Production and isolation of guinea pig IgE antibody

Boosted systemic immune and local responsiveness after intestinal inflammation in orally sensitized guinea pigs

BACKGROUND & AIMS

Intestinal inflammation resulting in disruption of the mucosal barrier function has been proposed as a cause of increased incidence of allergic diseases. This study was designed to evaluate whether intestinal inflammation is able to change the immune responsiveness to sensitization and antigen challenge responses.

METHODS

Guinea pigs orally sensitized to cow's milk proteins were either treated or not treated with trinitrobenzenesulfonic acid (TNBS) to induce intestinal inflammation and compared with control animals (not sensitized). Systemic immune and local responsiveness to antigen challenge were assessed by measuring antibody serum titers, colonic fluid secretion, mucosal histamine level, and mucus depletion. Intestinal permeability was evaluated from 51Cr-ethylenediaminetetraacetic acid (EDTA) recovery and beta-lactoglobulin serum level.

RESULTS

Immunoglobulin E titers were higher in TNBS-treated animals than in non-TNBS-treated sensitized animals. Antigen challenge in TNBS-treated animals induced a fourfold increase of colonic secretion and greater histamine and mucus depletion than in non-TNBS-treated animals. Permeability to 51Cr-EDTA increased 5 days after TNBS treatment but was unchanged after antigen challenge. In contrast to controls, beta-lactoglobulin was not detected in the sera of challenged sensitized and TNBS-treated animals.

CONCLUSIONS

Intestinal inflammation increasing gut permeability enhances the sensitization process. Therefore, local anaphylactic reactions are exacerbated after antigen challenge.

Purification of immunoglobulin E (IgE) antibodies from sera with high IgE titers

A three stage method for the ultrapurification of polyclonal IgE from human serum is reported using anion exchange chromatography followed by monoclonal antibody based positive and negative affinity chromatography. Following dialysis of 25-100 ml of serum (2.3-14 micrograms IgE/ml, n = 4) against 0.05 M Tris pH 8, each specimen was subjected to diethylaminoethyl (DEAE)-cellulose chromatography (serum/matrix = 1/4). IgE was eluted with 0.05 M Tris, 0.05 M NaCl pH 8, yielding an IgE recovery of 61-93%, with removal of approximately 90% of other serum proteins and an IgE purity ([IgE]/[Igs]) of 0.1-1.1%. After adjusting to 0.1 M NaCl and concentrating approximately 30-fold, the eluted IgE was further purified by affinity chromatography using a panel of IUIS/WHO-documented mouse monoclonal anti-human immunoglobulin antibodies (alpha hIg-MAbs). First, the IgE-enriched DEAE-cellulose chromatography fraction was incubated in a batch mode with two alpha hIgE-Fc MAbs (HP6029, HP6061) coupled to CNBr-Sepharose, CL-4B. IgE was eluted with 0.05 M glycine pH 2.8 and immediately neutralized. The IgE recovery was 32-52% and IgE purity was 72-97%. Silver-stained SDS-PAGE and noncompetitive solid-phase two-site immunoenzymetric assays for total human IgA, IgE, IgG and IgM indicated that IgA, IgG and IgM were the only contaminants. Next, the IgE was concentrated 10-30-fold in the presence of 0.1% HSA. One IgE specimen was ultrapurified in a batch mode by negative selection chromatography using three pairs of alpha hIg-MAbs (alpha hIgA: HP6111 + HP6123; alpha hIgG: HP6017 + HP6046; alpha hIgM: HP6081 + HP6083) coupled to CNBr-Sepharose, CL-4B. IgE purity increased from 91% to > 99.9% with approximately 70% recovery of IgE for this step. The ultrapurified IgE antibody was shown to be functionally reactive for allergen and Fc epsilon RI receptors on human basophils. We conclude that alpha hIg-MAbs are powerful tools to facilitate the affinity purification of functionally active human IgE from serum; however, when the analyte is present in low concentration, a carrier protein needs to be added to minimize non-specific loss of the material during this process.

Purification of murine immunoglobulin M from spent tissue culture supernatant by one-step gel filtration chromatography procedure

Optimal purification of immunoglobulin M (IgM) grown as spent tissue culture supernatant can be achieved by a straightforward size-exclusion chromatography procedure. Preparative isolation of IgM was achieved by precipitation with saturated ammonium sulphate to achieve a 45% solution. IgM was then purified by gel filtration chromatography with a solution of 100 mM Tris + 150 mM NaCl at pH 8. Denaturing electrophoresis and Western immunoblotting revealed two prominent bands at 80 and 25 kDa, indicative of the heavy and light chains of IgM respectively. The specific immunoreactivity of this IgM was assessed by a modified enzyme antigen capture assay. In contrast to affinity and ion-exchange chromatographies, gel filtration allows retention of IgM immunoreactivity.

Studies on the isolation and characterisation of a reaginic antibody in a cat

A reaginic antibody has been demonstrated, by passive cutaneous anaphylaxis (PCA), in the serum of a cat infected with the microfilariae of Brugia pahangi. Recipient cats and pigs were challenged with an extract of Ascaris suum after either a four-hour or a 72-hour period of sensitisation. When the serum was heat treated at 56 degrees C it lost its PCA activity. Gel filtration of the serum revealed a pattern of positive PCA fractions similar to that observed in other species. Attempts to purify the PCA-positive material by Superose gel filtration and ion exchange chromatography by fast protein liquid chromatography (FPLC) were unsuccessful. Affinity chromatography of PCA-positive material by FPLC on protein A demonstrated two bound peaks, the second of which was PCA-positive and eluted as a single peak by ion exchange chromatography. The PCA-positive material from gel filtration did not bind to protein G. The protein A, PCA-positive peak provides a partially purified reaginic antibody for further study.

Protective action of diosmectite treatment on digestive disturbances induced by intestinal anaphylaxis in the guinea-pig

METHODS

Colonic transit time, faecal moisture and intestinal permeability were assessed in guinea-pigs sensitized intraperitoneally with cow's milk and challenged with an oral administration of beta-lactoglobulin. One group of animals was treated for 1 week with diosmectite (500 mg.kg/day) and another with placebo. A control group was not sensitized but treated with diosmectite.

RESULTS

In sensitized animals receiving placebo, challenge with beta-lactoglobulin induced a significant (P < 0.05) decrease in colonic transit time, and increases in faecal moisture and intestinal permeability. These changes were not observed in animals treated with diosmectite.

CONCLUSION

Diosmectite pre-treatment protects against allergic digestive disturbances induced by antigen administration in guinea-pigs sensitized to cow's milk.

Role of purified IgG1 in pulmonary hypersensitivity responses of the guinea pig

Guinea pigs have been used extensively to model pulmonary hypersensitivity responses. Although guinea pigs produce mainly immunoglobulin G1 (IgG1) antibodies and humans produce IgE, both immunoglobulin classes have been shown to be regulated similarly. We used an established guinea pig model to examine the role of IgG1 in immediate- and late-onset pulmonary hypersensitivity responses. IgG1 was purified from the serum of ovalbumin-immunized animals and shown to be free of IgE. It was transferred into naive recipients in doses quantified on the basis of its biological activity as measured in the passive cutaneous anaphylaxis (PCA) assay. Inhalation challenge of recipient animals 24 h later with an ovalbumin aerosol produced immediate-onset airway constrictive responses, with response dependent upon the quantity of antibody passively administered. None of the recipient animals displayed a late-phase response previously shown to be characterized by increased breathing frequency, airflow limitation during exhalation, and mild fever. However, pulmonary eosinophilia, measured at 24 h postinhalation challenge, was detected with the severity of the eosinophilia dependent upon the quantity of IgG1 administered. The results indicated that immediate-, but not late-onset, responses were associated with IgG1 antibody. Occurrence of late-onset pulmonary eosinophilia indicated that eosinophilic inflammation, a recognized characteristic of hypersensitivity responses, was related to antigen-specific IgG1 antibody.