Antibiotics (ABX) compromise the efficacy of programmed cell death protein 1 (PD-1) blockade in cancer patients, but the mechanisms underlying their immunosuppressive effects remain unknown. By inducing the down-regulation of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the ileum, post-ABX gut recolonization by Enterocloster species drove the emigration of enterotropic α4β7 ⁺ CD4 ⁺ regulatory T 17 cells into the tumor. These deleterious ABX effects were mimicked by oral gavage of Enterocloster species, by genetic deficiency, or by antibody-mediated neutralization of MAdCAM-1 and its receptor, α4β7 integrin. By contrast, fecal microbiota transplantation or interleukin-17A neutralization prevented ABX-induced immunosuppression. In independent lung, kidney, and bladder cancer patient cohorts, low serum levels of soluble MAdCAM-1 had a negative prognostic impact. Thus, the MAdCAM-1–α4β7 axis constitutes an actionable gut immune checkpoint in cancer immunosurveillance.

Biomarkers guiding the neoadjuvant use of immune-checkpoint blockers (ICB) are needed for patients with localized muscle-invasive bladder cancers (MIBC). Profiling tumor and blood samples, we found that follicular helper CD4+ T cells (TFH) are among the best therapeutic targets of pembrolizumab correlating with progression-free survival. TFH were associated with tumoral CD8 and PD-L1 expression at baseline and the induction of tertiary lymphoid structures after pembrolizumab. Blood central memory TFH accumulated in tumors where they produce CXCL13, a chemokine found in the plasma of responders only. IgG4+CD38+ TFH residing in bladder tissues correlated with clinical benefit. Finally, TFH and IgG directed against urothelium-invasive Escherichia coli dictated clinical responses to pembrolizumab in three independent cohorts. The links between tumor infection and success of ICB immunomodulation should be prospectively assessed at a larger scale. Significance: In patients with bladder cancer treated with neoadjuvant pembrolizumab, E. coli–specific CXCL13 producing TFH and IgG constitute biomarkers that predict clinical benefit. Beyond its role as a biomarker, such immune responses against E. coli might be harnessed for future therapeutic strategies. This article is highlighted in the In This Issue feature, p. 2221

Scientometrics enables scholars to assess and visualize emerging research trends and hot-spots in the scientific literature from a quantitative standpoint. In the last decades, Africa has nearly doubled its absolute count of scholarly output, even though its share in global knowledge production has dramatically decreased. The still-ongoing COVID-19 pandemic has profoundly impacted the way scholarly research is conducted, published, and disseminated. However, the COVID-19-related research focus, the scientific productivity, and the research collaborative network of African researchers during the ongoing COVID-19 pandemic remain to be elucidated. This study aimed to clarify the COVID-19 research patterns among African researchers and estimate the strength of collaborations and partnerships between African researchers and scholars from the rest of the world during the COVID-19 pandemic, collecting data from electronic scholarly databases such as Web of Science (WoS), PubMed/MEDLINE and African Journals OnLine (AJOL), the largest and prominent platform of African-published scholarly journals. We found that COVID-19-related collaboration patterns varied among African regions. For instance, most of the scholarly partnerships occurred with formerly colonial countries (such as European or North-American countries). In other cases, scholarly ties of North African countries were above all with the Kingdom of Saudi Arabia. In terms of number of publications, South Africa and Egypt were among the most productive countries. Bibliometrics and, in particular, scientometrics can help scholars identify research areas of particular interest, as well as emerging topics, such as the COVID-19 pandemic. With a specific focus on the still-ongoing viral outbreak, they can assist decision- and policy-makers in allocating funding and economic-financial, logistic, organizational, and human resources, based on the specific gaps and needs of a given country or research area.

The Coronavirus 2019 (COVID-19) pandemic has caused worldwide concern and has become a major medical problem. Vaccines and therapeutics are important interventions for the management of this outbreak. This study aims to used bibliometric methods to identify research trends in the domain of therapeutics and vaccines to cure patients with COVID-19 since the beginning of the pandemic. The Web of Science Core Collection database was retrieved for articles on therapeutic approaches to coronavirus disease management published between January 1, 2020 and May 20, 2020. Identified and analyzed the data included title, corresponding author, language, publication time, publication type, research focus. A total of 1569 articles on coronavirus therapeutic means from 84 countries were published in 620 journals. We note the remarkable progressive increase in the number of publications related to research on therapies and vaccines for COVID-19. The United States provided the largest number of articles (405), followed by China (364). Journal of Medical Virology published most of them (n = 40). 1005 (64.05%) were articles, 286 (18.23%) were letters, 230 (14.66%) were reviews. The terms “COVID- 19” or “SARS-CoV-2” or “Coronavirus” or “hydroxychloroquine” or “chloroquine” or “2019-nCOV” or “ACE2” or “treatment” or “remdesivir” or “pneumonia” were most frequently used, as shown in the density visualization map. A network analysis based on keyword co-occurrence revealed five distinct types of studies: clinical, biological, epidemiological, pandemic management, and therapeutics (vaccines and treatments). COVID-19 is a major disease that has had an impact on international public health at the global level. Several avenues for treatment and vaccines have been explored. Most of them focus on older drugs used to treat other diseases that have been effective for other types of coronaviruses. There is a discrepancy in the results obtained from the studies of the drugs included in this study. Randomized clinical trials are needed to evaluate older drugs and develop new treatment options.

: Over the past 12 years, culturomics, a high-throughput culture method, has been developed, considerably widening the repertoire of known cultured bacteria. An exhaustive database, including a list of microbes isolated by culture from human skin, was recently established by performing a review of the literature. The aim of the present study was to use the culturomics approach to explore the African skin microbiota. Skin swabs from the palms of human hands were collected between January and December 2016 from healthy subjects from the villages of Dielmo and Ndiop in rural Senegal. Three culture media were selected for the isolation of bacteria in aerobic conditions. Bacterial colonies were subjected to matrix-assisted laser desorption ionization–time of flight mass spectroscopy and the 16 S rRNA gene was sequenced for unidentified colonies. A total of 176 bacterial species were isolated. This increased the repertoire of bacterial species on the skin by 14.0%, by adding 71 bacteria, including seven new species. The culturomics approach characterizing microbial diversity has significantly changed our view of the skin microbiota, raising many important questions about the host-microorganism relationship and its relevance to skin diseases. In particular, the difference between the palm microbiota of these African populations (composed mainly of the genera Staphylococcus, Arthrobacter, Bacillus, and Microbacterium) and that of Western populations, whose main genera are Staphylococcus, Propionibacterium, Micrococcus, Corynebacterium, Enhydrobacter, and Streptococcus. This study demonstrates the need to continue to explore the skin microbiome using the culturomics approach