Sacituzumab Govitecan for Metastatic Triple-Negative Breast Cancer: Clinical Overview and Management of Potential Toxicities.

Patients with metastatic triple-negative breast cancer have a poor prognosis. Sacituzumab govitecan (IMMU-132) is an antibody-drug conjugate that contains the irinotecan active metabolite, SN-38, linked to a humanized monoclonal antibody targeting trophoblast cell surface antigen 2, which is overexpressed in many solid tumors. In a basket design phase I/II study, sacituzumab govitecan demonstrated promising single-agent therapeutic activity in multiple cancer cohorts, leading to accelerated approval by the U.S. Food and Drug Administration of sacituzumab govitecan-hziy (TRODELVY) for the treatment of patients with metastatic triple-negative breast cancer who had received at least two prior therapies in the metastatic setting. Recently, results of the phase III trial, ASCENT, were confirmatory. There is limited available information on the adverse event management with sacituzumab govitecan needed to maximize the dose and duration of effective therapy while maintaining patient quality of life. This review summarizes the clinical development and the practical management of patients receiving sacituzumab govitecan. Sacituzumab govitecan has a well-defined and manageable toxicity profile, and rapid recognition and appropriate early and proactive management will allow clinicians to optimize sacituzumab govitecan treatment for patients. IMPLICATIONS FOR PRACTICE: Sacituzumab govitecan (TRODELVY) is a novel antibody-drug conjugate composed of the active metabolite of irinotecan (SN-38) conjugated to a monoclonal antibody targeting trophoblast cell surface antigen 2, an epithelial cell surface antigen overexpressed in many cancers. Because of the rapid approval of sacituzumab govitecan, there is limited available information on adverse event (AE) management with this agent. As such, this article reviews the clinical development of the drug, the AE profile, and provides recommendations regarding AE management to help optimize therapy with sacituzumab govitecan.

Characteristic evaluation of a simple hand-made semiconductor dosimeter for mammography.

Daily quality control of mammography equipment is important for providing optimal images and determining appropriate doses. To popularise dosimeters, the Measurement Division, the Japanese Society of Radiological Technology hold a seminar on making simple dosimeters. At this seminar, a hand-made dosimeter for mammography (HD-M) can be made at low cost. However, HD-Ms employ semiconductors, and their energy responses are subject to significant variations. This investigation involved the determination of precautions when using HD-Ms, examining their energy response characteristics and measurable energy ranges. HD-M has four types of selectors for response correction. When the selector and the tube voltage were equal, the HD-M readings matched that of the ionisation chamber within 5%. However, in case of target filter combinations and measuring tube voltages that the selector does not support, the HD-M readings differed by up to 53% from the ionisation chamber values. HD-M may use different measurement circuits and semiconductor elements depending on the time of the seminar. In this study, it was clarified that the correction factork, which is the average value of the ratio of the measured value of the ionisation chamber dosimeter to the measured value of HD-M, changes from 0.62 to 1.53 depending on irradiation conditions such as the combination of target filters and the tube voltage. It was demonstrated that HD-M functions sufficiently as a dosimeter for daily management by determining the correction factor using the method proposed in this study.

Chemokine expression profiles in liver and kidney of mice with different susceptibilities to leptospirosis.

Leptospirosis is a global disease that affects humans and animals, impacting public health and the economy. The symptoms caused by Leptospira infection can vary from mild to severe, affecting liver, lungs, and kidneys. The host-pathogen interaction in leptospirosis is still poorly understood, but there is evidence for the role of the host immune response in the pathogenesis. Chemokines are a family of structurally-related low-molecular-mass proteins (8-14 kDa) that signal the recruitment of leukocytes. In this study the profile of 22 chemokines were evaluated in liver and kidney of three mice strains with different phenotypes of susceptibility to leptospirosis. We extended our previously reported observations showing that expression of chemokines with homeostatic function, activation and chemotaxis of leukocytes are essential to modulate and to induce resistance to leptospirosis. Our findings support that an early induction of CXC chemokines in resistant BALB/c mice can be associated with the control of the infection. The correlation of chemokine expression between liver and kidney observed in BALB/c suggests that a balance of chemokine induction in the organs may contribute to resistance to leptospirosis.

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts.

Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu2 O3 or Tb2 O3 ) nanoparticles (guests) were encapsulated into chiral non-helical SiO2 nanofibres (host) through calcination of chiral SiO2 hybrid nanofibres, trapping Eu3+ (or Tb3+ ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu3+ and 545 nm for Tb3+ . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts.

Ultrasonographic prediction of antepartum deterioration of growth-restricted fetuses after late preterm.

AIM: To examine the predictive value of ultrasound parameters for antepartum non-reassuring fetal status (NRFS) in fetal growth restriction (FGR) cases after late preterm. METHODS: Retrospective review of singleton FGR cases before 37 weeks gestation who delivered after 34 weeks gestation was performed. The association between ultrasound parameters that was assessed from 34 to 36 weeks gestation and the development of antepartum NRFS that was diagnosed by nonstress test and biophysical profile was analyzed by using multivariate Cox proportional hazards analyses. RESULTS: A total of 214 patients were included in final data analyses. Antepartum NRFS occurred in 23 cases (10.7%) including five cases of placental abruption. Lower standard deviation (SD) of estimated fetal weight (EFW), lower cerebroplacental ratio (CPR) and the presence of oligohydramnios were independently associated with antepartum NRFS. The prevalence of antepartum NRFS was highest (50.4%) in the group of EFW ≤-2.5 SD with CPR ≤1.45. CONCLUSION: Ultrasound parameters of lower SD of EFW, lower CPR and oligohydramnios were predictive for antepartum NRFS in FGR after late preterm.

Determination of the thermal and epithermal neutron sensitivities of an LBO chamber.

An LBO (Li2B4O7) walled ionization chamber was designed to monitor the epithermal neutron fluence in boron neutron capture therapy clinical irradiation. The thermal and epithermal neutron sensitivities of the device were evaluated using accelerator neutrons from the 9Be(d, n) reaction at a deuteron energy of 4 MeV (4 MeV d-Be neutrons). The response of the chamber in terms of the electric charge induced in the LBO chamber was compared with the thermal and epithermal neutron fluences measured using the gold-foil activation method. The thermal and epithermal neutron sensitivities obtained were expressed in units of pC cm2, i.e., from the chamber response divided by neutron fluence (cm-2). The measured LBO chamber sensitivities were 2.23 × 10-7 ± 0.34 × 10-7 (pC cm2) for thermal neutrons and 2.00 × 10-5 ± 0.12 × 10-5 (pC cm2) for epithermal neutrons. This shows that the LBO chamber is sufficiently sensitive to epithermal neutrons to be useful for epithermal neutron monitoring in BNCT irradiation.

Characterization of a new radiochromic film (LD-V1) using mammographic beam qualities.

PURPOSE: Radiochromic film (RCF) is a detector that can obtain a two-dimensional dose distribution with high resolution; it is widely used in medical and industrial fields. Several types of RCFs exist based on their application. The type of RCF mainly used for mammography dose assessment has been discontinued; however, a new type of RCF (LD-V1) has been distributed as a successor. Since the medical use of LD-V1 has rarely been studied, we investigated the response characteristics of LD-V1 in mammography. METHODS: Measurements were performed using Mo/Mo and Rh/Ag on a Senographe Pristina mammography device (GE, Fairfield, CT, USA). The reference air kerma was measured using a parallel-plate ionization chamber (PPIC) (C-MA, Applied Engineering Inc, Tokyo, Japan). Pieces of LD-V1 film model were irradiated at the same position where the reference air kerma in air was measured by the PPIC. Irradiation was performed using the time scale method based on the load on the equipment. Two methods of irradiation were considered: placing the detector in air and on the phantom. The LD-V1 was scanned five times at 72 dpi in RGB (48 bit) mode using a flatbed scanner (ES-G11000, Seiko Epson Corp, Nagano, Japan) 24 h following irradiation. The response ratio of the reference air kerma and the air kerma obtained from the LD-V1 were compared and examined for each beam quality and air kerma range. RESULTS AND DISCUSSION: When the beam quality was altered, the response ratio varied from 0.8 to 1.2 with respect to the measurement value of the PPIC; however, some outliers were observed. Response ratios were highly variable in the low-dose range; however, as the air kerma increased, the ratios approached 1. Thus, LD-V1 does not need calibration for each beam quality used in mammography. LD-V1 enables air kerma evaluation by creating air kerma response curves under certain X-ray conditions used in mammography. CONCLUSION: We suggest that the dose range be limited to 12 mGy or more to keep the response variation with beam qualities below ±20%. If further measurement is required for reducing the response variation, the dose range should be shifted to a higher dose range.

Validation of the Use of Discharge Diagnostic Codes for the Verification of Secondary Atrial Fibrillation in Administrative Databases.

Background: "Secondary" atrial fibrillation (AF) denotes AF that is precipitated by short-term triggers and that may be reversible. Using administrative data to study secondary AF is of interest, but the ability of these data to verify secondary AF has not been studied. Methods: We conducted a cross-sectional analysis of 1000 randomly selected hospitalizations of patients discharged alive between January 1, 2016 and March 31, 2020, with AF coded as the most responsible diagnosis (type 1), post-admit comorbidity (type 2), or secondary diagnosis (type 3). We compared diagnosis types to AF category (secondary or not) as determined by a physician blinded to the discharge diagnosis type. We calculated the positive predictive value (PPV) of the designation of secondary AF in comparison to physician determination. Results: A total of 421 hospitalizations had AF documented as a type 2 diagnosis; this had a PPV of 94.8% for physician determination of secondary AF. After excluding hospitalizations with preexisting AF, and those for which AF type could not be determined by the physician, the PPV of a type 2 diagnosis (n = 391) for secondary AF was 99.7%. Type 3 diagnoses of AF (n = 222) mostly captured hospitalizations with preexisting AF (87.8% of type 3 diagnoses). Conclusions: A type 2 diagnosis can be used to verify secondary AF in people who were first diagnosed with AF while hospitalized for other causes. This verification facilitates cohort studies and clinical trial recruitment of people with this AF subtype, although it should not be used to determine the prevalence or incidence of secondary AF.

Contexte: Une fibrillation auriculaire (FA) « secondaire ¼ signifie que la FA est précipitée par des déclencheurs apparus depuis peu et pouvant être réversibles. L'utilisation de données administratives en vue d'étudier la FA secondaire peut être pertinente, mais la possibilité que ces données permettent d'évaluer les FA secondaires n'a pas été étudiée. Méthodologie: Nous avons effectué une analyse transversale de 1 000 hospitalisations, sélectionnées au hasard, de patients ayant reçu leur congé alors qu'ils étaient en vie entre le 1er janvier 2016 et le 31 mars 2020, et dans le dossier desquels la FA était codée comme étant le diagnostic principal de l'hospitalisation (type 1), une affection concomitante diagnostiquée après l'admission à l'hôpital (type 2) ou un diagnostic secondaire (type 3). Nous avons comparé les types des diagnostics à la catégorie de FA (secondaire ou pas), déterminée par un médecin qui ignorait le type de diagnostic confirmé au moment du congé. Nous avons calculé la valeur prédictive positive (VPP) de la désignation de FA secondaire, comparativement à ce que le médecin a déterminé. Résultats: Au total, 421 hospitalisations étaient associées à un diagnostic confirmé de FA de type 2, ce qui a produit une VPP de 94,8 % pour ce que le médecin avait déterminé comme étant une FA se-condaire. Après l'exclusion des hospitalisations de patients qui présentaient une FA préexistante et de ceux pour qui le type de FA ne pouvait pas être déterminé par le médecin, la VPP d'un diagnostic de FA de type 2 (n = 391) pour une FA secondaire était de 99,7 %. Les diagnostics de FA de type 3 (n = 222) étaient principalement associés à des hospitalisations de patients présentant une FA préexistante (87,8 % des diagnostics de type 3). Conclusions: Un diagnostic de FA de type 2 peut servir à vérifier la présence d'une FA secondaire chez les personnes ayant reçu un premier diagnostic de FA alors qu'elles étaient hospitalisées pour d'autres causes. Cette vérification facilite les études de cohortes et le recrutement pour des essais cliniques de personnes atteintes de ce sous-type de FA, mais elle ne doit pas servir à déterminer la prévalence ou l'incidence de la FA secondaire.

Adjuvant trastuzumab and vinorelbine for early-stage HER2+ breast cancer.

Background: The single-arm phase II APT trial established trastuzumab and paclitaxel (TH) as the standard adjuvant regimen for small human epidermal growth factor receptor 2 (HER2+) tumors. However, paclitaxel causes alopecia and has high rates of neuropathy and hypersensitivity reactions. In patients with metastatic HER2+ breast cancer (BC), the combination of trastuzumab and vinorelbine (TV) is effective and well tolerated. There is a need for alternative non-anthracycline/taxane-based regimens for patients with HER2+ early-stage BC, especially for those with contraindications or who wish to avoid side effects of taxane-based regimens. Here we describe our institutional experience with adjuvant TV for patients with early-stage HER2+ BC. Methods: Clinicopathological characteristics, treatment details, and outcomes of patients with localized HER2+ BC treated with adjuvant TV from 2007 to 2021 at a large academic medical institution were collected. Study endpoints included invasive disease-free survival (IDFS), overall survival (OS), and safety/tolerability. IDFS and OS were measured from start date of TV treatment to date of event/last follow-up and date of death/last follow-up, respectively. Results: A total of 30 patients were treated with TV. All patients received trastuzumab at standard dosing and vinorelbine at a starting dose of 25 mg/m2 either on days 1/8 or on days 1/8/21 (weekly) of a 21-day cycle with four planned cycles. Median age at diagnosis was 59 years (range: 36-81). 90.3% of patients had anatomic pathologic stage IA BC and 9.7% stage IIA BC. Of the 30 patients, 24 of them opted to pursue TV due to concerns related to alopecia, neuropathy, and other toxicities, and 6 switched from treatment with TH to TV due to toxicities. Eight patients experienced neutropenia with no cases of febrile neutropenia. No patients experienced alopecia or long-term neuropathy. With a median follow-up of 68 months (5.7 years), the 5-year IDFS rate was 90.9%, with one local and one distant recurrence. The 5-year OS was 100%. Conclusions: Trastuzumab in combination with vinorelbine in the adjuvant, early-stage setting for low-risk HER2+ BC demonstrated clinical efficacy and appeared to be well tolerated. TV warrants further evaluation as an alternative regimen to TH for patients with early-stage HER2+ BC.

RELATIONSHIPS BETWEEN TYPES OF PROTECTIVE EYEWEAR AND EYE LENS DOSE WITHIN ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY.

In this study, variations in eye lens dose across different types of protective operator eyewear as well as the most appropriate protective methods when conducting endoscopic retrograde cholangiopancreatography were evaluated. The eye lens doses of 10 types of commercially available protective eyewear were compared. The ratio of the measured value near the eye to the measured value at the eye lens position ranged from 0.65 to 5.40 and it varied according to the mounting position of the dosemeter as well as the type of protective eyewear. Thus, the eye lens dose may have been overestimated or underestimated. Regardless of the working conditions, a face shield type of protective eyewear is recommended to reduce the eye lens dose. Moreover, it is preferable to attach a lens dosemeter near the eye to measure and evaluate the eye lens dose.

Chitinase 3 like 1 contributes to the development of pulmonary vascular remodeling in pulmonary hypertension.

Chitinase 3 like 1 (CHI3L1) is the prototypic chitinase-like protein mediating inflammation, cell proliferation, and tissue remodeling. Limited data suggest CHI3L1 is elevated in human pulmonary arterial hypertension (PAH) and is associated with disease severity. Despite its importance as a regulator of injury/repair responses, the relationship between CHI3L1 and pulmonary vascular remodeling is not well understood. We hypothesize that CHI3L1 and its signaling pathways contribute to the vascular remodeling responses that occur in pulmonary hypertension (PH). We examined the relationship of plasma CHI3L1 levels and severity of PH in patients with various forms of PH, including group 1 PAH and group 3 PH, and found that circulating levels of serum CHI3L1 were associated with worse hemodynamics and correlated directly with mean pulmonary artery pressure and pulmonary vascular resistance. We also used transgenic mice with constitutive knockout and inducible overexpression of CHI3L1 to examine its role in hypoxia-, monocrotaline-, and bleomycin-induced models of pulmonary vascular disease. In all 3 mouse models of pulmonary vascular disease, pulmonary hypertensive responses were mitigated in CHI3L1-null mice and accentuated in transgenic mice that overexpress CHI3L1. Finally, CHI3L1 alone was sufficient to induce pulmonary arterial smooth muscle cell proliferation, inhibit pulmonary vascular endothelial cell apoptosis, induce the loss of endothelial barrier function, and induce endothelial-mesenchymal transition. These findings demonstrate that CHI3L1 and its receptors play an integral role in pulmonary vascular disease pathobiology and may offer a target for the treatment of PAH and PH associated with fibrotic lung disease.

Immunogenicity of SARS-CoV-2 vaccines in patients with breast cancer.

Purpose: To explore the immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in patients with breast cancer based on type of anticancer treatment. Methods: Patients with breast cancer had anti-spike antibody concentrations measured ⩾14 days after receiving a full SARS-CoV-2 vaccination series. The primary endpoint was IgA/G/M anti-spike antibody concentration. Multiple regression analysis was used to analyze log10-transformed antibody titer concentrations. Results: Between 29 April and 20 July 2021, 233 patients with breast cancer were enrolled, of whom 212 were eligible for the current analysis. Patients who received mRNA-1273 (Moderna) had the highest antibody concentrations [geometric mean concentration (GMC) in log10: 3.0 U/mL], compared to patients who received BNT162b2 (Pfizer) (GMC: 2.6 U/mL) (multiple regression adjusted p = 0.013) and Ad26.COV2.S (Johnson & Johnson/Janssen) (GMC: 2.6 U/mL) (p = 0.071). Patients receiving cytotoxic therapy had a significantly lower antibody titer GMC (2.5 U/mL) compared to patients on no therapy or endocrine therapy alone (3.0 U/mL) (p = 0.005). Patients on targeted therapies (GMC: 2.7 U/mL) also had a numerically lower GMC compared to patients not receiving therapy/on endocrine therapy alone, although this result was not significant (p = 0.364). Among patients who received an additional dose of vaccine (n = 31), 28 demonstrated an increased antibody response that ranged from 0.2 to >4.4 U/ mL. Conclusion: Most patients with breast cancer generate detectable anti-spike antibodies following SARS-CoV-2 vaccination, though systemic treatments and vaccine type impact level of response. Further studies are needed to better understand the clinical implications of different antibody levels, the effectiveness of additional SARS-CoV-2 vaccine doses, and the risk of breakthrough infections among patients with breast cancer.

Immunogenicity and Reactogenicity of SARS-CoV-2 Vaccines in Patients With Cancer: The CANVAX Cohort Study.

PURPOSE: The immunogenicity and reactogenicity of SARS-CoV-2 vaccines in patients with cancer are poorly understood. METHODS: We performed a prospective cohort study of adults with solid-organ or hematologic cancers to evaluate anti-SARS-CoV-2 immunoglobulin A/M/G spike antibodies, neutralization, and reactogenicity ≥ 7 days following two doses of mRNA-1273, BNT162b2, or one dose of Ad26.COV2.S. We analyzed responses by multivariate regression and included data from 1,638 healthy controls, previously reported, for comparison. RESULTS: Between April and July 2021, we enrolled 1,001 patients; 762 were eligible for analysis (656 had neutralization measured). mRNA-1273 was the most immunogenic (log10 geometric mean concentration [GMC] 2.9, log10 geometric mean neutralization titer [GMT] 2.3), followed by BNT162b2 (GMC 2.4; GMT 1.9) and Ad26.COV2.S (GMC 1.5; GMT 1.4; P < .001). The proportion of low neutralization (< 20% of convalescent titers) among Ad26.COV2.S recipients was 69.9%. Prior COVID-19 infection (in 7.1% of the cohort) was associated with higher responses (P < .001). Antibody titers and neutralization were quantitatively lower in patients with cancer than in comparable healthy controls, regardless of vaccine type (P < .001). Receipt of chemotherapy in the prior year or current steroids were associated with lower antibody levels and immune checkpoint blockade with higher neutralization. Systemic reactogenicity varied by vaccine and correlated with immune responses (P = .002 for concentration, P = .016 for neutralization). In 32 patients who received an additional vaccine dose, side effects were similar to prior doses, and 30 of 32 demonstrated increased antibody titers (GMC 1.05 before additional dose, 3.17 after dose). CONCLUSION: Immune responses to SARS-CoV-2 vaccines are modestly impaired in patients with cancer. These data suggest utility of antibody testing to identify patients for whom additional vaccine doses may be effective and appropriate, although larger prospective studies are needed.

Hermansky-Pudlak Syndrome and Lung Disease: Pathogenesis and Therapeutics.

Hermansky-Pudlak Syndrome (HPS) is a rare, genetic, multisystem disorder characterized by oculocutaneous albinism (OCA), bleeding diathesis, immunodeficiency, granulomatous colitis, and pulmonary fibrosis. HPS pulmonary fibrosis (HPS-PF) occurs in 100% of patients with subtype HPS-1 and has a similar presentation to idiopathic pulmonary fibrosis. Upon onset, individuals with HPS-PF have approximately 3 years before experiencing signs of respiratory failure and eventual death. This review aims to summarize current research on HPS along with its associated pulmonary fibrosis and its implications for the development of novel treatments. We will discuss the genetic basis of the disease, its epidemiology, and current therapeutic and clinical management strategies. We continue to review the cellular processes leading to the development of HPS-PF in alveolar epithelial cells, lymphocytes, mast cells, and fibrocytes, along with the molecular mechanisms that contribute to its pathogenesis and may be targeted in the treatment of HPS-PF. Finally, we will discuss emerging new cellular and molecular approaches for studying HPS, including lentiviral-mediated gene transfer, induced pluripotent stem cells (iPSCs), organoid and 3D-modelling, and CRISPR/Cas9-based gene editing approaches.

Phenotype-genotype correlations in patients with GNB1 gene variants, including the first three reported Japanese patients to exhibit spastic diplegia, dyskinetic quadriplegia, and infantile spasms.

We report the first three Japanese patients with missense variants in the GNB1 gene. Patients exhibited severe dyskinetic quadriplegia with cortical blindness and epileptic spasms, West syndrome (but with good outcomes), and hypotonic quadriplegia that later developed into spastic diplegia. Whole-exome sequencing revealed two recurrent GNB1 variants (p.Leu95Pro and p.Ile80Thr) and one novel variant (p.Ser74Leu). A recent investigation revealed large numbers of patients with GNB1 variants. Functional studies of such variants and genotype-phenotype correlation are required to enable future precision medicine.

New strategies for Leptospira vaccine development based on LPS removal.

Pathogenic spirochetes from genus Leptospira are etiologic agents of leptospirosis. Cellular vaccines against Leptospira infection often elicit mainly response against the LPS antigen of the serovars present in the formulation. There is no suitable protein candidate capable of replacing whole-cell vaccines, thus requiring new approaches on vaccine development to improve leptospirosis prevention. Our goal was to develop a whole-cell vaccine sorovar-independent based on LPS removal and conservation of protein antigens exposure, to evaluate the protective capacity of monovalent or bivalent vaccines against homologous and heterologous virulent Leptospira in hamster. Leptospire were subjected to heat inactivation, or to LPS extraction with butanol and in some cases further inactivation with formaldehyde. Hamsters were immunized and challenged with homologous or heterologous virulent serovars, blood and organs were collected from the survivors for bacterial quantification, chemokine evaluation, and analysis of sera antibody reactivity and cross-reactivity by Western blot. Immunization with either heated or low LPS vaccines with serovar Copenhageni or Canicola resulted in 100% protection of the animals challenged with homologous virulent bacteria. Notably, different from the whole-cell vaccine, the low LPS vaccines produced with serovar Canicola provided only partial protection in heterologous challenge with the virulent Copenhageni serovar. Immunization with bivalent formulation results in 100% protection of immunized animals challenged with virulent serovar Canicola. All vaccines produced were able to eliminate bacteria from the kidney of challenged animals. All the vaccines raised antibodies capable to recognize antigens of serovars not present in the vaccine formulation. Transcripts of IFNγ, CXCL16, CCL5, CXCL10, CXCR6, and CCR5, increased in all immunized animals. Conclusion: Our results showed that bivalent vaccines with reduced LPS may be an interesting strategy for protection against heterologous virulent serovars. Besides the desirable multivalent protection, the low LPS vaccines are specially promising due to the expected lower reatogenicity.

Two SmDLC antigens as potential vaccines against schistosomiasis.

The Schistosoma mansoni transcriptome revealed new members of the dynein light chain family (DLC/LC8). The antigenicity and immunogenicity of these proteins, and their potential as vaccine candidates were investigated. Two DLC genes (DLC12_JI392413.1 and DLC13_JI387686.1) were cloned and the recombinant proteins produced in E. coli. The immunization of mice with the rDLCs, using alhydrogel as adjuvant, resulted in high titers of antibodies, indicated that these proteins are highly immunogenic. The anti-DLCs antibodies presented cross reactivity with both recombinant antigens and also recognized proteins from S. mansoni adult worm extracts. The DLC12 and DLC13 immunized animals were challenged by infection with cercariae and a protective profile was observed in three different assays, with a significant decreased in worm burden, of 43% and 51% respectively, when compared to the non-vaccinated group. The granulomas formation due to egg retention in the hepatic tissues was evaluated 45 days after infection. Smaller granulomas were observed in the liver of DLC immunized animals, up to 70% reduction in comparison to the granulomas size in the non-vaccinated animals. Fifty-five days after infection, the average size of the hepatic granulomas was still 25-35% smaller in the DLCs vaccinated groups. The interference of DLC immunization on the hepatic granuloma formation may reflect the lower worm burden and consequent decrease on the number of eggs retained in the liver, resulting in lower pro-inflammatory level in the tissue. The protective effect of DLCs immunization, decreasing the worm burden and delaying the rate of granuloma formation, suggests that these antigens should be further studied as potential vaccine candidates.

VapC from the leptospiral VapBC toxin-antitoxin module displays ribonuclease activity on the initiator tRNA.

The prokaryotic ubiquitous Toxin-Antitoxin (TA) operons encode a stable toxin and an unstable antitoxin. The most accepted hypothesis of the physiological function of the TA system is the reversible cessation of cellular growth under stress conditions. The major TA family, VapBC is present in the spirochaete Leptospira interrogans. VapBC modules are classified based on the presence of a predicted ribonucleasic PIN domain in the VapC toxin. The expression of the leptospiral VapC in E. coli promotes a strong bacterial growth arrestment, making it difficult to express the recombinant protein. Nevertheless, we showed that long term induction of expression in E. coli enabled the recovery of VapC in inclusion bodies. The recombinant protein was successfully refolded by high hydrostatic pressure, providing a new method to obtain the toxin in a soluble and active form. The structural integrity of the recombinant VapB and VapC proteins was assessed by circular dichroism spectroscopy. Physical interaction between the VapC toxin and the VapB antitoxin was demonstrated in vivo and in vitro by pull down and ligand affinity blotting assays, respectively, thereby indicating the ultimate mechanism by which the activity of the toxin is regulated in bacteria. The predicted model of the leptospiral VapC structure closely matches the Shigella's VapC X-ray structure. In agreement, the ribonuclease activity of the leptospiral VapC was similar to the activity described for Shigella's VapC, as demonstrated by the cleavage of tRNAfMet and by the absence of unspecific activity towards E. coli rRNA. This finding suggests that the cleavage of the initiator transfer RNA may represent a common mechanism to a larger group of bacteria and potentially configures a mechanism of post-transcriptional regulation leading to the inhibition of global translation.

Refolding of the recombinant protein Sm29, a step toward the production of the vaccine candidate against schistosomiasis.

Schistosomiasis is an important parasitic disease, with about 240 million people infected worldwide. Humans and animals can be infected, imposing an enormous social and economic burden. The only drug available for chemotherapy, praziquantel, does not control reinfections, and an efficient vaccine for prophylaxis is still missing. However, the tegumental protein Sm29 of Schistosoma mansoni was shown to be a promising antigen to compose an anti-schistosomiasis vaccine. Though, recombinant Sm29 is expressed in Escherichia coli as insoluble inclusion bodies requiring an efficient process of refolding, thus, hampering its production in large scale. We present in this work studies to refold the recombinant Sm29 using high hydrostatic pressure, a mild condition to dissociate aggregated proteins, leading to refolding on a soluble conformation. Our studies resulted in high yield of rSm29 (73%) as a stably soluble and structured protein. The refolded antigen presented protective effect against S. mansoni development in immunized mice. We concluded that the refolding process by application of high hydrostatic pressure succeeded, and the procedure can be scaled-up, allowing industrial production of Sm29.