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Drawing on the social hierarchy within teams literature, we contend that leader-member exchange differentiation (LMXD) may function as a coordination-enablingmechanism and as a conflict-enablingmechanism in transmitting its positive and negative effects on team performance. Specifically, we propose that the positive effect of LMXD on team performance is due to its impact on team role clarity, whereas the negative effects operate through team relationship conflict. To shed light on the boundary conditions that qualify the divergent mechanisms, we further examine the moderating roles of three team structural characteristics (also referred to as team type dimensions), including authority differentiation (AD), skill differentiation (SD), and temporal stability (TS). We conducted twostudies to examine our model, which involve multi-source and multi-phase lagged data from multiple organizations from diverse industries. Across the two studies, we find consistent support for the coordinationenablingmechanism and the roles of AD and SD in qualifying this mechanism. Regarding the conflict-enablingmechanism, both studies support the moderating effect of SD. In contrast, we find limited support for the moderating effect of TS on both the coordination-enabling and conflict-enabling mechanisms, although we were only able to examine this in Study 2. We discuss the implications of these findings for future research on LMXD and team performance. [ABSTRACT FROM AUTHOR]

Merkel cell carcinomas (MCCs) are rare but highly malignant skin cancers associated with a recently described polyomavirus. MCC tumors were infiltrated by T cells, including effector, central memory, and regulatory T cells. Infiltrating T cells showed markedly reduced activation as evidenced by reduced expression of CD69 and CD25. Treatment of MCC tumors in vitro with IL-2 and IL-15 led to T-cell activation, proliferation, enhanced cytokine production, and loss of viable tumor cells from cultures. Expanded tumor-infiltrating lymphocytes showed TCR repertoire skewing and upregulation of CD137. MCC tumors implanted into immunodeficient mice failed to grow unless human T cells in the tumor grafts were depleted with denileukin diftitox, suggesting that tumor-specific T cells capable of controlling tumor growth were present in MCC. Both CD4(+) and CD8(+) FOXP3(+) regulatory T cells were frequent in MCC. Fifty percent of nonactivated T cells in MCC-expressed PD-1, a marker of T-cell exhaustion, and PD-L1 and PD-L2 were expressed by a subset of tumor dendritic cells and macrophages. In summary, we observed tumor-specific T cells with suppressed activity in MCC tumors. Agents that stimulate T-cell activity, block regulatory T cell function, or inhibit PD-1 signaling may be effective in the treatment of this highly malignant skin cancer.

A human polyomavirus was recently discovered in Merkel cell carcinoma (MCC) specimens. The Merkel cell polyomavirus (MCPyV) genome undergoes clonal integration into the host cell chromosomes of MCC tumors and expresses small T antigen and truncated large T antigen. Previous studies have consistently reported that MCPyV can be detected in approximately 80% of all MCC tumors. We sought to increase the sensitivity of detection of MCPyV in MCC by developing antibodies capable of detecting large T antigen by immunohistochemistry. In addition, we expanded the repertoire of quantitative PCR primers specific for MCPyV to improve the detection of viral DNA in MCC. Here we report that a novel monoclonal antibody detected MCPyV large T antigen expression in 56 of 58 (97%) unique MCC tumors. PCR analysis specifically detected viral DNA in all 60 unique MCC tumors tested. We also detected inactivating point substitution mutations of TP53 in the two MCC specimens that lacked large T antigen expression and in only 1 of 56 tumors positive for large T antigen. These results indicate that MCPyV is present in MCC tumors more frequently than previously reported and that mutations in TP53 tend to occur in MCC tumors that fail to express MCPyV large T antigen., Introduction Merkel cell carcinoma (MCC) is a rare skin cancer with high risk for metastasis and death (1). MCC has features of a neuroendocrine tumor, with expression of synaptophysin (SYP) [...]

The purpose of the current study is to develop an integrated theoretical model based upon social exchange theory focused on the simultaneous interplay of leader–member exchange (LMX) and team–member exchange (TMX) in team‐based contexts. We propose a model that extends current theories related to social exchange by integrating currently independent propositions in the literatures on LMX and TMX, showing how these propositions are contingent on the nature of the team in which leaders and followers are embedded. In a sample of 439 employees on 61 teams, the results show that when it comes to predicting individual performance (a) high TMX quality eliminates the otherwise negative effects of low LMX quality, (b) low authority differentiation weakens the otherwise positive effects of LMX, and (c) high skill differentiation weakens the otherwise positive effects of high LMX quality on performance. We discuss how the role of LMX may be changing in contemporary team‐based work contexts relative to what was true in the historical literature when the construct was originally developed. [ABSTRACT FROM AUTHOR]