Infection of the genitourinary tract with Group B Streptococcus (GBS), an opportunistic gram positive pathogen, is associated with premature rupture of amniotic membrane and preterm birth. In this work, we demonstrate that GBS produces membrane vesicles (MVs) in a serotype independent manner. These MVs are loaded with virulence factors including extracellular matrix degrading proteases and pore forming toxins. Mice chorio-decidual membranes challenged with MVs ex vivo resulted in extensive collagen degradation leading to loss of stiffness and mechanical weakening. MVs when instilled vaginally are capable of anterograde transport in mouse reproductive tract. Intra-amniotic injections of GBS MVs in mice led to upregulation of pro-inflammatory cytokines and inflammation mimicking features of chorio-amnionitis; it also led to apoptosis in the chorio-decidual tissue. Instillation of MVs in the amniotic sac also resulted in intrauterine fetal death and preterm delivery. Our findings suggest that GBS MVs can independently orchestrate events at the feto-maternal interface causing chorio-amnionitis and membrane damage leading to preterm birth or fetal death. Preterm birth is a major health concern globally as it is not only a leading cause of neonatal death, but also has long term consequences including defective brain development. Infection of vagina and cervix of pregnant women with the bacteria, Group B Streptococcus (GBS), causes chorio-amnionitis that significantly increases the probability of preterm births. We report that, GBS produces small extracellular membrane vesicles (MVs) which are toxic to both fetal and maternal cells. In animal studies, we found that the MVs disrupt the connective tissue of the fetal membrane reducing its mechanical strength which may cause premature rupture of amniotic sac. Further we show that even in absence of the bacteria, the MVs directly led to extensive inflammation in the mouse resulting in chorio-amnionitis, preterm births and still births. Collectively, our findings reveal how GBS while colonizing the lower genitourinary tract might orchestrate events at the fetal membrane leading to premature birth.

A protective vaccine against human immunodeficiency virus (HIV) will likely need to induce broadly neutralizing antibodies (bnAbs) that engage relatively conserved epitopes on the HIV envelope glycoprotein (Env) trimer. Nearly all vaccine strategies to induce bnAbs require the use of complex immunization regimens involving a series of different immunogens, most of which are Env trimers. Producing protein-based clinical material to evaluate such relatively complex regimens in humans presents major challenges in cost and time. Furthermore, immunization with HIV trimers as soluble proteins induces strong nonneutralizing responses to the trimer base, which is normally occluded on the virion. These base responses could potentially detract from the elicitation of nAbs and the eventual induction of bnAbs. mRNA vaccine platforms offer potential advantages over protein delivery for HIV vaccine development, including increased production speed, reduced cost, and the ability to deliver membrane-bound trimers that might facilitate improved immuno-focusing to nonbase epitopes. We report the design of mRNA-delivered soluble and membrane-bound forms of a stabilized native-like Env trimer (BG505 MD39.3); initial immunogenicity evaluation in rabbits that triggered clinical evaluation; and more comprehensive evaluation of B cell, T cell, and antibody responses in nonhuman primates. mRNA-encoded membrane-bound Env immunization elicited reduced off-target base-directed Env responses and stronger nAb responses compared with mRNA-encoded soluble Env. Overall, mRNA delivery of membrane-bound Env appears promising for enhancing B cell responses to subdominant epitopes and facilitating rapid translation to clinical testing, which should assist HIV vaccine development.

Dual stimuli pH and temperature-responsive nanohydrogels based on poly(N-isopropylacrylamide)-chitosan have been synthesized. Fe₃O₄ magnetic nanoparticles (NPs) (∼12 nm) have been incorporated into hydrogels to achieve temperature optimized magnetic nanohydrogel (MNHG) for magnetic hyperthermia with lower critical solution temperature, LCST >42 °C. The composite was further investigated for its potential application in drug delivery and in vitro cancer cell cytotoxicity. Waterbath assisted drug release studies were carried out using anti-cancer drug doxorubicin (DOX) in acetate buffer medium (pH ∼ 4.6) to mimic tumor cell environment which is slightly acidic in nature. The pH and temperature responsiveness of the system was demonstrated by DOX release under different conditions. The released amount of DOX was found to be nearly 4 μg/mg above hyperthermia temperature (∼42 °C) as opposed to only 1.9 μg/mg of MNHG at physiological temperature (37 °C) under acidic environment (pH ∼ 4.6). Further, AC magnetic field (AMF) induced heating of NPs entrapped inside hydrogels showed appreciable reduction of cell population in human breast (MCF-7) and cervical carcinoma (HeLa) cell lines for given duration of field exposures. Quantitatively, death percentages of HeLa cells were nearly 35 and 45% while for MCF-7, these were 20 and 70% when exposed to AMF for 10 and 30 min, respectively. Further the cell killing efficacy of MNHG loaded with DOX was assessed under AMF using HeLa cell lines. The AMF induced heat triggered DOX release from the MNHG which enhances the cell death up to 85% due to combined effect of thermo-chemotherapeutics. The present system with both pH and temperature responsivity serves as a promising candidate for a combination therapy.

Type I interferons (IFN-I) are critical mediators of innate control of viral infections but also drive the recruitment of inflammatory cells to sites of infection, a key feature of severe coronavirus disease 2019. Here, IFN-I signaling was modulated in rhesus macaques (RMs) before and during acute SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection using a mutated IFN-α2 (IFN-modulator; IFNmod), which has previously been shown to reduce the binding and signaling of endogenous IFN-I. IFNmod treatment in uninfected RMs was observed to induce a modest up-regulation of only antiviral IFN-stimulated genes (ISGs); however, in SARS-CoV-2–infected RMs, IFNmod reduced both antiviral and inflammatory ISGs. IFNmod treatment resulted in a potent reduction in SARS-CoV-2 viral loads both in vitro in Calu-3 cells and in vivo in bronchoalveolar lavage (BAL), upper airways, lung, and hilar lymph nodes of RMs. Furthermore, in SARS-CoV-2–infected RMs, IFNmod treatment potently reduced inflammatory cytokines, chemokines, and CD163 ⁺ MRC1 ⁻ inflammatory macrophages in BAL and expression of Siglec-1 on circulating monocytes. In the lung, IFNmod also reduced pathogenesis and attenuated pathways of inflammasome activation and stress response during acute SARS-CoV-2 infection. Using an intervention targeting both IFN-α and IFN-β pathways, this study shows that, whereas early IFN-I restrains SARS-CoV-2 replication, uncontrolled IFN-I signaling critically contributes to SARS-CoV-2 inflammation and pathogenesis in the moderate disease model of RMs.