Benzylpenicillin preparations can evoke a systemic anaphylactic reaction in guinea pigs

[Pathogenic Mechanism and Diagnostic Testing for Drug Allergies]

　Three stages of the pathogenic mechanism of drug allergies can be considered: antigen formation, immune reaction and inflammation/disorder reaction. Drugs are thought to form 4 types of antigens: drug only, polymers, drug-carrier conjugates, and metabolite-carrier complexes. Antigens are recognized by B cell receptors and T cell receptors. Helper T cells (Th) are differentiated into four subsets, namely, Th1, Th2, Th17 and regulatory T cells (Treg). Th1 produces interleukin (IL)-2 and interferon (IFN)-γ, and activates macrophages and cytotoxic T cells (Tc). Macrophages induce type IV allergies, and Tc lead to serious type IV allergies. On the other hand, Th2 produces IL-4, IL-5, and IL-6, etc., and activates B cells. B cells produce IgE antibodies, and the IgE antibody affects mast cells and induces type I allergies. Activated eosinophil leads to the chronic state of type I allergy. Diagnostic testing for allergenic drugs is necessary for patients with drug allergies. Because in vivo diagnostic tests for allergenic drugs are associated with a risk and burden to the patient, in vitro allergy tests are recommended to identify allergenic drugs. In allergy tests performed in vitro, cytological tests are more effective than serological tests, and the leukocyte migration test (LMT) presently has the highest efficacy. An LMT-chamber is better than LMT-agarose in terms of usability and sensitivity, and it can detect about 80% of allergenic drugs.

An assessment of antigenic potential of beta-lactam antibiotics, low molecular weight drugs, using guinea pig models

Allergic reactions are among the common adverse effects in humans. However, it is widely assumed that there are practically no reliable animal models for preclinical tests of low-molecular weight drugs that are available to predict such reactions. This study was designed to compare the detecting ability of test methods for antigenic potential of eight beta-lactam antibiotics with which allergic outcome has been reported in humans. The tests included active systemic anaphylaxis (ASA), delayed type skin reaction (DSR), maximization test (GPMT) in guinea pigs sensitized with antibiotics emulsified with Freund's complete adjuvant, passive cutaneous anaphylaxis (PCA) and enzyme-linked immunosorbent assay (ELISA) as serological tests. PCA and ELISA though using protein-conjugates as detecting antigens, especially ELISA, showed positive reactions with relatively high incidence. On the other hand, GPMT was the most sensitive method to detect antigenic potential of antibiotics despite the use of antibiotics alone for sensitizing and challenging phases. It is suggested that GPMT can be considered the most reliable method in preclinical testing.

Eliciting IgE-mediated passive cutaneous anaphylactic reaction by synthetic D-benzylpenilloic acid analogs

The ability of various D-benzylpenilloic acid analogs to evoke the passive cutaneous anaphylactic (PCA) reaction was tested in rats sensitized with mouse IgE antibodies to a benzylpenicillin preparation. D-benzylpenilloic acid synthesized chemically from materials that had no potency to evoke the PCA reaction showed almost the same antigenicity in eliciting the reaction as that prepared from benzylpenicillin. Changes in the chemical structures of the side-chain and thiazolidine ring of D-benzylpenilloic acid resulted in a reduction in the activity, but the removal of either alpha- or beta-methyl did not greatly affect it. From these results, it was concluded that benzyl and amidomethyl at C-2, the D-configuration at C-4, and dimethyl at C-5 on the thiazolidine ring have a significant effect on the PCA reaction.

Gold-induced reduction in reactivity to histamine in isolated guinea pig tracheal rings

Direct effects of gold preparations on the smooth muscle were investigated on isolated guinea pig tracheal rings. Pretreatment of the tracheal rings for 150 min with 100 microM of gold sodium thiomalate [Au(I)] significantly reduced the contraction heights induced by 4.5 microM histamine from 0.24 +/- 0.02 to 0.14 +/- 0.01 g (p less than 0.01). Gold chloride [Au(III)] was far more potent in its inhibitory effects than gold sodium thiomalate. With 15 min preincubation, gold chloride significantly suppressed the histamine-induced contraction (p less than 0.05) at such a low concentration as 10 microM (3.4 micrograms/ml). Gold chloride as well as gold sodium thiomalate did not interfere with the ciliary motion of the tracheal epithelium, whereas colchicine, having no effect on the histamine-induced contraction, did interfere with ciliary motion. These results reveal that gold itself inhibits noncaustically the guinea pig tracheal contraction induced by histamine.

Antigenicity of semisynthetic penicillin preparations to evoke systemic anaphylactic reactions in animal models

Four commercially available penicillin preparations (benzylpenicillin, aminobenzylpenicillin, carbenicillin and sulbenicillin) and two kinds of the new semisynthetic penicillin preparations (mezlocillin and piperacillin) evoked systemic anaphylactic reactions in guinea pigs immunized with one of the following penicillin-Ascaris extract (As) conjugates in aluminum hydroxide gel (alum), i.e., benzylpenicilloyl (BPO)-As, aminobenzylpenicilloyl (ABPO)-As, carbenicilloyl (CBPO)-As, sulbenicilloyl (SBPO)-As, mezlocillin-As conjugate (MEZ-As) and piperacillin-As conjugate (PIP-As). The tracheal chains prepared from the tracheas of the guinea pigs immunized with BPO-As, MEZ-As, or PIP-As revealed anaphylactic contractions in vitro on addition of benzylpenicillin, mezlocillin, or piperacillin preparations. These results indicated that the semisynthetic penicillin preparations as well as benzylpenicillin preparation have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with penicillin-As conjugate. Such guinea pigs seem to be suitable animals for investigations of penicillin allergy.