BACKGROUND:Although BCG provides protection against severe forms of tuberculosis in children, its efficacy against pulmonary tuberculosis in adolescents and adults is highly variable, and it offers limited and inconsistent protection against infection and transmission. VPM1002 is a recombinant BCG vaccine that showed manageable toxicity and immunogenicity in phase 1 trials in adults and in phase 2 trials in South African newborns. We compared VPM1002 with BCG for the prevention of Mycobacterium tuberculosis infection in infants. METHODS:This double-blind, randomised, active-controlled, phase 3 trial was conducted at ten main sites and four satellite sites in sub-Saharan Africa, ranging from rural to urban settings, with experience in tuberculosis trials. Healthy newborn infants, aged 0-14 days and with a birthweight of at least 2·3 kg, were randomly assigned (1:1) to receive single 0·05 mL doses of either VPM1002 or BCG, administered intradermally. Follow-up was extended from 36 months up to 48 months (due to the lower than expected event rate) or until 632 cases of M tuberculosis had accrued. The randomisation was done centrally through an interactive web response system and allocation was stratified by maternal HIV status at a 1:10 ratio, using a permuted block design with variable block sizes. Only the site personnel involved in preparation and administration of the vaccines were not masked to the trial. Mothers were aged 18 years or older, free from active tuberculosis, and without household contact with an individual with tuberculosis within the 3 months before enrolment. Neonates were excluded for any fever, acute or chronic illness, congenital malformation, substantial skin lesion or infection at the site of injection, or previous receipt of routine BCG vaccination. The primary endpoint was non-inferiority of VPM1002 versus BCG for prevention of M tuberculosis infection, defined by incident QuantiFERON-TB Gold Plus (QFT; an interferon-γ release assay [IGRA]) conversion, assessed every 6 months from month 6 until the final visit and more frequently in suspected cases of tuberculosis. In the time-to-event efficacy analysis, participants with missing event occurrence data were censored at the last timepoint for which there was no clear evidence of the event occurrence. The primary efficacy analysis was in the per-protocol population (randomly assigned, vaccinated participants with at least one post-vaccination result and no major efficacy-relevant protocol deviations) with a supportive intention-to-treat analysis of all randomly assigned participants; both were analysed as assigned. As estimates were concordant, intention-to-treat results are presented. Safety was analysed as treated in all vaccinated participants. Non-inferiority required the upper bound of the 95% CI for the hazard ratio (HR) to be less than 1·25. The trial was registered on ClinicalTrials.gov (NCT04351685) and PACTR (PACTR202007868402718) and is complete. FINDINGS:Between Nov 9, 2020, and June 21, 2022, we enrolled 6950 infants. The trial was terminated early in October, 2024, due to a lower than expected QFT conversion rate. After the withdrawal of ten infants, 6940 were randomly assigned to treatment, including 720 infants born to mothers living with HIV and 6220 HIV-unexposed infants. Overall, 3449 male and 3491 female infants were included in the intention-to-treat population. 6897 infants received vaccination (3452 received VPM1002 and 3445 received BCG). Median follow-up was 35 months (IQR 30-38). QFT conversion occurred in 184 (5·3%) of 3471 infants in the VPM1002 group and 150 (4·3%) of 3469 infants in the BCG group. Cox proportional hazards regression analysis (VPM1002 vs BCG) revealed VPM1002 was not non-inferior to BCG, with an HR of 1·23 (95% CI 0·99-1·53). Adverse event profiles, including serious adverse events and deaths, were similar between groups; no vaccine-related serious adverse events were reported. INTERPRETATION:VPM1002 did not show non-inferiority to BCG on the primary endpoint of QFT conversion. Because fewer infections occurred than expected (334 of 632 planned events, despite extending the duration to 48 months), the trial did not have sufficient statistical certainty to definitively compare the two vaccines. Moreover, discordance between the QFT surrogate and confirmed tuberculosis endpoints, approximately 33·0% higher household tuberculosis exposure in the VPM1002 group, and violation of the proportional hazards assumption when tuberculosis exposure was included as a covariate (that is, the effect of tuberculosis exposure on QFT conversion was not constant over time, precluding reliable HR estimation without penalised modelling) collectively add to this uncertainty. Both vaccines showed similar adverse event profiles. These findings highlight challenges in using IGRA-defined infection endpoints in infant vaccine trials. FUNDING:European and Developing Countries Clinical Trials Partnership 2 (EDCTP2) programme (RIA2016V-1645-priMe), supported by the European Union and co-funded by Deutsches Zentrum für Luft- und Raumfahrt (DLR) and the European Investment Bank (EIB).

Despite the crucial roles of GATA-3 in lymphocyte biology, little is known about its intracellular distribution and the mechanisms regulating its nuclear import. Single-cell analyses on confocal microscopy images revealed that GATA-3 was enriched in the nucleus of naive and T helper (Th)2 cells, whereas Th1 cells preferentially accumulated it in the cytoplasm. This GATA-3 compartmentalization was mirrored in innate lymphoid cells ex vivo. In vitro or in vivo reprogramming of Th1 and Th2 cells reversed the subset-specific GATA-3 localization and triggered the acquisition or loss of GATA-3-dependent effector functions, respectively. We identified importin-β as the transporter mediating GATA-3's nuclear import. In Th2 cells, the subtle cytoplasmic accumulation of GATA-3 following importin-β blockade disrupted the GATA-3 autoactivation loop and impeded type 2 cell features. This sensitivity was explained by the prompt nuclear degradation of GATA-3, thus emphasizing that Th2 cell function depends on continuous and maximal nuclear import of GATA-3. Our results highlight the control of GATA-3 import into the nucleus as a fundamental rheostat of lymphocyte biology.

Über Akzeptanz oder Abstoßung von Transplantaten entscheiden bestimmte Antigene, die vom Haupthistokompatibilitätskomplex (»major histocompatibility complex«, MHC) kodiert werden. Die Hauptaufgabe des MHC besteht darin, T-Zellen antigene Peptide zu präsentieren. Der MHC des Menschen wird als HLA-Komplex bezeichnet (Maus: H-2-Komplex). HLA ist die Abkürzung für »humane Leukozytenantigene«. Diese Antigene wurden beim Menschen als Transplantationsantigene erstmals auf Leukozyten gefunden. H-2 steht für das bei Mäusen schon früh als besonders wichtig für die Abstoßungsreaktion erkannte Antigen 2.

Tuberculosis (TB) remains a leading global cause of death, with approximately 1.3 million fatalities annually. While males are more susceptible to TB, the underlying immune differences and their impact on vaccine efficacy are not fully understood. In this study, we vaccinated male and female C57BL/6 mice with BCG and 2 recombinant derivatives, VPM1002 and BCGΔBCG1419c, and assessed their protection against Mycobacterium tuberculosis (Mtb) HN878. While all 3 vaccines showed comparable efficacy in females, BCG did not protect males from Mtb-induced death. Instead, recombinant vaccines provided improved protection in males. Vaccination of males with BCGΔBCG1419c, but not BCG, enhanced CD8 T-cell and B-cell recall responses in vaccine-draining lymph nodes, and reduced lung inflammation after Mtb challenge. These findings underscore the impact of sex differences on vaccine efficacy and suggest that future research should consider sex as a biological variable to optimize TB vaccination strategies.

Der Nachweis von Antigenen oder Serumantikörpern spielt in der medizinischen Diagnostik eine bedeutende Rolle. Folgende Erscheinungen zeigen eine abgelaufene Antigen-Antikörper-Reaktion an:

Eine Gruppe von Lymphozyten erlangt ihre biologische Funktionsfähigkeit durch Reifung im Thymus. Man bezeichnet diese Zellen als T-Lymphozyten. Die T-Lymphozyten stellen die zentrale Schaltstelle der erworbenen Immunantwort dar. Die wichtigsten, durch T-Zellen vermittelten Effektorfunktionen sind in ◘ Tab. 12.1 dargestellt. Sie werden zusammenfassend als zelluläre Immunität bezeichnet. Die Benennung soll darauf hinweisen, dass bei diesen Prozessen T-Zellen in entscheidendem Maße beteiligt sind, wenn auch eine untergeordnete Rolle von B-Lymphozyten und deren Antikörpern nicht ausgeschlossen wird. Andererseits wirken bei der humoralen Antwort in der Regel auch T-Lymphozyten mit. Eine scharfe Trennung zwischen humoraler und zellvermittelter Immunität ist deshalb nicht möglich. Beide Funktionsbereiche sind miteinander verzahnt.

Antikörper oder Immunglobuline sind die Ver mittler der erworbenen humoralen Immunantwort. Sie werden von Plasmazellen gebildet, die sich aus B-Lymphozyten entwickeln. Eine Plasmazelle produziert Antikörper einer Spezifität und einer Klasse. Gedächtnis-B-Zellen bauen nach Zweitkontakt mit dem Antigen eine stärkere Immun ant wort auf.

Tuberculosis (TB) remains a threat for human and livestock health. Mycobacteria causing TB are host-adapted pathogens that occasionally spill over into other species. Mycobacterium bovis causes bovine TB, a well-known zoonosis. Mycobacterium tuberculosis is adapted to humans and can occasionally trigger symptomatic infection in cattle. However, immunocompetent cattle are resistant to experimental infection with M. tuberculosis. Hallmarks of TB in susceptible hosts are organized multicellular tissue lesions termed granulomas. In the absence of suitable in vitro systems that enable investigations of bovine tuberculous granuloma, we developed a three-dimensional granuloma model using bovine leukocytes and magnetic cell labeling. This model was termed the in vitro granuloma-like structure (IVGLS). We generated stable IVGLS resembling TB granulomas at the innate stage, composed of macrophages, and at adaptive stages, containing lymphocytes in addition. M. bovis Bacillus Calmette-Guérin (BCG) replicated within IVGLS and triggered the progression of macrophages to foamy phenotypes. Within the IVGLS, the lymphocytes accelerated BCG-induced apoptotic cell death over time. IVGLS released abundant chemoattractants and Th1-associated cytokines and adopted a glycolytically polarized metabolism. Magnetic bioprinted bovine granulomas recapitulate features of TB granulomas and thus facilitate the study of immune responses to mycobacteria, including spatial and temporal mapping, as well as establishing precise cell death patterns within multicellular microenvironments. Deciphering protective immune responses within IVGLS can contribute to vaccine development for bovine TB, and elucidation of resistance mechanisms can facilitate the design of novel interventions for human TB. IMPORTANCE:Mycobacterial infections, including bovine tuberculosis (TB), have a profound impact on global health. This is exemplified by zoonotic TB in humans and animal TB, which is a life-threatening disease in livestock and wildlife. Mycobacteria cause the formation of granulomas, which significantly impact disease progression. Therefore, decoding granulomas is essential for an in-depth understanding of immune responses to mycobacteria. Conventional mouse models frequently fail to develop organized granulomas, and the procurement of samples from granulomatous lesions in cattle and humans is challenging, offering limited insights into the course of infection. Most in vitro TB research is confined to two-dimensional cell cultures, which neglect the spatial characteristics and cellular architecture of granulomas in vivo. To address this gap in knowledge, we have developed a novel multicellular in vitro model for TB. Our spheroid granuloma model, derived from bovine leukocytes using nanotechnologies, offers an adaptable platform for deciphering immune events within granulomas.

Das Überstehen einer Infektionskrankheit verleiht dem Genesenen häufig Schutz vor deren Wiederholung. Wer einmal an Masern erkrankte, ist für den Rest seines Lebens masernunempfänglich. Diese Eigenschaft ist nicht angeboren, sondern erworben: Jeder Mensch ist nach seiner Geburt empfänglich für Masern; die Resistenz entsteht erst durch die Krankheit selbst. Hierfür ist das Immunsystem zuständig.

Die Zellen des Immunsystems werden in den primären Immunorganen gebildet und halten sich bevorzugt in den sekundären Immunorganen auf. Immunzellen erreichen über die Blut- und Lymphgefäße fast alle Körperteile und gelangen von dort zurück zu den Immunorganen. Als primäre Organe betrachtet man das Knochenmark und den Thymus, als sekundäre Organe gelten Milz, Lymphknoten und diffuses Lymphgewebe.

ABSTRACT The Bacillus Calmette–Guérin (BCG) vaccine is the oldest cancer immunotherapeutic agent in use. Despite its effectiveness, its initial mechanisms of action remain largely unknown. Here, we elucidate the earliest cellular mechanisms involved in BCG-induced tumor clearance. We developed a fast preclinical in vivo assay to visualize in real time and at single-cell resolution the initial interactions among bladder cancer cells, BCG and innate immunity using the zebrafish xenograft model. We show that BCG induced the recruitment and polarization of macrophages towards a pro-inflammatory phenotype, accompanied by induction of the inflammatory cytokines tnfa, il1b and il6 in the tumor microenvironment. Macrophages directly induced apoptosis of human cancer cells through zebrafish TNF signaling. Macrophages were crucial for this response as their depletion completely abrogated the BCG-induced phenotype. Contrary to the general concept that macrophage anti-tumoral activities mostly rely on stimulating an effective adaptive response, we demonstrate that macrophages alone can induce tumor apoptosis and clearance. Thus, our results revealed an additional step to the BCG-induced tumor immunity model, while providing proof-of-concept experiments demonstrating the potential of this unique model to test innate immunomodulators.

ABSTRACTActivin A strongly influences immune responses; yet, few studies have examined its role in infectious diseases. We measured serum activin A levels in two independent tuberculosis (TB) patient cohorts and in patients with pneumonia and sarcoidosis. Serum activin A levels were increased in TB patients compared to healthy controls, including those with positive tuberculin skin tests, and paralleled severity of disease, assessed by X-ray scores. In pneumonia patients, serum activin A levels were also raised, but in sarcoidosis patients, levels were lower. To determine whether blockade of the activin A signaling axis could play a functional role in TB, we harnessed a soluble activin type IIB receptor fused to human IgG1 Fc, ActRIIB-Fc, as a ligand trap in a murine TB model. The administration of ActRIIB-Fc to Mycobacterium tuberculosis-infected mice resulted in decreased bacterial loads and increased numbers of CD4 effector T cells and tissue-resident memory T cells in the lung. Increased frequencies of tissue-resident memory T cells corresponded with downregulated T-bet expression in lung CD4 and CD8 T cells. Altogether, the results suggest a disease-exacerbating role of ActRIIB signaling pathways. Serum activin A may be useful as a biomarker for diagnostic triage of active TB or monitoring of anti-tuberculosis therapy.IMPORTANCETuberculosis remains the leading cause of death by a bacterial pathogen. The etiologic agent of tuberculosis, Mycobacterium tuberculosis, can remain dormant in the infected host for years before causing disease. Significant effort has been made to identify biomarkers that can discriminate between latently infected and actively diseased individuals. We found that serum levels of the cytokine activin A were associated with increased lung pathology and could discriminate between active tuberculosis and tuberculin skin-test-positive healthy controls. Activin A signals through the ActRIIB receptor, which can be blocked by administration of the ligand trap ActRIIB-Fc, a soluble activin type IIB receptor fused to human IgG1 Fc. In a murine model of tuberculosis, we found that ActRIIB-Fc treatment reduced mycobacterial loads. Strikingly, ActRIIB-Fc treatment significantly increased the number of tissue-resident memory T cells. These results suggest a role for ActRIIB signaling pathways in host responses to Mycobacterium tuberculosis and activin A as a biomarker of ongoing disease.

Carl Flügge is best known for the promotion of studies demonstrating the transmission of all manner of infections, but particularly tuberculosis, by coughed droplets. But it is seldom recognised that Flügge was also influential in a number of other fields comprising the practice of hygiene. One-hundred years following his death in 1923, we review literature related to the studies of Flügge and his colleagues and students and illustrate the particular emphasis he laid upon the environment within which disease and its transmission might be fostered or prevented, embracing and studying aspects essential to the health of any community ranging from fundamental microbiology in the laboratory to subjects as disparate as housing, clean water supply, nutrition, sanitation, socio-economic circumstances and climate. Very early in his career he promoted breast feeding for the prevention of seasonal gastro-enteritis and later the sheltering of cough as a means of preventing the transmission of infected respiratory droplets, not only as regards tuberculosis, but also concerning all manner of other respiratory infections. By the time of Flügge's death the complexification of available scientific methodologies comprising hygiene made it difficult for any individual to comprehend and study the wide range of hygiene-related subjects such as Flügge did. Carl Flügge was one of the last holistic hygienists and an originator of the study of environmental health as a pillar of hygiene.

Host-microorganism encounters take place in many different ways and with different types of outcomes. Three major types of microorganisms need to be distinguished: (1) pathogens that cause harm to the host and must be controlled; (2) environmental microorganisms that can be ignored but must be controlled at higher abundance; and (3) symbiotic microbiota that require support by the host. Recent evidence indicates that the aryl hydrocarbon receptor (AHR) senses and initiates signalling and gene expression in response to a plethora of microorganisms and infectious conditions. It was originally identified as a receptor that binds xenobiotics. However, it was subsequently found to have a critical role in numerous biological processes, including immunity and inflammation and was recently classified as a pattern recognition receptor. Here we review the role of the AHR in host-pathogen interactions, focusing on AHR sensing of different microbial classes, the ligands involved, responses elicited and disease outcomes. Moreover, we explore the therapeutic potential of targeting the AHR in the context of infection.

The mononuclear phagocyte system includes monocytes, macrophages, some dendritic cells, and multinuclear giant cells. These cell populations display marked heterogeneity depending on their differentiation from embryonic and bone marrow hematopoietic progenitors, tissue location, and activation. They contribute to tissue homeostasis by interacting with local and systemic immune and non-immune cells through trophic, clearance, and cytocidal functions. During evolution, they contributed to the innate host defense before effector mechanisms of specific adaptive immunity emerged. Mouse macrophages appear at mid-gestation and are distributed throughout the embryo to facilitate organogenesis and clear cells undergoing programmed cell death. Yolk sac, AGM, and fetal liver-derived tissue-resident macrophages persist throughout postnatal and adult life, supplemented by bone marrow-derived blood monocytes, as required after injury and infection. Nobel awards to Elie Metchnikoff and Paul Ehrlich in 1908 drew attention to cellular phagocytic and humoral immunity, respectively. In 2011, prizes were awarded to Jules Hoffmann and Bruce Beutler for contributions to innate immunity and to Ralph Steinman for the discovery of dendritic cells and their role in antigen presentation to T lymphocytes. We trace milestones in the history of mononuclear phagocyte research from the perspective of Nobel awards bearing directly and indirectly on their role in cellular immunity.

Deeper understanding of the crosstalk between host cells and Mycobacterium tuberculosis (Mtb) provides crucial guidelines for the rational design of novel intervention strategies against tuberculosis (TB). Mycobacteria possess a unique complex cell wall with arabinogalactan (AG) as a critical component. AG has been identified as a virulence factor of Mtb which is recognized by host galectin-9. Here, we demonstrate that galectin-9 directly inhibited mycobacterial growth through AG-binding property of carbohydrate-recognition domain 2. Furthermore, IgG antibodies with AG specificity were detected in the serum of TB patients. Based on the interaction between galectin-9 and AG, we developed a monoclonal antibody (mAb) screening assay and identified AG-specific mAbs which profoundly inhibit Mtb growth. Mechanistically, proteomic profiling and morphological characterizations revealed that AG-specific mAbs regulate AG biosynthesis, thereby inducing cell wall swelling. Thus, direct AG-binding by galectin-9 or antibodies contributes to protection against TB. Our findings pave the way for the rational design of novel immunotherapeutic strategies for TB control.

Goats are natural hosts of Mycobacterium (M.) bovis, and affected herds can be the cause of significant economic losses. Similarites in disease course and lesions of M. bovis infections in goats and M. tuberculosis in humans make goats good models for human tuberculosis. The aim of this investigation was to characterize M. bovis challenge models in goats. For this, goats were endobronchially inoculated with three doses of M. bovis or culture medium. Clinical signs, shedding, and immune responses were monitored until 146 days post inoculation (dpi). At necropsy, lesions were examined by computed tomography, histology, and bacteriological culture. Infected goats did not develop clinical signs. M. bovis was cultured from feces, but never from nasal swabs. IGRAs were positive from 28 dpi onwards, antibodies at 140 dpi, and SICCT at 146 dpi. The increase in CD25+, IFN-γ+, and IFN-γ-releasing T-cell subpopulations was time-related, but not dose-dependent. All infected goats developed paucibacillary granulomas in the lungs and regional lymph nodes. M. bovis was regularly cultured. Dose-dependent effects included the size of pulmonary lesions, caverns, intestinal lesions, and early generalization in the high-dose group. In summary, reproducible challenge models with dose-dependent differences in lesions were established, which may serve for testing vaccines for veterinary or medical use.