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During rollout of mRNA-based COVID-19 vaccines, several jurisdictions extended the interval between the first and second doses to prioritize wider population access to limited vaccine supply. This study evaluated the effects of an extended dose interval on development of antibody and cell-mediated responses following the primary dose series and a subsequent booster dose. Blood samples were collected from mRNA COVID-19 vaccine recipients at baseline and longitudinally after each dose. Samples were analyzed for SARS-CoV-2-specific antibody titers, neutralizing antibodies and memory T cell responses. An extended dose interval was associated with improved breadth of neutralizing antibody responses against both ancestral and early SARS-CoV-2 variants, but not Omicron variants. Dose interval had no impact on the development of antigen-specific memory T cell responses, the memory or T helper phenotypes of responding T cells or cytokine production. The effects of the primary dose interval on immune outcomes were no longer evident after a third dose of mRNA vaccine. An extended primary dose interval resulted in short-term benefits to humoral immunity but these were transient in the context of subsequent exposures. However, in addition to the public health benefits of wider population access to vaccines, the short-term immunological benefits of extending the dose interval may have been sustained in the absence of boosters. These findings underscore the importance of evaluating dosing intervals during the development of future vaccine candidates.

End-stage renal disease (ESRD) is associated with an increased susceptibility to infectious diseases, including infection with . Mucosal-associated invariant T (MAIT) cells recognize vitamin B metabolites produced by many bacterial species, including Mtb, and may play an important role in providing protective immunity against tuberculosis infection in the lung. To date, little is known about MAIT cell frequency, phenotype, or function in ESRD patients. MAIT cells, identified by surface marker expression or MR1 tetramer binding, were characterized in 20 ESRD and 20 healthy control participants by multicolor flow cytometry. MAIT cell phenotype and cytokine production following PMA/ionomycin, IL-12/IL-18, or stimulation were determined. Monocyte phenotype and plasma C-reactive protein/inflammatory cytokine levels were quantified by flow cytometry, ELISA, and multiplex bead array. Peripheral blood MAIT cells were significantly depleted among ESRD patients compared to controls by both phenotypic and tetramer analysis and exhibited a loss of CXCR3 expression coupled to increased expression of CCR6 and CXCR6. ESRD was also associated with a shift in MAIT PMA-induced cytokine production away from IFNγ production and toward granulocyte macrophage-colony stimulating factor (GM-CSF) secretion, and a loss of -stimulated tumor necrosis factor α expression. Loss of IFNγ expression was associated with a combination of age, alterations in Tbet and Eomes expression, and inflammatory plasma cytokine levels. The loss of peripheral blood MAIT cells and associated shifts in tissue homing receptor expression and GM-CSF production may contribute to an immune environment that is permissive to bacterial replication, particularly in the lungs.

Objectives Tuberculosis comorbidity with chronic diseases including diabetes, HIV and chronic kidney disease is of rising concern. In particular, latent tuberculosis infection (LTBI) comorbidity with end‐stage kidney disease (ESKD) is associated with up to 52.5‐fold increased risk of TB reactivation to active tuberculosis infection (ATBI). The immunological mechanisms driving this significant rise in TB reactivation are poorly understood. To contribute to this understanding, we performed a comprehensive assessment of soluble and cellular immune features amongst a unique cohort of patients comorbid with ESKD and LTBI. Methods We assessed the plasma and cellular immune profiles from patients with and without ESKD and/or LTBI (N = 40). We characterised antibody glycosylation, serum complement and cytokine levels. We also assessed classical and non‐classical monocytes and T cells with flow cytometry. Using a systems‐based approach, we identified key immunological features that discriminate between the different disease states. Results Individuals with ESKD exhibited a highly inflammatory plasma profile and an activated cellular state compared with those without ESKD, including higher levels of inflammatory antibody Fc glycosylation structures and activated CX3CR1+ monocytes that correlate with increased inflammatory plasma cytokines. Similar elevated inflammatory signatures were also observed in ESKD+/LTBI+ compared with ESKD−/LTBI+, suggesting that ESKD induces an overwhelming inflammatory immune state. In contrast, no significant inflammatory differences were observed when comparing LTBI+ and LTBI− individuals. Conclusion Our study highlights the highly inflammatory state induced by ESKD. We hypothesise that this inflammatory state could contribute to the increased risk of TB reactivation in ESKD patients. End‐stage kidney disease (ESKD), regardless of aetiology, shares a common, highly inflammatory course promoting monocyte activation, leukocyte chemoattraction, and generalised inflammation. With substantial rates of TB reactivation in this patient group and mechanistic uncertainty, our study assesses plasma and cellular immune profiles from ESKD patients with and without latent tuberculosis infection (LTBI). We learn how ESKD+/LTBI+ co‐infection remains a highly inflammatory state compared to ESKD−/LTBI+ and find unique inflammatory signatures driven by the presence of ESKD.

Vaccines against SARS-CoV-2 have shown high efficacy in clinical trials, yet a full immunologic characterization of these vaccines, particularly within the human upper respiratory tract, is less well known. Here, we enumerate and phenotype T cells in nasal mucosa and blood using flow cytometry before and after vaccination with the Pfizer-BioNTech COVID-19 vaccine ( n  = 21). Tissue-resident memory (Trm) CD8 + T cells expressing CD69 + CD103 + increase in number ~12 days following the first and second doses, by 0.31 and 0.43 log 10 cells per swab respectively ( p  = 0.058 and p  = 0.009 in adjusted linear mixed models). CD69 + CD103 + CD8 + T cells in the blood decrease post-vaccination. Similar increases in nasal CD8 + CD69 + CD103 − T cells are observed, particularly following the second dose. CD4 + cells co-expressing CCR6 and CD161 are also increased in abundance following both doses. Stimulation of nasal CD8 + T cells with SARS-CoV-2 spike peptides elevates expression of CD107a at 2- and 6-months ( p  = 0.0096) post second vaccine dose, with a subset of donors also expressing increased cytokines. These data suggest that nasal T cells may be induced and contribute to the protective immunity afforded by this vaccine. Whether mRNA SARS-CoV-2 vaccines promote T cells within the nasal mucosa of vaccine recipients is not known. Here the authors show that after mRNA SARS-CoV-2 vaccination, antigen specific T cells can be measured in the nasal mucosa and that these T cells may be localised to respond to a subsequent virus infection. Clinical trial registration NCT04713163

The identification of a type I interferon-induced transcriptomic signature in active tuberculosis suggests a potential role for these interferons in the pathogenesis of tuberculosis. Comorbidities such as human immunodeficiency virus, diabetes, systemic lupus erythematosus, end-stage renal disease, and coronavirus disease are epidemiologically linked to an increased risk for reactivation of latent tuberculosis infection. Notably, type I interferons are also implicated in the pathogenesis of these conditions, with a recognizable type I interferon transcriptomic signature. The mechanisms by which type I interferons in tuberculosis-risk-associated comorbidities may drive the progression of tuberculosis or maintenance of latent infection however remain largely unknown. This review summarizes the existing literature on the increased association between type I interferons, focusing on interferon-α and -β, and the heightened risk of tuberculosis reactivation. It also underscores the similarities in the immunopathogenesis of these comorbidities. A better understanding of these mechanisms is essential to guide the development of host-directed interferon therapies and improving diagnostic biomarkers in M. tuberculosis infection.

The coronavirus disease 2019 (Covid-19) pandemic, caused by SARS-CoV-2, has resulted in a global testing supply shortage. In response, pooled testing has emerged as a promising strategy that can immediately increase testing capacity. In pooled sample testing, multiple samples are combined (or pooled) together and tested as a single unit. If the pool is positive, the individual samples can then be individually tested to identify the positive case(s). Here, we provide support for the adoption of sample pooling with the point-of-care Cepheid Xpert ® Xpress SARS-CoV-2 molecular assay. Corroborating previous findings, the limit of detection of this assay was comparable to laboratory-developed reverse-transcription quantitative PCR SARS-CoV-2 tests, with observed detection below 100 copies/mL. The Xpert ® Xpress assay detected SARS-CoV-2 after samples with minimum viral loads of 461 copies/mL were pooled in groups of six. Based on these data, we recommend the adoption of pooled testing with the Xpert ® Xpress SARS-CoV-2 assay where warranted based on public health needs. The suggested number of samples per pool, or the pooling depth, is unique for each point-of-care testing site and can be determined by the positive test rates. To statistically determine appropriate pooling depth, we have calculated the pooling efficiency for numerous combinations of pool sizes and test rates. This information is included as a supplemental dataset that we encourage public health authorities to use as a guide to make recommendations that will maximize testing capacity and resource conservation.

Participation in an EQA program is critical to the quality assurance process. Reliable and precise CD4 T-cells enumeration are essential to improve the clinical management of patients by evaluating the disease progression and by monitoring the effectiveness of ART in HIV-patients. The CIRCB, CD4 reference laboratory, in collaboration with the Canadian QASI-program, recruited sites, distributed and analyzed CD4-panels in 61 sites across Cameroon. A trend and performance analysis in the pre-analytical, analytical and post-analytical phases was performed. Continuous training and corrective actions carried out from 2014 to 2018 increased the number of participating sites from 15 to 61 sites, the number of unacceptable results decreased from 50 to 10%. Specific challenges included errors in pre analytic (17.5%), analytic (77.0%) and post-analytic (5.5%) phases. This EQA requires the application of good laboratory practices, fluidic communication between all the stakeholders, continuous training, application of specific on-site corrective measures, and timely equipment maintenance in order to avoid repetitive errors and to increase laboratory performance. It could be extended to other HIV-1 testing like viral load and EID point-of-care. Partnership with QASI serve as a model for implementation of a successful EQA model for resource limited countries wanting to implement EQA for HIV testing and monitoring in alignment with 90–90–90 targets.

The coronavirus disease 2019 (Covid-19) pandemic, caused by SARS-CoV-2, has resulted in a global testing supply shortage. In response, pooled testing has emerged as a promising strategy that can immediately increase testing capacity. In pooled sample testing, multiple samples are combined (or pooled) together and tested as a single unit. If the pool is positive, the individual samples can then be individually tested to identify the positive case(s). Here, we provide support for the adoption of sample pooling with the point-of-care Cepheid Xpert.sup.® Xpress SARS-CoV-2 molecular assay. Corroborating previous findings, the limit of detection of this assay was comparable to laboratory-developed reverse-transcription quantitative PCR SARS-CoV-2 tests, with observed detection below 100 copies/mL. The Xpert.sup.® Xpress assay detected SARS-CoV-2 after samples with minimum viral loads of 461 copies/mL were pooled in groups of six. Based on these data, we recommend the adoption of pooled testing with the Xpert.sup.® Xpress SARS-CoV-2 assay where warranted based on public health needs. The suggested number of samples per pool, or the pooling depth, is unique for each point-of-care testing site and can be determined by the positive test rates. To statistically determine appropriate pooling depth, we have calculated the pooling efficiency for numerous combinations of pool sizes and test rates. This information is included as a supplemental dataset that we encourage public health authorities to use as a guide to make recommendations that will maximize testing capacity and resource conservation.

The GNB3 C825T polymorphism is associated with increased G protein-mediated signal transduction, SDF-1α-mediated lymphocyte chemotaxis, accelerated HIV-1 progression, and altered responses to antiretroviral therapy among Caucasian subjects. The GNB3 825T allele is highly prevalent in African populations, and as such any impact on HIV-1 acquisition or progression rates could have a dramatic impact. This study examines the association of the 825T polymorphism with HIV-1 acquisition, disease progression and immune activation in two African cohorts. GNB3 825 genotyping was performed for enrolees in both a commercial sex worker cohort and a perinatal HIV transmission (PHT) cohort in Nairobi, Kenya. Ex vivo immune activation was quantified by flow cytometry, and plasma chemokine levels were assessed by cytokine bead array. GNB3 genotype was not associated with sexual or vertical HIV-1 acquisition within these cohorts. Within the Pumwani cohort, GNB3 genotype did not affect HIV-1 disease progression among seroconverters or among HIV-1-positive individuals after adjustment for baseline CD4 count. Maternal CD4 decline and viral load increase in the PHT cohort did not differ between genotypes. Multi-parametric flow cytometry assessment of T cell activation (CD69, HLA-DR, CD38) and Treg frequency (CD25(+)FOXP3(+)) found no differences between genotype groups. Plasma SDF-1α, MIP-1β and TRAIL levels quantified by cytokine bead array were also similar between groups. In contrast to previous reports, we were unable to provide evidence to suggest that the GNB3 C825T polymorphism affects HIV-1 acquisition or disease progression within African populations. Ex vivo immune activation and plasma chemokine levels were similarly unaffected by GNB3 genotype in both HIV-1-negative and HIV-1-positive individuals. The paucity of studies investigating the impact of GNB3 polymorphism among African populations and the lack of mechanistic studies make it difficult to assess the true biological significance of this polymorphism in HIV-1 infection.

Background The GNB3 C825T polymorphism is associated with increased G protein-mediated signal transduction, SDF-1α-mediated lymphocyte chemotaxis, accelerated HIV-1 progression, and altered responses to antiretroviral therapy among Caucasian subjects. The GNB3 825T allele is highly prevalent in African populations, and as such any impact on HIV-1 acquisition or progression rates could have a dramatic impact. This study examines the association of the 825T polymorphism with HIV-1 acquisition, disease progression and immune activation in two African cohorts. GNB3 825 genotyping was performed for enrolees in both a commercial sex worker cohort and a perinatal HIV transmission (PHT) cohort in Nairobi, Kenya. Ex vivo immune activation was quantified by flow cytometry, and plasma chemokine levels were assessed by cytokine bead array. Results GNB3 genotype was not associated with sexual or vertical HIV-1 acquisition within these cohorts. Within the Pumwani cohort, GNB3 genotype did not affect HIV-1 disease progression among seroconverters or among HIV-1-positive individuals after adjustment for baseline CD4 count. Maternal CD4 decline and viral load increase in the PHT cohort did not differ between genotypes. Multi-parametric flow cytometry assessment of T cell activation (CD69, HLA-DR, CD38) and Treg frequency (CD25 + FOXP3 + ) found no differences between genotype groups. Plasma SDF-1α, MIP-1β and TRAIL levels quantified by cytokine bead array were also similar between groups. Conclusions In contrast to previous reports, we were unable to provide evidence to suggest that the GNB3 C825T polymorphism affects HIV-1 acquisition or disease progression within African populations. Ex vivo immune activation and plasma chemokine levels were similarly unaffected by GNB3 genotype in both HIV-1-negative and HIV-1-positive individuals. The paucity of studies investigating the impact of GNB3 polymorphism among African populations and the lack of mechanistic studies make it difficult to assess the true biological significance of this polymorphism in HIV-1 infection.