Background: Anti-HIV neutralizing antibodies (anti-HIV-nAbs) play a critical role in the immune defense against HIV by preventing viral entry and limiting replication. This study longitudinally evaluated the titers and variability of anti-HIV-nAbs in individuals coinfected with HIV and HCV. Samples were collected at three time points: before starting HCV treatment, one year after completion, and five years post-treatment. Methods: A retrospective analysis was conducted on 71 HIV/HCV-coinfected patients who achieved a sustained virologic response following antiviral therapy for HCV. A control group of 41 HIV-monoinfected individuals was also included. Anti-HIV-nAb titers were evaluated by HIV neutralization assays using a panel of six recombinant HIV viruses representing multiple genetic subtypes. Generalized Linear Mixed Models and Generalized Linear Models were used for statistical analysis. p-values were adjusted using the Benjamini–Hochberg procedure (q-value). Results: HIV-neutralizing antibody responses in HIV/HCV-coinfected individuals remained stable over five years following HCV therapy without significant changes (q-value > 0.05). The mean neutralization scores remained stable, with baseline scores of 6.1 (95% CI: 5.4–6.7), 6.2 (95% CI: 5.5–6.8) at one year post-HCV therapy, and 6.0 (95% CI: 5.3–6.7) at five years post-HCV therapy. HIV/HCV-coinfected individuals consistently showed lower neutralization scores compared to the control group throughout the follow-up (q-value < 0.05). Regression analyses adjusted for age, gender, nadir CD4+, and baseline CD4+ counts confirmed that the observed differences between HIV-monoinfected and HIV/HCV-coinfected individuals persisted (q-value < 0.05) at both the baseline and after HCV therapy completion. Conclusions: Successful HCV eradication in HIV/HCV-coinfected individuals did not normalize anti-HIV-nAb titers, which remained consistently lower than those in HIV-monoinfected controls over five years.

Background/Objectives: This study aimed to explore how HTLV-2 infection affects the production of broadly neutralizing antibodies (bNAbs) in persons with HIV-1 (PWH) and to assess the impact of boosted protease inhibitors (PIs). Methods: We evaluated broadly neutralizing antibody (bNAb) activity in 65 PWH, which included 27 who were also co-infected with HTLV-2. All participants were former injection drug users with HCV antibodies and were receiving suppressive antiretroviral therapy (ART). Neutralizing activity was assessed against six recombinant HIV-1 viruses that represent five different subtypes. B cell subsets were also analyzed. Results: HTLV-2 co-infection and the lack of ritonavir-boosted protease inhibitors (r-PIs) were both independently associated with higher neutralization scores (p = 0.017 and p = 0.005, respectively). Among those not on r-PIs, individuals co-infected with HTLV-2 showed significantly higher neutralization scores (p = 0.027) and a broader neutralization breadth (83.4% vs. 48.5%, p = 0.015) compared to those infected only with HIV-1. Additionally, HTLV-2 co-infected individuals had more resting memory B cells (p = 0.001) and fewer activated memory B cells (p = 0.017) than the HIV-1 mono-infected individuals. In our multivariate analysis, only HTLV-2 co-infection remained independently associated with neutralization scores (p = 0.027). Elite neutralizers (with a breadth score of ≥10) had more naive B cells and fewer resting memory B cells compared to those with weaker neutralization in both groups. Conclusions: Co-infection with HTLV-2 enhances bNAb production in PWH on suppressive ART and, in particular, in the absence of r-PI regimens. The prominent neutralizing activity corresponded with B cell subset distributions. The results suggest the complexity regarding the interaction between viral co-infections, antiretroviral regimens, and humoral immune compartments and may inform further H1V-1 pathogenesis inquiries or the appropriate design of a vaccine.

Broadly neutralizing antibodies (bnAbs) bind and neutralize diverse HIV isolates and demonstrate protective effects in primate models and humans against specific isolates. To develop an effective HIV vaccine, it is widely believed that inducing these antibodies is crucial. However, the high somatic hypermutation in bnAbs and the limited affinity of HIV Env proteins for bnAb germline precursors suggest that extended antigen exposure is necessary for their production. Consequently, HIV vaccine research is exploring complex sequential vaccination strategies to guide the immune response through maturation stages. In this context, the exploration of the factors linked to the generation of these antibodies across diverse age groups becomes critical. In this study, we assessed the anti-HIV-1 neutralization potency and breadth in 108 aviremic adults and 109 aviremic children under 15 years of age who were receiving ART. We used a previously described minipanel of recombinant viruses and investigated the factors associated with neutralization in these individuals. We identified individuals in both groups who were capable of neutralizing viruses from three different subtypes, with greater cross-neutralization observed in the adult group (49.0% vs. 9.2%). In both groups, we observed an inverse association between neutralization breadth and the CD4+/CD8+ ratio, as well as a direct association with the time to ART initiation. However, we found no association with time post-infection, cumulative ART duration, or CD8+ cell levels. The present study demonstrates that children receiving antiretroviral therapy generate broadly neutralizing responses to HIV-1, albeit with lower magnitude compared to adults. We also observed that neutralization breadth is associated with CD4+/CD8+ levels and time to treatment initiation in both children and adults living with HIV-1. Our interpretation of these results is that a delay in ART initiation could have prolonged the antigenic stimulation associated with viral replication and thus facilitate the capacity to elicit long-lasting broadly neutralizing responses. These results corroborate prior findings that show that HIV-1-neutralizing responses can persist for years, even at low antigen levels, implying an HIV-1 vaccine may induce lasting neutralizing antibody response.

In ICU settings, screening patients upon admission for potential multiresistant bacteria (BMR) carriers is crucial. Traditionally, clinical decisions relied on delayed culture results, but a rapid PCR molecular test called RealCycler-Rezero-U/G (Progenie-molecular©), emerged as an alternative. This study aimed to validate its effectiveness in detecting gram-negative BMR in rectal swabs at ICU admission.Over 24 months, an observational study was conducted on 1,234 admitted patients, with 217 meeting isolation criteria and undergoing both PCR and culture tests. Results showed a 17.5% positive rate for screening. The PCR test exhibited impressive accuracy at 98.6% and a strong negative predictive value of 99.4%. The area under the ROC curve (AUC) was 0.98, indicating high reliability. Notably, PCR results were available 44.5 hours earlier than culture.In conclusion, PCR-based molecular testing for gram-negative BMR offers excellent diagnostic performance and a valuable negative predictive value, making it a suitable screening tool for ICU admissions.

Background/Objectives: The impact of virion maturation on neutralizing antibody responses in HIV treatment is not fully understood. This study examines whether antiretroviral regimens (ART) with boosted protease inhibitors (b-PI), which increase exposure to immature virions, affect neutralization capacity compared to Non-b-PI regimens. Methods: Neutralization activity was assessed in 45 HIV-infected individuals on b-PI regimens and 56 on Non-b-PI regimens, adjusting for factors like infection duration, ART initiation, and immune markers. Individuals on b-PI regimens had significantly lower neutralization scores [mean: 6.1, 95% Confidence Interval (CI): 5.3–6.9] than those on Non-b-PI regimens (mean: 8.9, 95% CI: 8.0–9.9; p < 0.0001). This difference was not explained by infection duration or CD4+ counts. CD4+/CD8+ ratios were positively associated with neutralization, while b-PI use was negatively associated. A regression model indicated that b-PI use significantly predicted lower neutralization scores (beta = −0.30, p = 0.049). Conclusions: These findings suggest that exposure to immature virions via b-PI use reduces neutralizing antibody responses, highlighting the importance of virion maturation in antibody induction. ART regimens promoting exposure to mature virions may enhance neutralization, with potential implications for HIV vaccine design. Further research is needed to explore implications for HIV vaccine design, especially using virus-like particles.

Background and Importance One of the measures to reduce the rate of infections by multidrug-resistant bacteria in Intensive Care Unit (ICU) services promoted in the Pneumonia Zero (NZ) programme is oropharyngeal decontamination (DOF) and/or selective digestive decontamination (SDD). Of the different existing protocols, we implemented the administration of non-absorbable topical antimicrobials (colistin, gentamicin and nystatin) in the oropharynx (paste) and gastrointestinal tract (solution). Both were developed as magistral formulas. In the event of MRSA isolation or an increase in the MRSA rate in our hospital, vancomycin would be added. Aim and Objectives The aim was to assess the effect of such a measure on studies of the prevalence of multidrug-resistant bacteria in critically ill patients, and to see if there is selection for resistance mechanisms. Material and Methods Ambispective study comprising the pre-DDS (01/01/2022–30/04/2022) and DDS (01/01/2023–30/04/2023) periods conducted in the 22-bed ICU. From July 2022, ICU patients with isolation of multidrug-resistant bacteria in both clinical or surveillance samples, as well as patients with estimated intubation >72 h or non-intubated patients with risk factors for developing pneumonia are administered DDS/DOF. In addition, nasal, pharyngo-tonsillar and perianal exudate samples are collected for microbiological surveillance cultures on admission and every Tuesday thereafter. Incubate at 37°C for 48h. Results In the pre-DDS period in the ICU, 626 samples are received for colonisation studies from 132 patients. Excluding repeat isolates in each patient,2 3 multidrug-resistant bacteria were detected. In the DDS period, 537 samples are received from 124 patients, detecting nine multi-resistant bacteria. There is a significant difference (p=0.0138) between the proportion of multi-drug resistant bacteria detected in the surveillance studies after applying ICU decontamination measures. In the first period, the following bacteria were detected: one MRSA, one Acinetobacter baumannii, eight extended-spectrum beta-lactamase (ESBL)-producing enterobacteria and 13 carbapenemase-producing gram-negative bacilli. Pathogens isolated in the post-decontamination period were: one MRSA, one A.baumannii and 8 BLEE-producing enterobacteria. None of the isolates are carbapenemase-producing. Conclusion and Relevance The DDS/DOF protocols applied in the ICU of our hospital have shown a significant decrease in colonisation by multidrug-resistant bacteria in critically ill patients. As for MRSA, no differences could be seen in this period, so it would be advisable to extend the study period. However, the role of this measure in the disappearance of carbapenemase-producing bacteria should be highlighted. References and/or Acknowledgements Conflict of Interest No conflict of interest.

The long-term storage stability of vaccines has a major impact on the roll-out and success of global immunization programs. For the Human Immunodeficiency Virus type 1 (HIV-1) virus-like particle (VLP) vaccine prototype evaluated here, nanoparticle tracking analysis (NTA), and enzyme-linked immunoabsorbent assay (ELISA) results demonstrated a remarkable structural stability. VLPs maintained their integrity and the recognition of relevant B-cell epitopes for three months at 4 and −20 °C. Interestingly, most particles remained intact and preserved the recognition of relevant epitopes even after a week of storage at room temperature.

Longitudinal studies in HIV-1-infected individuals have indicated that 2 to 3 years of infection are required to develop broadly neutralizing antibodies. However, we have previously identified individuals with broadly neutralizing activity (bNA) in early HIV-1 infection, indicating that a vaccine may be capable of bNA induction after short periods of antigen exposure. Here, we describe 5 HIV-1 envelope sequences from individuals who have developed bNA within the first 100 days of infection (early neutralizers) and selected two of them to design immunogens based on HIV-1-Gag virus-like particles (VLPs). These VLPs were homogeneous and incorporated the corresponding envelopes (7 to 9 mg of gp120 in 10(10) VLPs). Both envelopes (Envs) bound to well-characterized broadly neutralizing antibodies (bNAbs), including trimer-specific antibodies (PGT145, VRC01, and 35022). For immunogenicity testing, we immunized rabbits with the Env-VLPs or with the corresponding stabilized soluble envelope trimers. A short immunization protocol (105 days) was used to recapitulate the early nAb induction observed after HIV-1 infection in these two individuals. All VLP and trimeric envelope immunogens induced a comparably strong anti-gp120 response despite having immunized rabbits with 30 times less gp120 in the case of the Env-VLPs. In addition, animals immunized with VLP-formulated Envs induced antibodies that cross-recognized the corresponding soluble stabilized trimer and vice versa, even though no neutralizing activity was observed. Nevertheless, our data may provide a new platform of immunogens, based on HIV-1 envelopes from patients with early broadly neutralizing responses, with the potential to generate protective immune responses using vaccination protocols similar to those used in classical preventive vaccines. IMPORTANCE It is generally accepted that an effective HIV-1 vaccine should be able to induce broad-spectrum neutralizing antibodies. Since most of these antibodies require long periods of somatic maturation in vivo, several groups are developing immunogens, based on the HIV envelope protein, that require complex and lengthy immunization protocols that would be difficult to implement in the general population. Here, we show that rabbits immunized with new envelopes (VLP formulated) from two individuals who demonstrated broadly neutralizing activity very early after infection induced specific HIV-1 antibodies after a short immunization protocol. This evidence provides the basis for generating protective immune responses with classic vaccination protocols with vaccine prototypes based on HIV envelope sequences from individuals who have developed early broadly neutralizing responses.

Preventive HIV-1 vaccine strategies rely on the elicitation of broadly neutralizing antibody (bNAb) responses, but their induction in vivo by vaccination remains challenging. Considering that the ability of an epitope to elicit effective humoral immunity depends on its exposure on the virion, we have used a reverse genetics approach to select variants from an HIV-1 AC10_29 randomly mutated envelope library that showed increased affinity for a selected bNAb (4E10 bNAb targeting the HIV-1 MPER region). Isolated envelope sequences were analyzed by deep-sequencing showing a small number of dominant changes, including the loss of four potential N-linked glycosylation sites and disruption of the V1/V2 loop. Accordingly, the dominant variant (LR1-C1), showed not only increased affinity for MPER bNAbs 4E10 and 2F5, but also higher affinity for an additional antibody targeting the V3 loop (447-52D) that could be a consequence of an open conformation tier 1-like Env. Furthermore, the amino acids specific for the selected variant are associated with an increased sensitivity for 4E10 and 2F5 antibodies. In vivo studies showed that sera from mice immunized with LR1-C1 viruses possessed an improved neutralizing activity compared to the wild-type AC10_29 env. While Virus Like Particles (VLPs) carrying this envelope were unable to induce detectable neutralizing activity in immunized rabbits, one animal showed antibody response to the 4E10-proximal region. Our data establish a novel approach that has the potential to yield HIV envelope immunogen sequences that direct antibody responses to specific envelope regions.

Background Only a small fraction of HIV-1-infected patients develop broadly neutralizing antibodies (bNAbs), a process generally associated to chronic antigen stimulation. It has been described that rare aviremic HIV-1-infected patients can generate bNAbs but this issue remains controversial. To address this matter we have assessed bNAb responses in a large cohort of long-term non-progressors (LTNPs) with low or undetectable viremia. Methods Samples from the LTNP cohort of the Spanish AIDS Research Network (87 elite and 42 viremic controllers) and a control population of 176 viremic typical-progressors (TPs) were screened for bNAbs using Env-recombinant viruses. bNAb specificities were studied by ELISA using mutated gp120, neutralization assays with mutated viruses, and peptide competition. Epitope specificities were also elucidated from the serum pattern of neutralization against a panel of diverse HIV-1 isolates. Results Broadly neutralizing sera were found among 9.3% LTNPs, both elite (7%) and viremic controllers (14%). Within the broadly neutralizing sera, CD4 binding site antibodies were detected by ELISA in 4/12 LTNPs (33%), and 16/33 of TPs (48%). Anti-MPER antibodies were detected in 6/12 LTNPs (50%) and 14/33 TPs (42%) whereas glycan-dependent HIV-1 bNAbs were more frequent in LTNPs (11/12, 92%) as compared to TPs (12/33, 36%). A good concordance between standard serum mapping and neutralization-based mapping was observed. Conclusion LTNPs, both viremic and elite controllers, showed broad humoral immune responses against HIV-1, including activity against many major epitopes involved in bNAbs-mediated protection.

Previous studies support the hypothesis that the envelope GB virus C (GBV-C) E1 protein interferes the HIV-1 entry and that a peptide, derived from the region 139-156 of this protein, has been defined as a novel HIV-1 entry inhibitor. In this work, we firstly focus on the characterization of the structural features of this peptide, which are determinant for its anti-HIV-1 activity and secondly, on the study of its interaction with the proposed viral target (i.e., the HIV-1 fusion peptide). We report the structure of the peptide determined by NMR spectroscopy in dodecylphosphocholine (DPC) micelles solved by using restrained molecular dynamics calculations. The acquisition of different NMR experiments in DPC micelles (i.e., peptide-peptide titration, diffusion NMR spectroscopy, and addition of paramagnetic relaxation agents) allows a proposal of an inhibition mechanism. We conclude that a 18-mer peptide from the non-pathogenic E1 GBV-C protein, with a helix-turn-helix structure inhibits HIV-1 by binding to the HIV-1 fusion peptide at the membrane level, thereby interfering with those domains in the HIV-1, which are critical for stabilizing the six-helix bundle formation in a membranous environment.

BACKGROUND:Over the years, numerous studies have been carried out demonstrating the role of antibodies in HIV control leading to the development of antibody-based therapeutic and prophylactic strategies.OBJECTIVE:The objective of this review is to provide updated information on the role of antibodies in the prevention and control of HIV infection and the strategies against HIV that have been designed based on this information.RESULTS:Passive transfer of anti-HIV antibodies in animal models has proven the efficacy of certain antibodies in the prevention and treatment of infection. The capacity of antibodies to control the virus was first attributed to their neutralizing capacity. However, we now know that there are other Fc-mediated antibody activities associated with virus protection. When it comes to better understanding protection against HIV, we ought to pay particular attention to mucosal immune responses. The evidence accumulated so far indicates that an effective vaccine against HIV should generate both mucosal IgAs and systemic IgGs. Due to the problematic induction of protective anti-HIV antibodies, several groups have developed alternative approaches based on antibody delivery via gene therapy vectors. Experiments in animal models with these vectors have shown impressive protection levels and this strategy is now being clinically trialed.CONCLUSION:Taking into account all the information included in this review, it seems evident that anti-HIV-1 antibodies play an important role in virus control and prevention. This review aims to give an overview of the strategies used and the advances in antibody-based preventive and therapeutic strategies against HIV-1.

The work reports the design and synthesis of a chimeric peptide that is composed of the peptide sequences of two entry inhibitors which target different sites of HIV-1 gp41. The chimeric peptide offers the advantage of targeting two gp41 regions simultaneously: the fusion peptide and the loop both of which are membrane active and participate in the membrane fusion process. We therefore use lipid raft-like liposomes as a tool to specifically direct the chimeric inhibitor peptide to the membrane domains where the HIV-1 envelope protein is located. Moreover, the liposomes that mimic the viral membrane composition protect the chimeric peptide against proteolytic digestion thereby increasing the stability of the peptide. The described liposome preparations are suitable nanosystems for managing hydrophobic entry-inhibitor peptides as putative therapeutics.

BACKGROUND:A slower progression of AIDS and increased survival in GBV-C positive individuals, compared with GBV-C negative individuals has been demonstrated; while the loss of GBV-C viremia was closely associated with a rise in mortality and increased progression of AIDS. Following on from the previous reported studies that support the thesis that GBV-C E2 interferes with HIV-1 entry, in this work we try to determine the role of the GBV-C E1 protein in HIV-1 inhibition.METHODS:The present work involves the construction of several overlapping peptide libraries scanning the GBV-C E1 protein and the evaluation of their anti-HIV activity.RESULTS:Specifically, an 18-mer synthetic peptide from the GBV-C E1 protein, E1(139-156), showed similar antiviral activity against HIVs from viruses from clades A, B, C, D and AE. Competitive ELISA using specific gp41-targeting mAbs, fluorescence resonance energy transfer as well as haemolysis assays demonstrated that this E1 peptide sequence interacts with the highly conserved N-terminal region of the HIV-1 gp41 (the fusion peptide) which is essential for viral entry.CONCLUSIONS:We have defined a novel peptide lead compound and described the inhibitory role of a highly conserved fragment of the E1 protein.GENERAL SIGNIFICANCE:The results together allow us to consider the non-pathogenic E1 GBV-C protein as an attractive source of peptides for the development of novel anti-HIV therapies.

ABSTRACTA fraction of HIV-1 patients are able to generate broadly neutralizing antibodies (bNAbs) after 2 to 4 years of infection. In rare occasions such antibodies are observed close to the first year of HIV-1 infection but never within the first 6 months. In this study, we analyzed the neutralization breadth of sera from 157 antiretroviral-naive individuals who were infected for less than 1 year. A range of neutralizing activities was observed with a previously described panel of six recombinant viruses from five different subtypes (M. Medina-Ramirez et al., J Virol85:5804–5813, 2011,http://dx.doi.org/10.1128/JVI.02482-10). Some sera were broadly reactive, predominantly targeting envelope epitopes within the V2 glycan-dependent region. The neutralization breadth was positively associated with time postinfection (P= 0.0001), but contrary to what has been reported for chronic infections, no association with the viral load was observed. Notably, five individuals within the first 6 months of infection (two as early as 77 and 96 days postinfection) showed substantial cross-neutralization. This was confirmed with an extended panel of 20 Env pseudoviruses from four different subtypes (two in tier 3, 14 in tier 2, and four in tier 1). Sera from these individuals were capable of neutralizing viruses from four different subtypes with a geometric mean 50% infective dose (ID50) between 100 and 800. These results indicate that induction of cross-neutralizing responses, albeit rare, is achievable even within 6 months of HIV-1 infection. These observations encourage the search for immunogens able to elicit this kind of response in preventive HIV-1 vaccine approaches.IMPORTANCEThere are very few individuals able to mount broadly neutralizing activity (bNA) close to the first year postinfection. It is not known how early in the infection cross-neutralizing responses can be induced. In the present study, we show that bNAbs, despite being rare, can be induced much earlier than previously thought. The identification of HIV-1-infected patients with these activities within the first months of infection and characterization of these responses will help in defining new immunogen designs and neutralization targets for vaccine-mediated induction of bNAbs.

We describe the type of patient and the main nosocomial infections in a level II hospital ICU unit, 18 beds (12 polyvalent-general, six coronary).

This study evaluated the neutralization breadth in dually infected (DI) HIV-1 long-term non-progressor elite controller patients (LTNP-EC) using a representative minipanel of 6 viruses from 5 different subtypes. Our results showed an improved neutralization breadth in DI LTNP-EC patients when compared with matched LTNP single-infected patients. The role of viral diversity in neutralization was estimated with the Shannon Entropy and the p-distance in viral quasispecies. We found a positive correlation between neutralization breadth and diversity within the viral quasispecies. This correlation could explain why a group of LTNP-EC patients developed a broad neutralizing response despite having undetectable levels of viremia.