Gp120 Antibodies Research Articles

Hybrid glycophorin GP (A-B) and anti-Ena antibody in a multiparous woman

Abstract The MNS system is a large, complex group of antigens, with 50 antigens at present. The major antigens of the system are carried on glycophorins A and B, which are important red cell sialoglycoproteins. Altered expression of MNS antigens is possible in cases where there is a formation of hybrid glycophorins. Some of these patients may make clinically significant antibodies which can be associated with hemolytic transfusion reactions (HTR) or hemolytic disease of the fetus and the newborn. This is a report of one such case with both these phenomena, in a multiparous woman. Incompatible cross-matches at the referral center caused the samples to be sent to this immunohematological laboratory where the serological profile was detailed. On sending the samples to a third blood group reference laboratory, gene sequencing was done and the antibody was identified. At this immunohematological laboratory, the phenotype was determined as M-N+. The patient’s sera showed panreactivity with all panel cells (3-cell and 11-cell). At blood group reference laboratory, the findings were as follows- GYP (A-B) hybrid gene consistent with hemi/homozygosity for GYP*JL was confirmed and the panreactive antibody was identified as anti - Ena. Rare, atypical phenotypes in the MNS system can result from mutations affecting the sialoglycoproteins the antigens are carried on. The subset of antigens expressed in individual phenotypes varies and these patients can develop antibodies against the antigens they lack. When they present with immunohematological challenges such as panreactivity and incompatibility, a combination of serology, molecular technologies, and family studies help solve the problem. Alternatives to transfusion are also useful options in managing such cases.

Stable expression of HIV-1 MPER extended epitope on the surface of the recombinant probiotic bacteria Escherichia Coli Nissle 1917 using CRISPR/Cas9

BackgroundMucosal vaccines have the potential to induce protective immune responses at the sites of infection. Applying CRISPR/Cas9 editing, we aimed to develop a probiotic-based vaccine candidate expressing the HIV-1 envelope membrane-proximal external region (MPER) on the surface of E. coli Nissle 1917.ResultsThe HIV-1 MPER epitope was successfully introduced in the porin OmpF of the E. coli Nissle 1917 (EcN-MPER) and the modification was stable over 30 passages of the recombinant bacteria on the DNA and protein level. Furthermore, the introduced epitope was recognized by a human anti-HIV-1 gp41 (2F5) antibody using both live and heat-killed EcN-MPER, and this antigenicity was also retained over 30 passages. Whole-cell dot blot suggested a stronger binding of anti-HIV-1 gp41 (2F5) to heat-killed EcN-MPER than their live counterpart. An outer membrane vesicle (OMV) – rich extract from EcN-MPER culture supernatant was equally antigenic to anti-HIV-1 gp41 antibody which suggests that the MPER antigen could be harboured in EcN-MPER OMVs. Using quantitative ELISA, we determined the amount of MPER produced by the modified EcN to be 14.3 µg/108 cfu.ConclusionsThe CRISPR/Cas9 technology was an effective method for establishment of recombinant EcN-MPER bacteria that was stable over many passages. The developed EcN-MPER clone was devoid of extraneous plasmids and antibiotic resistance genes which eliminates the risk of plasmid transfer to animal hosts, should this clone be used as a vaccine. Also, the EcN-MPER clone was recognised by anti-HIV-1 gp41 (2F5) both as live and heat-killed bacteria making it suitable for pre-clinical evaluation. Expression of OmpF on bacterial surfaces and released OMVs identifies it as a compelling candidate for recombinant epitope modification, enabling surface epitope presentation on both bacteria and OMVs. By applying the methods described in this study, we present a potential platform for cost-effective and rational vaccine antigen expression and administration, offering promising prospects for further research in the field of vaccine development.

Deciphering Thrombosis Risk in Vexas Syndrome Patients through Thrombin Generation Assay Andthromboelastography

Introduction: VEXAS syndrome (for Vacuoles in myeloid progenitors, E1 ubiquitin ligase, X-linked, Autoinflammatory manifestations and Somatic) is the consequence of the clonal expansion of hematopoietic stem or progenitor cells with somatically acquired mutation of UBA1. VEXAS is a rare disease characterized by a variety of autoinflammatory manifestations and frequently associated with other hematological malignancies. Venous (VTE) and arterial thrombosis (AT) are recurrently observed in disease course and may affect up to 50% of patients. The exact pathophysiological mechanism underlying thrombosis genesis in UBA1 mut patients is not yet elucidated. Thrombin generation assay (TGA) and thromboelastography (ROTEM) are global hemostasis assays that might be used to identify hemostatic profiles at risk of thrombosis (Ay C et al. J Clin Oncol 2011). In this study, we aimed to evaluate TGA and ROTEM as potential surrogate markers of clot formation in UBA1 mut patients to predict their risk for thrombosis. Methods: TGA and ROTEM assays were performed in UBA1 mut patients between March 2022 and July 2023 , in Hospices Civils de Lyon, France. Patients were tested whether or not they had a personal history of VTE/AT. For patients already treated with oral anticoagulant interfering with exploratory assays, a temporary heparin switch was realized. TGA allows to evaluate concentration of generated thrombin through time, resulting in a dynamic thrombin generation curve, from which various parameters can be determined that describe thrombin activity, such as endogenous thrombin potential (ETP; area under the TG curve). Regarding ROTEM, analyses have been performed on citrated tubes using the ROTEM delta. For each test, the parameters CT (clotting time in seconds), A5 and A10 (measured clot amplitude at 5 and 10 minutes in mm), angle alpha (velocity in °), maximum clot firmness (in mm) and LI30 (% clot lysis at 30 minutes) have been measured. Results: We screened 15 UBA1 mut patients, while only 14 were evaluable for TGA/ROTEM (1 patient excluded due to concomitant use of apixaban the day of TGA). Five out of 15 (33%) had an history of VTE (N=3) or AT (N=2) at the time of TGA/ROTEM blood tests. With a median follow-up of 11.8 months after hmostastic explorations, none of screened patients experienced VTE/AT. On the 14 evaluable patients, TGA/ROTEM exploration was performed in 4 of them at the time of diagnosis prior any treatment onset (including steroids). Active disease (defined by increased CRP and/or clinical manifestations) at the time of TGA did not influence significantly time to peak (mins), peak thrombin (nM) and endogeneous thrombin potential (ETP, nM. min) either in platelet rich- and platelet poor- plasma. Interestingly, patients with prior history of VTE/AT (N=4) had significantly higher ETP compared to those without thrombosis history (N=10) either in platelet rich- and platelet poor-plasmas. Moreover, UBA1 mut patients without thrombosis history exhibited similar ETP values than controls ( figure 1). There was no significant correlation between type of UBA1 mutation, UBA1 allelic frequency, concomitant MDS, type of treatment at the time of TGA assay. Regarding ROTEM analysis, there was no significant differences in clot formation between patients with or without thrombosis history in EXTEM, NATEM, and FIBTEM channels. However, in TEMACT channel (activation as in EXTEM but with a plasminogen activator), we observed higher MCF (Maximum Clot Firmness) in UBA1 mutpatients with prior history of VTE/AT ( Figure 2). Acquired and inherited thrombophilia (protein C and S activities, lupus anticoagulant, anticardiolipine antibodies, anti-beta2 GP1 antibodies, factor V Leiden and prothrombin G20210A mutations, antithrombin evels) were explored in 8 out 15 of our patients. Two of them harbored lupus anticoagulant but without antiphospholipid antibodies. They do not have eitherthrombosis history or higher ETP levels. Conclusions: Based on these preliminary results, TGA and more specifically ETP might identify UBA1 mutpatients at risk of VTE or AT. ROTEM identified an hypofibrinolytic phenotype UBA1 mutpatients with thrombosis history paving the way for future explorations. The small sample size and the retrospective (post-VTE/AT) nature of these explorations are main limitations of this study, which need to be confirmed with a larger follow-up.

Feline osteochondromatosis in a 12-year-old feline leukaemia virus-negative cat

Feline osteochondromatosis is a spontaneous osteocartilaginous exostosis associated with feline leukaemia virus (FeLV) infection or due to a frameshift variant in the exostosin glycosyltransferase 1 (EXT1) gene. Osteochondromatosis was diagnosed in an indoor-only, 12-year-old, neutered female, Russian Blue cat. Radiographs revealed bilateral calcified proliferations in the elbow, costochondral and sternochondral joints, which distorted the normal skeletal structure. Grossly, the proliferated joints presented with consistent, rounded masses, causing complete ankylosis. The main histopathological finding was an osteocartilaginous proliferation composed of multiple irregular islands of well-differentiated hyaline cartilage surrounded and delimited by osteoid tissue. Immunohistochemistry of the osteochondromas, bone marrow and mediastinal lymph nodes, using a primary anti-FeLV gp70 antibody, and FeLV proviral DNA real-time polymerase chain reaction on bone marrow were negative. Sequencing of exon 6 of the EXT1 gene was performed and nucleotide BLAST analysis demonstrated the absence of a frameshift variant. This study reports the only case of spontaneous feline osteochondromatosis in an animal more than 10 years old.

Passive Transfer of Animal-Derived Polyclonal Hyperimmune Antibodies Provides Protection of Mice from Lethal Lassa Virus Infection.

Lassa virus (LASV) can cause severe acute systemic infection in humans. No approved antiviral drugs or vaccines are currently available. Antibody-based therapeutics are considered a promising treatment strategy in the management of LASV disease. We used chimeric Ifnar-/- C57BL/6 (Ifnar-/- Bl6) mice, a lethal LASV mouse model, to evaluate the protective efficacy of polyclonal antibodies purified from sera of rabbits hyperimmunized with virus-like particles displaying native-like LASV glycoprotein GP spikes. Polyclonal anti-LASV GP antibodies provided 100% protection against lethal LASV infection in a pre- and post-exposure treatment setting and prevented LASV disease. Treatment also significantly lowered viremia level and virus load in organs. When treatment was initiated at the onset of symptoms, the hyperimmune antibodies provided partial protection and increased the survival rate by 80%. Our findings support the consideration of animal-derived hyperimmune antibodies targeting GP as an effective treatment option for highly pathogenic LASV.

Phase I Study Evaluating Outcomes of Autologous HIV-Specific T Cells Targeting Non-Escaped Epitopes (HST-NEET) Therapy in HIV+ Individuals on ART (NCT03485963)

While allogeneic bone marrow transplant (alloBMT) can offer a curative approach for HIV, successes have been limited. HIV-specific CD8+ T cells may be harnessed to eliminate or control HIV, but these responses are limited by factors including viral immune escape mutations. In this study, we hypothesized that T cell therapies targeting conserved HIV epitopes would be safe and show in vivo antiviral activity. This phase I clinical trial (NCT03485963) evaluated the safety, immunologic and virologic responses of a novel HIV-1 multi-antigen specific T cell therapy (HST-NEET) targeting HIV Nef and conserved epitopes of Gag and Pol in people with HIV suppressed on antiretroviral therapy (ART). We investigated whether infused autologous HST-NEETs expand, persist, and elicit anti-viral responses in vivo. Six participants with HIV (ages 33-57 years, 3 males and 2 females identifying as African or African American, 1 male identifying as White) received two infusions (2x107 cells/m2 BSA/dose) of HST-NEETs without prescribed lymphodepletion. Treatment follow-up was conducted for 48 weeks post-infusions. RESIST001 and 005 received infusions 4 weeks apart. RESIST003 and 004 received infusions >4 weeks apart (58 weeks and 35 weeks, respectively) due to delays caused by the COVID-19 pandemic. RESIST006 and 007 received infusions 2 weeks apart. RESIST004 was hospitalized for COVID-19 between infusions, but no attributable severe adverse events were observed for any participant irrespective of the timing of their infusions. All participants remained on ART throughout the study period. To determine the epitope specificities and breadth of the T cell repertoire within the infusion products, IFNγ ELISPOT and intracellular cytokine flow cytometric assays were used to evaluate antigen-specific responses to HIV Gag, Pol, and Nef in the HST-NEET products. These studies also support tracking of the infused T cells in vivo. ELISPOT, flow cytometry and TCR sequencing were conducted to evaluate expansion and persistence of HIV-specific T cell clones in vivo. Pre- and post-infusion, the genetically intact HIV reservoir was quantified using the intact proviral DNA assay (IPDA), while HIV Envelope gp120 (Env)-specific antibody levels were assessed using ELISA. HST-NEET infusion products met clinical dose requirements, with predominantly CD3+CD8+ (med 70.7%, range 19% to 95.6%) populations expressing effector memory (CD45RO+CCR7-CD62L-) (86.8-98.4%) markers. HST-NEET products had specificity for 1-3 viral antigens with a dominance of Nef-specific responses (Table 1). Epitope mapping of the products identified 10 recognized epitopes, including repeated Nef epitopes associated with the HLA-B07 supertype. Post-infusion studies (including TCR sequencing) for RESIST001 revealed marked in vivo expansion and persistence of T cells recognizing the same Nef peptide in the HST-NEETs product. However, no changes in HIV gp120 antibody levels or viral load were observed. RESIST005 HST-NEETs recognized 3 Nef epitopes but again, no changes in viral load were observed. RESIST004 also received a predominantly Nef-specific HST-NEET product eliciting expansion of Nef-specific T cells in vivo post-infusion. In contrast to RESIST001 and 005, a decrease in HIV reservoir size was observed in RESIST004 post-infusion #1 from 32.1 (pre) to 0 (at 36 weeks) intact proviruses/million CD4+ T cells (INTACT/M), which remained low at 8.4 INTACT/M post-infusion #2. RESIST003 products were broadly specific, mapping to 4 HIV Pol and 2 Nef CD8-restricted epitopes and at 5 weeks post-infusion #1, HIV reservoir size markedly decreased from 24.4 to 0 INTACT/M. Further, post HST-NEET infusion #2, the levels remained low (mean 6.3 INTACT/M). The immune and anti-viral studies are ongoing for RESIST006 and 007. In summary, these data suggest that infusions of HST-NEETs are safe, can elicit expansion and persistence of HIV-specific T cell populations post-infusion even without prescribed lymphodepletion, and may be associated with durable decreases in the HIV reservoir, as measured by intact proviruses. Although these studies are ongoing, the infusion of HST-NEETs may be a viable therapeutic strategy in the lymphodepleted setting post autologous and allogeneic stem cell transplant as is also being evaluated in 2 ongoing clinical trials (NCT04975698 and NCT04248192, respectively). Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A case of primary antiphospholipid antibody syndrome with intermittent cerebral venous sinus thrombosis manifested with recurrent epilepsy

Antiphospholipid syndrome (APS) is an acquired autoimmune clinical disorder characterized by persistently raised levels of anti-phospholipid antibodies and clinical feature of hypercoagulability (recurrent vascular thrombosis and pregnancy morbidities). Primary APS is idiopathic in nature though secondary APS is associated with other connective tissue diseases like SLE. Here, we present an instance of primary APS with recurrent cerebral venous sinus thrombosis in a youthful unmarried female who clinically presented with generalized epilepsy. Level of anti-cardiolipin (aCL) and anti-beta 2 GP1 antibodies were found elevated on two occasions 12 weeks apart. The patient was treated with anticoagulation therapy along with anti-epileptic therapy and she responded well to the therapy. This case report highlights that clinicians should always suspect APS in female patients who had history of seizures and ischemic or thrombotic lesions on brain imaging, irrespective of presence of pregnancy comorbidities. Keywords: antiphospholipid syndrome; cerebral venous; sinus thrombosis; epilepsy

Hematological involvement in pediatric systemic lupus erythematosus: A multi-center study.

Introduction: Systemic lupus erythematosus (SLE) may present with features of several systems, including hematological manifestations. In this study, we aimed to evaluate the characteristics of hematological involvement and assess possible associations and correlations in pediatric SLE patients. Method: This is a retrospective multi-center study. The medical records of pediatric SLE patients followed between January 2000 and June 2020 were analyzed. All children fulfilled the criteria of the Systemic Lupus International Collaborating Clinics. Results: The study included 215 children with SLE, 118 of whom had hematological manifestations. Concomitant renal involvement and low C3 levels were significantly more frequent in patients with hematological involvement (p = 0.04, p = 0.008, respectively). Also, anti-cardiolipin, anti-beta-2-glycoprotein I (anti-β2 GP1), and anti-Sm antibody positivity, and the presence of lupus anticoagulant were more common in the group with hematological findings (p = 0.001 for anti-cardiolipin antibody positivity and p < 0.001 for the positivity of anti-β2 GP1 antibody, anti-Sm antibody, and lupus anticoagulant). The most common hematologic abnormality was anemia (n = 88, 74.5%), with autoimmune hemolytic anemia constituting the majority (n = 40). Corticosteroids followed by IVIG were the mainstay of treatment. In patients resistant to corticosteroid and IVIG treatments, the most preferred drug was rituximab. Low levels of C3, high SLEDAI score, high incidence of renal involvement, and positive antiphospholipid antibodies were associated with hematological involvement in the univariate analysis. The presence of antiphospholipid antibodies and high SLEDAI score were independently associated with hematological involvement in multivariate analysis (OR: 4.021; 95% CI: 2.041-7.921; p < 0.001 and OR: 1.136; 95% CI: 1.065-1.212; p < 0.001). Conclusion: Hematological abnormalities are frequently encountered in pediatric SLE. Positive antiphospholipid antibodies and high SLEDAI scores were associated with hematological involvement.

Zoonotic risk factors associated with seroprevalence of Ebola virus GP antibodies in the absence of diagnosed Ebola virus disease in the Democratic Republic of Congo.

BackgroundEbola virus (EBOV) is a zoonotic filovirus spread through exposure to infected bodily fluids of a human or animal. Though EBOV is capable of causing severe disease, referred to as Ebola Virus Disease (EVD), individuals who have never been diagnosed with confirmed, probable or suspected EVD can have detectable EBOV antigen-specific antibodies in their blood. This study aims to identify risk factors associated with detectable antibody levels in the absence of an EVD diagnosis.MethodologyData was collected from September 2015 to August 2017 from 1,366 consenting individuals across four study sites in the DRC (Boende, Kabondo-Dianda, Kikwit, and Yambuku). Seroreactivity was determined to EBOV GP IgG using Zaire Ebola Virus Glycoprotein (EBOV GP antigen) ELISA kits (Alpha Diagnostic International, Inc.) in Kinshasa, DRC; any result above 4.7 units/mL was considered seroreactive. Among the respondents, 113 (8.3%) were considered seroreactive. Several zoonotic exposures were associated with EBOV seroreactivity after controlling for age, sex, healthcare worker status, location, and history of contact with an EVD case, namely: ever having contact with bats, ever having contact with rodents, and ever eating non-human primate meat. Contact with monkeys or non-human primates was not associated with seroreactivity.ConclusionsThis analysis suggests that some zoonotic exposures that have been linked to EVD outbreaks can also be associated with EBOV GP seroreactivity in the absence of diagnosed EVD. Future investigations should seek to clarify the relationships between zoonotic exposures, seroreactivity, asymptomatic infection, and EVD.

AIDSVAX protein boost improves breadth and magnitude of vaccine-induced HIV-1 envelope-specific responses after a 7-year rest period

BackgroundEliciting durable humoral immunity with sufficient breadth and magnitude is important for HIV-1 vaccine design. The HVTN 114 vaccine trial evaluated different boost regimens administered after a 7-year rest period in participants previously enrolled in HVTN 205, who received either three MVA/HIV62B (MMM) or two DNA and two MVA/HIV62B (DDMM) injections; both vaccines expressed multiple HIV-1 antigens in non-infectious virus-like-particles. The primary objective of HVTN 114 was to assess the impact of a heterologous gp120 protein AIDSVAX B/E boost on the magnitude, breadth and durability of vaccine-induced immune responses. MethodsWe enrolled 27 participants from HVTN 205 into five groups. Eight participants who previously received MMM were randomized and boosted with either MVA/HIV62B alone (T1; n = 4) or MVA/HIV62B and AIDSVAX B/E (T2; n = 4). Nineteen participants who received DDMM were randomized and boosted with MVA/HIV62B alone (T3; n = 6), MVA/HIV62B and AIDSVAX B/E (T4; n = 6), or AIDSVAX B/E alone (T5; n = 7). Boosts were at months 0 and 4. Participants were followed for safety and immunogenicity for 10 months and were pooled for analysis based on the regimen: MVA-only (T1 + T3), MVA + AIDSVAX (T2 + T4), and AIDSVAX-only (T5). ResultsAll regimens were safe and well-tolerated. Prior to the boost vaccination, binding antibody and CD4+T-cell responses were observed 7 years after HVTN 205 vaccinations. Late boosting with AIDSVAX, with or without MVA, resulted in high binding antibody responses to gp120 and V1V2 epitopes, with increased magnitude and breadth compared to those observed in HVTN 205. Late boosting with MVA, with or without AIDSVAX, resulted in increased gp140 and gp41 antibody responses and higher CD4+T-cell responses to Env and Gag. ConclusionsLate boosting with AIDSVAX, alone or in combination with MVA, can broaden binding antibody responses and increase T-cell responses even years following the original MVA/HIV62B with or without DNA-priming vaccine.

WITHDRAWN: Hematological involvement in pediatric systemic lupus erythematosus: A multi-center study.

Introduction Systemic lupus erythematosus (SLE) may present with features of several systems, including hematological manifestations. In this study, we aimed to evaluate the characteristics of hematological involvement and assess possible associations and correlations in pediatric SLE patients. Method This is a retrospective multi-center study. The medical records of pediatric SLE patients followed between January 2000 and June 2020 were analyzed. All children fulfilled the criteria of the Systemic Lupus International Collaborating Clinics. Results The study included 215 children with SLE, 118 of whom had hematological manifestations. Concomitant renal involvement and low C3 levels were significantly more frequent in patients with hematological involvement ( p = 0.04, p = 0.008, respectively). Also, anti-cardiolipin, anti-beta-2-glycoprotein I (anti-β2 GP1), and anti-Smith (anti-Sm) antibody positivity, and the presence of lupus anticoagulant were more common in the group with hematological findings ( p = 0.001 for anti-cardiolipin antibody positivity and p &lt; 0.001 for the positivity of anti-β2 GP1 antibody, anti-Sm antibody, and lupus anticoagulant). The most common hematologic abnormality was anemia ( n = 88, 74.5%), with autoimmune hemolytic anemia constituting the majority ( n = 40). Corticosteroids followed by IVIG were the mainstay of treatment. In patients resistant to corticosteroid and IVIG treatments, the most preferred drug was rituximab. The presence of antiphospholipid antibodies and high SLEDAI score were independently associated with hematological involvement in multivariate analysis (OR: 0.249; 95%CI: 0.126–0.490; p &lt; 0.001 and OR: 1.136; 95%CI: 1.065–1.212; p &lt; 0.001). Conclusion Hematological abnormalities are frequently encountered in pediatric SLE. Positive antiphospholipid antibodies and high SLEDAI scores were associated with hematological involvement.

A microfluidic field-effect transistor biosensor with rolled-up indium nitride microtubes

Field-effect-transistor (FET) biosensors capable of rapidly detecting disease-relevant biomarkers have long been considered as a promising tool for point-of-care (POC) diagnosis. Rolled-up nanotechnology, as a batch fabrication strategy for generating three-dimensional (3D) microtubes, has been demonstrated to possess unique advantages for constructing FET biosensors. In this paper, we report a new approach combining the two fascinating technologies, the FET biosensor and the rolled-up microtube, to develop a microfluidic diagnostic biosensor. We integrated an excellent biosensing III-nitride material—indium nitride (InN)—into a rolled-up microtube and used it as the FET channel. The InN possesses strong, intrinsic, and stable electron accumulation (~1013 cm−2) on its surface, thereby providing a high device sensitivity. Multiple rolled-up InN microtube FET biosensors fabricated on the same substrate were integrated with a microfluidic channel for convenient fluids handling, and shared the same external electrode (inserted into the microchannel outlet) for gating voltage modulation. Using human immunodeficiency virus (HIV) antibody as a model disease marker, we characterized the analytical performance of the developed biosensor and achieved a limit of detection (LOD) of 2.5 pM for serum samples spiked with HIV gp41 antibodies. The rolled-up InN microtube FET biosensor represents a new type of III-nitride-based FET biosensor and holds significant potential for practical POC diagnosis.

Acceptability of blood-based HIV self-testing among adolescents aged 15-19 years at risk of HIV acquisition in Bangkok.

Young men who have sex with men (YMSM) and young transgender women (YTGW) in Thailand are at high HIV risk. HIV self-tests (HIVSTs) are rapidly administrable and prompt linkage to HIV treatment or prevention services. This study assesses the acceptability and feasibility of blood-based HIVST use in adolescents. A cross-sectional study was conducted among YMSM and YTGW aged 15-19years with HIV acquisition risk. Participants completed questionnaires on the HIVST and then administered INSTI® independently, an HIVST immunoassay detecting gp41 and gp36 antibodies from finger-stick blood. Confirmatory HIV antibody tests were performed. Between July and September 2020, 90 adolescents were enrolled. Mean (SD) age was 17.6 (1.1) years. Half (N = 45) were YMSM. Forty-six (51%) were first-time HIV testers, and 32 (36%) had "ever used" HIV pre-exposure prophylaxis (PrEP). Two (2.2%, 95% CI: 0.0-5.3) tested positive, 21 (23.4%) invalid, and 67 (74.4%) negative. Invalidity causes included 17 (81%) insufficient blood, 3 (14%) buffer spillage, and 1 (5%) procedural missteps; all had negative HIV antibody tests. HIV self-test acceptability was 87.8% (95% CI: 81.0-94.5). Most (79%) preferred HIVST performance in hospital rather than at home. HIVSTs are acceptable in HIV at-risk adolescents. Blood-based HIVSTs should be positioned as rapid point-of-care tests with real-time linkage to HIV services.

Altered Antibody Responses in Persons Infected with HIV-1 While Using Preexposure Prophylaxis.

Preexposure prophylaxis (PrEP) is an effective HIV prevention tool, although effectiveness is dependent upon adherence. It is important to characterize the impact of PrEP on HIV antibody responses in people who experience breakthrough infections to understand the potential impact on timely diagnosis and treatment. Longitudinal HIV-1-specific antibody responses were evaluated in 42 people who inject drugs (PWID) from the Bangkok Tenofovir Study (BTS) (placebo = 28; PrEP = 14) who acquired HIV while receiving PrEP. HIV-1 antibody levels and avidity to three envelope proteins (gp41, gp160, and gp120) were measured in the plasma using a customized Bio-Plex (Bio-Rad Laboratories, Hercules, CA) assay. A time-to-event analysis was performed for each biomarker to compare the distribution of times at which study subjects exceeded the recent/long-term assay threshold, comparing PrEP and placebo treatment groups. We fit mixed-effects models to identify longitudinal differences in antibody levels and avidity between groups. Overall, longitudinal antibody levels and avidity were notably lower in the PrEP breakthrough group compared to the placebo group. Time-to-event analyses demonstrated a difference in time to antibody reactivity between treatment groups for all Bio-Plex biomarkers. Longitudinal gp120 antibody levels within the PrEP breakthrough group were decreased compared to the placebo group. When accounting for PrEP adherence, both gp120 and gp160 antibody levels were lower in the PrEP breakthrough group compared to the placebo group. We demonstrate hindered envelope antibody maturation in PWID who became infected while receiving PrEP in the BTS, which has significant implications for HIV diagnosis. Delayed maturation of the antibody response to HIV may increase the time to detection for antibody-based tests. Clinical Trial Registration Number, NCT00119106.

Feeding Eggs from Hens Immunized with Specific KLH-Conjugated HIV Peptide Candidate Vaccines to Chicks Induces Specific Anti-HIV gp120 and gp41 Antibodies that Neutralize the Original HIV Antigens

Feeding Eggs from Hens Immunized with Specific KLH-Conjugated HIV Peptide Candidate Vaccines to Chicks Induces Specific Anti-HIV gp120 and gp41 Antibodies that Neutralize the Original HIV Antigens

Assessing donor suitability for blood donation: Utility of Geenius HIV 1/2 confirmatory assay

BackgroundBlood donor care and blood safety require a quick and accurate decision on the presence or absence of Human Immunodeficiency Virus (HIV) infection, based on the proper selection of blood donors, serological and molecular HIV testing as well as western blot test. The aim was investigating the possibility of inclusion of Geenius HIV 1/2 Confirmatory Assay in blood donor testing algorithm in order to shorten test time and decrease the number of indeterminate results. MethodsA total of 75 archived serum/plasma samples were tested. Their previous serological and molecular HIV results were: 3 negative samples, 7 positive samples, 65 serological indeterminate or positive but confirmatory testing and NAT negative samples. ResultsGeenius assay confirmed the presence of antibodies in all blood donors with HIV positive serology and Nucleic Acid Testing (NAT). HIV-1 gp160 and gp41 antibodies were detected in these donors, while p31 and p24 antibodies were not detected in two and three donors, respectively. HIV-2 antibodies gp36 and gp140 were not found. Blood donor with HIV indeterminate or positive serology but negative confirmatory testing and NAT, were negative in Geenius assay.Conclusion The results obtained are consistent with western blot results. The assay proved simple and quick to perform. Studies have confirmed the possibility of introducing Bio-Rad Geenius into a routine blood donor testing protocol.

Therapeutic vaccination of SIV-infected, ART-treated infant rhesus macaques using Ad48/MVA in combination with TLR-7 stimulation.

Globally, 1.8 million children are living with HIV-1. While antiretroviral therapy (ART) has improved disease outcomes, it does not eliminate the latent HIV-1 reservoir. Interventions to delay or prevent viral rebound in the absence of ART would be highly beneficial for HIV-1-infected children who now must remain on daily ART throughout their lifespan. Here, we evaluated therapeutic Ad48-SIV prime, MVA-SIV boost immunization in combination with the TLR-7 agonist GS-986 in rhesus macaque (RM) infants orally infected with SIVmac251 at 4 weeks of age and treated with a triple ART regimen beginning 4 weeks after infection. We hypothesized immunization would enhance SIV-specific T cell responses during ART-mediated suppression of viremia. Compared to controls, vaccinated infants had greater magnitude SIV-specific T cell responses (mean of 3475 vs 69 IFN-γ spot forming cells (SFC) per 106 PBMCs, respectively, P = 0.01) with enhanced breadth of epitope recognition and increased CD8+ and CD4+ T cell polyfunctionality (P = 0.004 and P = 0.005, respectively). Additionally, SIV-specific gp120 antibodies against challenge and vaccine virus strains were significantly elevated following MVA boost (P = 0.02 and P < 0.001, respectively). GS-986 led to expected immune stimulation demonstrated by activation of monocytes and T cells 24 hours post-dose. Despite the vaccine-induced immune responses, levels of SIV DNA in peripheral and lymph node CD4+ T cells were not significantly different from controls and a similar time to viral rebound and viral load set point were observed following ART interruption in both groups. We demonstrate infant RMs mount a robust immunological response to this immunization, but vaccination alone was not sufficient to impact viral reservoir size or modulate rebound dynamics following ART release. Our findings hold promise for therapeutic vaccination as a part of a combination cure approach in children and highlight the importance of a pediatric model to evaluate HIV-1 cure interventions in this unique setting of immune development.

Exploring optical spectroscopic techniques and nanomaterials for virus detection.

Viral infections pose significant health challenges globally by affecting millions of people worldwide and consequently resulting in a negative impact on both socioeconomic development and health. Corona virus disease 2019 (COVID-19) is a clear example of how a virus can have a global impact in the society and has demonstrated the limitations of detection and diagnostic capabilities globally. Another virus which has posed serious threats to world health is the human immunodeficiency virus (HIV) which is a lentivirus of the retroviridae family responsible for causing acquired immunodeficiency syndrome (AIDS). Even though there has been a significant progress in the HIV biosensing over the past years, there is still a great need for the development of point of care (POC) biosensors that are affordable, robust, portable, easy to use and sensitive enough to provide accurate results to enable clinical decision making. The aim of this study was to present a proof of concept for detecting HIV-1 pseudoviruses by using anti-HIV1 gp41 antibodies as capturing antibodies. In our study, glass substrates were treated with a uniform layer of silane in order to immobilize HIV gp41 antibodies on their surfaces. Thereafter, the HIV pseudovirus was added to the treated substrates followed by addition of anti-HIV gp41 antibodies conjugated to selenium nanoparticle (SeNPs) and gold nanoclusters (AuNCs). The conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies was characterized using UV–vis spectroscopy, transmission electron microscopy (TEM) and zeta potential while the surface morphology was characterized by fluorescence microscopy, atomic force microscopy (AFM) and Raman spectroscopy. The UV–vis and zeta potential results showed that there was successful conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies and fluorescence microscopy showed that antibodies immobilized on glass substrates were able to capture intact HIV pseudoviruses. Furthermore, AFM also confirmed the capturing HIV pseudoviruses and we were able to differentiate between substrates with and without the HIV pseudoviruses. Raman spectroscopy confirmed the presence of biomolecules related to HIV and therefore this system has potential in HIV biosensing applications.

Topical Tenofovir Pre-exposure Prophylaxis and Mucosal HIV-Specific Fc-Mediated Antibody Activities in Women

The RV144 HIV-vaccine trial highlighted the importance of envelope-specific non-neutralizing antibody (nNAb) Fc-mediated functions as immune correlates of reduced risk of infection. Since pre-exposure prophylaxis (PrEP) and HIV-vaccines are being used as a combination prevention strategy in at risk populations, the effects of PrEP on nNAb functions both mucosally and systemically remain undefined. Previous animal and human studies demonstrated reduced HIV-specific antibody binding avidity post-HIV seroconversion with PrEP, which in turn may affect antibody functionality. In seroconverters from the CAPRISA 004 tenofovir gel trial, we previously reported significantly higher detection and titres of HIV-specific binding antibodies in the plasma and genital tract (GT) that distinguished the tenofovir from the placebo arm. We hypothesized that higher HIV-specific antibody titres and detection reflected corresponding increased antibody-dependent neutrophil-mediated phagocytosis (ADNP) and NK-cell-activated antibody-dependent cellular cytotoxic (ADCC) activities. HIV-specific V1V2-gp70, gp120, gp41, p66, and p24 antibodies in GT and plasma samples of 48 seroconverters from the CAPRISA 004 tenofovir gel trial were tested for ADCP and ADCC at 3, 6- and 12-months post-HIV-infection. GT gp41- and p24-specific ADNP were significantly higher in the tenofovir than the placebo arm at 6 and 12 months respectively (p < 0.05). Plasma gp120-, gp41-, and p66-specific ADNP, and GT gp41-specific ADCC increased significantly over time (p < 0.05) in the tenofovir arm. In the tenofovir arm only, significant inverse correlations were observed between gp120-specific ADCC and gp120-antibody titres (r = −0.54; p = 0.009), and gp41-specific ADNP and gp41-specific antibody titres at 6 months post-infection (r = −0.50; p = 0.015). In addition, in the tenofovir arm, gp41-specific ADCC showed significant direct correlations between the compartments (r = 0.53; p = 0.045). Certain HIV-specific nNAb activities not only dominate specific immunological compartments but can also exhibit diverse functions within the same compartment. Our previous findings of increased HIV specific antibody detection and titres in women who used tenofovir gel, and the limited differences in nNAb activities between the arms, suggest that prior PrEP did not modulate these nNAb functions post-HIV seroconversion. Together these data provide insight into envelope-specific-nNAb Fc-mediated functions at the site of exposure which may inform on ensuing immunity during combination HIV prevention strategies including PrEP and HIV vaccines.

An Ebola virus vaccine that leverages helper T cells induced by prior BCG immunization

Abstract Protective antibody responses against the Ebola virus (EBOV) are dependent on the quality of CD4+ helper T (Th) cells. We propose that BCG specific Th cells may provide a source of Th cells that can be recruited to drive antibody responses against EBOV, given that the majority of individuals residing in EBOV endemic regions have been previously vaccinated with BCG. To take advantage of pre-existing BCG Th cells, a vaccine was developed that consists of the EBOV GP fused to the mycobacteria Th cell epitope (P25) of Ag85B (P25-EBOV GP). Presentation of the P25 epitope by B cells recruited cognate interactions with P25 Th cells to promote antibody responses against the EBOV GP. Experiments in mice showed BCG priming induced a broad range of Th cells including Th1, Th2, and Tfh subsets. These P25 Th subsets provided a significant dose sparing effect on the P25-EBOV GP vaccine in the induction of EBOV GP antibodies and resulted in increased titers of high affinity neutralizing IgG1 antibodies. The induction of IgG2c antibodies only occurred in BCG primed mice, where BCG vaccination is known to be a strong inducer of Th1 responses that drive class-switching to IgG2c. Microscopy of sections from secondary lymphoid organs of BCG primed mice showed that the majority of P25 Th cells remained in extrafollicular regions outside germinal centers and were most responsible for the induction of the IgG2c class-switched antibodies that were weakly neutralizing but capable of mediating antibody-dependent cellular toxicity (ADCC). BCG priming followed by vaccination with P25-EBOV GP protected mice against lethal EBOV infection, thus suggesting a potentially useful strategy for vaccination against EBOV in populations with high prevalence of previous BCG vaccination.