Biology subjects

Vance, R.

Publications and source records attributed to Vance, R..

6 recordsLinked to original sources

bioRxiv2026

Mechanisms of mucosal immunity to oral Shigella infection in a physiological mouse model

Shigella flexneri causes bacillary dysentery, a diarrheal disease responsible for significant global morbidity and mortality. Despite extensive efforts, there is no licensed Shigella vaccine, and due to the lack of tractable and physiological models, mechanisms of adaptive immunity to Shigella are poorly understood. Here, we establish a mouse model that permits mechanistic dissection of adaptive immunity to a physiological oral challenge with Shigella. We find primary Shigella infection confers robust cross-serotype protection against secondary challenge, in a manner strictly dependent on the adaptive immune compartment. Shigella infection induces Shigella-specific CD4+ and CD8+ T cells, but only CD4+ T cells are required for protection. CD4+ T cells produce IFN{gamma} upon secondary challenge, and help B cells produce Shigella-specific IgA. Neither anti-Shigella antibodies nor IFN{gamma} are individually required for immunity to Shigella, but loss of both eliminates protective immunity. Collectively, our results demonstrate that CD4+ T cells orchestrate antibody and cytokine defense against shigellosis.

immunology↗

bioRxiv2025

Diverse infection models demonstrate robust resistance of Mycobacterium tuberculosis to innate immunity

Mycobacterium tuberculosis (Mtb) is a robust activator of innate immunity. However, there is little evidence that innate immune mechanisms control Mtb before the onset of adaptive immunity. Prior work has generally used specific pathogen-free (SPF) mouse models and relatively large infectious doses, which may obscure the capacity of innate immunity to control Mtb. Here, we performed ultra-low dose Mtb infections and found that the initial innate immune response was unable to curb even minimal Mtb infectious doses. Additionally, we primed the immune systems of C57BL/6 mice by co-housing with "pet shop" mice prior to Mtb exposure. Co-housed mice were as susceptible to Mtb infection as SPF mice. To pre-activate innate immunity at the site of Mtb infection more specifically, we also infected the lungs of mice with Legionella pneumophila (Lp) prior to Mtb. Innate immunity alone can clear large doses (>100,000 CFU) of Lp from the lung within a few days. However, priming the mouse lung by pre-infection with Lp only modestly reduced Mtb CFU compared to mice infected with only Mtb, indicating that Mtb can robustly replicate even in the presence of a strong anti-bacterial innate response. We performed single-cell RNA-sequencing on myeloid cells from mice either infected with Mtb alone or mice primed with Lp. We found that Lp priming before Mtb infection induced measurable changes in myeloid cells responding to Mtb, but these changes had little effect on innate control of Mtb. Together, these data demonstrate the robust resistance of Mtb to innate immune clearance under diverse experimental conditions.

immunology↗

bioRxiv2024

The SP140-RESIST pathway regulates interferon mRNA stability and antiviral immunity

Type I interferons (IFN-Is) are essential for antiviral immunity but must be tightly regulated1-3. The conserved transcriptional repressor SP140 inhibits interferon beta (Ifnb1) expression via an unknown mechanism4,5. Here we report that SP140 does not directly repress Ifnb1 transcription. Instead, SP140 negatively regulates Ifnb1 mRNA stability by directly repressing the expression of a previously uncharacterized regulator we call RESIST (REgulated Stimulator of Interferon via Stabilization of Transcript, previously annotated as Annexin-2 Receptor). RESIST promotes Ifnb1 mRNA stability by counteracting Ifnb1 mRNA destabilization mediated by the Tristetraprolin (TTP) family of RNA-binding proteins and the CCR4-NOT deadenylase complex. SP140 localizes within nuclear bodies, punctate structures that play important roles in silencing DNA virus gene expression in the nucleus4. Consistent with this observation, we found that SP140 inhibits replication of the gammaherpesvirus MHV68. The antiviral activity of SP140 was independent of its ability to regulate Ifnb1. Our results establish dual antiviral and interferon regulatory functions for SP140. We propose that SP140 and RESIST participate in antiviral effector-triggered immunity6,7.

immunology↗

bioRxiv2023

Tuberculosis susceptibility in genetically diverse mice reveals functional diversity of neutrophils

Tuberculosis (TB) is a heterogenous disease in humans with individuals exhibiting a wide range of susceptibility. This heterogeneity is not captured by standard laboratory mouse lines. We used a new collection of 19 wild-derived inbred mouse lines collected from diverse geographic sites to identify novel phenotypes during Mycobacterium tuberculosis (Mtb) infection. Wild derived mice have heterogenous immune responses to infection that result in differential ability to control disease at early timepoints. Correlation analysis with multiple parameters including sex, weight, and cellular immune responses in the lungs revealed that enhanced control of infection is associated with increased numbers of CD4 T cells, CD8 T cells and B cells. Surprisingly, we did not observe strong correlations between IFN-{gamma} production and control of infection. Although in most lines high neutrophils were associated with susceptibility, we identified a mouse line that harbors high neutrophils numbers yet controls infection. Using single-cell RNA sequencing, we identified a novel neutrophil signature associated with failure to control infection.

immunology↗

bioRxiv2019

STING controls Herpes Simplex Virus in vivo independent of type I interferon induction

The Stimulator of Interferon Genes (STING) pathway initiates potent immune responses upon recognition of DNA derived from bacteria, viruses and tumors. To signal, the C-terminal tail (CTT) of STING recruits TBK1, a kinase that phosphorylates serine 365 (S365) in the CTT. Phospho-S365 acts as a docking site for IRF3, a transcription factor that is phosphorylated and activated by TBK1, leading to transcriptional induction of type I interferons (IFNs). IFNs are essential for antiviral immunity and are widely viewed as the primary output of STING signaling in mammals. However, other more evolutionarily ancestral responses, such as induction of NF-{kappa}B or autophagy, also occur downstream of STING. The relative importance of the various outputs of STING signaling during in vivo infections is unclear. Here we report that mice harboring a serine 365-to-alanine (S365A) point mutation in STING exhibit normal susceptibility to Mycobacterium tuberculosis infection but, unexpectedly, are resistant to Herpes Simplex Virus (HSV)-1, despite lacking STING-induced type I IFN responses. Likewise, we find Irf3-/- mice exhibit resistance to HSV-1. By contrast, resistance to HSV-1 is abolished in mice lacking the STING CTT or TBK1, suggesting that STING protects against HSV-1 upon TBK1 recruitment by the STING CTT, independent of IRF3 or type I IFNs. Interestingly, we find that STING-induced autophagy is a TBK1-dependent IRF3-independent process that is conserved in the STING S365A mice, and autophagy has previously been shown to be required for resistance to HSV-1. We thus propose that autophagy and perhaps other ancestral interferon-independent functions of STING are required for STING-dependent antiviral responses in vivo.

immunology↗

bioRxiv2019

IRG1 and iNOS act redundantly with other interferon gamma induced factors to restrict intracellular replication of Legionella pneumophila.

Interferon gamma (IFN{gamma}) restricts the intracellular replication of many pathogens, but how IFN{gamma} confers cell-intrinsic pathogen resistance remains unclear. For example, intracellular replication of the bacterial pathogen Legionella pneumophila in macrophages is potently curtailed by IFN{gamma}, but consistent with prior results, no individual genetic deficiency we tested compromised IFN{gamma}-mediated control. Intriguingly, however, we observed that the glycolysis inhibitor 2-deoxyglucose (2DG) partially rescued L. pneumophila replication in IFN{gamma}-treated macrophages. 2DG inhibits glycolysis and triggers the unfolded protein response, but unexpectedly, it appears these effects are not responsible for perturbing the antimicrobial activity of IFN{gamma}. Instead, we found that 2DG rescues bacterial replication predominantly by inhibiting the induction of two key antimicrobial factors, inducible nitric oxide synthase (iNOS) and immune responsive gene 1 (IRG1). Using immortalized and primary macrophages deficient in iNOS and IRG1, we confirm that loss of both iNOS and IRG1, but not individual deficiency in each gene, partially reduces IFN{gamma}-mediated restriction of L. pneumophila. Further, using a combinatorial CRISPR/Cas9 mutagenesis approach, we find that mutation of iNOS and IRG1 in combination with four other genes (CASP11, IRGM1, IRGM3 and NOX2) results in a total loss of L. pneumophila restriction by IFN{gamma} in primary bone marrow macrophages. There are few, if any, other examples in which the complete set of cell-intrinsic factors required for IFN{gamma}-mediated restriction of an intracellular bacterial pathogen have been genetically identified. Our results highlight the combinatorial strategy used by hosts to block the exploitation of macrophages by pathogens.\n\nImportanceLegionella pneumophila is one example among many species of pathogenic bacteria that replicate within mammalian macrophages during infection. The immune signaling factor interferon gamma (IFN{gamma}) blocks L. pneumophila replication in macrophages and is an essential component of the immune response to L. pneumophila and other intracellular pathogens. However, to date, no study has determined the exact molecular factors induced by IFN{gamma} that are required for its activity. We generated macrophages lacking different combinations of IFN{gamma}-induced genes in an attempt to find a genetic background in which there is a complete loss of IFN{gamma}-mediated restriction of L. pneumophila. We successfully identified six genes that comprise the totality of the IFN{gamma}-dependent restriction of L. pneumophila replication in macrophages. Our results clarify the molecular basis underlying the potent effects of IFN{gamma} and highlight how redundancy downstream of IFN{gamma} is key to prevent exploitation of the macrophage niche by pathogens.

immunology↗