Ninhydrin as a reversible protecting group of amino‐terminal cysteine

Abstract: The proximity of the α‐amine and β‐thiol of α‐amino terminal‐cysteine (NT‐Cys) residues in peptides imparts unique chemical properties that have been exploited for inter‐ and intra‐molecular ligation of unprotected peptides obtained through both synthetic and biological means. A reversible protecting group orthogonal to other protection strategies and reversible under mild conditions would be useful in simplifying the synthesis, cleavage, purification and handling of such NT‐Cys peptides. It could also be useful for the sequential ligation of peptides. To this end, we explored tri‐one chemistry and found that ninhydrin (indane‐1,2,3 trione) reacted readily with cysteine or an NT‐Cys‐containing peptide on‐ or off‐resin at pH 2–5 to form Ninhydrin‐protected Cys (Nin‐Cys) as a thiazolidine (Thz). The Thz ring, protecting both the amino and thiol groups in Nin‐Cys, completely avoids the formylation and Thz side reactions found during hydrofluoric acid (HF) cleavage when N‐π‐benzyloxymethyl histidine groups are present. Nin‐Cys is stable during coupling reactions and various cleavage conditions with trifluoroacetic acid or HF, but is deprotected under thiolytic or reducing conditions. These properties enable a facile one‐step deprotection and end‐to‐end‐cyclization reaction of Nin‐Cys peptides containing C‐terminal thioesters.     

Immunogenicity and safety of the new intradermal influenza vaccine in adults and elderly: A randomized phase 1/2 clinical trial

BackgroundRecent clinical evidence indicates that an intradermal (ID) delivery of vaccines confers superior immunogenicity as compared to a standard intramusclular or subcutaneous (SC) delivery.MethodsIn this exploratory study, 600 healthy adults were randomized to 6 study groups with subgroups of young adults (20–64 years old) and older adults (65 years and older). The subjects were either injected by a novel ID injection system with a single dose of 6, 9, or 15 μg HA or two doses (21 days apart) of 15 μg HA per strain or injected by an SC injection method with a single or two doses (21 days apart) of 15 μg HA per strain. Immunogenicity was assessed using hemagglutination inhibition (HAI) titer and microneutralization titer on Days 0, 10, 21, and 42. Solicited and unsolicited adverse events were recorded for 7 and 21 days post-vaccination, respectively.ResultsIn both young adults and older adults groups, the geometric titer (GMT) ratios of HAI in the ID 15 μg HA group were higher than those in the SC 15 μg HA group on both Day 10 and Day 21, while those in the ID 6 and ID 9 μg HA groups were comparable with those in the SC 15 μg HA group. The kinetics of GMTs of HAI suggested that the ID vaccine has the potential to induce the prompt immune response, which is rather hampered in older adults as seen in the SC vaccine groups. The injection-site AEs were generally mild and transient, and did not occur in a dose or dosage-dependent manner.ConclusionsThe results of this study clearly suggest that the immunologic profile of the ID vaccine is better than that of the SC vaccine, while the safety profile of the ID vaccine is similar to that of the SC vaccine. In this exploratory study with almost 100 subjects per each group, single or two-dose administration of the ID vaccine containing 15 μg HA was suggested to be an appropriate regimen in order to prevent influenza and to reduce the associated disease burden.Trial registrationJAPIC Clinical Trials Information (JapicCTI-132096).     

The Differential Diagnostic Value of Serum NT‐proBNP in Hospitalized Patients of Heart Failure With Pneumonia

Serum N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) is considered as an effective predictor for patients with heart failure (HF), while a strong body of evidence has found its utility in inflammatory diseases. It is difficult to differentiate HF and HF coexisting with other inflammations by measuring NT‐proBNP. The aim of this study was to estimate the differential diagnostic performance of serum NT‐proBNP in hospitalized HF patients with pneumonia. A prospective study was launched. Sixty nine HF patients, 51 HF patients complicated with pneumonia, and 38 patients with pneumonia were enrolled. Serum NT‐proBNP levels were measured on Roche Elecsys. X‐ray and the European Society of Cardiology (ESC) diagnostic principles were adopted to identify patients with pneumonia and HF, respectively. The diagnostic performance of NT‐proBNP was assessed by ROC. Serum NT‐proBNP [7,039(1,008–24,672) pg/ml] in patients of HF complicated with pneumonia was significantly higher than that in those of patients with single HF [3,147(616–24,062) pg/ml] or single pneumonia [911(98–3,812) pg/ml] (P < 0.0001). No correlation was found between the level of NT‐proBNP and hospital stay. The area under ROC curve (AUC) of NT‐proBNP for distinguishing patients of HF with pneumonia was 0.8082. At the level of 4,691 pg/ml, the optimal cutoff value, 74.5% sensitivity and 81.8% specificity of NT‐proBNP were predicted. Evaluation of serum NT‐proBNP is conducive for clinicians to identify patients of HF with pneumonia, but its poor efficacy in monitoring the curative therapy in this entire cohort is not recommended.     

Correlation between NT proBNP and left ventricular ejection fraction in elderly patients presenting to emergency department with dyspnoea

ObjectiveShortness of breath is a common complaint for which the elderly seek medical attention in the emergency department (ED). Differentiating cardiac from respiratory causes of dyspnoea in this population is quite a challenge. N Terminal pro brain-natriuretic-peptide (NT proBNP) has been studied extensively as a biomarker of left ventricular (LV) failure.MethodsThe NT proBNP was measured in 100 patients above 60 years of age who presented to the ED with shortness of breath. The level was compared with echocardiographic findings to assess correlation with ejection fraction (EF).ResultsThe NT proBNP values increased significantly as the functional severity of heart failure (HF) increased (P < 0.001). The mean NT proBNP level was 1503.33 pg/mL. Patients with respiratory causes of dyspnoea had a mean NT proBNP level of 309.28 pg/mL with normal LV function.ConclusionThe NT proBNP levels had a good correlation with worsening LVEF.     

Tocilizumab for the treatment of chimeric antigen receptor T cell-induced cytokine release syndrome

ABSTRACT

Introduction: Cancer-directed immunotherapies are transforming the landscape in oncology as new and exciting therapies move from the laboratory to the bedside. Chimeric antigen receptor T (CAR-T) cells are one of these novel therapies, demonstrating impressive efficacy against B-cell malignancies. With the development of new therapies, it is not uncommon to identify new and unanticipated toxicities. CAR-T cells cause unique toxicities not typically found with traditional cytotoxic chemotherapy or small molecule inhibitors.

Areas covered: CAR-T cell associated toxicities include cytokine release syndrome (CRS) and CAR-T cell-related encephalopathy syndrome (CRES), alternatively known as immune effector cell-associated neurotoxicity syndrome (ICANS). Prompt identification and management of CRS and CRES are imperative for the prevention of life-threatening complications of these innovative therapies. This literature review describes the seminal trials of CD19-directed immunotherapy and the pathophysiology and management of the toxicities found with CAR-T cells. In addition, the use of the interleukin-6 receptor antibody tocilizumab for CRS is reviewed.

Expert opinion: This review describes the recommended management of CRS and CRES and examines the current limitations in management. Alternative therapies for the treatment of CAR-T cell related toxicities are also explored. Furthermore, the review proposes future directions for research.     

Analysis of relationships between polymorphisms in the genes encoding the pentameric complex and neutralization of clinical cytomegalovirus isolates

IntroductionAs congenital cytomegalovirus (CMV) infection is one of the major causes of birth defects and developmental abnormalities, it is essential to develop vaccines and therapeutic antibodies against CMV. Clinical trials demonstrated that the subunit vaccine based on glycoprotein B, which had been believed to be the major target for neutralization, did not induce sufficient protective immunity. On the other hand, it has been reported that the immunization of animals with the Pentamer, the pentameric complex of gH/gL/UL128/UL130/UL131A, induced strong neutralizing antibodies. Here, we sought to clarify whether any polymorphic alterations present in the Pentamer of clinical isolates affect neutralization by anti-Pentamer antibodies.MethodsSequences of the genes encoding the Pentamer components of 25 Japanese clinical isolates were determined. Neutralization of infection by two seropositive sera and by anti-Pentamer serum was measured using a CMV reporter cell line based on ARPE-19.ResultsPolymorphisms of the amino acid sequence of UL128, UL130, and UL131A ORFs were limited and clustered into two major groups. The identified alterations, except UL128 I140T, were mapped outside of the reported regions recognized by neutralizing antibodies. Anti-Pentamer serum neutralized infection with all isolates to a similar degree and had no correlation with the polymorphic groups.ConclusionsOur findings indicate that Pentamer antigens prepared from Merlin Fix strain induce antibodies that neutralize infection with all isolates to a similar level and that anti-Pentamer antibodies neutralize CMV infection better than do human sera, suggesting that vaccines and therapeutic antibodies based on Pentamer as an antigen have some promise.