Effector memory CD4 T cells engage myeloid cells through TNFR and CD40 to induce innate inflammation and autoimmune pathology independent of pattern recognition receptors

T cell mediated autoimmune diseases and associated tissue pathology is commonly attributed to inflammatory cytokines produced by the innate immune system. Similarly, CAR-T cell therapy and checkpoint blockades lead to innate cytokine storms and inflammation. While blocking individual cytokines can alleviate some of this pathology, the upstream mechanisms permitting self-reactive T cells to facilitate an innate inflammatory response remain unknown. We have discovered critical players that are engaged by effector memory CD4 (Tem) T cells to induce a broad transcriptional program in cells of the innate immune system. The pro-inflammatory response induced in innate immune cells is independent of pattern recognition receptors (PRRs), but mirrors genes induced by microbial recognition. We find that the innate inflammation is driven by combined engagement of TNFR and CD40 on myeloid cells presenting cognate antigen to Tem cells. Pro-inflammatory cytokine production and autoimmune pathology can be completely rescued by ablating the CD40 and TNFR pathways in several models of T cell driven inflammation. Thus, we have discovered a previously unknown trigger of innate inflammation and autoimmune pathology and propose that targeting this signaling node could be a more effective therapeutic approach than previously characterized cytokine-specific remedies.

Supported by grant from NIH (R01 AI123176)

Vps33B is a crucial regulator of Type I Interferon response downstream of the cGAS-STING pathway

Vacuolar protein sorting-associated protein 33B (Vps33B) plays a critical role in the trafficking of endosomal contents to lysosomes in macrophages, particularly following Toll-like receptor (TLR) activation. Upon activation by microbial ligands, TLRs are internalized into endosomes, then trafficked to lysosomes for degradation. We have previously shown that endosomal to lysosomal trafficking, and subsequent degradation of TLR4, is mediated by Vps33B. Without this crucial degradation step, TLRs remain trapped within altered endosomes, leading to an enhanced inflammatory response. Since Vps33B is critical for termination of signaling following TLR ligation, we wanted to determine if it had a conserved role in regulating other pattern recognition receptor (PRR) signaling pathways. Specifically, we investigated the role of Vps33B in regulating cytosolic DNA sensing by the cGAS-STING pathway. Absence of Vps33B in macrophages and mouse embryonic fibroblasts resulted in an exaggerated type 1 interferon and interferon-stimulated gene response after stimulation with dsDNA and other STING ligands. Our findings suggest that Vps33B has a conserved role as a regulator of innate inflammatory responses downstream of both plasma membrane as well as cytosolic PRRs. Mechanistically, we hypothesize that Vps33B plays a role in STING degradation, similarly to how it permits TLR4 degradation, through mediating endo-lysosomal trafficking. This would suggest a broad and critical role for Vps33B in PRR-induced vesicular transportation and receptor degradation. Future work will investigate the mechanisms by which Vps33B regulates STING-mediated signaling as well as its importance for anti-viral immunity.

The Validation of the VereBeef™ Detection Kit

VereBeef™ Detection Kit, incorporating both multiplex PCR and microarray technologies on a lab-on-chip platform, is intended for qualitative detection and differentiation of Escherichia coli O157:H7, E. coli O26, E. coli O45, E. coli O103, E. coli O111, E. coli O121, E. coli O145, Shiga toxin-producing E. coli (STEC) virulence factors (stx1A, stx2A, eae), and Salmonella species in one test using raw beef trim samples. This product underwent extensive evaluations, including inclusivity-exclusivity, method comparison, robustness, lot-to-lot variability, and stability studies. The inclusivity/exclusivity study demonstrated that VereBeef Detection Kit specifically detects and identifies target analytes without occurrence of false-positive and false-negative detection. In the method comparison study, the performance of the VereBeef Detection Kit was compared with U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook's methods for target organism detection in raw beef trim using E. coli O157:H7 single inoculation and Salmonella and non-O157 STEC dual inoculation. Data demonstrated equivalence in both methods. The robustness study showed that changes in the test parameters do not impact assay performance. Collectively, VereBeef Detection Kit is able to detect target pathogens in raw beef trim with a minimum enrichment time of 8 h for E. coli O157:H7 detection and 10 h for Salmonella and non-O157 STEC detection.

Method Modification to Extend the Matrix Claim of the Thermo Scientific RapidFinder Salmonella species, Typhimurium, and Enteritidis Multiplex PCR Kit

Background: The Thermo Scientific RapidFinder™ Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit is a real-time multiplex PCR assay for the detection and differentiation of Salmonella species, Salmonella Typhimurium, and S. Enteritidis from poultry, pork, and environmental samples. The method has previously been granted certification as Performance Tested Method SM (PTM) 081701, validated according to the AOAC Research Institute (RI) PTM program for poultry (chicken thighs with skin, chicken wings with skin, and chicken nuggets), raw pork sausage matrixes, and stainless steel environmental surface sponges. Objective: This report details the method modification study to validate ground turkey (375 g sample size), chicken carcass rinse, and shell egg matrixes. Methods: The candidate method was compared with the U.S. Food and Drug Administration's Bacteriological Analytical Manual Chapter 5 for shell eggs and the U.S. Department of Agriculture Food Safety and Inspection Service's Microbiology Laboratory Guidebook 4.09 for ground turkey (375 g) and chicken carcass rinse matrixes. Results: The statistically significant differences found between the candidate and reference methods upon analysis by probability of detection were in favor of the candidate method. Inclusivity and exclusivity testing demonstrated that the RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit was able to detect all the major groups of Salmonella. All exclusivity isolates were correctly excluded. Conclusions: The data presented in this report show that the candidate is suitable for the detection and differentiation of Salmonellae from shell egg, chicken carcass rinse, and ground turkey (375 g) matrixes. Highlights: Thermo Scientific RapidFinder Salmonella species, Typhimurium and Enteritidis Multiplex PCR Kit (candidate method) matrix claims extended to include ground turkey (375 g), chicken carcass rinse and shell egg samples.