TLR4- and TRIF-dependent stimulation of B lymphocytes by peptide liposomes enables T cell-independent isotype switch in mice.

Immunoglobulin class switching from IgM to IgG in response to peptides is generally T cell-dependent and vaccination in T cell-deficient individuals is inefficient. We show that a vaccine consisting of a dense array of peptides on liposomes induced peptide-specific IgG responses totally independent of T-cell help. Independency was confirmed in mice lacking T cells and in mice deficient for MHC class II, CD40L, and CD28. The IgG titers were high, long-lived, and comparable with titers obtained in wild-type animals, and the antibody response was associated with germinal center formation, expression of activation-induced cytidine deaminase, and affinity maturation. The T cell-independent (TI) IgG response was strictly dependent on ligation of TLR4 receptors on B cells, and concomitant TLR4 and cognate B-cell receptor stimulation was required on a single-cell level. Surprisingly, the IgG class switch was mediated by TIR-domain-containing adapter inducing interferon-ß (TRIF), but not by MyD88. This study demonstrates that peptides can induce TI isotype switching when antigen and TLR ligand are assembled and appropriately presented directly to B lymphocytes. A TI vaccine could enable efficient prophylactic and therapeutic vaccination of patients with T-cell deficiencies and find application in diseases where induction of T-cell responses contraindicates vaccination, for example, in Alzheimer disease.

An effector-reduced anti-ß-amyloid (Aß) antibody with unique aß binding properties promotes neuroprotection and glial engulfment of Aß.

Passive immunization against ß-amyloid (Aß) has become an increasingly desirable strategy as a therapeutic treatment for Alzheimer's disease (AD). However, traditional passive immunization approaches carry the risk of Fcγ receptor-mediated overactivation of microglial cells, which may contribute to an inappropriate proinflammatory response leading to vasogenic edema and cerebral microhemorrhage. Here, we describe the generation of a humanized anti-Aß monoclonal antibody of an IgG4 isotype, known as MABT5102A (MABT). An IgG4 subclass was selected to reduce the risk of Fcγ receptor-mediated overactivation of microglia. MABT bound with high affinity to multiple forms of Aß, protected against Aß1-42 oligomer-induced cytotoxicity, and increased uptake of neurotoxic Aß oligomers by microglia. Furthermore, MABT-mediated amyloid plaque removal was demonstrated using in vivo live imaging in hAPP((V717I))/PS1 transgenic mice. When compared with a human IgG1 wild-type subclass, containing the same antigen-binding variable domains and with equal binding to Aß, MABT showed reduced activation of stress-activated p38MAPK (p38 mitogen-activated protein kinase) in microglia and induced less release of the proinflammatory cytokine TNFα. We propose that a humanized IgG4 anti-Aß antibody that takes advantage of a unique Aß binding profile, while also possessing reduced effector function, may provide a safer therapeutic alternative for passive immunotherapy for AD. Data from a phase I clinical trial testing MABT is consistent with this hypothesis, showing no signs of vasogenic edema, even in ApoE4 carriers.

Abeta42 neurotoxicity is mediated by ongoing nucleated polymerization process rather than by discrete Abeta42 species.

The identification of toxic Aß species and/or the process of their formation is crucial for understanding the mechanism(s) of Aß neurotoxicity in Alzheimer disease and also for the development of effective diagnostic and therapeutic interventions. To elucidate the structural basis of Aß toxicity, we developed different procedures to isolate Aß species of defined size and morphology distribution, and we investigated their toxicity in different cell lines and primary neurons. We observed that crude Aß42 preparations, containing a monomeric and heterogeneous mixture of Aß42 oligomers, were more toxic than purified monomeric, protofibrillar fractions, or fibrils. The toxicity of protofibrils was directly linked to their interactions with monomeric Aß42 and strongly dependent on their ability to convert into amyloid fibrils. Subfractionation of protofibrils diminished their fibrillization and toxicity, whereas reintroduction of monomeric Aß42 into purified protofibril fractions restored amyloid formation and enhanced their toxicity. Selective removal of monomeric Aß42 from these preparations, using insulin-degrading enzyme, reversed the toxicity of Aß42 protofibrils. Together, our findings demonstrate that Aß42 toxicity is not linked to specific prefibrillar aggregate(s) but rather to the ability of these species to grow and undergo fibril formation, which depends on the presence of monomeric Aß42. These findings contribute significantly to the understanding of amyloid formation and toxicity in Alzheimer disease, provide novel insight into mechanisms of Aß protofibril toxicity, and important implications for designing anti-amyloid therapies.

A Randomised Controlled Trial Comparing the Pharmacokinetics and Tolerability of the Proposed Adalimumab Biosimilar MSB11022 Delivered via Autoinjector and Pre-filled Syringe in Healthy Subjects.

INTRODUCTION: The aim of the study was to demonstrate the bioequivalence, and compare the safety and tolerability of MSB11022, a proposed biosimilar of adalimumab, when delivered by either an autoinjector (AI) or a pre-filled syringe (PFS). METHODS: In this pharmacokinetic (PK), parallel group, open-label study, 216 healthy volunteers were randomised 1:1 to receive a single subcutaneous injection of a 40 mg/0.8 mL dose of MSB11022 administered via AI or PFS. Coprimary PK endpoints were maximum observed concentration (Cmax), area under the concentration-time curve (AUC) from time 0 to the last quantifiable concentration (AUC0-t), and AUC from time 0 extrapolated to infinity (AUC0-inf). PK equivalence between the AI and PFS administration methods was declared if the 90% confidence intervals (CIs) for the ratio of geometric least square means was entirely contained within the 80-125% equivalence margin for all coprimary endpoints. Safety and tolerability were also evaluated. RESULTS: The 90% CI for the three coprimary PK endpoints (Cmax, AUC0-t and AUC0-inf) were entirely contained within the predefined equivalence margins of 80-125%. Mean serum concentration-time profiles were similar following injection via AI or PFS. Treatment-emergent adverse events (TEAEs) were comparable across both treatment groups. Study device-related TEAEs were reported by 11.3% and 13.1% of subjects in the AI and PFS treatment groups, respectively. Study drug-related TEAEs were reported by 28.3% and 34.6% of subjects in the AI and PFS treatment groups, respectively. Few subjects experienced injection-site reactions, mainly pain and erythema, regardless of the administration method. CONCLUSION: Delivery of MSB11022 via an AI is bioequivalent to delivery via a PFS. The safety and tolerability profile of MSB11022 was comparable across administration methods. The development of an AI for MSB11022 provides a choice of self-injection devices available to patients, potentially improving treatment compliance. TRIAL REGISTRATION: ClinicalTrials.gov trial identifier: NCT04018599.