Plasma proteomics analysis of Chinese HIV-1 infected individuals focusing on the immune and inflammatory factors afford insight into the viral control mechanism.

Background: Long-term non-progressors (LTNPs) with HIV infection can naturally control viral replication for up to a decade without antiretroviral therapy (ART), but the underlying mechanisms of this phenomenon remain elusive. Methods: To investigate the relevant immune and inflammatory factors associated with this natural control mechanism, we collected plasma samples from 16 LTNPs, 14 untreated viral progressors (VPs), 17 successfully ART-treated patients (TPs), and 16 healthy controls (HCs). The OLINK immune response panel and inflammation panel were employed to detect critical proteins, and the plasma neutralizing activity against a global panel of pseudoviruses was assessed using TZM-bl cells. Results: The combination of IL17C, IL18, DDX58, and NF2 contributed to discriminating LTNPs and VPs. IL18 and CCL25 were positively associated with CD4+ T cell counts but negatively correlated with viral load. Furthermore, CXCL9 and CXCL10 emerged as potential supplementary diagnostic markers for assessing the efficacy of antiretroviral therapy (ART). Finally, TNFRSF9 displayed positive correlations with neutralization breadth and Geometry Median Titer (GMT) despite the lack of significant differences between LTNPs and VPs. Conclusion: In summary, this study identified a set of biomarkers in HIV-infected individuals at different disease stages. These markers constitute a potential network for immune balance regulation in HIV infection, which is related to the long-term control of HIV by LTNPs. It provides important clues for further exploring the immune regulatory mechanism of HIV.

The value of dual time-point fluorine-18 fluorodeoxyglucose PET/computed tomography imaging in predicting lymph node metastasis in non-small cell lung cancer patients.

OBJECTIVE: The purpose of this study was to analyze the correlation between specified dual time-point fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) imaging parameters and pathological characteristics in non-small cell lung cancer (NSCLC) patients. METHODS: This study retrospectively analyzed 47 patients with NSCLC. All patients underwent dual time-point 18F-FDG PET/CT imaging. We obtained the metabolic parameters, standardized uptake value (SUV) maximum, SUVmean, delayed standardized uptake value (DSUV) maximum, DSUVmean, delay index standardized uptake value (DISUV) maximum, and DISUVmean, of the primary tumor. The tumor size was measured by CT. All lymph nodes had a definite pathological diagnosis. We next evaluated the status of the lymph node metastases (LNM) and the correlations between metabolic parameters and clinical characteristics. Receiver operating characteristic curves were drawn for the prediction of LNM. RESULTS: We found that the DSUVmax, DISUVmax, DSUVmean, and tumor size were significantly related to LNM (P = 0.036, 0.009, and 0.049, respectively). Multivariate analysis revealed that tumor size and DISUVmax were independent risk factors for LNM in lung cancer patients. According to the receiver operating characteristic curve analysis, the optimal cutoff values for DISUVmax and tumor size were 0.33 and 2.8 cm, respectively. When these two parameters were combined, the area under the curve for predicting LNM in NSCLC was 0.768, and the sensitivity was 95.7% for predicting LNM in lung cancer patients. We further allocated the patients to three groups: the high-risk group (tumor size ≥ 2.8 cm, DISUVmax ≥ 0.33), the moderate-risk group (tumor size ≥ 2.8 cm, DISUVmax < 0.33, or tumor size < 2.8 cm, DISUVmax ≥ 0.33), and the low-risk group (tumor size < 2.8 cm, DISUVmax < 0.33). The rates of LNM were 70, 50, and 0%, respectively. CONCLUSION: Tumor size and DISUVmax are risk factors for predicting LNM, and they are more useful in combination. Compared with standard PET/CT imaging, dual time-point PET/CT imaging has added value in predicting LNM in NSCLC patients.

DRAIC mediates hnRNPA2B1 stability and m6A-modified IGF1R instability to inhibit tumor progression.

Type 1 insulin-like growth factor receptor (IGF1R) plays an important role in cancer, however, posttranscriptional regulation such as N6-methyladenosine (m6A) of IGF1R remains unclear. Here, we reveal a role for a lncRNA Downregulated RNA in Cancer (DRAIC) suppress tumor growth and metastasis in clear cell Renal Carcinoma (ccRCC). Mechanistically, DRAIC physically interacts with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and enhances its protein stability by blocking E3 ligase F-box protein 11 (FBXO11)-mediated ubiquitination and proteasome-dependent degradation. Subsequently, hnRNPA2B1 destabilizes m6A modified-IGF1R, leading to inhibition of ccRCC progression. Moreover, four m6A modification sites are identified to be responsible for the mRNA degradation of IGF1R. Collectively, our findings reveal that DRAIC/hnRNPA2B1 axis regulates IGF1R mRNA stability in an m6A-dependent manner and highlights an important mechanism of IGF1R fate. These findings shed light on DRAIC/hnRNPA2B1/FBXO11/IGF1R axis as potential therapeutic targets in ccRCC and build a link of molecular fate between m6A-modified RNA and ubiquitin-modified protein.

Knowledge, Attitudes, and Practices Among Elderly CHD Patients Towards Self-Perceived Health Abilities.

Objective: This study aimed to assess the knowledge, attitudes and practices (KAP) among elderly coronary heart disease (CHD) patients toward self-perceived health abilities. Methods: This web-based study was carried out between April 2023 and September 2023 at Guang'anmen Hospital, China Academy of Chinese Medical Sciences. A self-developed questionnaire was utilized to collect demographic information from elderly CHD patients, and evaluate their KAP towards self-perceived health abilities. Results: A total of 568 valid questionnaires were collected. Among the participants, the average age was 65.97±5.50 years, and 298 (52.46%) were female, and the mean scores for knowledge, attitudes, and practices were 6.34±2.29 (possible range: 0-9), 35.24±4.99 (possible range: 9-45), and 27.79±10.09 (possible range: 9-45), respectively. The structural equation model demonstrated that elderly CHD patients' knowledge directly affects attitudes and practices, with path coefficient of 0.93 (P<0.001) and 0.39 (P=0.033), respectively. Moreover, attitudes play an intermediary role between knowledge and practice with path coefficient of 0.75 (P<0.001). Furthermore, residence directly affects knowledge with path coefficient of 0.67 (P<0.001), cardiac function directly affects knowledge with path coefficient of -0.97 (P<0.001) and history of interventional therapy directly affects practice with path coefficient of 4.23 (P<0.001). Conclusion: Elderly CHD patients demonstrated sufficient knowledge, positive attitudes, and proactive practices towards self-perceived health abilities. However, educational programs and behavior modification are recommended, particularly for elderly with lower age and education, living in rural areas, lacking interventional therapy, obese, or taking multiple CHD medications.

Nonlinear relationship between platelet count and 30-day in-hospital mortality in intensive care unit stroke patients: a multicenter retrospective cohort study.

Background: Evidence of the relationship between platelet count and 30-day in-hospital mortality in ICU stroke patients is still scarce. Therefore, the purpose of this study was to explore the relationship between platelet count and 30-day in-hospital mortality among ICU stroke patients. Methods: We conducted a multicenter retrospective cohort study using data from 8,029 ICU stroke patients in the US eICU-CRD v2.0 database from 2014 to 2015. Utilizing binary logistic regression, smooth curve fitting, and subgroup analyses, we examined the link between platelet count and 30-day in-hospital mortality. Results: The 30-day in-hospital mortality prevalence was 14.02%, and the mean platelet count of 223 × 109/L. Adjusting for covariates, our findings revealed an inverse association between platelet count and 30-day in-hospital mortality (OR = 0.975, 95% CI: 0.966, 0.984). Subgroup analyses supported the robustness of these results. Moreover, a nonlinear relationship was observed between platelet count and 30-day in-hospital mortality, with the inflection point at 163 × 109/L. On the left side of the inflection point, the effect size (OR) was 0.92 (0.89, 0.95), while on the right side, the relationship was not statistically significant. Conclusion: This study establishes an independent negative association between platelet count and 30-day in-hospital mortality in ICU stroke patients. Furthermore, a nonlinear relationship with a saturation effect was identified, suggesting that maintaining the platelet count around 163 × 109/L can reduce 30-day in-hospital mortality in these patients.

DNA vaccine prime and replicating vaccinia vaccine boost induce robust humoral and cellular immune responses against MERS-CoV in mice.

As of December 2022, 2,603 cases laboratory-identified Middle East respiratory syndrome coronavirus (MERS-CoV) infections and 935 associated deaths, with a mortality rate of 36%, had been reported to the World Health Organization (WHO). However, there are still no vaccines for MERS-CoV, which makes the prevention and control of MERS-CoV difficult. In this study, we constructed two vaccine candidates of DNA and replicating Vaccinia Tian Tan (VTT) vector that carried the MERS-CoV Spike (S) protein. Compared with homologous immunization with either vaccine, mice immunized with DNA vaccine prime and VTT vaccine boost exhibited much stronger and durable humoral and cellular immune responses. The mice immunized generated robust binding antibodies and broader neutralizing antibodies against the EMC2012, England1 and KNIH strains of MERS-CoV. Prime-Boost immunization also induced strong MERS-S specific T cells responses, with high memory and poly-functional (CD107a-IFN-γ-TNF-α) effector CD8+ T cells. In conclusion, the research demonstrated that DNA-Prime/VTT-Boost strategy could elicit robust and balanced humoral and cellular immune responses against MERS-CoV-S. This study not only provides a promising set of MERS-CoV vaccine candidates but also proposes a heterologous sequential immunization strategy worthy of further development.

The standardized training and assessment system for magnetically controlled capsule gastroscopy (with video).

BACKGROUND AND AIM: To explore the feasibility of a standardized training and assessment system for magnetically controlled capsule gastroscopy (MCCG). METHODS: The results of 90 trainees who underwent the standardized training and assessment system of the MCCG at the First Affiliated Hospital of Xi'an Jiaotong University from May 2020 to November 2023 was retrospectively analyzed. The trainees were divided into three groups according to their medical backgrounds: doctor, nurse, and non-medical groups. The training and assessment system adopted the '7 + 2' mode, seven days of training plus two days of theoretical and operational assessment. The passing rates of theoretical, operational, and total assessment were the primary outcomes. Satisfaction and mastery of the MCCG was checked. RESULTS: Ninety trainees were assessed; theoretical assessment's passing rates in the three groups were 100%. The operational and total assessment passing rates were 100% (25/25), 97.92% (47/48), and 94.12% (16/17), for the doctor, nurse, and non-doctor groups respectively, with no significant difference (χ2 = 1.741, p = 0.419). No bleeding or perforation occurred during the procedure. Approximately, 96.00% (24/25), 95.83% (46/48), and 94.12% (16/17) of the doctor, nurse and non-medical groups anonymously expressed great satisfaction, respectively, without statistically significant difference (χ2 = 0.565, p = 1.000). The average follow-up time was 4-36 months, and 87 trainees (96.67%) had mastered the operation of the MCCG in daily work. CONCLUSIONS: Standardized training and assessment of magnetically controlled capsule endoscopists is effective and feasible. Additionally, a strict assessment system and long-term communication and learning can improve teaching effects.

Solute carrier family 16 member 1 as a potential prognostic factor for pancreatic ductal adenocarcinoma and its influence on tumor immunity.

Background: Solute carrier family 16 member 1 (SLC16A1) serves as a biomarker in numerous types of cancer. Tumor immune infiltration has drawn increasing attention in cancer progression and treatment. The objective of our study was to explore the association between SLC16A1 and the tumor immune microenvironment in pancreatic ductal adenocarcinoma (PDAC). Methods: Data were obtained from The Cancer Genome Atlas. The xCell web tool was used to calculate the proportion of immune cells according to SLC16A1 expression. To further explore the mechanism of SLC16A1, immunity-related genes were screened from differentially expressed genes through weighted gene coexpression network analysis, examined via Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, and filtrated using univariate Cox regression and least absolute shrinkage and selection operator regression model combined correlation analysis (P<0.05). Next, CIBERSORT was used to analyze the correlation between immune cells and five important genes. SLC16A1 expression and its clinical role in pancreatic cancer was clarified via immunohistochemical staining experiments. Finally, the effects of SLC16A1 on the results of cancer immunity were evaluated by in vitro experiments. Results: SLC16A1 was overexpressed in PDAC tissues and could be an independent prognostic factor. SLC16A1 was significantly negatively correlated with overall survival and suppressed the tumor immunity of PDAC. In clinic, SLC16A1 expression was significantly positively correlated with tumor progression and poor prognosis. We also found that SLC16A1 could suppress the antitumor ability of CD8+ T cells. Conclusions: SLC16A1 is a biomarker for the prognosis of PDAC and can influence the immune environment of PDAC. These findings provide new insights into the treatment of PDAC.

Influence of coupled water and thermal treatments on the fracture characteristics of a typical sandstone.

Understanding the fracture behavior of rock after coupled water and thermal environment is important for many geotechnical projects. This study examines the influence of coupled water and thermal treatments on the fracture toughness and characteristics of a typical sandstone under mode I and mode II loading conditions. Notched deep beam (NDB) specimens were utilized and subjected to soaking treatments at various water temperatures (23 °C, 60 °C, and 99 °C). The experimental results indicate a significant reduction in both mode I and mode II fracture toughness values, with reductions ranging from 15.4% to 13.2% for mode I and 26.1% to 8.9% for mode II respectively. As the water temperatures increase, a slightly rising trend is observed in both mode I and mode II fracture toughness within the examined temperature range. Sandstone specimens displayed typical brittle fracture characteristics at lower soaking temperatures. For mode I specimens, an increase in ductility was evident with higher soaking temperatures, while the ductile behavior is less pronounced in the mode II specimens. Based on the Maximum Tangential Stress (MTS) criterion and the Generalized Maximum Tangential Stress (GMTS) criterion, the predicted values of mode II fracture toughness and the fracture process zone (FPZ) were discussed. The results show that both the GMTS and MTS criteria exhibit inaccuracies in predicting the mode II fracture toughness of sandstone treated at different soaking water temperatures. However, the GMTS criterion, which incorporates T-stress, demonstrates smaller errors compared to the MTS criterion. The study shows that the radius r0 of the fracture process zone is not a constant under both mode I and mode II loading conditions. The calculation of the fracture process zone radius r0 in the GMTS criterion requires further theoretical and experimental study.

A 5-hydroxymethylcytosine-based non-invasive model for early detection of colorectal carcinomas and advanced adenomas: the METHOD-2 study.

PURPOSE: Detection of colorectal carcinomas (CRC) at a time when there are more treatment options is associated with better outcomes. This prospective case-control study assessed the 5-hydroxymethylcytosine (5hmC) biomarkers in circulating cell-free DNA (cfDNA) for early detection of CRC and advanced adenomas (AA) Experimental Design: Plasma cfDNA samples from 2,576 study participants from the multi-center METHOD-2 study (NCT03676075) were collected, comprising patients with newly diagnosed CRC (n=1,074), AA (n=356), other solid tumors (n=80), and non-CRC/AA controls (n=1,066), followed by genome-wide 5hmC profiling using the 5hmC-Seal technique and the next-generation sequencing (NGS). A weighted diagnostic model for CRC (stage I-III) and AA was developed using the elastic net regularization in a discovery set and validated in independent samples. RESULTS: Distribution of 5hmC in cfDNA reflected gene regulatory relevance and tissue of origin. Besides being confirmed in internal validation, a 96-gene model achieved an area under the curve (AUC) of 90.7% for distinguishing stage I-III CRC from controls in 321 samples from multiple centers for external validation, regardless of primary location or mutation status. This model also showed cancer-type specificity as well as high capacity for distinguishing AA from controls with an AUC of 78.6%. Functionally, differential 5hmC features associated with CRC and AA demonstrated relevance to CRC biology, including pathways such as calcium and MAPK signaling. CONCLUSIONS: Genome-wide mapping of 5hmC in cfDNA shows the promise as a highly sensitive and specific non-invasive blood test to be integrated in screening programs for improving early detection of CRC and high-risk AA.

Genome-wide association study and development of molecular markers for yield and quality traits in peanut (Arachis hypogaea L.).

BACKGROUND: This study aims to decipher the genetic basis governing yield components and quality attributes of peanuts, a critical aspect for advancing molecular breeding techniques. Integrating genotype re-sequencing and phenotypic evaluations of seven yield components and two grain quality traits across four distinct environments allowed for the execution of a genome-wide association study (GWAS). RESULTS: The nine phenotypic traits were all continuous and followed a normal distribution. The broad heritability ranged from 88.09 to 98.08%, and the genotype-environment interaction effects were all significant. There was a highly significant negative correlation between protein content (PC) and oil content (OC). The 10× genome re-sequencing of 199 peanut accessions yielded a total of 631,988 high-quality single nucleotide polymorphisms (SNPs), with 374 significant SNP loci identified in association with the nine traits of interest. Notably, 66 of these pertinent SNPs were detected in multiple environments, and 48 of them were linked to multiple traits of interest. Five loci situated on chromosome 16 (Chr16) exhibited pleiotropic effects on yield traits, accounting for 17.64-32.61% of the observed phenotypic variation. Two loci on Chr08 were found to be strongly associated with protein and oil contents, accounting for 12.86% and 14.06% of their respective phenotypic variations, respectively. Linkage disequilibrium (LD) block analysis of these seven loci unraveled five nonsynonymous variants, leading to the identification of one yield-related candidate gene and two quality-related candidate genes. The correlation between phenotypic variation and SNP loci in these candidate genes was validated by Kompetitive allele-specific PCR (KASP) marker analysis. CONCLUSIONS: Overall, molecular markers were developed for genetic loci associated with yield and quality traits through a GWAS investigation of 199 peanut accessions across four distinct environments. These molecular tools can aid in the development of desirable peanut germplasm with an equilibrium of yield and quality through marker-assisted breeding.

Executive function deficits in patients with the first episode of late-life depression before and after SSRI treatment: A pilot fMRI study.

BACKGROUND: Executive function deficits (EFD) in late-life depression (LLD) has been reported to be associated with antidepressant treatment resistance, increased disability, and poor quality of life. However, the underlying neutral mechanisms of EFD in patients with the first episode of LLD remains unclear. METHODS: A total of 27 patients with first-episode, drug-naive LLD and 27 non-depressed controls (NC) were recruited for the present research. Participants underwent the Trail Making Test, the 17-item Hamilton depression rating scale (HAMD-17) test, and task-state functional magnetic resonance imaging scans under the neutral Stroop task. LLD patients' executive functions, depressive symptoms, and brain activity were examined again after 6 months of antidepressant treatment. RESULTS: Of the 27 LLD patients, 16 cases completed 6-month follow-ups. Patients in the LLD baseline group spent more time on the Trail Making Test A test than those in the NC group (p < 0.05). In the presence of an incongruency between the word color and meaning, the accuracy rate of the neutral Stroop task in the LLD baseline group was lower, and the reaction time was greater than that in the NC group, with statistically significant difference (p < 0.05). The HAMD-17 score in the LLD follow-up group was significantly lower than that in the LLD baseline group (p < 0.05). More activated brain regions were present in the LLD baseline group than in the NC group when performing the neutral Stroop task. Compared with the LLD baseline group, abnormal activation of relevant brains in the cingulate-prefrontal-parietal network of LLD patients still existed in the LLD follow-up group. CONCLUSIONS: LLD patients engaged more brain areas than the NC group while performing the neutral Stroop task. Abnormal activation of the cingulate-prefrontal-parietal network could be a contributing factor to EFD in LLD. TRIAL REGISTRATION: ChiCTR, ChiCTR2100042370 (Date of registration: 21/01/2021). LIMITS: We didn't enroll enough first-episode, LLD patients, the robustness of the findings need to be confirmed by large sample clinical trials.

Modular Microgel-Based Bioassembly Scaffold Induced Chondrogenic and Osteogenic Differentiation of BMSCs.

Bioactive scaffolds capable of simultaneously repairing osteochondral defects remain a big challenge due to the heterogeneity of bone and cartilage. Currently modular microgel-based bioassembly scaffolds are emerged as potential solution to this challenge. Here, microgels based on methacrylic anhydride (MA) and dopamine modified gelatin (GelMA-DA) are loaded with chondroitin sulfate (CS) (the obtained microgel named GC Ms) or bioactive glass (BG) (the obtained microgel named GB Ms), respectively. GC Ms and GB Ms show good biocompatibility with BMSCs, which suggested by the adhesion and proliferation of BMSCs on their surfaces. Specially, GC Ms promote chondrogenic differentiation of BMSCs, while GB Ms promote osteogenic differentiation. Furthermore, the injectable GC Ms and GB Ms are assembled integrally by bottom-up in situ cross-linking to obtain modular microgel-based bioassembly scaffold (GC-GB/HM), which show a distinct bilayer structure and good porous properties and swelling properties. Particularly, the results of in vivo and in vitro experiments show that GC-GB/HM can simultaneously regulate the expression levels of chondrogenic- and osteogenesis-related genes and proteins. Therefore, modular microgel-based assembly scaffold in this work with the ability to promote bidirectional differentiation of BMSCs and has great potential for application in the minimally invasive treatment of osteochondral tissue defects.

A Dual Functional Bioinspired Lubricant for Osteoarthritis Treatment and Potential Prevention.

Osteoarthritis (OA), primarily characterized by the deterioration of articular cartilage, is a highly prevalent joint-disabling disease. The pathological onset and progression of OA are closely related to cartilage lubrication dysfunction and synovial inflammation. Synergistic options targeted at restorative lubrication and anti-inflammation are expected to be the most attractive candidates to treat OA and perhaps help prevent it. Herein, a bioinspired lubricant (HA/PA@Lipo) was fabricated by combining anionic hyaluronan-graft-poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) (HA/PA) with cationic liposomes (Lipo) via electrostatic interaction. HA/PA@Lipo mimicked the lubrication complex located on the outer cartilage surface and was endowed cartilage with excellent cartilage-lubricating performances. After the antioxidant gallic acid (GA) was loaded for dual functionality, HA/PA@Lipo-GA was prepared with added anti-inflammatory properties. HA/PA@Lipo-GA showed favorable biocompatibility with C28/I2 cells, inhibited the production of reactive oxygen, and regulated the expression levels of anabolic genes and proteins. The therapeutic effects of HA/PA@Lipo-GA were evaluated using a sodium iodoacetate-induced OA rat model, and the preventive effects of HA/PA@Lipo-GA were estimated in vivo. The results suggested the robust potential of HA/PA@Lipo-GA with dual functions as a candidate option for OA treatment and prevention.

Revision of the Chinese Pachynotus Kollar & L. Redtenbacher, 1844 (Coleoptera, Curculionidae), with descriptions of two new species.

The Chinese species of the highland weevil genus Pachynotus is revised, including a single known species, P.lampoglobus Chao & Y.-Q. Chen, 1980, and the descriptions of two new species, P.pilosussp. nov. and P.arcuatussp. nov. All Chinese Pachynotus species occur in Xizang (Tibet), China, and a key to these species is presented. Additionally, the COI sequences of two species, P.lampoglobus and P.pilosussp. nov., are provided, with details of the genetic distance.

Identification of an IGHV3-53-Encoded RBD-Targeting Cross-Neutralizing Antibody from an Early COVID-19 Convalescent.

Since November 2021, Omicron has emerged as the dominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, and its sublineages continue to appear one after another, significantly reducing the effectiveness of existing therapeutic neutralizing antibodies (NAbs). It is urgent to develop effective NAbs against circulating Omicron variants. Here, we isolated receptor binding domain (RBD)-specific single memory B cells via flow cytometry from a COVID-19 convalescent. The antibody variable region genes of the heavy chain (VHs) and light chain (VLs) were amplified and cloned into expression vectors. After antibody expression, ELISA screening and neutralizing activity detection, we obtained an IGHV3-53-encoded RBD-targeting cross-neutralizing antibody D6, whose VL originated from the IGKV1-9*01 germlines. D6 could potently neutralize circulating Omicron variants (BA.1, BA.2, BA.4/5 and BF.7), with IC50 values of less than 0.04 µg/mL, and the neutralizing ability against XBB was reduced but still effective. The KD values of D6 binding with RBD of the prototype and BA.1 were both less than 1.0 × 10-12 M. The protein structure of the D6-RBD model indicates that D6 interacts with the RBD external subdomain and belongs to the RBD-1 community. The sufficient contact and deep interaction of D6 HCDR3 and LCDR3 with RBD may be the crucial reason for its cross-neutralizing activity. The sorting and analysis of mAb D6 will provide important information for the development of anti-COVID-19 reagents.

Amino acid substitution of the membrane-proximal external region alter neutralization sensitivity in a chronic HIV-1 clade B infected patient.

The membrane-proximal external region (MPER) represents a highly conserved region of the Human Immunodeficiency Virus (HIV) envelope glycoprotein (env) targeted by several broadly neutralizing antibodies (bnAbs). In this study, we employed single genome amplification to amplify 34 full-length env sequences from the 2005 plasma sample of CBJC504, a chronic HIV-1 clade B infected individual. We identified three amino acid changes (N671S, D674N, and K677R) in the MPER. A longitudinal analysis revealed that the proportion of env sequences with MPER mutations increased from 26.5 % in 2005 to 56.0 % in 2009, and the sequences with the same mutation clustered together. Nine functional pseudoviruses were generated from the 34 env sequences to examine the effect of these mutations on neutralizing activity. Pseudoviruses carrying N674 or R677 mutations demonstrate increased sensitivity to autologous plasma and monoclonal antibodies 2F5, 4E10, and 10E8. Reverse mutations were performed in env including N674, R677, D659, and S671/N677 mutations, to validate the impact of the mutations on neutralizing sensitivity. Neutralization assays indicated that the N671S mutation increased neutralization sensitivity to 2F5 and 10E8. The amino acid R at position 677 increased viral resistance to 10E8, whereas N enhanced viral resistance to 4E10 and 10E8. It has been proposed that critical amino acids in the extra-MPER and the number of potential N-like glycosylation sites (PNGSs) in the V1 loop may have an impact on neutralizing activity. Understanding the mutations and evolution of MPER in chronically infected patients with HIV-1 is crucial for the design and development of vaccines that trigger bnAbs against MPER.