multiple effects.This study was carried out to evaluate the hypolipidemic activity of virgin olive oil in experimentally induced hyperlipemic Wistar. A total of 24 rats were randomly allocated to 4 equal groups and treated as follows for 50 days: (1) Normal control (NC); that were fed with a standart diet; (2) High Cholesterol Diet Control (HCD); which received high cholesterol diet for 50 days; (3) Animals receiving high cholesterol diet for 50 days, after this period the animals are fed for eight days by the standard foodand receiving by gavage virgin olive oil (HCD+VOO) and(4) Animals fed for eight days with the standard food and receiving by gavage olive oil (VOO). High Cholesterol Diet containing yolk egg and coconut oil. Results showed that olive oil caused a significant (p < 0.01) reduction in serum levels of Total Cholesterol (TC), Triglycerides (TG), Low­Density Lipoprotein Cholesterol (LDL) and Atherogenic Index Serum (AIS). The results also demonstrated a significant (p < 0.01) increase in High­Density Lipoprotein Cholesterol (HDL). Moreover, virgin olive oil induced a significant reduction in liver lipid content. On the other hand, a High cholesterol diet induced oxidative stress was measured by estimating reduced glutathione level and amount of thiobarbituric acid reactive substances (TBARS) formed as an index of lipid peroxidation in a liver and a heart. Virgin olive oil supplementation attenuated all these variations. Our observations of the study indicate that the virgin olive oil has a significant antihyperlipidemic potential.

Role of macrophage scavenger receptor MSR1 in the progression of non-alcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease (NAFLD), and the dysregulation of lipid metabolism and oxidative stress are the typical features. Subsequent dyslipidemia and oxygen radical production may render the formation of modified lipids. Macrophage scavenger receptor 1 (MSR1) is responsible for the uptake of modified lipoprotein and is one of the key molecules in atherosclerosis. However, the unrestricted uptake of modified lipoproteins by MSR1 and the formation of cholesterol-rich foamy macrophages also can be observed in NASH patients and mouse models. In this review, we highlight the dysregulation of lipid metabolism and oxidative stress in NASH, the alteration of MSR1 expression in physiological and pathological conditions, the formation of modified lipoproteins, and the role of MSR1 on macrophage foaming and NASH development and progression.

A brief history of OspA vaccines including their impact on diagnostic testing for Lyme disease.

The only United States Food and Drug Administration approved vaccine preparation to prevent Lyme disease consisted of a single recombinant outer surface protein A (OspA), which was marketed for use from late 1998 until early 2002, with no vaccine currently available for humans for nearly 20 years. OspA vaccines generate an antibody-mediated, transmission blocking immunity, that prevents Borrelia burgdorferi from being transmitted during a tick bite. Although this OspA vaccine was safe and effective, it likely would have required booster doses to maintain immunity, and vaccination regularly caused false positive results on first-tier serologic testing for Lyme disease, when a whole cell-based enzyme immunoassay was used. Clinical trials are in progress to test a new multivalent OspA vaccine designed to prevent Lyme disease in both the United States and Europe.

Leptospira collagenase and LipL32 for antibody detection in leptospirosis.

Various Leptospira components have been identified as candidate antigens for the detection of antibody to Leptospira. LipL32 is a Leptospira membrane protein which has been widely studied. The report of Leptospira whole-genome sequencing demonstrated that pathogenic Leptospira contained the nucleotide sequence (colA gene) coding for the collagenase. Expression of ColA protein and its enzymatic activity was demonstrated. In this study, cloned ColA protein, in comparison with LipL32, was used as an antigen for antibody detection. Thirty pairs of sera from human leptospirosis patients were tested. Sera from blood donors, and patients with scrub typhus and dengue virus infection (20 samples from each group) were tested for the specificity. All sera from leptospirosis patients tested in this study reacted with both ColA and LipL32 proteins. Sera from blood donors, patients with scrub typhus and dengue virus infection did not react with ColA protein. Data suggested that sensitivity and specificity of ColA protein for Leptospira antibody detection were 100%. In addition, ColA protein showed higher specificity than LipL32. Our data suggested that ColA protein could be another candidate antigen for antibody detection in leptospirosis diagnosis.