Compartmentalized T cell profile in the lungs of patients with HIV-1-associated pulmonary Kaposi sarcoma.

Pulmonary Kaposi sarcoma (pKS) caused by Human herpesvirus 8 (HHV-8) is a devastating form of KS in patients with advanced acquired immunodeficiency syndrome (AIDS) and is associated with increased morbidity and mortality. Blood T cells play a central role in the response of HIV-1 and HHV-8. However, little information is available on T cells in the alveolar space of HIV-1-associated pKS patients.Therefore, we examined CD8+ and CD4+ T cells in the alveolar space in comparison with the blood of patients with pKS. We recruited 26 HIV-1 positive patients with KS, including 15 patients with pKS. Bronchoalveolar lavage (BAL) cells and blood mononuclear cells were analyzed for T cell memory phenotypes, surface markers associated with exhaustion, and intracellular cytokine staining (ICS) using flow cytometry. HIV-1 and HHV-8 viral loads were measured in plasma by quantitative PCR.BAL T cells showed reduced inflammatory capacities and significantly diminished polyfunctionality compared to blood T cells from patients with pKS. This was not accompanied by increased expression of exhaustion markers, such as TIM-3 and PD-1.More importantly, we found a negative correlation between the production of MIP1-β and TNF-α in T cells in BAL and blood, indicating compartmentalised immune responses to pKS and accentuated chronic HIV-1/HHV-8 pathogenesis via T cells in the lungs of people with pKS

Early type I Interferon response induces upregulation of human β-defensin 1 during acute HIV-1 infection

HIV-1 is able to evade innate antiviral responses during acute infection to establish a chronic systemic infection which, in the absence of antiretroviral therapy (ART), typically progresses to severe immunodeficiency. Understanding these early innate immune responses against HIV-1 and their mechanisms of failure is relevant to the development of interventions to better prevent HIV-1 transmission. Human beta defensins (HBDs) are antibacterial peptides but have recently also been associated with control of viral replication. HBD1 and 2 are expressed in PBMCs as well as intestinal tissue, but their expression in vivo during HIV-1 infection has not been characterized. We demonstrate that during acute HIV-1 infection, HBD1 but not HBD2 is highly upregulated in circulating monocytes but returns to baseline levels during chronic infection. HBD1 expression in monocytes can be induced by HIV-1 in vitro, although direct infection may not entirely account for the increase in HBD1 during acute infection. We provide evidence that HIV-1 triggers antiviral IFN-α responses, which act as a potent inducer of HBD1. Our results show the first characterization of induction of an HBD during acute and chronic viral infection in humans. HBD1 has been reported to have low activity against HIV-1 compared to other defensins, suggesting that in vivo induced defensins may not significantly contribute to the robust early antiviral response against HIV-1. These data provide important insight into the in vivo kinetics of HBD expression, the mechanism of HBD1 induction by HIV-1, and the role of HBDs in the early innate response to HIV-1 during acute infection

Phosphatidylinositolmannoside vaccination induces lipid-specific Th1-responses and partially protects guinea pigs from Mycobacterium tuberculosis challenge

Abstract The concept of donor-unrestricted T cells (DURTs) comprises a heterogeneity of lymphoid cells that respond to an abundance of unconventional epitopes in a non-MHC-restricted manner. Vaccinologists strive to harness this so far underexplored branch of the immune system for new vaccines against tuberculosis. A particular division of DURTs are T cells that recognize their cognate lipid antigen in the context of CD1-molecules. Mycobacteria are characterized by a particular lipid-rich cell wall. Several of these lipids have been shown to be presented to T cells via CD1b-molecules. Guinea pigs functionally express CD1b and are hence an appropriate small animal model to study the role of CD1b-restricted, lipid-specific immune responses. In the current study, guinea pigs were vaccinated with BCG or highly-purified, liposome-formulated phosphatidylinositol-hexa-mannoside (PIM6) to assess the effect of CD1-restricted DURTs on the course of infection after virulent Mycobacterium tuberculosis (Mtb) challenge. Robust PIM6-specific T cell-responses were observed both after BCG- and PIM6-vaccination. The cellular response was significantly reduced in the presence of monoclonal, CD1b-blocking antibodies, indicating that a predominant part of this reactivity was CD1b-restricted. When animals were challenged with Mtb, BCG- and PIM6-vaccinated animals showed significantly reduced pathology, smaller necrotic granulomas in lymph node and spleen and reduced bacterial loads. While BCG conferred an almost sterile protection in this setting, compared to control animals’ lesions were reduced roughly by two thirds in PIM6-vaccinated. Comprehensive histological and transcriptional analyses in the draining lymph node revealed that protected animals showed reduced transcription-levels of inflammatory cyto- and chemokines and higher levels of CD1b-expression on professional antigen cells compared to controls. Although BCG as a comparator induced by far stronger effects, our observations in the guinea pig model suggest that CD1b-restricted, PIM6-reactive DURTs contribute to immune-mediated containment of virulent Mtb

HBD1 is expressed by circulating monocytes and gut epithelial cells.

<p>(A, B) Cells were sorted from 5 different bulk colon excess tissue (n = 5) or PBMCs (n = 5), RNA extracted and HBD1 transcription quantified by qPCR. For colon, epithelial cells were identified using the surface marker CD326 and CD45 (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173161#pone.0173161.s002" target="_blank">S2 Fig</a>). For PBMCs, monocytes were identified as CD14+, DCs as CD11c+ (mDCs) or CD123+ (pDCs) and lymphocytes as CD3+CD19+ (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173161#pone.0173161.s002" target="_blank">S2 Fig</a>). Epithelial cells were the main producers of HBD1 in colon whereas CD14+ cells were the main producers in PBMCs. (C, D) The frequency of HBD1 producing cells is not altered during acute infection. Frequency of monocytes (C) and DC (D) populations in PMBCs from HIV-1- (n = 9) or acutely (Acute; n = 8) infected individuals was determined by flow cytometry. Conventional monocytes were identified as CD14+ CD16-, inflammatory monocytes as CD14+ CD16+ and mDCs as well as pDCs as described above (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173161#pone.0173161.s002" target="_blank">S2 Fig</a>). No significant difference in cell frequencies was found between HIV-1- and sample from subjects with acute HIV-1 infection for any of the analyzed cell populations (Kruskal-Wallis and Dunn’s multiple post comparison test). (A-D) Data points are presented with median and interquartile range.</p

HIV-1 induces HBD1 <i>in vitro</i> but is unlikely to be sufficient <i>in vivo</i>.

<p>(A-C) CD14+ monocytes isolated using Miltenyi MACS technology were incubated with either HIV-1 R5, poly I:C (TLR3 ligand), 5’ppp-dsRNA (RIG-I ligand), R837 (TLR7 ligand), LPS (TLR4 ligand) or FLA-ST (TLR5 ligand), or left untreated. After 24 h cells were harvested and RNA extracted. Relative expression of HBD1 (A, C) or HBD2 (B) was assessed using quantitative PCR. HBD1 expression was found to be significantly increased in monocytes when incubated with HIV-1 R5, poly I:C or 5’pppdsRNA (A), whereas LPS and FLA-ST induced HBD2 (B). (C) Significant upregulation of HBD1 by HIV-1 was only achieved at 1x10^6 infection HIV-1 particles (i.p.) (Kruskal-Wallis and Dunn’s multiple post comparison test). Data points are presented with median and interquartile range which each dot representing an independent experiment from a different healthy control subject. (D) HBD1 transcription in PBMCs of subjects with acute HIV-1 infection (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0173161#pone.0173161.g001" target="_blank">Fig 1A</a>) was plotted against the corresponding viral load which each dot representing one subject. No significant correlation was found between viral load and HBD1 transcription (Spearman r correlation). (E, F) CD4+ T cells or CD14+ monocytes were isolated from PBMCs and incubated with either β-lactamase packaged HIV-1 X4 (CXCR4 tropic)/ HIV-1 R5 (CCR5 tropic) or left untreated. Where indicated cells were pre-treated with the CCR5 antagonist maraviroc (Mav) for 30min before HIV-1 treatment. All virus contained Vpr-BlaM which allowed assessment of HIV-1 entry into cells 12h after exposure. The highest entry was observed in CD4+ T cells by HIV-1 X4, whereas HIV-1 R5 entered CD4+ T cells as well CD14+ monocytes at low frequency. The graph shows the median and interquartile range with each dot representing one independent experiment from a different healthy control subject (F).</p

Assessment of Immunogenicity and Efficacy of CV0501 mRNA-Based Omicron COVID-19 Vaccination in Small Animal Models

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron and its subvariants (BA.2, BA.4, BA.5) represented the most commonly circulating variants of concern (VOC) in the coronavirus disease 2019 (COVID-19) pandemic in 2022. Despite high vaccination rates with approved SARS-CoV-2 vaccines encoding the ancestral spike (S) protein, these Omicron subvariants have collectively resulted in increased viral transmission and disease incidence. This necessitates the development and characterization of vaccines incorporating later emerging S proteins to enhance protection against VOC. In this context, bivalent vaccine formulations may induce broad protection against VOC and potential future SARS-CoV-2 variants. Here, we report preclinical data for a lipid nanoparticle (LNP)-formulated RNActive® N1-methylpseudouridine (N1mΨ) modified mRNA vaccine (CV0501) based on our second-generation SARS-CoV-2 vaccine CV2CoV, encoding the S protein of Omicron BA.1. The immunogenicity of CV0501, alone or in combination with a corresponding vaccine encoding the ancestral S protein (ancestral N1mΨ), was first measured in dose-response and booster immunization studies performed in Wistar rats. Both monovalent CV0501 and bivalent CV0501/ancestral N1mΨ immunization induced robust neutralizing antibody titers against the BA.1, BA.2 and BA.5 Omicron subvariants, in addition to other SARS-CoV-2 variants in a booster immunization study. The protective efficacy of monovalent CV0501 against live SARS-CoV-2 BA.2 infection was then assessed in hamsters. Monovalent CV0501 significantly reduced SARS-CoV-2 BA.2 viral loads in the airways, demonstrating protection induced by CV0501 vaccination. CV0501 has now advanced into human Phase 1 clinical trials (ClinicalTrials.gov Identifier: NCT05477186)