Immunology

eLife assessment

This is a very elegant study which clearly demonstrates the existence of CMV specific memory T cells in CMV+ pre-pandemic individuals that are capable of recognising epitopes from SARS-CoV-2. It provides new insights into the development of cross-reactive immune cells that was not anticipated. The study has been elegantly performed and presents important findings. In particular, the discovery of a public TCR which mediates the crossreactivity described is an important finding.

eLife assessment

This fundamental study demonstrates that the two isoforms of the ARPC5 subunit (ARPC5 and ARPC5L) of the Arp2/3 complex have specific functions in regulating cytoplasmic and nuclear actin filament assembly in response to DNA replication stress and T cell receptor signaling in T lymphocytes. The data presented in the manuscript are convincing and of good technical quality, and the study provides interesting new insights into specific cellular roles of different Arp2/3 isoforms in T lymphocytes.

Evaluation Summary:

The manuscript by Kane et al. described transcriptional profiles of various subsets of activated iNKT cells using longitudinal scRNA-Seq analysis. The finding that IL-10 producing iNKT cells have a cMAF-associated gene signature similar to Tr1 cells is novel. Overall, the data is well presented, however, functional consequences of some findings require further investigation.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. The reviewers remained anonymous to the authors.)

Evaluation Summary:

The authors dissect the phenotypes of bone-marrow derived myeloid cells in a murine model of pulmonary vasculitis with relevance to human disease, revealing the association of novel phenotypic subsets associated with lung injury, yet the role of these subsets in regulating or contributing to tissue injury is less clearly determined.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. The reviewer remained anonymous to the authors.)

Evaluation Summary:

This manuscript addresses a long-standing question regarding the highly variable cellular composition and functions as well as immune environments along the epididymis. Using multiple mouse models (bacterial infection and parabiosis between WT and Ccr2 KO) in conjunction with powerful scRNA-seq analyses, the authors provided solid evidence supporting the notion that resident immune cells are strategically positioned along the epididymal duct, potentially providing different immunological environments required for sperm maturations and elimination of pathogens ascending the urogenital tract.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. The reviewers remained anonymous to the authors.)

Evaluation Summary:

The authors investigate how HIV-1 infection affects the immune response in the context of SARS-CoV-2 infection by characterising the circulating B cell response. They conclude that people with HIV-1 infection, who become infected by SARS-CoV-2, produce B cell responses via an extra-follicular pathway to a greater degree than people who do not have HIV-1 infection. These findings imply that in HIV-1 infected individuals, long-term B cell and antibody responses against SARS-CoV-2 might not be as robust and durable compared to those in people without HIV-1 infection. The manuscript will be of interest to infectious disease specialists, virologists, and immunologists.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 and Reviewer #2 agreed to share their name with the authors.)

Evaluation Summary:

In this manuscript entitled "Dietary palmitic acid induces innate immune memory via ceramide production that enhances severity of acute septic shock and clearance of infection" Seufert and colleagues have investigated how saturated fatty acids increase susceptibility of the host in a murine model of LPS-mediated septic shock. Pretreatment of macrophages with palmitic acid (PA) was found to reprogram macrophages towards hyper-inflammatory phenotype, which was dependent on ceremide. Importantly, depletion of macrophages intracellular ceremide with oleic acid reversed their hyper-inflammatory phenotype. Interestingly, while PA was harmful in the LPS-acute septic shock model, it was beneficial in clearance of C. albicans in Rag-deficient mice lacking both B and T cells. While this is an exciting study, the presented data don't fully support the central hypothesis and the link with trained immunity is currently weak.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 agreed to share their name with the authors.)

eLife assessment

This paper reports on important observations regarding human CD8 T cells that express shared T cell receptors amongst individuals and exhibit poly-specificity directed mainly to several unrelated viral antigens. Although the majority of the claims are convincingly supported by results from both in silico and experimental approaches, mechanistic molecular details underlying poly-specificity remain incomplete. The results from these studies will enhance the ongoing debate on T cell specificity and potentially, will impact fields related to immunology, for example, immunoparasitology, cell biology, and vaccine development.

Evaluation Summary:

PTPN22 is a protein tyrosine phosphatase which negatively regulates antigen receptor signaling. It has been proposed that several genetic variants of PTPN22 might be loss of function (LOF) variants, leading to hyper-responsive T cell proliferative and effector responses. The authors investigate how the PTPN22 R620W variant, associated with multiple autoimmune diseases, might contribute to breech of peripheral T cell tolerance. This work greatly advances and clarifies ongoing confusion of whether PTPN22 SNP(620W) is a LOF mutant.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 and Reviewer #3 agreed to share their name with the authors.)

Evaluation Summary:

Iago De Castro et al, constitute an exciting study conveying to readers that neutrophil-to-lymphocyte ratio dynamics predict pancreatic cancer pathologic response to neoadjuvant therapy. Specifically, the authors aim to determine the effect of gemcitabine/paclitaxel and anti-Ly6G treatment on stromal T cells and CAF populations. They conclude that neutrophil-to-lymphocyte ratios are associated with survival following this treatment and use animal models to show metastatic effects allied to it. The authors attempt to convey that microenvironmental neutrophils could play a causal role in pancreatic cancer chemoresistance. It was agreed that while the discoveries are very interesting, the public could benefit from the authors improving: the relevance to the human condition, providing a stronger link to fibroblastic cell functional transitions, broadening the discussion regarding previous/related published studies, and strengthening the anti-Ly6G specificity proof within the provided data.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #2 agreed to share their name with the authors.)