Intra-tumoral tertiary lymphoid structures are associated with a low risk of early recurrence of hepatocellular carcinoma

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Aging and probabilistic learning in single- and multiple-cue tasks

The objective of the study was to examine some of the conditions under which elderly people are able to learn probabilistic inverse relationships and when this type of learning is no longer possible. Two kind of tasks were used: (a) two single-cue learning tasks with either direct or inverse relationships (the Single-Cue Probability Learning paradigm), and (b) three two-cue learning tasks, one with two direct relationships, one with a combination of direct and inverse relationships, and one with two inverse relationships (the Multiple-Cue Probability Learning paradigm). Four groups of participants were included in the study: young adults (18- to 25-year-olds), adults (40- to 50-year-olds), elderly people (65- to 74-year-olds), and very elderly people (75- to 90-year-olds). It was shown that (a) older adults are able to reject the direct relationship "default" hypothesis and select the inverse relationship hypothesis when outcome feedback contradicting the default hypothesis is given, and provided that the learning setting be a very simple one, involving only one cue; (b) some older adults are able to select the inverse relationship hypothesis provided that the learning setting be a simple one,involving only two inverse relationship cues; and (c) very few older adults are able to select the inverse relationship hypothesis when the learning setting is a complex one, involving two cues with both direct and inverse relationships with the criterion. These results led to the revision of the "gradual decrease of cognitive flexibility in older adults" hypothesis proposed by Chasseigne, Mullet, and Stewart (Acta Psychologicgrave;a, 103, 229-238, 1997).     

Capture of plasma membrane fragments from target cells by trogocytosis requires signaling in T cells but not in B cells

Upon recognition of their respective cellular partners, T and B cells acquire their antigens by a process of membrane capture called trogocytosis. Here, we report that various inhibitors of actin polymerization or of kinases involved in intracellular signaling partially or fully inhibited trogocytosis by CD8⁺ and CD4⁺ T cells, whereas they had no effect on trogocytosis by B cells. Similarly, trogocytosis by T cells was inhibited at 4°C, whereas in B cells it was independent of temperature, indicating that trogocytosis by B cells does not rely on active processes. By contrast, most inhibitors we tested impaired both T-cell and B-cell activation. The differential effect of inhibitors on T-cell and B-cell trogocytosis was not due to the higher affinity of the B-cell receptor for its cognate antigen compared with the affinity of the T-cell receptor for its own antigen, but it correlated tightly with the abilities of T cells and B cells to form conjugates with their target cells in the presence of inhibitors. Trogocytosis thus has different requirements in different cell types. Moreover, the capture of membrane antigen by B cells is identified as a novel signaling-independent event of B-cell biology.