Aberrant B cell repertoire selection associated with HIV neutralizing antibody breadth.

A goal of HIV vaccine development is to elicit antibodies with neutralizing breadth. Broadly neutralizing antibodies (bNAbs) to HIV often have unusual sequences with long heavy-chain complementarity-determining region loops, high somatic mutation rates and polyreactivity. A subset of HIV-infected individuals develops such antibodies, but it is unclear whether this reflects systematic differences in their antibody repertoires or is a consequence of rare stochastic events involving individual clones. We sequenced antibody heavy-chain repertoires in a large cohort of HIV-infected individuals with bNAb responses or no neutralization breadth and uninfected controls, identifying consistent features of bNAb repertoires, encompassing thousands of B cell clones per individual, with correlated T cell phenotypes. These repertoire features were not observed during chronic cytomegalovirus infection in an independent cohort. Our data indicate that the development of numerous B cell lineages with antibody features associated with autoreactivity may be a key aspect in the development of HIV neutralizing antibody breadth.

Maturation Pathway from Germline to Broad HIV-1 Neutralizer of a CD4-Mimic Antibody.

Antibodies with ontogenies from VH1-2 or VH1-46-germline genes dominate the broadly neutralizing response against the CD4-binding site (CD4bs) on HIV-1. Here, we define with longitudinal sampling from time-of-infection the development of a VH1-46-derived antibody lineage that matured to neutralize 90% of HIV-1 isolates. Structures of lineage antibodies CH235 (week 41 from time-of-infection, 18% breadth), CH235.9 (week 152, 77%), and CH235.12 (week 323, 90%) demonstrated the maturing epitope to focus on the conformationally invariant portion of the CD4bs. Similarities between CH235 lineage and five unrelated CD4bs lineages in epitope focusing, length-of-time to develop breadth, and extraordinary level of somatic hypermutation suggested commonalities in maturation among all CD4bs antibodies. Fortunately, the required CH235-lineage hypermutation appeared substantially guided by the intrinsic mutability of the VH1-46 gene, which closely resembled VH1-2. We integrated our CH235-lineage findings with a second broadly neutralizing lineage and HIV-1 co-evolution to suggest a vaccination strategy for inducing both lineages.

Viral receptor-binding site antibodies with diverse germline origins.

Vaccines for rapidly evolving pathogens will confer lasting immunity if they elicit antibodies recognizing conserved epitopes, such as a receptor-binding site (RBS). From characteristics of an influenza-virus RBS-directed antibody, we devised a signature motif to search for similar antibodies. We identified, from three vaccinees, over 100 candidates encoded by 11 different VH genes. Crystal structures show that antibodies in this class engage the hemagglutinin RBS and mimic binding of the receptor, sialic acid, by supplying a critical dipeptide on their projecting, heavy-chain third complementarity determining region. They share contacts with conserved, receptor-binding residues but contact different residues on the RBS periphery, limiting the likelihood of viral escape when several such antibodies are present. These data show that related modes of RBS recognition can arise from different germline origins and mature through diverse affinity maturation pathways. Immunogens focused on an RBS-directed response will thus have a broad range of B cell targets.

Cooperation of B cell lineages in induction of HIV-1-broadly neutralizing antibodies.

Development of strategies for induction of HIV-1 broadly neutralizing antibodies (bnAbs) by vaccines is a priority. Determining the steps of bnAb induction in HIV-1-infected individuals who make bnAbs is a key strategy for immunogen design. Here, we study the B cell response in a bnAb-producing individual and report cooperation between two B cell lineages to drive bnAb development. We isolated a virus-neutralizing antibody lineage that targeted an envelope region (loop D) and selected virus escape mutants that resulted in both enhanced bnAb lineage envelope binding and escape mutant neutralization-traits associated with increased B cell antigen drive. Thus, in this individual, two B cell lineages cooperated to induce the development of bnAbs. Design of vaccine immunogens that simultaneously drive both helper and broadly neutralizing B cell lineages may be important for vaccine-induced recapitulation of events that transpire during the maturation of neutralizing antibodies in HIV-1-infected individuals.

Pathological Interplay and Clinical Complications between COVID-19 and Cardiovascular Diseases: An Overview in 2023.

BACKGROUND: The coronavirus disease 2019 (COVID-19) involves all organs of the body, of which the interaction with cardiovascular diseases is the most important. SUMMARY: Numerous studies have reported that COVID-19 patients complicated with cardiovascular comorbidities (hypertension, coronary heart disease, chronic heart failure (HF), cerebrovascular disease) are more likely to develop into critical illness and have higher mortality. Conversely, COVID-19 may also cause myocardial injury in patients through various pathological mechanisms such as direct virus attack on cardiomyocytes, overactivation of immune response, microthrombus formation, which may lead to fatal acute ST-segment elevation myocardial infarction, arrhythmia, acute worsening of chronic HF, etc. In addition, the symptoms of the so-called long-COVID may remain in some patients who survived the acute viral infection. Positional tachycardia has been widely reported, and cardiovascular autonomic disorders are thought to play a pathogenic role. KEY MESSAGE: The review summarizes the interaction between COVID-19 and cardiovascular disease in terms of pathological mechanism, clinical features, and sequelae. Therapeutic and rehabilitation programs after COVID-19 infection are compiled and need to be further standardized in the future.

Frizzled receptors (FZDs) in Wnt signaling: potential therapeutic targets for human cancers.

Frizzled receptors (FZDs) are key contributors intrinsic to the Wnt signaling pathway, activation of FZDs triggering the Wnt signaling cascade is frequently observed in human tumors and intimately associated with an aggressive carcinoma phenotype. It has been shown that the abnormal expression of FZD receptors contributes to the manifestation of malignant characteristics in human tumors such as enhanced cell proliferation, metastasis, chemotherapy resistance as well as the acquisition of cancer stemness. Given the essential roles of FZD receptors in the Wnt signaling in human tumors, this review aims to consolidate the prevailing knowledge on the specific status of FZD receptors (FZD1-10) and elucidate their respective functions in tumor progression. Furthermore, we delineate the structural basis for binding of FZD and its co-receptors to Wnt, and provide a better theoretical foundation for subsequent studies on related mechanisms. Finally, we describe the existing biological classes of small molecule-based FZD inhibitors in detail in the hope that they can provide useful assistance for design and development of novel drug candidates targeted FZDs.

Perinatal outcomes and growth discordance of triplet pregnancies based on chorionicity: a retrospective cohort study.

BACKGROUND: The worldwide occurrence of triplet pregnancy is estimated to be 0.093%, with a natural incidence of approximately 1 in 8000. This study aims to analyze the neonatal health status and birth weight discordance (BWD) of triplets based on chorionicity from birth until discharge. METHODS: This was a retrospective study. We reviewed a total of 136 triplet pregnancies at our tertiary hospital between January 1, 2001, and December 31, 2021. Maternal and neonatal outcomes, inter-triplet BWD, neonatal morbidity, and mortality were analyzed. RESULTS: Among all cases, the rates of intrauterine death, neonatal death, and perinatal death were 10.29, 13.07, and 24.26%, respectively. Thirty-seven of the cases resulted in fetal loss, including 13 with fetal anomalies. The maternal complications and neonatal outcomes of the 99 triplet pregnancies without fetal loss were compared across different chorionicities, including a dichorionic (DC) group (41 cases), trichorionic (TC) group (37 cases), and monochorionic (MC) group (21 cases). Neonatal hypoproteinemia (P < 0.001), hyperbilirubinemia (P < 0.019), and anemia (P < 0.003) exhibited significant differences according to chorionicity, as did the distribution of BWD (P < 0.001). More than half of the cases in the DC and TC groups had a BWD < 15%, while those in the MC group had a BWD < 50% (47.6%). TC pregnancy decreased the risk of neonatal anemia (adjusted odds ratio [AOR] = 0.084) and need for blood transfusion therapy after birth (AOR = 0.119). In contrast, a BWD > 25% increased the risk of neonatal anemia (AOR = 10.135) and need for blood transfusion after birth (AOR = 7.127). TC pregnancy, MCDA or MCTA, and BWD > 25% increased neonatal hypoproteinemia, with AORs of 4.629, 5.123, and 5.343, respectively. CONCLUSIONS: The BWD differed significantly according to chorionicity. Additionally, TC pregnancies reduced the risk of neonatal anemia and need for blood transfusion, but increased the risk of neonatal hypoproteinemia. In contrast, the BWD between the largest and smallest triplets increased the risk of neonatal anemia and the need for blood transfusion. TC pregnancy, MCDA or MCTA, and BWD > 25% increased the risks of neonatal hypoproteinemia. However, due to the limited number of triplet pregnancies, further exploration of the underlying mechanism is warranted.

1G6-D7 Inhibits Homologous Recombination Repair by Targeting Extracellular HSP90α to Promote Apoptosis in Non-Small Cell Lung Cancer.

Despite recent advances in treatment, non-small cell lung cancer (NSCLC) continues to have a high mortality rate. Currently, NSCLC pathogenesis requires further investigation, and therapeutic drugs are still under development. Homologous recombination repair (HRR) repairs severe DNA double-strand breaks. Homologous recombination repair deficiency (HRD) occurs when HRR is impaired and causes irreparable double-strand DNA damage, leading to genomic instability and increasing the risk of cancer development. Poly(ADP-ribose) polymerase (PARP) inhibitors can effectively treat HRD-positive tumors. Extracellular heat shock protein 90α (eHSP90α) is highly expressed in hypoxic environments and inhibits apoptosis, thereby increasing cellular tolerance. Here, we investigated the relationship between eHSP90α and HRR in NSCLC. DNA damage models were established in NSCLC cell lines (A549 and H1299). The activation of DNA damage and HRR markers, apoptosis, proliferation, and migration were investigated. In vivo tumor models were established using BALB/c nude mice and A549 cells. We found that human recombinant HSP90α stimulation further activated HRR and reduced DNA damage extent; however, eHSP90α monoclonal antibody, 1G6-D7, effectively inhibited HRR. HRR inhibition and increased apoptosis were observed after LRP1 knockdown; this effect could not be reversed with hrHSP90α addition. The combined use of 1G6-D7 and olaparib caused significant apoptosis and HRR inhibition in vitro and demonstrated promising anti-tumor effects in vivo. Extracellular HSP90α may be involved in HRR in NSCLC through LRP1. The combined use of 1G6-D7 and PARP inhibitors may exert anti-tumor effects by inhibiting DNA repair and further inducing apoptosis of NSCLC cells.

Clinical applications and cadaveric study of the free descending genicular artery perforator flap without the saphenous vein.

BACKGROUND: The descending genicular artery (DGA) and medial thigh region have been underused as donor sites for perforator flaps. This study evaluated the anatomical relationship between the perforators of the DGA and the saphenous vein (SV) to review the clinical applications of the free descending genicular artery perforator (DGAP) flap for locoregional reconstruction. METHODS: Fifteen cadavers were arterially perfused with red latex and dissected. Thirty-one patients with extremity tissue defects were treated with a free DGAP flap, including six patients who received a chimeric flap. The minimum distance between the DGAP and the SV was measured during surgery. RESULTS: In all patients, the skin branch of the descending genicular artery was found in the medial femoral condyle plane in front of the SV. The average distance between the descending genicular artery perforator and the SV was 3.71 ± 0.38 cm (range: 2.9-4.3 cm). Thirty flaps survived completely, and one flap developed partial necrosis; however, this flap healed two weeks after skin grafting. The average follow-up time was 11.23 months. CONCLUSIONS: We conclude that the SV can be preserved when harvesting the descending genicular artery perforator flap, causing less damage to the donor site and having no effect on flap survival. The free descending genicular artery perforator flap without the SV is a better therapy for complicated tissue defects.

IL-17A promotes tumorigenesis and upregulates PD-L1 expression in non-small cell lung cancer.

BACKGROUND: The tumor microenvironment plays a key role in non-small cell lung cancer (NSCLC) development and also influences the effective response to immunotherapy. The pro-inflammatory factor interleukin-17A mediates important immune responses in the tumor microenvironment. In this study, the potential role and mechanisms of IL-17A in NSCLC were investigated. METHODS: We detected IL-17A by immunohistochemistry (IHC) in 39 NSCLC patients. Its expression was correlated with the programmed cell death-ligand1 (PD-L1). IL-17A knockdown and overexpression in A549 and SPC-A-1 cell models were constructed. The function of IL-17A was examined in vitro by wound healing, migration, invasion, plate colony formation and T cell killing assay. Western blot analysis, immunofluorescence assay and IHC were performed to investigate the regulation effects of IL-17A on autophagy in A549 and SPC-A-1. The effect of IL-17A on ROS/Nrf2/p62 signaling pathway was detected. Subcutaneous tumor models were established to examine the tumor-promoting effect of IL-17A in vivo and its effect on immunotherapy. RESULTS: We found a prevalent expression of IL-17A in NSCLC tumor tissues and it was positively correlated with PD-L1 expression (r = 0.6121, p < 0.0001). In vitro, IL-17A promotes lung cancer cell migration, invasion and colony formation ability. Moreover, IL-17A upregulated N-cadherin, Twist, and Snail, and downregulated E-cadherin in NSCLC cells. IL-17A enhanced cell survival in the T cell killing assay. Mechanistically, IL-17A induced ROS production and increased Nrf2 and p62 expression, thereby inhibiting autophagy and reducing PD-L1 degradation. In vivo experiments, anti-IL-17A monoclonal antibody alone slowed the growth of subcutaneous tumors in mice. When combined with anti-PD-L1 monoclonal antibody, tumor tissue expression of PD-L1 was reduced and the therapeutic effect was diminished. CONCLUSION: We found that IL-17A promoted NSCLC progression and inhibited autophagy through the ROS/Nrf2/p62 pathway leading to increased PD-L1 expression in cancer cells. Modulation of IL-17A may affect the therapeutic efficacy of immunotherapy.

Right Ventricular Function in Takayasu's Arteritis Patients With Pulmonary Artery Involvement Using MRI Feature Tracking.

BACKGROUND: Pulmonary artery involvement (PAI) is not rare in Takayasu arteritis (TA). Persistently elevated pulmonary arterial pressure in TA-PAI patients leads to pulmonary hypertension (PH), and eventually cardiac death. Thus, the early detection of right ventricular dysfunction before the onset of PH is important. PURPOSE: To explore the potential of right ventricular global peak longitudinal and circumferential strain (RVGLS and RVGCS, respectively) in detecting right ventricular myocardial damage in TA-PAI patients without PH. STUDY TYPE: Retrospective. POPULATION: One hundred and six TA patients (39.6 ± 13.9 years), of whom 52 were non-PAI and 54 were PAI patients (36 without PH and 18 with PH), along with 58 sex- and age-matched healthy volunteers (HVs) (36.7 ± 13.2 years). The involved arteries were validated by aorta magnetic resonance (MR) angiography and pulmonary artery computed tomography angiography. FIELD STRENGTH/SEQUENCE: 3 T/Cine imaging sequence with a steady-state free precession readout. ASSESSMENT: Cardiac MRI-derived parameters measured by two radiologists independently were compared among HVs, and TA patients with and without PAI. In addition, these indices were further compared among HVs, and TA-PAI patients with and without PH. STATISTICAL TESTS: Student's t test, one-way ANOVA analysis, Pearson and Spearman correlation analysis, and reproducibility analysis. A P-value of <0.05 was considered statistically significant. RESULTS: Although the TA-PAI patients without PH had a similar RV ejection fraction (RVEF) with HV (P = 0.348), RVGLS (non-PH 20.6 ± 3.7% vs. HV 24.0 ± 3.1%) was significantly lower and RVGCS (non-PH 14.8 ± 3.9% vs. HV 13.0 ± 2.7%) higher. The TA-PAI patients with PH had significantly poorer RVGLS (PH 13.5 ± 3.8% vs. non-PH 20.6 ± 3.7%) and RVGCS (PH 10.9 ± 3.2% vs. non-PH 14.8 ± 3.9%) than those without PH. DATA CONCLUSION: Right ventricular dysfunction was detected in the TA-PAI patients without PH. MR-feature tracking may be an effective method for detecting early cardiac damage in the TA-PAI patients without PH. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 3.

Myofiber directs macrophages IL-10-Vav1-Rac1 efferocytosis pathway in inflamed muscle following CTX myoinjury by activating the intrinsic TGF-ß signaling.

BACKGROUND: To explore the role of skeletal muscle specific TGF-ß signaling on macrophages efferocytosis in inflamed muscle caused by Cardiotoxin (CTX) injection. METHODS: CTX myoinjury was manipulated in TGF-ßr2flox/flox (control) mice or transgenic mice with TGF-ß receptor 2 (TGF-ßr2) being specifically deleted in skeletal muscle (SM TGF-ßr2-/-). Gene levels of TGF-ß signal molecules, special inflammatory mediators in damaged muscle or in cultured and differentiated myogenic precursor cells (MPC-myotubes) were monitored by transcriptome microarray or qRT-PCR. TGF-ß pathway molecules, myokines and embryonic myosin heavy chain in regenerating myofibers, the phenotype and efferocytosis of macrophages were evaluated by immunofluorescence, immunoblotting, Luminex, or FACS analysis. In vitro apoptotic cells were prepared by UV-irradiation. RESULTS: In control mice, TGF-ß-Smad2/3 signaling were significantly up-regulated in regenerating centronuclear myofibers after CTX-myoinjury. More severe muscle inflammation was caused by the deficiency of muscle TGF-ß signaling, with the increased number of M1, but the decreased number of M2 macrophages. Notably, the deficiency of TGF-ß signaling in myofibers dramatically affected on the ability of macrophages to conduct efferocytosis, marked by the decreased number of Annexin-V-F4/80+Tunel+ macrophages in inflamed muscle, and the impaired uptake of macrophages to PKH67+ apoptotic cells transferred into damaged muscle. Further, our study suggested that, the intrinsic TGF-ß signaling directed IL-10-Vav1-Rac1 efferocytosis signaling in muscle macrophages. CONCLUSIONS: Our data demonstrate that muscle inflammation can be suppressed potentially by activating the intrinsic TGF-ß signaling in myofibers to promote IL-10 dependent-macrophages efferocytosis. Video Abstract.

Antibody light-chain-restricted recognition of the site of immune pressure in the RV144 HIV-1 vaccine trial is phylogenetically conserved.

In HIV-1, the ability to mount antibody responses to conserved, neutralizing epitopes is critical for protection. Here we have studied the light chain usage of human and rhesus macaque antibodies targeted to a dominant region of the HIV-1 envelope second variable (V2) region involving lysine (K) 169, the site of immune pressure in the RV144 vaccine efficacy trial. We found that humans and rhesus macaques used orthologous lambda variable gene segments encoding a glutamic acid-aspartic acid (ED) motif for K169 recognition. Structure determination of an unmutated ancestor antibody demonstrated that the V2 binding site was preconfigured for ED motif-mediated recognition prior to maturation. Thus, light chain usage for recognition of the site of immune pressure in the RV144 trial is highly conserved across species. These data indicate that the HIV-1 K169-recognizing ED motif has persisted over the diversification between rhesus macaques and humans, suggesting an evolutionary advantage of this antibody recognition mode.

Extreme temperatures, mortality, and adaptation: Evidence from the county level in China.

Extreme temperatures are known to cause adverse health outcomes. Yet knowledge on the magnitude of this effect in developing countries is limited due to data availability and reliability issues. Collecting data for 2872 counties in China, we estimate the effects of daily temperatures on the monthly mortality rate. The results indicate that an additional day for which the maximum temperature is 38°C or above on average increases the monthly mortality rate by about 1.7% relative to if that day's maximum temperature had been in the range 16-21°C. This is after deducting deaths harvested from the subsequent month. Higher gross domestic product per capita at the county level is associated with lower mortality effects of hot and cold days. Improved dwelling conditions are found to be associated with a lower mortality effect of hot days and improved local healthcare infrastructure to be associated with a lower mortality effect of cold days. In the absence of strong adaptation efforts, the estimates suggest net upward pressure on annual mortality rates over coming decades in many populous counties, especially under more extreme climate change scenarios.

IRE1α arm of unfolded protein response in muscle-specific TGF-ß signaling-mediated regulation of muscle cell immunological properties.

Endoplasmic reticulum stress (ERS) and the unfolded protein response (UPR) are involved in various muscle pathological states. The IRE1α arm of UPR can affect immunological properties of myofiber through restraining p38 mitogen-activated protein kinases (MAPK) activation under inflammatory milieu. However, the relevant pathway molecules regulating the initiation of the IRE1α arm in myofiber remain unclear. In this work, expression of transforming growth factor-beta (TGF-ß) and TGF-ß receptor II (TGF-ßr2), and UPR pathway activation were examined in cardiotoxin (CTX)-damaged mouse muscle, which revealed the activation of TGF-ß signaling and UPR in CTX-damaged muscle and in regenerating myofibers. Using control or transgenic mice with TGF-ßr2 deleted in skeletal muscle (SM TGF-ßr2-/-) and the derived primary differentiating myogenic precursor cells (MPCs) treated with/without ERS activator or inhibitor, IRE1α pathway inhibitor, or TGF-ß signaling activator, this study further revealed an essential role of intrinsic TGF-ß signaling in regulating muscle cell to express inflammation-related molecules including H-2Kb, H2-Eα, TLR3, and special myokines. TGF-ß signaling prompted UPR IRE1α arm and restrained p38 MAPK activation in myofiber under inflammatory milieu. This study uncovers a previously unrecognized function of TGF-ß signaling acting as an upstream factor controlling myofiber immune capacities in the inflamed state through the UPR-IRE1α-p38 MAPK pathway.

Muscle cytotoxicity and immuno-reactivity analysis of the porous carbon nanospheres fabricated by high temperature calcination.

Carbon-based nanomaterials have a high specific surface area, biocompatibility, and controlled mesopore structures. These characteristics make carbon nanospheres excellent carriers for drugs, biological dyes, photosensitizers, etc. Nevertheless, little is known about the impact of topological features on the surface of carbon nanomaterials on their in vivo immunoreactivity. In this study, we fabricated mesoporous carbon nanoparticles (MCNs) and solvent-processable carbon vesicles (CVs) by high-temperature calcination. The hematoxylin and eosin (H&E) staining suggested CVs' relatively poor dispersion capacity compared to MCNs and carbon precursors (CPs), leading to more severe muscle inflammation and necrosis. Immunostaining and Fluorescence Activated Cell Sorter (FACS) analysis further showed that both MCNs and CVs triggered a transient immune response in transplanted muscle and muscle-draining lymph nodes, but did not alter muscle resistance to exogenous viruses. In conclusion, this study provides insights into how carbon nanoparticles modulate the activation of immune responses in vivo.

Perinatal outcomes of women with Müllerian anomalies.

PURPOSE: To investigate the perinatal outcomes of singleton pregnant women with Müllerian anomalies (MuAs). METHODS: A retrospective cohort study was conducted on singleton pregnant women with MuAs who delivered at the West China Second University Hospital between January 1, 2009 and December 31, 2020. RESULTS: Four hundred fifty-seven cases of MuAs were identified, with an incidence of 0.40%. The most common anomaly was a septate uterus (38.7%). Compared to the control group, the MuAs group had significantly higher incidences of perinatal complications, including preterm deliveries (PTDs) (27.4 vs. 9.8%, P < 0.001), preterm premature rupture of membranes (PPROM) (29.1 vs. 22.5%, P = 0.001), malpresentation (34.4 vs. 5.6%, P < 0.001), abruptio placentae (4.6 vs. 1.2%, P < 0.001), placental accreta/increta (19.7 vs. 11.8%, P < 0.001), and uterine rupture (2.8 vs. 1.6%, P = 0.035). The rates of in vitro fertilization and embryo transfer (IVF-ET), foetal growth restriction (FGR), and low birth weight were also significantly higher in the MuAs group (8.3 vs. 4.5%, P < 0.001; 2.6 vs. 0.9%, P = 0.001; 3.1 vs. 1.7%, P = 0.033, respectively). In the MuAs group, the incidence of PPROM was high in cases with unicornuate uterus (31.5%), and malpresentation was as high as 42.4 and 37.0% in cases with septate and didelphys uteri, respectively. CONCLUSION: The data suggest that pregnancy with MuAs may increase adverse perinatal outcomes, which calls for intensive supervision during pregnancy and delivery to reduce maternal and foetal complications. Individualized considerations should be emphasized according to the different categories of MuAs in pregnancies.

Regenerating myofiber directs Tregs and Th17 responses in inflamed muscle through the intrinsic TGF-ß signaling-mediated IL-6 production.

Transforming growth factor-ß (TGF-ß) is considered to be an important immune regulatory cytokine. However, it remains unknown whether and how the muscle fiber specific-TGF-ß signaling is directly involved in intramuscular inflammatory regulation by affecting T cells. Here, we addressed these in a mouse tibialis anterior muscle Cardiotoxin injection-induced injury repair model in muscle creatine kinase (MCK)-Cre control or transgenic mice with TGF-ß receptor II (TGF-ßr2) being specifically deleted in muscle cells (SM TGF-ßr2-/-). In control mice, TGF-ß2 and TGF-ßr2 were found significantly upregulated in muscle after the acute injury. In mutant mice, deficiency of TGF-ß signaling in muscle cells caused more serious muscle inflammation, with the increased infiltration of macrophages and CD4+ T cells at the degeneration stage (D4) and the early stage of regeneration (D7) after myoinjury. Notably, the loss of TGF-ß signaling in myofibers dramatically affected CD4+ T cell function and delayed T cells withdrawal at the later stage of muscle regeneration (D10 and D15), marked by the elevated Th17, but the impaired Tregs response. Furthermore, in vivo and in vitro, the intrinsic TGF-ß signaling affected immune behaviors of muscle cells and directed CD4+ T cells differentiation by impairing IL-6 production and release. It suggests that local muscle inflammation can be inhibited potentially by directly activating the TGF-ß signaling pathway in muscle cells to suppress Th17, but induce Tregs responses. Thus, according to the results of this study, we found a new idea for the control of local acute inflammation in skeletal muscle.NEW & NOTEWORTHY Myofiber mediates muscle inflammatory response through activating the intrinsic TGF-ß signaling. The specific TGF-ß signaling activation contributes to myofiber IL-6 production and directs muscle-specific Th17 and Treg cell responses.

Vaccine induction of antibodies against a structurally heterogeneous site of immune pressure within HIV-1 envelope protein variable regions 1 and 2.

The RV144 HIV-1 trial of the canary pox vector (ALVAC-HIV) plus the gp120 AIDSVAX B/E vaccine demonstrated an estimated efficacy of 31%, which correlated directly with antibodies to HIV-1 envelope variable regions 1 and 2 (V1-V2). Genetic analysis of trial viruses revealed increased vaccine efficacy against viruses matching the vaccine strain at V2 residue 169. Here, we isolated four V2 monoclonal antibodies from RV144 vaccinees that recognize residue 169, neutralize laboratory-adapted HIV-1, and mediate killing of field-isolate HIV-1-infected CD4(+) T cells. Crystal structures of two of the V2 antibodies demonstrated that residue 169 can exist within divergent helical and loop conformations, which contrasted dramatically with the ß strand conformation previously observed with a broadly neutralizing antibody PG9. Thus, RV144 vaccine-induced immune pressure appears to target a region that may be both sequence variable and structurally polymorphic. Variation may signal sites of HIV-1 envelope vulnerability, providing vaccine designers with new options.

Exploiting Pre-Existing CD4+ T Cell Help from Bacille Calmette-Guérin Vaccination to Improve Antiviral Antibody Responses.

The continuing emergence of viral pathogens and their rapid spread into heavily populated areas around the world underscore the urgency for development of highly effective vaccines to generate protective antiviral Ab responses. Many established and newly emerging viral pathogens, including HIV and Ebola viruses, are most prevalent in regions of the world in which Mycobacterium tuberculosis infection remains endemic and vaccination at birth with M. bovis bacille Calmette-Guérin (BCG) is widely used. We have investigated the potential for using CD4+ T cells arising in response to BCG as a source of help for driving Ab responses against viral vaccines. To test this approach, we designed vaccines comprised of protein immunogens fused to an immunodominant CD4+ T cell epitope of the secreted Ag 85B protein of BCG. Proof-of-concept experiments showed that the presence of BCG-specific Th cells in previously BCG-vaccinated mice had a dose-sparing effect for subsequent vaccination with fusion proteins containing the Ag 85B epitope and consistently induced isotype switching to the IgG2c subclass. Studies using an Ebola virus glycoprotein fused to the Ag 85B epitope showed that prior BCG vaccination promoted high-affinity IgG1 responses that neutralized viral infection. The design of fusion protein vaccines with the ability to recruit BCG-specific CD4+ Th cells may be a useful and broadly applicable approach to generating improved vaccines against a range of established and newly emergent viral pathogens.