By mirroring their function as tissue repair organizers in normal tissues, immune cells regulate tumor growth. To understand the different facets of immune-tumor collaboration through genetics, spatial transcriptomics, and immunological manipulation with non-invasive, longitudinal imaging, we generated a penetrant double oncogene-driven autochthonous model of neuroblastoma. Using spatial transcriptomic analysis, we co-localized CD4+ and myeloid populations within the tumor parenchyma, while CD8+ T cells and B cells were peripherally dispersed. Depletion of CD4+ T cells or CCR2+ macrophages, but not B cells, CD8+, or NK cells, prevented tumor formation. Tumor CD4+ T cells displayed unconventional phenotypes, were clonotypically diverse, and antigen-independent. Within the myeloid fraction, tumor growth required myeloid cells expressing Arginase-1. Overall, our results suggest that arginine-metabolizing myeloid cells conspire with pathogenic CD4+ T cells to create permissive conditions for tumor formation, and therefore suggest that these pro-tumorigenic pathways can be disabled by targeting myeloid amino acid metabolism.

Distributing responsibility across several individuals in social decisions helps minimize a burden of responsibility for consequences of decisions. Here we investigated the neural expression of this effect using magnetoencephalography (MEG). Participants performed a reward-based learning decision-making task in contexts where their sense of responsibility over outcomes decreased with group size. An MEG outcome processing effect was reduced as a function of decreasing responsibility at 200ms post outcome onset and centred over parietal and precentral brain regions. During social decisions, prior to outcome revelation, a motor preparation signature at 500ms after stimulus onset was attenuated. A boost in responsibility for positive outcomes in social contexts was associated with increased activity in regions related to social and reward processing. Together, these results show that sharing responsibility with others reduces agency through an influence on pre-outcome motor preparation and post-outcome processing, affording an opportunity for flexibility in credit for positive outcomes.