Human Antibodies that Slow Erythrocyte Invasion Potentiate Malaria-Neutralizing Antibodies.

The Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is the leading target for next-generation vaccines against the disease-causing blood-stage of malaria. However, little is known about how human antibodies confer functional immunity against this antigen. We isolated a panel of human monoclonal antibodies (mAbs) against PfRH5 from peripheral blood B cells from vaccinees in the first clinical trial of a PfRH5-based vaccine. We identified a subset of mAbs with neutralizing activity that bind to three distinct sites and another subset of mAbs that are non-functional, or even antagonistic to neutralizing antibodies. We also identify the epitope of a novel group of non-neutralizing antibodies that significantly reduce the speed of red blood cell invasion by the merozoite, thereby potentiating the effect of all neutralizing PfRH5 antibodies as well as synergizing with antibodies targeting other malaria invasion proteins. Our results provide a roadmap for structure-guided vaccine development to maximize antibody efficacy against blood-stage malaria. Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved

The hippocampus constructs narrative memories across distant events

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Time regained: how the human brain constructs memory for time

Life's episodes unfold against a context that changes with time. Recent neuroimaging studies have revealed significant findings about how specific areas of the human brain may support the representation of temporal information in memory. A consistent theme in these studies is that the hippocampus appears to play a central role in representing temporal context, as operationalized in neuroimaging studies of arbitrary lists of items, sequences of items, or meaningful, lifelike events. Additionally, activity in a posterior medial cortical network may reflect the representation of generalized temporal information for meaningful events. The hippocampus, posterior medial network, and other regions-particularly in prefrontal cortex-appear to play complementary roles in memory for temporal context

Narrative coherence bends the arrow of time when recalling naturalistic events

How are our everyday memories structured? Standard laboratory paradigms such as list-learning tasks have shown that recall clusters based on temporal context and semantic relationships between items. Understanding whether these phenomena manifest in daily life—a realm often characterized by narrative threads of interconnected experiences—has only recently become a focus among memory researchers. Here, we investigate how time and narrative coherence influence the organization of recall, as well as memory for the timing of naturalistic experiences. Participants encoded picturebook-style stories that included multiple side plots. Some of these connected across time to form a single overarching narrative (Coherent Narratives) while others did not (Unrelated Narratives). We systematically varied the number of intervening events between connected narrative elements. Across three experiments using multiple recall tasks, Coherent Narratives were consistently better remembered than Unrelated Narratives. Critically, this narrative coherence benefit occurred regardless of the temporal distance between connected events. Narrative coherence did not directly influence memory for temporal location or distance but distorted the temporal organization of events during free recall: meaningfully connected events were recalled closer together than they appeared in the story. These findings reveal that people leverage meaningful connections between events when constructing memories from naturalistic experiences, affecting what is recalled and in what order