Preparation of goat and rabbit anti-camel immunoglobulin G whole molecule labeled with horseradish peroxidase

Characterization of rabbit polyclonal antibody against camel recombinant nanobodies

Nanobodies (Nbs) are recombinant single-domain fragments derived from camelids’ heavy-chain antibodies (HCAbs). Nanobodies are increasingly used in numerous biotechnological and medical applications because of their high stability, solubility, and yield. However, one major obstacle prohibiting Nb expansion is the affordability of specific detector antibodies for their final revelation. In this work, the production of a specific anti-Nb antibody as a general detector for camel antibodies, conventional cIgG, and HCAb, and their derived Nbs was sought. Thus, a T7 promoter plasmid was constructed and used to highly express six different Nbs that were used in a successful rabbit immunization. Affinity-purified rabbit anti-Nb rIgG was able to detect immobilized or antigen-bound Nbs via enzyme-linked immunosorbent assay, and its performance was comparable to that of a commercial anti-6× His antibody. Its capacities in dosing impure Nbs, detecting Nbs displayed on M13 phages, and revealing denatured Nbs in immune blotting were all proven. As expected, and because of shared epitopes, rabbit anti-Nb cross-reacted with cIgG, HCAbs, and 6× His-tagged proteins, and the percentage of each fraction within anti-Nb rIgG was determined. Anti-Nb is a promising tool for the checkpoints throughout the recombinant Nb technology.

Indigenous production, characterization and evaluation of polyclonal antibody against Camelus dromedarius immunoglobulin

No diagnostic kits and reagents are available in the market to detect and evaluate camel immune responses to different pathogens. This study aimed to produce sheep anti-camel (Camelus dromedarius) polyclonal antibodies (pAbs) and to determine the specificity with other species immunoglobulin. Immunoglobulins (Igs) from camel serum samples were purified using ammonium sulfate precipitation (40.00% saturated ammonium sulfate). Purity of the camel Igs was tested by sodium dodecyl sulfate polyacrylamide gel electrophoresis. PAbs against (Camelus dromedarius) immunoglobulins were generated by immunizing sheep with purified Igs. Anti- camel Ig polyclonal antibodies titer and specificity were determined using ELISA and Western blot techniques. Polyclonal antibodies specific to camel Igs were significantly high in immunized sheep which confirmed the immunization procedure. PAbs reacted specifically with camel serum immunoglobulin and did not react with other species immunoglobulin of horse and chickens. Polyclonal antibodies produced in this study can be regarded as a valuable tool to be used for immune-diagnostic purposes in camel population world-wide.

Rapid detection of Vibrio parahaemolyticus using magnetic nanobead-based immunoseparation and quantum dot-based immunofluorescence

In recent years, the scale of population exposure and food poisoning caused by Vibrio parahaemolyticus (V. parahaemolyticus) has shown a significant upward trend, becoming one of the primary food-borne pathogens. Herein, we developed a rapid and sensitive detection of V. parahaemolyticus by integrating the technology of magnetic nanobeads (MBs) based immunoseparation (IMS) with quantum dots (QDs) based immunofluorescence. Firstly, specific rabbit polyclone IgG antibodies (IgG) and chicken egg yolk antibodies (IgY) of V. parahaemolyticus were prepared. Then two sizes of MBs (1 μm; 180 nm) were coupled with IgG to form immuno-MB (IMB) capture probes for evaluating the effect of different sizes on the detection efficiency. For QDs, they were conjugated with IgY to form fluorescent reporting probes. In the process of detection, IMB probes were used to separate V. parahaemolyticus and then these complexes were labeled by QD probes on the principle of double antibody sandwich. The fluorescence intensity of the IMB-V. parahaemolyticus-QD complexes was measured by a fluorescence spectrophotometer. The detection method takes 150 min with a detection limit of 102 cfu mL-1 ranging from 102 to 106 cfu mL-1 and it has been shown to work satisfactorily in real food samples.

Prophylactic Efficacy of Equine Immunoglobulin F(ab')2 Fragments Against Feline Parvovirus

Feline parvovirus (FPV), a type of parvovirus prevalent worldwide, can cause foetal death and acute enteritis in adult cats with severe leukopenia, and yet there are no effective drugs to prevent or treat FPV. Here, the immune effects of two FPV vaccines on horses were compared. IgG was extracted from FPV-immunized horse sera. Equine F(ab′)₂ fragments were obtained from pepsin-digested IgG and then purified by protein-G column chromatography. The results showed that the inactivated FPV oil vaccine was more effective than the inactivated FPV propolis vaccine in helping healthy horses to produce hyper-immune serum. Four methods were tested, among which the optimized octanoic acid-ammonium sulphate precipitation method was proved to be the best process for extracting IgG. The optimal condition for preparing F(ab′)₂ by pepsin digestion was 30 °C for 3.5 h, and the content, purity and recovery of F(ab′)₂ were 8.64 mg/mL, 90.36% and 93.24%, respectively. Our equine immunoglobulin F(ab′)₂ fragments effectively neutralized activity in vitro against FPV, alleviated the clinical symptoms of FPV-infected cats, reduced the viral loads in the intestine and had prophylactic effects in FPV-infected cats. These results indicate that the F(ab′)₂ fragment prepared from inactivated FPV-immunized horses may be used as a prophylactic agent for diseases caused by FPV.

Antibacterial efficacy of Moringa oleifera leaf extract against pyogenic bacteria isolated from a dromedary camel (Camelus dromedarius) abscess

Background:

Abscess in camel is one of the most important bacterial infections. It causes anemia and emaciation, resulting in an economic loss due to carcass condemnation and a decrease in reproductive and production efficiency.

Aim:

This investigation aimed to isolate the bacteria from abscesses in camels and evaluate the antibacterial activity of Moringa oleifera extracts.

Materials and Methods:

Disk diffusion method and minimum inhibitory concentration were used for the evaluation of the antibacterial activity of M. oleifera extracts against isolated bacteria from camel abscesses.

Results:

The isolated bacteria were displayed relatively as follows: Corynebacteriumpseudotuberculosis (30.4%), Staphylococcus aureus (25.8%), Escherichiacoli (17.8%), Corynebacteriumulcerans (10.5%), Klebsiellapneumoniae (8.5%), Pseudomonas aeruginosa (8.5%), Micrococcus spp. (6.7%), Proteus vulgaris (5.2%), Citrobacter spp. (4.2%), and Staphylococcus epidermidis (1.7%). The drugs of choice for Corynebacterium isolates were ciprofloxacin and trimethoprim/sulfamethoxazole, whereas amikacin, ciprofloxacin, gentamicin, neomycin, novobiocin, streptomycin, and vancomycin were for Staphylococcus isolates. Moreover, the ethanol extracts of M. oleifera showed higher antibacterial efficacy than the cold aqueous extracts.

Conclusion:

M. oleifera is considered one of the new infection-fighting strategies in controlling pyogenic bacteria responsible for camel abscesses.

Ficus sycomorus latex: An efficient alternative Egyptian source for horseradish peroxidase in labeling with antibodies for immunodiagnostic kits

Aim:

In view of various peroxidase applications, the searching for new sources of unique peroxidase properties is highly desirable. The present study aims to evaluate the efficiency of the peroxidase of locally grown sycamore latex (POL) for conjugation with antibodies and to study the conjugate optimal conditions, storage stability, and affinity toward different substrates as compared with commercial horseradish peroxidase (HRP).

Materials and Methods:

Anti-mouse antibodies were prepared in rabbits and purified by protein A sepharose affinity column chromatography. The POL and HRP conjugates were prepared by one-step glutaraldehyde coupling method. The reactivity of the prepared conjugates was examined using the enzyme-linked immunosorbent assay (ELISA). The optimal enzymatic conditions, storage stability, and affinity toward substrates were also determined for both the conjugates.

Results:

The POL showed higher percent recovery (98%) than HRP (78%) over the initial activity after conjugation process. The POL and HRP conjugates showed ELISA titers of 1:120 and 1:80, respectively, demonstrating high binding affinity of POL-conjugate. The POL-conjugate showed high thermal stability up to 70°C compared with HRP-conjugate up to 40°C. After conjugation, POL had wide pH stability (5.0-8.0) compared with HPR (4.5-6.0). Both of the prepared conjugates had a high affinity toward the substrates used in immunoassays with lower K_m values. The POL-conjugate showed high storage stability for its enzymatic activity and ELISA titer compared with HRP-conjugate after 1 year at −20°C.

Conclusion:

The POL of Ficus sycomorus latex is an efficient source for labeling antibodies and could be utilized in immunodiagnostic kits.

Generation of murine monoclonal antibodies with specificity against conventional camelid IgG1 and heavy-chain only IgG2/3

Camelids possess antibodies with a conventional four-chain structure consisting of two heavy and two light chains (of subclass IgG1) but further they also generate heavy-chain only antibodies (of subclass IgG2 and 3) which are fully functional in antigen binding. In this study subclass-specific murine monoclonal antibodies specific to conventional camelid IgG1 and heavy-chain only IgG2/3 were generated and validated for the use as potent secondary detection reagents. The monoclonal antibodies are able to differentiate between all camelid IgGs, conventional four-chain camelid antibodies (of subclass IgG1) and exclusively heavy chain-only antibodies (of subclasses IgG2 and IgG3). Further these antibodies were used to detect specific immune responses after vaccination of Camelids against bovine corona- and rotavirus strains and different E.coli and Clostridia - antigens and to identify Erysipelothrix rhusiopathiae infected animals within a herd. The described antibodies are suitable as new secondary agents for the detection of different camelid subclasses and the validation of camelid immune reactions.