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Polyvalent passive vaccines can act fast in resisting various bacteria with good efficacy, and they have application value in aquaculture. This study prepared live and inactivated Vibrio fluvialis mouse antisera (L-VF-antiserum and I-VF-antiserum), and administered them to goldfish (Carassius auratus) infected with V. fluvialis and Aeromonas hydrophila. The passive protective rates of live and inactivated mouse antisera against V. fluvialis were 60% (p < 0.05) and 40% (p < 0.05), and their passive cross-protective rates against A. hydrophila were 42.86% (p < 0.05) and 35.71% (p < 0.05), respectively. Furthermore, the two mouse antisera could recognize the bacteria in vitro; the content of bacteria in the C. auratus kidney decreased (p < 0.05), the phagocytic activity of C. auratus leukocytes was enhanced (p < 0.05), and the expression of inflammatory genes and activity of antioxidant factors decreased (p < 0.05). Moreover, the kidney, spleen, and intestinal tissue structures were intact, and the apoptosis and DNA damage were decreased (p < 0.05) among the kidney cells. The live V. fluvialis antiserum contained more antibodies against the outer membrane proteins of V. fluvialis than the inactivated mouse antiserum. The immunoprotective abilities of the live V. fluvialis antiserum were higher than those of the inactivated antiserum, and the antiserum of live V. fluvialis immunity demonstrated potential application value as a polyvalent passive immune vaccine in fish. [ABSTRACT FROM AUTHOR]

Recent years have seen an unprecedented rise in the incidence of multidrug-resistant (MDR) Gram-negative bacteria (GNBs) such as Acinetobacter and Klebsiella species. In view of the shortage of novel drugs in the pipeline, alternative strategies to prevent, and treat infections by GNBs are urgently needed. Previously, we have reported that the Candida albicans hypha-regulated protein Hyr1 shares striking three-dimensional structural homology with cell surface proteins of Acinetobacter baumannii. Moreover, active vaccination with rHyr1p-N or passive immunization with anti-Hyr1p polyclonal antibody protects mice from Acinetobacter infection. In the present study, we use molecular modeling to guide design of monoclonal antibodies (mAbs) generated against Hyr1p and show them to bind to priority surface antigens of Acinetobacter and Klebsiella pneumoniae. The anti-Hyr1 mAbs block damage to primary endothelial cells induced by the bacteria and protect mice from lethal pulmonary infections mediated by A. baumannii or K. pneumoniae. Our current studies emphasize the potential of harnessing Hyr1p mAbs as a cross-kingdom immunotherapeutic strategy against MDR GNBs.

Skeletal muscle is ideal for passive vaccine administration as it is easily accessible by intramuscular injection. Recombinant adeno-associated virus (rAAV) vectors are in consideration for passive vaccination clinical trials for HIV and influenza. However, greater human skeletal muscle transduction is needed for therapeutic efficacy than is possible with existing serotypes. To bioengineer capsids with therapeutic levels of transduction, we utilized a directed evolution approach to screen libraries of shuffled AAV capsids in pools of surgically resected human skeletal muscle cells from five patients. Six rounds of evolution were performed in various muscle cell types, and evolved variants were validated against existing muscle-tropic serotypes rAAV1, 6, and 8. We found that evolved variants NP22 and NP66 had significantly increased primary human and rhesus skeletal muscle fiber transduction from surgical explants ex vivo and in various primary and immortalized myogenic lines in vitro. Importantly, we demonstrated reduced seroreactivity compared to existing serotypes against normal human serum from 50 adult donors. These capsids represent powerful tools for human skeletal muscle expression and secretion of antibodies from passive vaccines.

BACKGROUND: Cryptosporidium parvum is a coccidian parasite with worldwide distribution. OBJECTIVES: It is considered one of the most important causes of diarrhea in many vertebrate species and immunocompromised humans. Due to the lack of effective treatment of cryptosporidiosis, protection strategy against this species can be focused on encouraging the immune system through vaccine development. METHODS: For this aim, we prepared oocysts lysate as a whole antigen vaccine candidate (420 μg) and immunized 3 pregnant cows 4 times every 2 weeks from 70 days to parturition. As a control group, 3 unimmunized pregnant cows were used. After parturition, each calf was fed with colostrum of his dam and challenged at 12h of age with 1×107C. parvum oocysts. RESULTS: In contrast to the test group, the calves in the control group developed severe watery diarrhea with excretion of oocysts from 4 days post-infection. The calves in the test group, which received the hyperimmune colostrum, showed no clinical signs and a significant reduction in oocysts excretion. CONCLUSIONS: The whole antigen prepared from oocysts of C. parvum can be considered a suitable candidate for immunizing pregnant cows producing hyperimmune colostrum. [ABSTRACT FROM AUTHOR]

Recent years have seen an unprecedented rise in the incidence of multidrug-resistant (MDR) Gram-negative bacteria (GNBs) such as Acinetobacter and Klebsiella species. In view of the shortage of novel drugs in the pipeline, alternative strategies to prevent, and treat infections by GNBs are urgently needed. Previously, we have reported that the Candida albicans hypha-regulated protein Hyr1 shares striking three-dimensional structural homology with cell surface proteins of Acinetobacter baumannii. Moreover, active vaccination with rHyr1p-N or passive immunization with anti-Hyr1p polyclonal antibody protects mice from Acinetobacter infection. In the present study, we use molecular modeling to guide design of monoclonal antibodies (mAbs) generated against Hyr1p and show them to bind to priority surface antigens of Acinetobacter and Klebsiella pneumoniae. The anti-Hyr1 mAbs block damage to primary endothelial cells induced by the bacteria and protect mice from lethal pulmonary infections mediated by A. baumannii or K. pneumoniae. Our current studies emphasize the potential of harnessing Hyr1p mAbs as a cross-kingdom immunotherapeutic strategy against MDR GNBs.

Recent years have seen an unprecedented rise in the incidence of multidrug-resistant (MDR) Gram-negative bacteria (GNBs) such as Acinetobacter and Klebsiella species. In view of the shortage of novel drugs in the pipeline, alternative strategies to prevent, and treat infections by GNBs are urgently needed. Previously, we have reported that the Candida albicans hypha-regulated protein Hyr1 shares striking three-dimensional structural homology with cell surface proteins of Acinetobacter baumannii. Moreover, active vaccination with rHyr1p-N or passive immunization with anti-Hyr1p polyclonal antibody protects mice from Acinetobacter infection. In the present study, we use molecular modeling to guide design of monoclonal antibodies (mAbs) generated against Hyr1p and show them to bind to priority surface antigens of Acinetobacter and Klebsiella pneumoniae. The anti-Hyr1 mAbs block damage to primary endothelial cells induced by the bacteria and protect mice from lethal pulmonary infections mediated by A. baumannii or K. pneumoniae. Our current studies emphasize the potential of harnessing Hyr1p mAbs as a cross-kingdom immunotherapeutic strategy against MDR GNBs. [ABSTRACT FROM AUTHOR]

The causative agent of acute hepatopancreatic necrosis disease (AHPND) is the bacterium, Vibrio parahaemolyticus, which secretes toxins into the gastrointestinal tract of its host. Vibrio parahaemolyticus toxins A and B (PirAvp/PirBvp) have been implicated in the pathogenesis of this disease, and are, therefore, the focus of studies developing treatments for AHPND. We previously produced recombinant antibodies based on the hagfish variable lymphocyte receptor B (VLRB) capable of neutralizing some viruses, suggesting that this type of antibody may have a potential application for treatment of AHPND. Here, recombinant PirAvp/PirBvp, produced using a bacterial expression system, were used as antigens to screen a hagfish VLRB cDNA library to obtain PirAvp/PirBvp-specific antibodies. A cell line secreting these antibodies was established by screening and cloning the DNA extracted from hagfish B cells. Supernatants collected from cells secreting the PirAvp/PirBvp antibodies were collected and concentrated, and used to passively immunize shrimp to neutralize the toxins PirAvp or PirBvp associated with AHPND. Briefly, 10 μg of PirAvp and PirBvp antibodies, 7C12 and 9G10, respectively, were mixed with the shrimp feed, and fed to shrimp for three days consecutive days prior to experimentally infecting the shrimp with V. parahaemolyticus (containing toxins A and B), and resulting mortalities recorded for six days. Results showed significantly higher level of survival in shrimp fed with the PirBvp-9G10 antibody (60%) compared to the group fed the PirAvp-7C12 antibody (3%) and the control group (0%). This suggests that VLRB antibodies may be a suitable alternative to immunoglobulin-based antibodies, as passive immunization treatments for effective management of AHPND outbreaks within shrimp farms.

Western equine encephalitis virus (WEEV) causes symptoms in humans ranging from mild febrile illness to life-threatening encephalitis, and no human medical countermeasures are licensed. A previous study demonstrated that immune serum from vaccinated mice protected against lethal WEEV infection, suggesting the utility of antibodies for pre- and post-exposure treatment. Here, three neutralizing and one binding human-like monoclonal antibodies were evaluated against WEEV aerosol challenge. Dose-dependent protection was observed with two antibodies administered individually, ToR69-3A2 and ToR68-2C3. In vitro neutralization was not a critical factor for protection in this murine model, as ToR69-3A2 is a strong neutralizing antibody, and ToR68-2C3 is a non-neutralizing antibody. This result highlights the importance of both neutralizing and non-neutralizing antibodies in the protection of mice from WEEV lethality.

Abstract: Passive vaccination is used to treat a wide range of infections and cancer. However, this approach has some limitations. An immune complex termed Y-complex was developed to intensify the effect of the passive vaccine. The complex is composed of a microbead that carries specific antibodies and an inducer. It enables targeting of pathogen or abnormal cells, and stimulation of a desired response by innate immune cells, depending on the inducer. The production and efficacy of Y-complex as a passive immune prophylaxis is demonstrated in this study by its use in treating cow mastitis. In an in vitro assay, Y-complex inhibited propagation and induced phagocytosis of bacteria. In challenge experiments, cows were inoculated through the udder with Escherichia coli or Streptococcus dysgalactiae. Following treatment with Y-complex, no bacteria were isolated in the milk and N-acetyl-ß-d-glucosaminidase activity had returned to normal levels. Thus the Y-complex approach can be used as an effective treatment for mastitis. Due to its modularity, this approach may serve as a treatment for a variety of disease agents. [Copyright &y& Elsevier]

Abstract: Antibody-genes undergo molecular events that produce unique binding-sites that recognize specific epitopes, thus, leading to B-cell clonal variation. As a result, different binding-site structures (paratope internal images) are produced even when two distinct B-cells bind one and the same epitope. Paratope structural variation can be exploited to enable one to evaluate antibody-diversity in a single polyclonal serum sample. This is accomplished through the selection of antibody-specific peptides isolated from combinatorial phage displayed peptide libraries. As an example, we demonstrate the analysis of macaque sera containing passively administered antibodies, given as a therapeutic vaccine and antibodies actively produced by the virus-infected monkeys. [Copyright &y& Elsevier]

The causative agent of acute hepatopancreatic necrosis disease (AHPND) is the bacterium, Vibrio parahaemolyticus, which secretes toxins into the gastrointestinal tract of its host. Vibrio parahaemolyticus toxins A and B (PirAvp/PirBvp) have been implicated in the pathogenesis of this disease, and are, therefore, the focus of studies developing treatments for AHPND. We previously produced recombinant antibodies based on the hagfish variable lymphocyte receptor B (VLRB) capable of neutralizing some viruses, suggesting that this type of antibody may have a potential application for treatment of AHPND. Here, recombinant PirAvp/PirBvp, produced using a bacterial expression system, were used as antigens to screen a hagfish VLRB cDNA library to obtain PirAvp/PirBvp-specific antibodies. A cell line secreting these antibodies was established by screening and cloning the DNA extracted from hagfish B cells. Supernatants collected from cells secreting the PirAvp/PirBvp antibodies were collected and concentrated, and used to passively immunize shrimp to neutralize the toxins PirAvp or PirBvp associated with AHPND. Briefly, 10 μg of PirAvp and PirBvp antibodies, 7C12 and 9G10, respectively, were mixed with the shrimp feed, and fed to shrimp for three days consecutive days prior to experimentally infecting the shrimp with V. parahaemolyticus (containing toxins A and B), and resulting mortalities recorded for six days. Results showed significantly higher level of survival in shrimp fed with the PirBvp-9G10 antibody (60%) compared to the group fed the PirAvp-7C12 antibody (3%) and the control group (0%). This suggests that VLRB antibodies may be a suitable alternative to immunoglobulin-based antibodies, as passive immunization treatments for effective management of AHPND outbreaks within shrimp farms. [ABSTRACT FROM AUTHOR]

Western equine encephalitis virus (WEEV) causes symptoms in humans ranging from mild febrile illness to life-threatening encephalitis, and no human medical countermeasures are licensed. A previous study demonstrated that immune serum from vaccinated mice protected against lethal WEEV infection, suggesting the utility of antibodies for pre- and post-exposure treatment. Here, three neutralizing and one binding human-like monoclonal antibodies were evaluated against WEEV aerosol challenge. Dose-dependent protection was observed with two antibodies administered individually, ToR69-3A2 and ToR68-2C3. In vitro neutralization was not a critical factor for protection in this murine model, as ToR69-3A2 is a strong neutralizing antibody, and ToR68-2C3 is a non-neutralizing antibody. This result highlights the importance of both neutralizing and non-neutralizing antibodies in the protection of mice from WEEV lethality. [ABSTRACT FROM AUTHOR]