Objectives: The aim of this study was to assess the safety and immunogenicity of a dose-sparing fractional intradermal (ID) booster strategy with the mRNA-1273 COVID-19 vaccine. Methods: COVID-19... Show moreObjectives: The aim of this study was to assess the safety and immunogenicity of a dose-sparing fractional intradermal (ID) booster strategy with the mRNA-1273 COVID-19 vaccine. Methods: COVID-19 naive adults aged 18e30 years were recruited from a previous study on primary vaccination regimens that compared 20 mg ID vaccinations with 100 mg intramuscular (IM) vaccinations with mRNA-1273 as the primary vaccination series. Participants previously immunized with ID regimens were randomly assigned (1:1) to receive a fractional ID booster dose (20 mg) or the standard-of-care intramuscular (IM) booster dose (50 mg) of the mRNA-1273 vaccine, 6 months after completing their primary series (ID-ID and ID-IM group, respectively). Participants that had received a full dose IM regimen as the primary series, received the IM standard-of-care booster dose (IM-IM group). In addition, COVID-19 naive individuals aged 18e40 years who had received an IM mRNA vaccine as the primary series were recruited from the general population to receive a fractional ID booster dose (IM-ID group). Immunogenicity was assessed using IgG anti-spike antibody responses and neutralizing capacity against SARS-CoV-2. Cellular immune responses were measured in a sub-group. Safety and tolerability were monitored. Results: In January 2022, 129 participants were included in the study. Fractional ID boosting was safe and well tolerated, with fewer systemic adverse events compared with IM boosting. At day 28 post-booster, anti-spike S1 IgG geometric mean concentrations were 9106 (95% CI, 7150e11 597) binding antibody units (BAU)/mL in the IM-IM group and 4357 (3003e6322) BAU/mL; 6629 (4913e8946) BAU/mL; and 5264 (4032e6873) BAU/mL in the ID-IM, ID-ID, and IM-ID groups, respectively. Discussion: Intradermal boosting provides robust immune responses and is a viable dose-sparing strategy for mRNA COVID-19 vaccines. The favourable side-effect profile supports its potential to reduce vaccine hesitancy. Fractional dosing strategies should be considered early in the clinical development of future mRNA vaccines to enhance vaccine availability and pandemic preparedness. Show less
Prins, M.L.M.; Roozen, G.V.T.; Pothast, C.R.; Huisman, W.; Binnendijk, R. van; Hartog, G. den; ... ; Roukens, A.H.E. 2024
Fractional dosing can be a cost-effective vaccination strategy to accelerate individual and herd immunity in a pandemic. We assessed the immunogenicity and safety of primary intradermal (ID)... Show moreFractional dosing can be a cost-effective vaccination strategy to accelerate individual and herd immunity in a pandemic. We assessed the immunogenicity and safety of primary intradermal (ID) vaccination, with a 1/5th dose compared with the standard intramuscular (IM) dose of mRNA-1273 in SARS-CoV-2 naive persons. We conducted an open-label, non-inferiority, randomized controlled trial in the Netherlands between June and December 2021. One hundred and fifty healthy and SARS-CoV-2 naive participants, aged 18-30 years, were randomized (1:1:1) to receive either two doses of 20 mu g mRNA-1273 ID with a standard needle (SN) or the Bella-mu (R) needle (BM), or two doses of 100 mu g IM, 28 days apart. The primary outcome was non-inferiority in seroconversion rates at day 43 (D43), defined as a neutralizing antibody concentration threshold of 465 IU/mL, the lowest response in the IM group. The non-inferiority margin was set at -15%. Neutralizing antibody concentrations at D43 were 1789 (95% CI: 1488-2150) in the IM and 1263 (951-1676) and 1295 (1020-1645) in the ID-SN and ID-BM groups, respectively. The absolute difference in seroconversion proportion between fractional and standard-dose groups was -13.95% (-24.31 to -3.60) for the ID-SN and -13.04% (-22.78 to -3.31) for the ID-BM group and exceeded the predefined non-inferiority margin. Although ID vaccination with 1/5th dose of mRNA-1273 did not meet the predefined non-inferior criteria, the neutralizing antibody concentrations in these groups are far above the proposed proxy for protection against severe disease (100 IU/mL), justifying this strategy in times of vaccine scarcity to accelerate mass protection against severe disease. Show less
Hoogerwerf, M.A.; Janse, J.J.; Kuiper, V.P.; Schuijlenburg, R. van; Kruize, Y.C.M.; Sijtsma, J.C.; ... ; Microbe, L. 2023
Background Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of... Show moreBackground Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of mechanisms of protective immunity and new vaccine targets. Immunisation with attenuated larvae has proven effective in dogs and partial immunity has been achieved using an irradiated larvae model in healthy volunteers. We aimed to investigate the protective efficacy of immunisation with short-term larval infection against hookworm challenge.Methods We did a single-centre, placebo-controlled, randomised, controlled, phase 1 trial at Leiden University Medical Center (Leiden, Netherlands). Healthy volunteers (aged 18-45 years) were recruited using advertisements on social media and in publicly accessible areas. Volunteers were randomly assigned (2:1) to receive three short-term infections with 50 infectious Necator americanus third-stage filariform larvae (50L3) or placebo. Infection was abrogated with a 3-day course of albendazole 400 mg, 2 weeks after each exposure. Subsequently all volunteers were challenged with two doses of 50L3 at a 2-week interval. The primary endpoint was egg load (geometric mean per g faeces) measured weekly between weeks 12 and 16 after first challenge, assessed in the per-protocol population, which included all randomly assigned volunteers with available data on egg counts at week 12-16 after challenge. This study is registered with ClinicalTrials.gov, NCT03702530.Findings Between Nov 8 and Dec 14, 2018, 26 volunteers were screened, of whom 23 enrolled in the trial. The first immunisation was conducted on Dec 18, 2018. 23 volunteers were randomly assigned (15 to the intervention group and eight to the placebo group). Egg load after challenge was lower in the intervention group than the placebo group (geometric mean 571 eggs per g [range 372-992] vs 873 eggs per g [268-1484]); however, this difference was not statistically significant (p=0 center dot 10). Five volunteers in the intervention group developed a severe skin rash, which was associated with 40% reduction in egg counts after challenge (geometric mean 742 eggs per g [range 268-1484] vs 441 eggs per g [range 380-520] after challenge; p=0 center dot 0025) and associated with higher peak IgG1 titres. Interpretation To our knowledge, this is the first study to describe a protective effect of short-term exposure to hookworm larvae and show an association with skin response, eosinophilic response, and IgG1. These findings could inform future hookworm vaccine development. Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Show less
Koopman, J.P.R.; Houlder, E.L.; Janse, J.J.; Casacuberta-Partal, M.; Lamers, O.A.C.; Sijtsma, J.C.; ... ; Roestenberg, M. 2023
Background A controlled human infection model for schistosomiasis (CHI-S) can speed up vaccine development and provides insight into early immune responses following schistosome exposure. Recently,... Show moreBackground A controlled human infection model for schistosomiasis (CHI-S) can speed up vaccine development and provides insight into early immune responses following schistosome exposure. Recently, we established CHI-S model using single-sex male-only Schistosoma mansoni (Sm) cercariae in Schistosoma-naive individuals. Given important differences in antigenic profile and human immune responses to schistosomes of different sex, we pioneered a single-sex female-only CHI-S model for future use in vaccine development.Methods We exposed 13 healthy, Schistosoma-naive adult participants to 10 (n = 3) or 20 (n = 10) female cercariae and followed for 20 weeks, receiving treatment with praziquantel (PZQ) 60 mg/kg at week 8 and 12 after exposure.Findings The majority (11/13) participants reported rash and/or itch at the site of exposure, 5/13 had transient symptoms of acute schistosomiasis. Exposure to 20 cercariae led to detectable infection, defined as serum circulating anodic antigen levels >1.0 pg/mL, in 6/10 participants. Despite two rounds of PZQ treatment, 4/13 participants showed signs of persistent infection. Additional one-or three-day PZQ treatment (1 x 60 mg/kg and 3 x 60 mg/kg) or artemether did not result in cure, but over time three participants self-cured. Antibody, cellular, and cytokine responses peaked at week 4 post infection, with a mixed Th1, Th2, and regulatory profile. Cellular responses were (most) discriminative for symptoms.Interpretation Female-only infections exhibit similar clinical and immunological profiles as male-only infections but are more resistant to PZQ treatment. This limits future use of this model and may have important implications for disease control programs. Show less
Vaccination is one of medicine's greatest achievements; however, its full potential is hampered by considerable variation in efficacy across populations and geographical regions. For example,... Show moreVaccination is one of medicine's greatest achievements; however, its full potential is hampered by considerable variation in efficacy across populations and geographical regions. For example, attenuated malaria vaccines in high-income countries confer almost 100% protection, whereas in low-income regions these same vaccines achieve only 20-50% protection. This trend is also observed for other vaccines, such as bacillus Calmette-Guerin (BCG), rotavirus and yellow fever vaccines, in terms of either immunogenicity or efficacy. Multiple environmental factors affect vaccine responses, including pathogen exposure, microbiota composition and dietary nutrients. However, there has been variable success with interventions that target these individual factors, highlighting the need for a better understanding of their downstream immunological mechanisms to develop new ways of modulating vaccine responses. Here, we review the immunological factors that underlie geographical variation in vaccine responses. Through the identification of causal pathways that link environmental influences to vaccine responsiveness, it might become possible to devise modulatory compounds that can complement vaccines for better outcomes in regions where they are needed most.The protective effect of vaccines is often poorest in low-income countries. Here, the authors explore the immunological factors that may explain the geographical variation in vaccine responsiveness and the ways in which they might be modulated to ensure effective vaccination in regions where it is needed most. Show less
Sluis, T.C. van der; Beyrend, G.; Gracht, E.T.I.V.; Abdelaal, T.; Jochems, S.P.; Belderbos, R.A.; ... ; Arens, R. 2023
Immune checkpoint therapy (ICT) has the power to eradicate cancer, but the mechanisms that determine effective therapy-induced immune responses are not fully understood. Here, using high... Show moreImmune checkpoint therapy (ICT) has the power to eradicate cancer, but the mechanisms that determine effective therapy-induced immune responses are not fully understood. Here, using high-dimensional sin-gle-cell profiling, we interrogate whether the landscape of T cell states in the peripheral blood predict re-sponses to combinatorial targeting of the OX40 costimulatory and PD-1 inhibitory pathways. Single-cell RNA sequencing and mass cytometry expose systemic and dynamic activation states of therapy-responsive CD4+ and CD8+ T cells in tumor-bearing mice with expression of distinct natural killer (NK) cell receptors, granzymes, and chemokines/chemokine receptors. Moreover, similar NK cell receptor-expressing CD8+ T cells are also detected in the blood of immunotherapy-responsive cancer patients. Targeting the NK cell and chemokine receptors in tumor-bearing mice shows the functional importance of these receptors for ther-apy-induced anti-tumor immunity. These findings provide a better understanding of ICT and highlight the use and targeting of dynamic biomarkers on T cells to improve cancer immunotherapy. Show less
Background. The COVIH study is a prospective coronavirus disease 2019 (COVID-19) vaccination study in 1154 people with HIV (PWH), of whom 14% showed reduced antibody levels after primary... Show moreBackground. The COVIH study is a prospective coronavirus disease 2019 (COVID-19) vaccination study in 1154 people with HIV (PWH), of whom 14% showed reduced antibody levels after primary vaccination. We evaluated whether an additional vaccination boosts immune responses in these hyporesponders.Methods. The primary end point was the increase in antibodies 28 days after additional mRNA-1273 vaccination. Secondary end points included neutralizing antibodies, S-specific T-cell and B-cell responses, and reactogenicity.Results. Of the 66 participants, 40 previously received 2 doses ChAdOx1-S, 22 received 2 doses BNT162b2, and 4 received a single dose Ad26.COV2.S. The median age was 63 years (interquartile range [IQR], 60-66), 86% were male, and median CD4(+) T-cell count was 650/mu L (IQR, 423-941). The mean S1-specific antibody level increased from 35 binding antibody units (BAU)/mL (95% confidence interval [CI], 24-46) to 4317 BAU/mL (95% CI, 3275-5360) (P<.0001). Of all participants, 97% showed an adequate response and the 45 antibody-negative participants all seroconverted. A significant increase in the proportion of PWH with ancestral S-specific CD4(+) T cells (P=.04) and S-specific B cells (P=.02) was observed.Conclusions. An additional mRNA-1273 vaccination induced a robust serological response in 97% of PWH with a hyporesponse after primary vaccination. Show less
Childhood pneumococcal conjugate vaccine (PCV) protects against invasive pneumococcal disease caused by vaccine-serotype (VT) Streptococcus pneumoniae by generating opsonophagocytic anti-capsular... Show moreChildhood pneumococcal conjugate vaccine (PCV) protects against invasive pneumococcal disease caused by vaccine-serotype (VT) Streptococcus pneumoniae by generating opsonophagocytic anti-capsular antibodies, but how vaccination protects against and reduces VT carriage is less well understood. Using serological samples from PCV-vaccinated Malawian individuals and a UK human challenge model, we explored whether antibody quality (IgG subclass, opsonophagocytic killing, and avidity) is associated with protection from carriage. Following experimental challenge of adults with S. pneumoniae serotype 6B, 3/21 PCV13-vaccinees were colonised with pneumococcus compared to 12/24 hepatitis Avaccinated controls; PCV13-vaccination induced serotype-specific IgG, IgG1, and IgG2, and strong opsonophagocytic responses. However, there was no clear relationship between antibody quality and protection from carriage or carriage intensity after vaccination. Similarly, among PCV13-vaccinated Malawian infants there was no relationship between serotype-specific antibody titre or quality and carriage through exposure to circulating serotypes. Although opsonophagocytic responses were low in infants, antibody titre and avidity to circulating serotypes 19F and 6A were maintained or increased with age. These data suggest a complex relationship between antibody-mediated immunity and pneumococcal carriage, and that PCV13-driven antibody quality may mature with age and exposure. (c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
The advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease.... Show moreThe advent of pneumococcal conjugate vaccines led to the near disappearance of most of the included serotypes in high-income settings but also the rise of nonvaccine-type colonization and disease. Alternative strategies, using genetically conserved proteins as antigens, have been evaluated preclinically and clinically for years, so far unsuccessfully. One possible explanation for the failure of these efforts is that the choice of antigens may not have been sufficiently guided by an understanding of the gene expression pattern in the context of infection. Here, we present a targeted transcriptomic analysis of 160 pneumococcal genes encoding bacterial surface-exposed proteins in mouse models, human colonization, and human meningitis. We present the overlap of these different transcriptomic profiles. We identify two bacterial genes that are highly expressed in the context of mouse and human infection: SP_0282, an IID component of a mannose phosphotransferase system (PTS), and SP_1739, encoding RNase Y. We show that these two proteins can confer protection against pneumococcal nasopharyngeal colonization and intraperitoneal challenge in a murine model and generate opsonophagocytic antibodies. This study emphasizes and confirms the importance of studies of pneumococcal gene expression of bacterial surface proteins during human infection and colonization and may pave the way for the selection of a protein-based vaccine candidate. Show less
Background: Increased nasopharyngeal carriage of pathogenic bacteria is found in low socioeconomic status (SES) settings. How SES affects local immune responses, important for controlling... Show moreBackground: Increased nasopharyngeal carriage of pathogenic bacteria is found in low socioeconomic status (SES) settings. How SES affects local immune responses, important for controlling colonization, is currently unknown. Objective: Examining bacterial colonization and cytokine response in the nasal mucosa of children from high and low SES. Methods: Nasosorption samples were collected in October 2019 from 48 high SES and 50 low SES schoolchildren, in a cross-sectional study in Makassar, Indonesia. Twenty-five cytokines were measured in nasal fluid. Quantitative polymerase chain reaction was performed to determine carriage and density of Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Staphylococcus aureus. Data were analyzed using multivariate regression. Results: H. influenzae and S. pneumoniae densities were increased in low SES settings compared to the high SES settings (P = 0.006, P = 0.026), with 6 and 67 times higher median densities, respectively. Densities of H. influenzae and S. pneumoniae were positively associated with levels of IL-1beta and IL-6. After correcting for bacterial density, IL-6 levels were higher in colonized children from high SES than low SES for H. influenzae and S. pneumoniae (both P = 0.039). Conclusion: Increased densities of H. influenzae and S. pneumoniae were observed in low SES children, whereas IL-6 levels associated with colonization were reduced in these children, indicating that immune responses to bacterial colonization were altered by SES. Show less
Roukens, A.H.E.; Pothast, C.R.; Konig, M.; Huisman, W.; Dalebout, T.; Tak, T.; ... ; Collaboration COVID-19 LUMC Grp 2021
Systemic immune cell dynamics during coronavirus disease 2019 (COVID-19) are extensively documented, but these are less well studied in the (upper) respiratory tract, where severe acute respiratory... Show moreSystemic immune cell dynamics during coronavirus disease 2019 (COVID-19) are extensively documented, but these are less well studied in the (upper) respiratory tract, where severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replicates(1-6). Here, we characterized nasal and systemic immune cells in individuals with COVID-19 who were hospitalized or convalescent and compared the immune cells to those seen in healthy donors. We observed increased nasal granulocytes, monocytes, CD11c(+) natural killer (NK) cells and CD4(+) T effector cells during acute COVID-19. The mucosal proinflammatory populations positively associated with peripheral blood human leukocyte antigen (HLA)-DRlow monocytes, CD38(+)PD1(+)CD4(+) T effector (T-eff) cells and plasmablasts. However, there was no general lymphopenia in nasal mucosa, unlike in peripheral blood. Moreover, nasal neutrophils negatively associated with oxygen saturation levels in blood. Following convalescence, nasal immune cells mostly normalized, except for CD127(+) granulocytes and CD38(+)CD8(+) tissue-resident memory T cells (T-RM). SARS-CoV-2-specific CD8(+) T cells persisted at least 2 months after viral clearance in the nasal mucosa, indicating that COVID-19 has both transient and long-term effects on upper respiratory tract immune responses. Show less
During acute COVID-19, there is little correlation between the nose and blood in terms of antibodies or cytokines; instead, these factors are associated with nasal microbiota.
Mouwenda, Y.D.; Ongwe, M.E.B.; Sonnet, F.; Stam, K.A.; Labuda, L.A.; Vries, S. de; ... ; Yazdanbakhsh, M. 2021
Two hookworm vaccine candidates, Na-GST-1 and Na-APR-1, formulated with Glucopyranosyl Lipid A (GLA-AF) adjuvant, have been shown to be safe, well tolerated, and to induce antibody responses in a... Show moreTwo hookworm vaccine candidates, Na-GST-1 and Na-APR-1, formulated with Glucopyranosyl Lipid A (GLA-AF) adjuvant, have been shown to be safe, well tolerated, and to induce antibody responses in a Phase 1 clinical trial (Clinicaltrials.gov NCT02126462) conducted in Gabon. Here, we characterized T cell responses in 24 Gabonese volunteers randomized to get vaccinated three times with Na-GST-1 and Na-APR-1 at doses of 30 mu g (n = 8) or 100 mu g (n = 10) and as control Hepatitis B (n = 6). Blood was collected pre- and post-vaccination on days 0, 28, and 180 as well as 2-weeks after each vaccine dose on days 14, 42, and 194 for PBMCs isolation. PBMCs were stimulated with recombinant Na-GST-1 or Na-APR-1, before (days 0, 28 and 180) and two weeks after (days 14, 42 and 194) each vaccination and used to characterize T cell responses by flow and mass cytometry. A significant increase in Na-GST-1 -specific CD4(+) T cells producing IL-2 and TNF, correlated with specific IgG antibody levels, after the third vaccination (day 194) was observed. In contrast, no increase in Na-APR-1 specific T cell responses were induced by the vaccine. Mass cytometry revealed that, Na-GST-1 cytokine producing CD4(+) T cells were CD161(+) memory cells expressing CTLA-4 and CD40-L. Blocking CTLA-4 enhanced the cytokine response to Na-GST-1.In Gabonese volunteers, hookworm vaccine candidate, Na-GST-1, induces detectable CD4(+) T cell responses that correlate with specific antibody levels. As these CD4(+) T cells express CTLA-4, and blocking this inhibitory molecules resulted in enhanced cytokine production, the question arises whether this pathway can be targeted to enhance vaccine immunogenicity.Author summaryTwo hookworm vaccine candidate (Na-GST-1 and Na-APR-1) have been tested in Gabonese and found to be safe and to induce antibody response. We aimed to study the cellular immune responses among vaccinated and unvaccinated volunteers. We found that Na-GST-1 induced CD4(+) T cell responses (IL-2, TNF) among the vaccinated volunteers that received the high vaccine dose (100 ug). Furthermore Na-GST-1 specific memory T cells were found to express the inhibitory molecule CTLA-4. These responses was not observed in those who received the low dose of the Na-GST-1 vaccine, or those who received Na-APR-1 or HBV. By blocking CTLA-4, we observed an increase in TNF production. Our data suggest that an intervention involving blockage of the CTLA-4 molecule in the vaccinated could be beneficial in endemic settings where vaccine responses have been shown to be lower compared to non-endemic settings. Show less
In humans, nasopharyngeal carriage of Streptococcus pneumoniae is common and although primarily asymptomatic, is a pre-requisite for pneumonia and invasive pneumococcal disease (IPD). Together,... Show moreIn humans, nasopharyngeal carriage of Streptococcus pneumoniae is common and although primarily asymptomatic, is a pre-requisite for pneumonia and invasive pneumococcal disease (IPD). Together, these kill over 500,000 people over the age of 70 years worldwide every year. Pneumococcal conjugate vaccines have been largely successful in reducing IPD in young children and have had considerable indirect impact in protection of older people in industrialized country settings (herd immunity). However, serotype replacement continues to threaten vulnerable populations, particularly older people in whom direct vaccine efficacy is reduced. The early control of pneumococcal colonization at the mucosal surface is mediated through a complex array of epithelial and innate immune cell interactions. Older people often display a state of chronic inflammation, which is associated with an increased mortality risk and has been termed 'Inflammageing'. In this review, we discuss the contribution of an altered microbiome, the impact of inflammageing on human epithelial and innate immunity to S. pneumoniae, and how the resulting dysregulation may affect the outcome of pneumococcal infection in older individuals. We describe the impact of the pneumococcal vaccine and highlight potential research approaches which may improve our understanding of respiratory mucosal immunity during pneumococcal colonization in older individuals. Show less
Jong, S.E. de; Unen, V. van; Manurung, M.D.; Stam, K.A.; Goeman, J.J.; Jochems, S.P.; ... ; Yazdanbakhsh, M. 2021
Controlled human infections provide opportunities to study the interaction between the immune system and malaria parasites, which is essential for vaccine development. Here, we compared immune... Show moreControlled human infections provide opportunities to study the interaction between the immune system and malaria parasites, which is essential for vaccine development. Here, we compared immune signatures of malaria-naive Europeans and of Africans with lifelong malaria exposure using mass cytometry, RNA sequencing and data integration, before and 5 and 11 days after venous inoculation with Plasmodium falciparum sporozoites. We observed differences in immune cell populations, antigen-specific responses and gene expression profiles between Europeans and Africans and among Africans with differing degrees of immunity. Before inoculation, an activated/differentiated state of both innate and adaptive cells, including elevated CD161(+)CD4(+) T cells and interferon-gamma production, predicted Africans capable of controlling parasitemia. After inoculation, the rapidity of the transcriptional response and clusters of CD4(+) T cells, plasmacytoid dendritic cells and innate T cells were among the features distinguishing Africans capable of controlling parasitemia from susceptible individuals. These findings can guide the development of a vaccine effective in malaria-endemic regions.Malaria immunity can be acquired through natural infection, but the correlates of protection are still being determined. Yazdanbakhsh and colleagues combine experimental infection of volunteers with Plasmodium falciparum with systems analysis to throw light on the nature of protective immune responses. Show less
Pichon, F.; Shen, Y.M.; Busato, F.; Jochems, S.P.; Jacquelin, B.; Grand, R. le; ... ; Tost, J. 2021
Aim: Nonhuman primates are essential for research on many human diseases. The Infinium Human Methylation450/EPIC BeadChips are popular tools for the study of the methylation state across the human... Show moreAim: Nonhuman primates are essential for research on many human diseases. The Infinium Human Methylation450/EPIC BeadChips are popular tools for the study of the methylation state across the human genome at affordable cost. Methods: We performed a precise evaluation and re-annotation of the BeadChip probes for the analysis of genome-wide DNA methylation patterns in rhesus macaques and African green monkeys through in silico analyses combined with functional validation by pyrosequencing. Results: Up to 165,847 of the 450K and 261,545 probes of the EPIC BeadChip can be reliably used. The annotation files are provided in a format compatible with a variety of standard bioinformatic pipelines. Conclusion: Our study will facilitate high-throughput DNA methylation analyses in Macaca mulatta and Chlorocebus sabaeus. Show less
Colonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human... Show moreColonization of the upper respiratory tract with Streptococcus pneumoniae is the precursor of pneumococcal pneumonia and invasive disease. Following exposure, however, it is unclear which human immune mechanisms determine whether a pathogen will colonize. We used a human challenge model to investigate host-pathogen interactions in the first hours and days following intranasal exposure to Streptococcus pneumoniae. Using a novel home sampling method, we measured early immune responses and bacterial density dynamics in the nose and saliva after volunteers were experimentally exposed to pneumococcus. Here, we show that nasal colonization can take up to 24 h to become established. Also, the following two distinct bacterial clearance profiles were associated with protection: nasal clearers with immediate clearance of bacteria in the nose by the activity of pre-existent mucosal neutrophils and saliva clearers with detectable pneumococcus in saliva at 1 h post challenge and delayed clearance mediated by an inflammatory response and increased neutrophil activity 24 h post bacterial encounter. This study describes, for the first time, how colonization with a bacterium is established in humans, signifying that the correlates of protection against pneumococcal colonization, which can be used to inform design and testing of novel vaccine candidates, could be valid for subsets of protected individuals.IMPORTANCE Occurrence of lower respiratory tract infections requires prior colonization of the upper respiratory tract with a pathogen. Most bacterial infection and colonization studies have been performed in murine and in vitro models due to the current invasive sampling methodology of the upper respiratory tract, both of which poorly reflect the complexity of host-pathogen interactions in the human nose. Self-collecting saliva and nasal lining fluid at home is a fast, low-cost, noninvasive, highfrequency sampling platform for continuous monitoring of bacterial encounter at defined time points relative to exposure. Our study demonstrates for the first time that, in humans, there are distinct profiles of pneumococcal colonization kinetics, distinguished by speed of appearance in saliva, local phagocytic function, and acute mucosal inflammatory responses, which may either recruit or activate neutrophils. These data are important for the design and testing of novel vaccine candidates. Show less
The molecular mechanisms underlying HIV-induced inflammation, which persists even during effective long-term treatment, remain incompletely defined. Here, we studied pathogenic and nonpathogenic... Show moreThe molecular mechanisms underlying HIV-induced inflammation, which persists even during effective long-term treatment, remain incompletely defined. Here, we studied pathogenic and nonpathogenic simian immunodeficiency virus (SIV) infections in macaques and African green monkeys, respectively. We longitudinally analyzed genome-wide DNA methylation changes in CD4 + T cells from lymph node and blood, using arrays. DNA methylation changes after SIV infection were more pronounced in lymph nodes than blood and already detected in primary infection. Differentially methylated genes in pathogenic SIV infection were enriched for Th1-signaling (e.g., RUNX3, STAT4, NFKB1) and metabolic pathways (e.g., PRKCZ). In contrast, nonpathogenic SIVagm infection induced DNA methylation in genes coding for regulatory proteins such as LAG-3, arginase-2, interleukin-21 and interleukin-31. Between 15 and 18% of genes with DNA methylation changes were differentially expressed in CD4 + T cells in vivo. Selected identified sites were validated using bisulfite pyrosequencing in an independent cohort of uninfected, viremic and SIV controller macaques. Altered DNA methylation was confirmed in blood and lymph node CD4 + T cells in viremic macaques but was notably absent from SIV controller macaques. Our study identified key genes differentially methylated already in primary infection and in tissues that could contribute to the persisting metabolic disorders and inflammation in HIV-infected individuals despite effective treatment. Show less
Mbow, M.; Lell, B.; Jochems, S.P.; Cisse, B.; Mboup, S.; Dewals, B.G.; ... ; Yazdanbakhsh, M. 2020
Schistosomiasis treatment relies on the use of a single drug, praziquantel, which is insufficient to control transmission in highly endemic areas(1). Novel medicines and vaccines are urgently... Show moreSchistosomiasis treatment relies on the use of a single drug, praziquantel, which is insufficient to control transmission in highly endemic areas(1). Novel medicines and vaccines are urgently needed(2,3). An experimental human model for schistosomiasis could accelerate the development of these products. We performed a dose-escalating clinical safety trial in 17 volunteers with male Schistosoma mansoni cercariae, which do not produce eggs (clinicaltrials.gov ), at the Leiden University Medical Center, the Netherlands. The primary endpoints were adverse events and infectivity. We found a dose-related increase in adverse events related to acute schistosomiasis syndrome, which occurred in 9 of 17 volunteers. Overall, 5 volunteers (all 3 of the high dose group and 2 of 11 of the medium dose group) reported severe adverse events. Worm-derived circulating anodic antigen, the biomarker of the primary infection endpoint, peaked in 82% of volunteers at 3-10 weeks following exposure. All volunteers showed IgM and IgG1 seroconversion and worm-specific cytokine production by CD4(+) T cells. All volunteers were cured with praziquantel provided at 12 weeks after exposure. Infection with 20 Schistosoma mansoni cercariae led to severe adverse events in 18% of volunteers and high infection rates. This infection model paves the way for fast-track product development for treatment and prevention of schistosomiasis.A new human challenge model of schistosomiasis, which affects more than 290 million people globally, will aid development of novel therapies and vaccines for this neglected tropical disease. Show less
