Paratrygon aiereba irradiated anti-mucus serum reduce edematogenic activity induced in experimental model

Accidents by freshwater stingrays are common in northern Brazil, there is no specific therapy for high morbidity and local tissue destruction. The irradiation of venoms and toxins by ionizing radiation has been used to produce appropriate immunogens for the production of antisera. We planned to study the efficacy of stinging mucus irradiation in the production of antisera, with serum neutralization assays of edematogenic activity and quantification of cytokines performed in animal models of immunization with native and irradiated mucus of Paratrygon aiereba, a large freshwater stingray. Antiserum potency and its cross-reactivity with mucus from other freshwater stingrays were detected by ELISA. Immunization models demonstrated the ability to stimulate a strong humoral response with elevated levels of serum IgG detectable by ELISA, and both native and irradiated mucus were immunogenic and capable of recognizing mucus proteins from other freshwater neotropical stingrays. Mucus P. aiereba causes cellular and humoral adaptive immune responses in cells of immunized mice producing antibodies and cytokines such as TNF-α, IL-6 and IL-17. Rabbit antisera immunized with mucus from P. aiereba irradiated at 2 kGy showed a significant reduction of mucus-induced edematogenic activity in mice. Our data suggest that the use of antisera against freshwater stingray mucus show the possibility of specific therapy for these accidents.

[Establishment and evaluation of a triple-color human papillomavirus pseudovirion neutralization assay]

Objective: To establish a triple-color pseudovirion-based neutralization assay (PBNA) and evaluate its capability of detecting immunogenicity of the sera generated by the immunization of HPV 9-valent vaccine. Methods: HPV pseudovirus (PsVs) 6/11/16/18/31/33/45/52/58 with the encapsidated fluorescence expressing red fluorescent plasmid N31-MCHREEY, green fluorescent N31-EGFP or blue fluorescent N31-mTagBFP were generated. The concentration of HPV PsVs and the infection titers of HPV PsVs were detected by double-antibody sandwich ELISA and TCID(50), respectively. The single- and triple color HPV 16/33/45 PsVs were used to detect the neutralization titers of mice sera immunized with HPV 9-valent vaccine and confirmed the accuracy and specificity of the triple-color PBNAs. Then, the single- and triple color HPV 6/11/18/31/33/45/52/58 PsVs were employed to detect the neutralization titers of cynomolgus macaques sera immunized with HPV 9-valent vaccine and determined whether the triple-color PBNAs could be applied to evaluate the immunogenicity of the sera generated by the immunization of HPV9-valent vaccine. Results: The concentration of HPV16 PsVs encapsulating green, red or blue fluorescent plasmid was 5.0 to 6.0 μg/ml and HPV6/11/18/31/33/45/52/59 triple-color HPV PsVs was about 1.0 to 3.0 μg/ml. 9 types HPV PsVs containing EGFP, Mcherry or mTagBFP reporter plasmid were obtained and the concentration can meet the need of neutralization detection. 9 types single-color fluorescent HPV PsVs had similar infectivity against 293FT cells with the infection titer values between 1×10(4) and 1×10(5). The results of PBNAs showed that there was no significant difference in the anti-HPV neutralization titers of mice sera induced by HPV 9-valent vaccine between single-color and triple-color HPV16/33/45 PsVs (P>0.05). Similarly, there was also no significant difference in the anti-HPV neutralization titers of cynomolgus macaques sera induced by HPV 9-valent vaccine between single-color and triple-color HPV6/11/18/31/33/45/52/58 PsVs (P>0.05). Conclusion: We successfully established the triple-color PBNAs and verified the accuracy and specificity of triple-color PBNAs consistent with single-color PBNAs. The triple-color PBNAs can be applied to evaluate the immunogenicity of HPV 9-valent vaccine's immune serum.

Immunogenicity of Cork and Loop Domains of Recombinant Baumannii acinetobactin Utilization Protein in Murine Model

BACKGROUND

Acinetobacter baumannii (A. baumannii) is a bothersome fatal pathogen, particularly in healthcare system. Persistence and successful invasion of A. baumannii in vertebrate host cells largely depends on iron acquisition methods. Siderophore molecules and Iron-Regulated Outer Membrane Proteins (IROMPs) are the two essential members of iron acquisition system. Siderophores are secreted by bacteria to bind peripheral ferric iron and the IROMPs are expressed at the bacterial outer membrane as the receptor of ferric-siderophore complex. BauA is the corresponding siderophore receptor of A. baumannii. In this study, an attempt was made to assess the immunogenicity of antigenic domains of BauA which could be effective in iron uptake restriction and protection against bacterial invasion of the host cells.

METHODS

The antigenic domains of bauA were amplified from A. baumannii ATCC-19606. The PCR products were ligated into pET32a and expressed in Escherichia coli (E. coli) BL21 (DE3). Purification of recombinant domains was done by Nickel-Nitri-lotriacetic Acid (Ni-NTA) affinity chromatography. The recombinant domains were injected into BALB/C mice separately and in combination. Sero-reactivities of the recombinant proteins and mouse challenge tests were carried out.

RESULTS

The antibodies raised in mice could successfully recognize and bind antigenic domains. Passive immunization studies accomplished by immune rabbit serum inhibited the establishment of infection in mice.

CONCLUSION

The results adapted from the present study disclose the protective role of functional domains of BauA, especially the cork domain, suggesting a novel recombinant immunogen candidate.

A novel ex vivo immunoproteomic approach characterising Fasciola hepatica tegumental antigens identified using immune antibody from resistant sheep

A more thorough understanding of the immunological interactions between Fasciola spp. and their hosts is required if we are to develop new immunotherapies to control fasciolosis. Deeper knowledge of the antigens that are the target of the acquired immune responses of definitive hosts against both Fasciola hepatica and Fasciola gigantica will potentially identify candidate vaccine antigens. Indonesian Thin Tail sheep express a high level of acquired immunity to infection by F. gigantica within 4weeks of infection and antibodies in Indonesian Thin Tail sera can promote antibody-dependent cell-mediated cytotoxicity against the surface tegument of juvenile F. gigantica in vitro. Given the high protein sequence similarity between F. hepatica and F. gigantica, we hypothesised that antibody from F. gigantica-infected sheep could be used to identify the orthologous proteins in the tegument of F. hepatica. Purified IgG from the sera of F. gigantica-infected Indonesian Thin Tail sheep collected pre-infection and 4weeks p.i. were incubated with live adult F. hepatica ex vivo and the immunosloughate (immunoprecipitate) formed was isolated and analysed via liquid chromatography-electrospray ionisation-tandem mass spectrometry to identify proteins involved in the immune response. A total of 38 proteins were identified at a significantly higher abundance in the immunosloughate using week 4 IgG, including eight predicted membrane proteins, 20 secreted proteins, nine proteins predicted to be associated with either the lysosomes, the cytoplasm or the cytoskeleton and one protein with an unknown cellular localization. Three of the membrane proteins are transporters including a multidrug resistance protein, an amino acid permease and a glucose transporter. Interestingly, a total of 21 of the 38 proteins matched with proteins recently reported to be associated with the proposed small exosome-like extracellular vesicles of adult F. hepatica, suggesting that the Indonesian Thin Tail week 4 IgG is either recognising individual proteins released from extracellular vesicles or is immunoprecipitating intact exosome-like extracellular vesicles. Five extracellular vesicle membrane proteins were identified including two proteins predicted to be associated with vesicle transport/ exocytosis (VPS4, vacuolar protein sorting-associated protein 4b and the Niemann-Pick C1 protein). RNAseq analysis of the developmental transcription of the 38 immunosloughate proteins showed that the sequences are expressed over a wide abundance range with 21/38 transcripts expressed at a relatively high level from metacercariae to the adult life cycle stage. A notable feature of the immunosloughates was the absence of cytosolic proteins which have been reported to be secreted markers for damage to adult flukes incubated in vitro, suggesting that the proteins observed are not inadvertent contaminants leaking from damaged flukes ex vivo. The identification of tegument protein antigens shared between F. gigantica and F. hepatica is beneficial in terms of the possible development of a dual purpose vaccine effective against both fluke species.

Rabbit antiserum to mouse embryonic stem cells delays compaction of mouse preimplantation embryos

BACKGROUND

Mouse embryonic stem (ES) cells are derived from the inner cell mass (ICM) of the preimplantation blastocysts. So it is suggested that ES and ICM cells should have similar cellular surface molecules and antiserum to ES cells can inhibit ICM development.

OBJECTIVE

The objective of this study was to evaluate the effect of rabbit antiserum to ES cells on mouse preimplantation embryo development and chimera production.

MATERIALS AND METHODS

Mouse 4-cell embryos were matured in vitro at 37.5(o)C, in humidified 5% CO2 atmosphere for 12-36 h. The embryos were cultured in KSOM medium with or without antiserum for 12-36 h. The ratios of in vitro embryo development of the blastocysts, cell division, attachment potential, alkaline phosphatase activity, post-implantation development, and chimera production were assessed and compared with the control group. P<0.05 was considered as significant.

RESULTS

The rabbit antiserum to mouse ES cells showed delay in embryo compaction and induced decompaction at 8-cell stage. The development of 4-cell embryos in the presence of the antiserum for 36h did not lead to a reduced or absent ICM. These embryos still displayed positive alkaline phosphatase activity, normal cell division, embryo attachment, outgrowth formation, implantation and post-implantation development. In addition, decompaction induced by antiserum did not increase production and germline transmission of chimeric mice.

CONCLUSION

The results showed that antiserum to ES cells delayed embryo compaction and did not affect post-implantation development and chimera production.

Immune response to verotoxin 1 and 2 in children with Escherichia coli O157:H7 hemorrhagic colitis and classic hemolytic uremic syndrome

OBJECTIVES

To compare neutralizing antibody titres against verotoxin (vt)-1 and vt-2 between children with uncomplicated hemorrhagic colitis (hc) and those with classic hemolytic uremic syndrome (hus). vt antibody titres were also compared in children with hc who received trimethoprim-sulfamethoxazole with those who did not.

DESIGN

Prospective study.

SETTING

Tertiary pediatric hospital.

POPULATION STUDIED

Children with hc (n=41) or classic hus (n=12).

INTERVENTIONS

Serum antibodies against vt-1 and vt-2 were determined by quantitative neutralization.

MAIN RESULTS

Antibodies were detected in 40% (21 of 53) of serum samples for vt-1 and in 100% (53 of 53) of samples for vt-2. A positive immune response, defined as a fourfold increase in vt antibody titres or as a single titre of 1/64 or greater, was found in 0% (0 of 12) of patients with hus compared with 7% (three of 41) of those with hc for vt-1 (P=0.4); and in 17% (two of 12) of patients with hus compared with 22% (nine of 41) of those with hc for vt-2 (P=0.3). The rate of seroconversion against either vt-1 or vt-2 was comparable in treated and untreated patients with uncomplicated hc.

CONCLUSIONS

There was no evidence that neutralizing antibody levels against vt-1 or vt-2 in classic hus or after antibiotic therapy are substantially different from those in patients with uncomplicated hc.