Dietary tryptophan metabolite released by intratumoral Lactobacillus reuteri facilitates immune checkpoint inhibitor treatment.

The use of probiotics by cancer patients is increasing, including among those undergoing immune checkpoint inhibitor (ICI) treatment. Here, we elucidate a critical microbial-host crosstalk between probiotic-released aryl hydrocarbon receptor (AhR) agonist indole-3-aldehyde (I3A) and CD8 T cells within the tumor microenvironment that potently enhances antitumor immunity and facilitates ICI in preclinical melanoma. Our study reveals that probiotic Lactobacillus reuteri (Lr) translocates to, colonizes, and persists within melanoma, where via its released dietary tryptophan catabolite I3A, it locally promotes interferon-γ-producing CD8 T cells, thereby bolstering ICI. Moreover, Lr-secreted I3A was both necessary and sufficient to drive antitumor immunity, and loss of AhR signaling within CD8 T cells abrogated Lr's antitumor effects. Further, a tryptophan-enriched diet potentiated both Lr- and ICI-induced antitumor immunity, dependent on CD8 T cell AhR signaling. Finally, we provide evidence for a potential role of I3A in promoting ICI efficacy and survival in advanced melanoma patients.

The gut protist Tritrichomonas arnold restrains virus-mediated loss of oral tolerance by modulating dietary antigen-presenting dendritic cells.

Loss of oral tolerance (LOT) to gluten, driven by dendritic cell (DC) priming of gluten-specific T helper 1 (Th1) cell immune responses, is a hallmark of celiac disease (CeD) and can be triggered by enteric viral infections. Whether certain commensals can moderate virus-mediated LOT remains elusive. Here, using a mouse model of virus-mediated LOT, we discovered that the gut-colonizing protist Tritrichomonas (T.) arnold promotes oral tolerance and protects against reovirus- and murine norovirus-mediated LOT, independent of the microbiota. Protection was not attributable to antiviral host responses or T. arnold-mediated innate type 2 immunity. Mechanistically, T. arnold directly restrained the proinflammatory program in dietary antigen-presenting DCs, subsequently limiting Th1 and promoting regulatory T cell responses. Finally, analysis of fecal microbiomes showed that T. arnold-related Parabasalid strains are underrepresented in human CeD patients. Altogether, these findings will motivate further exploration of oral-tolerance-promoting protists in CeD and other immune-mediated food sensitivities.

Expanding the adenovirus toolbox: reporter viruses for studying the dynamics of human adenovirus replication.

To streamline standard virological assays, we developed a suite of nine fluorescent or bioluminescent replication competent human species C5 adenovirus reporter viruses that mimic their parental wild-type counterpart. These reporter viruses provide a rapid and quantitative readout of various aspects of viral infection and replication based on EGFP, mCherry, or NanoLuc measurement. Moreover, they permit real-time non-invasive measures of viral load, replication dynamics, and infection kinetics over the entire course of infection, allowing measurements that were not previously possible. This suite of replication competent reporter viruses increases the ease, speed, and adaptability of standard assays and has the potential to accelerate multiple areas of human adenovirus research.IMPORTANCEIn this work, we developed a versatile toolbox of nine HAdV-C5 reporter viruses and validated their functions in cell culture. These reporter viruses provide a rapid and quantitative readout of various aspects of viral infection and replication based on EGFP, mCherry, or NanoLuc measurement. The utility of these reporter viruses could also be extended for use in 3D cell culture, organoids, live cell imaging, or animal models, and provides a conceptual framework for the development of new reporter viruses representing other clinically relevant HAdV species.

Cip1 tunes cell cycle arrest duration upon calcineurin activation.

Cells exposed to environmental stress arrest the cell cycle until they have adapted to their new environment. Cells adjust the length of the arrest for each unique stressor, but how they do this is not known. Here, we investigate the role of the stress-activated phosphatase calcineurin (CN) in controlling cell cycle arrest in Saccharomyces cerevisiae. We find that CN controls arrest duration through activation of the G1 cyclin­dependent kinase inhibitor Cip1. Our results demonstrate that multiple stressors trigger a G1/S arrest through Hog1-dependent down-regulation of G1 cyclin transcription. When a stressor also activates CN, this arrest is lengthened as CN prolongs Hog1-dependent phosphorylation of Cip1. Cip1 plays no role in response to stressors that activate Hog1 but not CN. These findings illustrate how stress response pathways cooperate to tailor the stress response and suggest that Cip1 functions to prolong cell cycle arrest when a cell requires additional time for adaptation.

Repression of essential cell cycle genes increases cellular fitness.

A network of transcription factors (TFs) coordinates transcription with cell cycle events in eukaryotes. Most TFs in the network are phosphorylated by cyclin-dependent kinase (CDK), which limits their activities during the cell cycle. Here, we investigate the physiological consequences of disrupting CDK regulation of the paralogous repressors Yhp1 and Yox1 in yeast. Blocking Yhp1/Yox1 phosphorylation increases their levels and decreases expression of essential cell cycle regulatory genes which, unexpectedly, increases cellular fitness in optimal growth conditions. Using synthetic genetic interaction screens, we find that Yhp1/Yox1 mutations improve the fitness of mutants with mitotic defects, including condensin mutants. Blocking Yhp1/Yox1 phosphorylation simultaneously accelerates the G1/S transition and delays mitotic exit, without decreasing proliferation rate. This mitotic delay partially reverses the chromosome segregation defect of condensin mutants, potentially explaining their increased fitness when combined with Yhp1/Yox1 phosphomutants. These findings reveal how altering expression of cell cycle genes leads to a redistribution of cell cycle timing and confers a fitness advantage to cells.

Systemic Immunoregulatory Consequences of Gut Commensal Translocation.

One major determinant of systemic immunity during homeostasis and in certain complex multifactorial diseases (e.g. cancer and autoimmune conditions), is the gut microbiota. These commensals can shape systemic immune responses via translocation of metabolites, microbial cell wall components, and viable microbes. In the last few years, bacterial translocation has revealed itself as playing a key, and potentially causal role in mediating immunomodulatory processes in nongastrointestinal diseases. Moreover, recent observations regarding the presence of complex microbial communities and viable bacteria within gut-distal tissues during homeostasis challenge the current paradigm that healthy mammals are entirely sterile at nonmucosal sites. This review discusses our current understanding of how the gut microbiota orchestrates systemic immunity during noninfectious extraintestinal diseases and homeostasis, focusing on the translocation of viable bacteria to gut-distal sites.

Stories of childhood sexual abuse (CSA) among older adults living with HIV (OALH) in South Carolina: a qualitative study.

Childhood sexual abuse (CSA) devastatingly impacts an individual's behavioral, psychological, and social health. Childhood, a developmental stage directly influenced by the home or school environment, leaves a life-long imprint. Compared with the general population, CSA prevalence is doubled among people living with HIV. Thus, the study aimed to explore CSA circumstances among older adults living with HIV (OALH) in South Carolina (SC). We included 24 OALH aged 50 and above who reported CSA. The data were collected at an immunology center in SC. In-depth semi-structured interviews were conducted, audio-recorded, transcribed, and analyzed using a thematic analysis approach. The iterative analytic process included a discussion of initial thoughts and key concepts, identification, and reconciliation of codes, and naming of emergent themes. Six themes emerged: known perpetrators, re-victimization, "nobody believed me", "cannot live like others", lack of CSA disclosure, and interconnections with other adverse childhood experiences (ACEs). CSA experiences and non-disclosure were found to be linked with shame, embarrassment, fear, and trust issues. Hence, trauma-focused interventions are required to resolve these issues and improve the quality of life of OALH with past trauma. Counseling or therapy programs should incorporate psychological and behavioral theoretical models to best target OALH who are CSA survivors.

Pathways of thymidine hypermodification.

The DNAs of bacterial viruses are known to contain diverse, chemically complex modifications to thymidine that protect them from the endonuclease-based defenses of their cellular hosts, but whose biosynthetic origins are enigmatic. Up to half of thymidines in the Pseudomonas phage M6, the Salmonella phage ViI, and others, contain exotic chemical moieties synthesized through the post-replicative modification of 5-hydroxymethyluridine (5-hmdU). We have determined that these thymidine hypermodifications are derived from free amino acids enzymatically installed on 5-hmdU. These appended amino acids are further sculpted by various enzyme classes such as radical SAM isomerases, PLP-dependent decarboxylases, flavin-dependent lyases and acetyltransferases. The combinatorial permutations of thymidine hypermodification genes found in viral metagenomes from geographically widespread sources suggests an untapped reservoir of chemical diversity in DNA hypermodifications.

Food parenting at-home vs. in restaurants among African American parents of 3-to-8-year-old children.

Feeding style refers to the approach that parents use to feed their child and the emotional climate during eating. Indulgent styles, characterized by low structure and high responsiveness, have been linked to childhood weight gain. Few studies have examined feeding styles within out-of-home contexts (e.g., restaurants), which are common eating environments for many families. This study sought to examine feeding styles at-home and in restaurants among African American parents. 52 African American parents with a 3-to-8-year-old child (M = 35.6 years, 86% mothers, 57% annual household income <$50,000, 57% Associate's degree or higher) who regularly dined at restaurants completed an online survey in winter 2022-2023. Parents reported on demographics, anthropometrics, and their feeding styles at home and in restaurants via The Caregiver's Feeding Style Questionnaire. Findings indicated that the indulgent style was the most common overall. Indulgent styles were more prevalent in restaurants (χ2 = 7.4, p = 0.007) than home, and authoritarian styles more prevalent at home (χ2 = 4.5, p = 0.03). Child weight status differed by feeding style in both contexts (p ≤ 0.04); indulgent styles in restaurants were linked to higher BMI z-scores, while authoritarian styles at home were linked to lower BMI z-scores. Higher parent BMI was linked to increased likelihood of having an indulgent style at home (OR = 1.13, p = 0.03), while lower parent BMI was linked to increased likelihood of the uninvolved style at home (OR = 0.76, p = 0.049). Overall, indulgent styles were common and more prevalent in restaurants, where they were linked to higher child weight status. Findings may inform future health promotion efforts in out-of-home eating contexts.

Phage-encoded ten-eleven translocation dioxygenase (TET) is active in C5-cytosine hypermodification in DNA.

TET/JBP (ten-eleven translocation/base J binding protein) enzymes are iron(II)- and 2-oxo-glutarate-dependent dioxygenases that are found in all kingdoms of life and oxidize 5-methylpyrimidines on the polynucleotide level. Despite their prevalence, few examples have been biochemically characterized. Among those studied are the metazoan TET enzymes that oxidize 5-methylcytosine in DNA to hydroxy, formyl, and carboxy forms and the euglenozoa JBP dioxygenases that oxidize thymine in the first step of base J biosynthesis. Both enzymes have roles in epigenetic regulation. It has been hypothesized that all TET/JBPs have their ancestral origins in bacteriophages, but only eukaryotic orthologs have been described. Here we demonstrate the 5mC-dioxygenase activity of several phage TETs encoded within viral metagenomes. The clustering of these TETs in a phylogenetic tree correlates with the sequence specificity of their genomically cooccurring cytosine C5-methyltransferases, which install the methyl groups upon which TETs operate. The phage TETs favor Gp5mC dinucleotides over the 5mCpG sites targeted by the eukaryotic TETs and are found within gene clusters specifying complex cytosine modifications that may be important for DNA packaging and evasion of host restriction.

Identification of 2-Sulfonyl/Sulfonamide Pyrimidines as Covalent Inhibitors of WRN Using a Multiplexed High-Throughput Screening Assay.

Werner syndrome protein (WRN) is a multifunctional enzyme with helicase, ATPase, and exonuclease activities that are necessary for numerous DNA-related transactions in the human cell. Recent studies identified WRN as a synthetic lethal target in cancers characterized by genomic microsatellite instability resulting from defects in DNA mismatch repair pathways. WRN's helicase activity is essential for the viability of these high microsatellite instability (MSI-H) cancers and thus presents a therapeutic opportunity. To this end, we developed a multiplexed high-throughput screening assay that monitors exonuclease, ATPase, and helicase activities of full-length WRN. This screening campaign led to the discovery of 2-sulfonyl/sulfonamide pyrimidine derivatives as novel covalent inhibitors of WRN helicase activity. The compounds are specific for WRN versus other human RecQ family members and show competitive behavior with ATP. Examination of these novel chemical probes established the sulfonamide NH group as a key driver of compound potency. One of the leading compounds, H3B-960, showed consistent activities in a range of assays (IC50 = 22 nM, KD = 40 nM, KI = 32 nM), and the most potent compound identified, H3B-968, has inhibitory activity IC50 ∼ 10 nM. These kinetic properties trend toward other known covalent druglike molecules. Our work provides a new avenue for screening WRN for inhibitors that may be adaptable to different therapeutic modalities such as targeted protein degradation, as well as a proof of concept for the inhibition of WRN helicase activity by covalent molecules.

Distinct functional roles for the M4 α-helix from each homologous subunit in the heteropentameric ligand-gated ion channel nAChR.

The outermost lipid-exposed α-helix (M4) in each of the homologous α, ß, δ, and γ/ε subunits of the muscle nicotinic acetylcholine receptor (nAChR) has previously been proposed to act as a lipid sensor. However, the mechanism by which this sensor would function is not clear. To explore how the M4 α-helix from each subunit in human adult muscle nAChR influences function, and thus explore its putative role in lipid sensing, we functionally characterized alanine mutations at every residue in αM4, ßM4, δM4, and εM4, along with both alanine and deletion mutations in the post-M4 region of each subunit. Although no critical interactions involving residues on M4 or in post-M4 were identified, we found that numerous mutations at the M4-M1/M3 interface altered the agonist-induced response. In addition, homologous mutations in M4 in different subunits were found to have different effects on channel function. The functional effects of multiple mutations either along M4 in one subunit or at homologous positions of M4 in different subunits were also found to be additive. Finally, when characterized in both Xenopus oocytes and human embryonic kidney 293T cells, select αM4 mutations displayed cell-specific phenotypes, possibly because of the different membrane lipid environments. Collectively, our data suggest different functional roles for the M4 α-helix in each heteromeric nAChR subunit and predict that lipid sensing involving M4 occurs primarily through the cumulative interactions at the M4-M1/M3 interface, as opposed to the alteration of specific interactions that are critical to channel function.

iCre recombinase expressed in the anti-Müllerian hormone receptor 2 gene causes global genetic modification in the mouse†.

Genetically engineered mice are widely used to study the impact of altered gene expression in vivo. Within the reproductive tract, the Amhr2-IRES-Cre(Bhr) mouse model is used to ablate genes in ovarian granulosa and uterine stromal cells. There are reports of Amhr2-IRES-Cre(Bhr) inducing recombination in non-target tissues. We hypothesized the inefficiency or off-target Cre action in Amhr2-IRES-Cre(Bhr) mice is due to lack of recombination in every cell that expresses Amhr2. To investigate, we created a new targeted knock-in mouse model, Amhr2-iCre(Fjd), by inserting a codon-optimized improved Cre (iCre) into exon 1 of the Amhr2 gene. Amhr2-iCre(Fjd)/+ males were mated with females that contain a lox-stop-lox cassette in the Sun1 gene so when DNA recombination occurs, SUN1-sfGFP fusion protein is expressed in a peri-nuclear pattern. In adult Amhr2-iCre(Fjd)/+ Sun1LsL/+ mice, Amhr2-iCre(Fjd)-mediated genetic recombination was apparent in uterine epithelial, stromal, and myometrial cells, while Amhr2-IRES-Cre(Bhr)/+ Sun1LsL/+ females demonstrated inter-mouse variability of Amhr2-IRES-Cre(Bhr) activity in uterine cells. Fluorescence was observed in Amhr2-iCre(Fjd)-positive mice at post-natal Day 1, indicating global genetic recombination, while fluorescence of individual Amhr2-IRES-Cre(Bhr)-positive pups varied. To determine the developmental stage that genetic recombination first occurs, Sun1LsL/LsL females were super-ovulated and mated with Amhr2-IRES-Cre(Bhr)/+ or Amhr2(iCre/+)Fjd males, then putative zygotes were collected and cultured. In the four-cell embryo, Amhr2-iCre(Fjd) and Amhr2-IRES-Cre(Bhr) activities were apparent in 100% and 25-100% of cells, respectively. In conclusion, Amhr2-IRES-Cre(Bhr) or Amhr2-iCre(Fjd) driven by the Amhr2 promoter is active in the early embryo and can lead to global genetic modification, rendering this transgenic mouse model ineffective.

Induced endometrial inflammation compromises conceptus development in dairy cattle†.

Endometrial inflammation is associated with reduced pregnancy per artificial insemination (AI) and increased pregnancy loss in cows. It was hypothesized that induced endometritis alters histotroph composition and induces inflammatory signatures on conceptus that compromise development. In Experiment 1, lactating cows were assigned to control (CON; n = 23) or to an intrauterine infusion of Escherichia coli and Trueperella pyogenes (ENDO; n = 34) to induce endometritis. Cows received AI 26 days after treatment, and the uterine fluid and conceptuses were collected on day 16 after AI. In Experiment 2, Holstein heifers were assigned to CON (n = 14) or ENDO (n = 14). An embryo was transferred on day 7 of the estrous cycle, and uterine fluid and conceptuses were recovered on day 16. Composition of histotroph and trophoblast and embryonic disc gene expression were assessed. Bacterial-induced endometritis in lactating cows altered histotroph composition and pathways linked to phospholipid synthesis, cellular energy production, and the Warburg effect. Also, ENDO reduced conceptus length in cows and altered expression of genes involved in pathogen recognition, nutrient uptake, cell growth, choline metabolism, and conceptus signaling needed for maternal recognition of pregnancy. The impact of ENDO was lesser on conceptuses from heifers receiving embryo transfer; however, the affected genes and associated pathways involved restricted growth and increased immune response similar to the observed responses to ENDO in conceptuses from lactating cows. Bacterial-induced endometrial inflammation altered histotroph composition, reduced conceptus growth, and caused embryonic cells to activate survival rather than anabolic pathways that could compromise development.

Detection and Monitoring of Viral Infections via Wearable Devices and Biometric Data.

Mounting clinical evidence suggests that viral infections can lead to detectable changes in an individual's normal physiologic and behavioral metrics, including heart and respiration rates, heart rate variability, temperature, activity, and sleep prior to symptom onset, potentially even in asymptomatic individuals. While the ability of wearable devices to detect viral infections in a real-world setting has yet to be proven, multiple recent studies have established that individual, continuous data from a range of biometric monitoring technologies can be easily acquired and that through the use of machine learning techniques, physiological signals and warning signs can be identified. In this review, we highlight the existing knowledge base supporting the potential for widespread implementation of biometric data to address existing gaps in the diagnosis and treatment of viral illnesses, with a particular focus on the many important lessons learned from the coronavirus disease 2019 pandemic.

Bulls fed a high-gain diet decrease blastocyst formation after in vitro fertilization.

In brief: Paternal high-gain diet reduces blastocyst development following in vitro fertilization and embryo culture but does not affect gene expression or cellular allocation of resultant blastocysts. Abstract: Bulls used in cattle production are often overfed to induce rapid growth, early puberty, and increase sale price. While the negative consequences of undernutrition on bull sperm quality are known, it is unclear how a high-gain diet influences embryo development. We hypothesized that semen collected from bulls fed a high-gain diet would have a reduced capacity to produce blastocysts following in vitro fertilization. Eight mature bulls were stratified by body weight and fed the same diet for 67 days at either a maintenance level (0.5% body weight per day; n = 4) or a high-gain rate (1.25% body weight per day; n = 4). Semen was collected by electroejaculation at the end of the feeding regimen and subjected to sperm analysis, frozen, and used for in vitro fertilization. The high-gain diet increased body weight, average daily gain, and subcutaneous fat thickness compared to the maintenance diet. Sperm of high-gain bulls tended to have increased early necrosis and had increased post-thaw acrosome damage compared with maintenance bulls, but diet did not affect sperm motility or morphology. Semen of high-gain bulls reduced the percentage of cleaved oocytes that developed to blastocyst stage embryos. Paternal diet had no effect on the number of total or CDX2-positive cells of blastocysts, or blastocysts gene expression for markers associated with developmental capacity. Feeding bulls a high-gain diet did not affect sperm morphology or motility, but increased adiposity and reduced the ability of sperm to generate blastocyst-stage embryos.

Gender and coping with HIV: a qualitative study of older childhood sexual abuse survivors living with HIV.

People living with HIV often have complex identities and histories. Understanding how these experiences influence adherence to treatment and quality of life are critical to the HIV care. The experiences of older adults living with HIV are uniquely embedded within biology and aging as well as gender. This study described the gendered strategies for coping with HIV among older adults who are childhood sexual abuse survivors. Audio-recorded semi-structured interviews were performed with 24 adults who are 50 years and older from a clinic in South Carolina. Thematic analysis approach was used to discuss key concepts, reconcile codes, and name emergent themes. Overall, the participants used a spectrum of coping strategies including spirituality, seclusion, social support, substance use, engagement in HIV care, information acquisition and sharing, and cognitive reframing. Our findings suggest the potential for growth and recovery is heightened if the interplay of HIV diagnosis, aging, coping, and mental health is considered. Healthcare providers should assess the ways in which individuals interpret their HIV diagnosis and other lived experiences to better understand their patients' mental health. Knowledge of gender-based coping strategies used in HIV-relevant outcomes can be translated into more effective treatment plans to improve the overall quality of life.

"Is it worth living?" psychosocial challenges of childhood sexual abuse survivors aging with HIV.

Older adults living with HIV (OALH) undergo challenges such as comorbidities, social isolation, and "double stigma" associated with their HIV and aging statuses. Simultaneously, research has shown that experiences of childhood sexual abuse (CSA) continue to impact the quality of life across the lifespan and may pose unique hardships for older adults. Despite the high prevalence of trauma among people living with HIV, research examining the psychosocial challenges of OALH with a CSA history is scant. To address this gap in the literature, this study aimed to explore psychosocial challenges among OALH who are CSA survivors using a qualitative approach. Twenty-four in-depth, semi-structured interviews were completed with OALH (age 50 years and older) who reported histories of CSA. Multiple coders and an inductive coding process were employed for data analysis. Four main themes regarding psychosocial challenges emerged from the analysis: (1) depression and suicidal ideation, (2) fear and anxiety, (3) social support issues, and (4) memory issues. The authors discuss the implications of these findings and the importance of trauma-informed treatment for these individuals.

Diagnostic accuracy of diffusion-weighted imaging in variant Creutzfeldt-Jakob disease.

PURPOSE: This study sought to investigate the diagnostic sensitivity of diffusion-weighted imaging (DWI) in variant Creutzfeldt-Jakob disease (vCJD), a prion disease with significant public health implications on account of its transmissibility. The importance of this research stemmed from the first neuropathologically confirmed vCJD case in a PRNP heterozygous individual in 2016, which displayed DWI features typical of sporadic CJD (sCJD). The case was classified as 'probable' sCJD in life, predominantly based on these imaging findings. While DWI has proven valuable in diagnosing sCJD, its utility in vCJD diagnosis remains unclear. METHODS: DWI and Fluid-attenuated inversion recovery (FLAIR) images from probable and definite vCJD cases referred to the National CJD Research and Surveillance Unit (NCJDRSU) were independently analysed by an expert neuroradiologist. Scans were reviewed within a mixed cohort of CJD cases including definite sCJD and non-CJD controls. RESULTS: FLAIR sequences demonstrated greater sensitivity in identifying the pulvinar sign in vCJD compared to DWI (73% vs 41%, p-value <0.001). Basal ganglia hyperintensities were more prevalent in DWI (84%) than FLAIR (64%), and cortical hyperintensities were exclusive to DWI (24%). The pulvinar sign showed a specificity of 98% for vCJD and was rare in sCJD. CONCLUSION: DWI showed reduced sensitivity compared to FLAIR imaging in detecting the pulvinar sign in vCJD. Conversely, DWI can more distinctively identify basal ganglia and cortical hyperintensities, thus leading to imaging patterns more characteristic of sCJD. Therefore, DWI should be cautiously interpreted in vCJD diagnosis, with axial FLAIR potentially providing a more precise evaluation of the pulvinar sign.

"If people are hesitant at all, you just want a really big front door": a rapid qualitative interview study on the Luton COVID-19 vaccination outreach clinics.

BACKGROUND: There is a lack of evidence on the usefulness, practicality, and acceptance of vaccination outreach clinics in the community especially during pandemics. In this qualitative study, we explored the experiences, motivations and perceptions of service users, health professionals, strategic staff, volunteers, and community workers involved in the COVID-19 vaccination outreach clinics in Luton. METHODS: Semi structured face to face, telephone, online interviews, and focus groups were conducted with 31 participants including health professionals, strategic staff, volunteers, community workers and service users. The Framework Method was used to analyse the data and generate themes. RESULTS: Service users expressed positivity towards the convenience and familiarity of the location of the vaccination outreach clinics and the flexibility of receiving the vaccination in a local setting. Participants involved in the planning and delivery of the service commented on the worthwhile and rewarding experience but suggested more attention should be given to preparation time, service user recruitment, the working environment, and staff welfare. CONCLUSIONS: The COVID-19 mobile vaccination outreach clinics in Luton tested and developed a different model of service delivery and demonstrated a collaborative way of working: "taking the health service to the patient, not the patient to the health service". Planning and local community engagement were seen as key to successful delivery of a mobile healthcare service.