Cross-Neutralizing and Protective Human Antibody Specificities to Poxvirus Infections.

Monkeypox (MPXV) and cowpox (CPXV) are emerging agents that cause severe human infections on an intermittent basis, and variola virus (VARV) has potential for use as an agent of bioterror. Vaccinia immune globulin (VIG) has been used therapeutically to treat severe orthopoxvirus infections but is in short supply. We generated a large panel of orthopoxvirus-specific human monoclonal antibodies (Abs) from immune subjects to investigate the molecular basis of broadly neutralizing antibody responses for diverse orthopoxviruses. Detailed analysis revealed the principal neutralizing antibody specificities that are cross-reactive for VACV, CPXV, MPXV, and VARV and that are determinants of protection in murine challenge models. Optimal protection following respiratory or systemic infection required a mixture of Abs that targeted several membrane proteins, including proteins on enveloped and mature virion forms of virus. This work reveals orthopoxvirus targets for human Abs that mediate cross-protective immunity and identifies new candidate Ab therapeutic mixtures to replace VIG.

Human monoclonal antibodies to pandemic 1957 H2N2 and pandemic 1968 H3N2 influenza viruses.

Investigation of the human antibody response to the 1957 pandemic H2N2 influenza A virus has been largely limited to serologic studies. We generated five influenza virus hemagglutinin (HA)-reactive human monoclonal antibodies (MAbs) by hybridoma technology from the peripheral blood of healthy donors who were born between 1950 and 1968. Two MAbs reacted with the pandemic H2N2 virus, two recognized the pandemic H3N2 virus, and remarkably, one reacted with both the pandemic H2N2 and H3N2 viruses. Each of these five naturally occurring MAbs displayed hemagglutination inhibition activity, suggesting specificity for the globular head domain of influenza virus HA. When incubated with virus, MAbs 8F8, 8M2, and 2G1 each elicited H2N2 escape mutations immediately adjacent to the receptor-binding domain on the HA globular head in embryonated chicken eggs. All H2N2-specific MAbs were able to inhibit a 2006 swine H2N3 influenza virus. MAbs 8M2 and 2G1 shared the V(H)1-69 germ line gene, but these antibodies were otherwise not genetically related. Each antibody was able to protect mice in a lethal H2N2 virus challenge. Thus, even 43 years after circulation of H2N2 viruses, these subjects possessed peripheral blood B cells encoding potent inhibiting antibodies specific for a conserved region on the globular head of the pandemic H2 HA.

Gold nanorod vaccine for respiratory syncytial virus.

Respiratory syncytial virus (RSV) is a major cause of pneumonia and wheezing in infants and the elderly, but to date there is no licensed vaccine. We developed a gold nanorod construct that displayed the major protective antigen of the virus, the fusion protein (F). Nanorods conjugated to RSV F were formulated as a candidate vaccine preparation by covalent attachment of viral protein using a layer-by-layer approach. In vitro studies using ELISA, electron microscopy and circular dichroism revealed that conformation-dependent epitopes were maintained during conjugation, and transmission electron microscopy studies showed that a dispersed population of particles could be achieved. Human dendritic cells treated with the vaccine induced immune responses in primary human T cells. These results suggest that this vaccine approach may be a potent method for immunizing against viruses such as RSV with surface glycoproteins that are targets for the human immune response.

In Vitro Diagnostic Assay to Detect SARS-CoV-2-Neutralizing Antibody in Patient Sera Using Engineered ACE-2 Mini-Protein.

The recent development and mass administration of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines allowed for disease control, reducing hospitalizations and mortality. Most of these vaccines target the SARS-CoV-2 Spike (S) protein antigens, culminating with the production of neutralizing antibodies (NAbs) that disrupt the attachment of the virus to ACE2 receptors on the host cells. However, several studies demonstrated that the NAbs typically rise within a few weeks after vaccination but quickly reduce months later. Thus, multiple booster administration is recommended, leading to vaccination hesitancy in many populations. Detecting serum anti-SARS-CoV-2 NAbs can instruct patients and healthcare providers on correct booster strategies. Several in vitro diagnostics kits are available; however, their high cost impairs the mass NAbs diagnostic testing. Recently, we engineered an ACE2 mimetic that interacts with the Receptor Binding Domain (RBD) of the SARS-2 S protein. Here we present the use of this engineered mini-protein (p-deface2 mut) to develop a detection assay to measure NAbs in patient sera using a competitive ELISA assay. Serum samples from twenty-one patients were tested. Nine samples (42.8%) tested positive, and twelve (57.1%) tested negative for neutralizing sera. The data correlated with the result from the standard commercial assay that uses human ACE2 protein. This confirmed that p-deface2 mut could replace human ACE2 in ELISA assays. Using bacterially expressed p-deface2 mut protein is cost-effective and may allow mass SARS-CoV-2 NAbs detection, especially in low-income countries where economical diagnostic testing is crucial. Such information will help providers decide when a booster is required, reducing risks of reinfection and preventing the administration before it is medically necessary.

Chemokine markers predict biochemical recurrence of prostate cancer following prostatectomy.

PURPOSE: Stratifying patients who have a high risk of prostate cancer recurrence following prostatectomy can potentiate the use of adjuvant therapy at an early stage. Inflammation has emerged as a mediator of prostate cancer metastatic progression. We hypothesized that chemokines can be biomarkers for distinguishing patients with high risk for biochemical recurrence of prostate cancer. EXPERIMENTAL DESIGN: In a nested case-control study, 82 subjects developed biochemical recurrence within 5 years of prostatectomy. Prostate tissues from 98 age-matched subjects who were recurrence-free following prostatectomy in the same period were the controls. A high-throughput lectin-based enrichment of prostate tissue enabled multiplex ELISA to identify the expression of three chemokines to discriminate the two patient populations. RESULTS: The expression of CX3CL1 and IL-15 in prostate tissue was associated with 5-year biochemical recurrence-free survival following prostatectomy. However, the expression of chemokine ligand 4 (CCL4) was associated with biochemical recurrence. Multivariable logistic regression model combining preoperative prostate-specific antigen, Gleason score, surgical margin, and seminal vesicle status with the three chemokines doubled the specificity of prediction at 90% sensitivity compared with use of the clinicopathologic variables alone (P < 0.0001). Survival analysis yielded a nomogram that supported the use of CX3CL1, IL-15, and CCL4 in predicting 1-, 3-, and 5-year recurrence-free survival after prostatectomy. CONCLUSIONS: Each of the three chemokines can serve as independent predictors of biochemical recurrence. However, the combination of chemokine biomarkers plus clinicopathologic variables discriminated prostatectomy subjects for the probability of biochemical recurrence significantly better than clinicopathologic variables alone.

CelF of Orpinomyces PC-2 has an intron and encodes a cellulase (CelF) containing a carbohydrate-binding module.

A cDNA, designated celF, encoding a cellulase (CelF) was isolated from the anaerobic fungus Orpinomyces PC-2. The open reading frame contains regions coding for a signal peptide, a carbohydrate-binding module (CBM), a linker, and a catalytic domain. The catalytic domain was homologous to those of CelA and CelC of the same fungus and to that of the Neocallimastix patriciarum CELA, but CelF lacks a docking domain, characteristic for enzymes of cellulosomes. It was also homologous to the cellobiohydrolase IIs and endoglucanases of aerobic organisms. The gene has a 111-bp intron, located within the CBM-coding region. Some biochemical properties of the purified recombinant enzyme are described.

Human antibodies that neutralize respiratory droplet transmissible H5N1 influenza viruses.

Recent studies described the experimental adaptation of influenza H5 HAs that confers respiratory droplet transmission (rdt) to influenza virus in ferrets. Acquisition of the ability to transmit via aerosol may lead to the development of a highly pathogenic pandemic H5 virus. Vaccines are predicted to play an important role in H5N1 control should the virus become readily transmissible between humans. We obtained PBMCs from patients who received an A/Vietnam/1203/2004 H5N1 subunit vaccine. Human hybridomas were then generated and characterized. We identified antibodies that bound the HA head domain and recognized both WT and rdt H5 HAs. We used a combination of structural techniques to define a mechanism of antibody recognition of an H5 HA receptor-binding site that neutralized H5N1 influenza viruses and pseudoviruses carrying the HA rdt variants that have mutations near the receptor-binding site. Incorporation or retention of this critical antigenic site should be considered in the design of novel H5 HA immunogens to protect against mammalian-adapted H5N1 mutants.

The human neonatal B cell response to respiratory syncytial virus uses a biased antibody variable gene repertoire that lacks somatic mutations.

The human Ab repertoire exhibits restrictions during fetal life characterized by biases of variable gene segment usage and lack of junctional diversity. We tested the hypotheses that Ab repertoire restriction persists in the early postnatal period and contributes to the observed poor quality of specific Ab responses made by neonates to viruses and vaccines. We analyzed the molecular determinants of B cell responses in humans to respiratory syncytial virus (RSV). Analysis of the variable gene segment usage of adult RSV-specific B cells revealed a repertoire profile in these cells similar to that seen in randomly selected B cells, which was V(H)3-dominant. Four gene segments (V(H)3-23, V(H)3-30, V(H)3-33 and V(H)4-04) accounted for almost half of the V(H) genes used. In contrast, very young infant RSV-specific antibodies exhibited a biased repertoire characterized by comparable use of the V(H)1, V(H)3, and V(H)4 families, and less common use of the four immunodominant gene segments. Infants and children older than three months used an antibody repertoire similar to that of adults. Mutational analysis revealed that the antibody variable genes of infants under three months of age also possessed significantly fewer somatic mutations in both framework and complementarity-determining region (CDR) regions than those of adults, even in a child with recurrent RSV infection. These data suggest that neonates use a biased antibody gene repertoire that is less V(H)3-focused and that possesses a dramatically lower frequency of somatic mutations. These biased features of the RSV-specific repertoire likely contribute to the poor functional Ab response in very young infants.

Detection of pre-neoplastic and neoplastic prostate disease by MALDI profiling of urine.

The heterogeneous progression to the development of prostate cancer (PCa) has precluded effective early detection screens. Existing prostate cancer screening paradigms have relatively poor specificity for cancer relative to other prostate diseases, commonly benign prostatic hyperplasia (BPH). A method for discrimination of BPH, HGPIN, and PCa urine proteome was developed through testing 407 patient samples using matrix assisted laser desorption-mass spectrometry time of flight (MALDI-TOF). Urine samples were adsorbed to reverse phase resin, washed, and the eluant spotted directly for MALDI-TOF analysis of peptides. The processing resolved over 130 verifiable signals of a mass range of 1000-5000 m/z to suggest 71.2% specificity and 67.4% sensitivity in discriminating PCa vs. BPH. Comparing BPH and HGPIN resulted in 73.6% specificity and 69.2% sensitivity. Comparing PCa and HGPIN resulted in 80.8% specificity and 81.0% sensitivity. The high throughput, low-cost assay method developed is amenable for large patient numbers required for supporting biomarker identification.

Automated carbohydrate profiling by capillary electrophoresis: a bioindustrial approach.

Automated, high-resolution, quantitative, high-throughput analysis of mono- and oligosaccharides, produced by enzymatic digestion of cellohexaose (model substrate) and lignocellulosic biomass, is demonstrated using high-performance capillary electrophoresis in conjunction with a single-step fluorophore labeling strategy for sensitive laser-induced fluorescence detection. Unattended batch sample processing from 96-well plates enabled reliable industrial-scale carbohydrate analysis. Excellent resolution of mono- and oligosaccharides was achieved under suppressed electroosmotic flow conditions, using either covalently or dynamically coated fused-silica capillary columns. The proposed approach readily supports the demands of bioindustrial operation environments with respect to high-throughput carbohydrate profiling.