The influence of a new corticosteroid,budesonide, on anaphylactic bronchoconstriction and SRS-A release in the guinea pig

Groups of guinea pigs sensitized with ovaibumin were treated with budesonide and beclomethasone dipropionate, respectively, in an intraperitoneal dose of 50 mg/kg. 20 h later, the anaphylactic release of histamine and slow reacting substance of anaphylaxis (SRS-A) from chopped lung tissue was studied. Whereas the corticosteroids studied had no effect on the tissue content of histamine or on the amount of antigen-induced release of this autacoid, budesonide and beclomethasone dipropionate to a great extent inhibited the release of SRS-A. The anti-anaphylactic effect of budesonide and beclomethasone was also shown in sensitized guinea pigs pretreated with mepyramine, 2.5 mg/kg intraperitoneally, and challenged with nebulized ovalbumin. We suggest that the partial protection given by the corticosteroids budesonide and beclomethasone dipropionate is due to the inhibition of SRS-A release.Subsidiary of AB Astra, Sweden.     

Airway responses to histamine, acetylcholine, and propranolol in anaphylactic hypersensitivity in guinea pigs

Using changes in tidal volume and dynamic lung compliance, airway responses to histamine, acetylcholine, and propranolol were investigated in different groups of guinea pigs before and after active or passive sensitization. The threshold doses to inhaled histamine, acetylcholine, and propranolol were identical before and after sensitization. Similarly, the slope of dose response curves to these drugs and the time course of recovery from airway constriction were comparable in control and sensitized animals. The slopes of dose response curves to histamine and acetylcholine were parallel. Threshold doses to acetylcholine (T_ACH) and histamine (T_H) were proportional. The average ratio T_ACH/T_H was 7.7. There was no correlation between threshold doses and slopes of dose response curves for propranolol and those for histamine or acetylcholine. Antigen challenge resulted in decreases of dynamic lung compliance and in increases of airway resistance and frequency, which were maximal 60 to 130 seconds after challenge. When functional parameters after antigen challenge had returned to normal, bronchial responses to histamine, acetylcholine, and propranolol were exaggerated. These exaggerated responses were reproducible, transient, variable from animal to animal, and related to the antigen dose. Guinea pig anaphylaxis does not lead to the prolonged hypersensitivity to chemical mediators, which characterizes human reaginic asthma, but to a temporary enhancement of responses to acetylcholine, histamine, and propranolol.     

Role of thrombin and plasmin in development of delayed hypersensitivity reaction in guinea pig skin

Induration is a prominent feature of delayed hypersensitivity reaction (DHR), and fibrin deposition is the central mechanism. We studied the effects of two inhibitors of DHR on the activities of thrombin and plasmin in the extract of the skin site of DHR and compared the two activities in the site of DHR with those in the site of the Arthus reaction (AR) that lacks induration. Warfarin, an anticoagulant, inhibited thrombin activity and induration, but not plasmin activity. Ferritin, a blocker of a macrophage-dependent reaction, inhibited the two activities and induration. The lesion of DHR had three to four times the thrombin activity of the lesion of AR, and the activity paralleled the development of induration. In contrast, plasmin activity of the site of DHR was lower than that of the site of AR and was associated with the reduction of induration. The two protease activities in the site of AR did not correlate with the development of the AR lesion. These results suggest that thrombin and plasmin mediate the development of induration and that induration is produced by a synergistic effect of high thrombin activity and low plasmin activity in the site of DHR.This work was supported in part by grants from the Japanese Ministry of Education.     

Intratracheally applied rSP-C surfactant exhibits no anaphylactic shock reactions in a guinea pig model of acute lung hypersensitivity.

The effect of the intratracheal administration of the recombinant SP-C surfactant apoprotein (rSP-C) with phospholipids (PL) in comparison to an ovalbumin induced anaphylactic shock reaction was studied in guinea pigs lungs. Narcotized guinea pigs were challenged by intratracheal administration on test day 24/25 once with a suspension of rSP-C/PL (reconstituted suspension). These animals were priorily sensitized on test day 1, 3 and 5 intraperitoneally with rSP-C/PL suspension or with Ovalbumin (OV) respectively. The following groups were used to assess the anaphylactic lung shock symptoms: group 1: positive control, 1 mg/kg OV protein, 2 ml/kg application volume, (Appl. vol.), N: 5 animals; group 2: 1 mg rSP-C/50 mg PL/0.5 ml/kg Appl. vol., N: 10; group 3: 2 mg rSP-C/100 mg PL/1.0 ml/kg Appl. vol., N: 10; group 4: 4 mg rSP-C/200 mg PL/2.0 ml/kg Appl. vol., N: 10. Clinical signs, mortality, lung weights and histopathological changes were evaluated. Additionally the lungs were investigated immunohistologically with polyclonal antibodies against rSP-C to determine the pulmonary distribution of the intratracheal applied rSP-C. In the OV-treated positive control group, all animals died within 4 minutes after intratracheal challenge, while only 1 animal of group 4 died probably due to an narcosis related respiratory arrest. In the rSP-C/PL treated groups, the lung weights showed a dose-related increase, but nevertheless all these rSP-C-treated groups showed a significant lower lung weight in comparison to the OV treated positive control group. The histopathology assessment of the lungs in the OV-treated animals revealed a severe generalised bronchoconstriction and a hyperemia in connection with a slight interstitial edema in all five animals. The rSP-C/PL-treated animals, which were sacrificed after 3 days, showed no bronchoconstriction but a slight increase in the severity of bronchus-associated infiltration with eosinophilic granulocytes and in the formation of peripheral emphysema, but with no dose-dependency. A slight dose-dependent increase in the deposition of peribronchiolar eosinophilic foreign material was evident. In contrast to this, the number of lipid-laden alveolar macrophages seemed to decrease with increasing doses of rSP-C/PL. The immunohistological investigation with a polyclonal antibody against rSP-C showed an intraalveolar distribution of the intratracheally applied rSP-C which is mainly located in the peribronchiolar alveolar parenchyma. A rSP-C-positive staining was visible within the cytoplasm of alveolar histiocytes, type II pneumocytes and also as an extracellularly rim along the alveolar walls. The polyclonal antibody showed no cross reaction with natural occuring SP-C-protein of the guinea pigs. We conclude that the intratracheal application of the rSP-C surfactant containing phospholipids (PL) exhibits no significant risk of an anaphylactic shock reaction in this guinea pig lung hypersensitivity model. The immunohistological investigation with polyclonal antibodies against rSP-C demonstrated clearly the distribution of intratracheal applied material in this toxicological animal model.     

Delayed hypersensitivity to myxoviruses and myxovirus vaccines in the guinea pig

Influenza, mumps and measles viruses were examined for their ability to induce in guinea pigs homologous and cross-reactive delayed hypersensitivity. A majority of the animals skin tested with homologous and a portion of the animals skin tested with heterologous viruses and vaccines developed positive reactions. Findings with the heterologous preparations suggest that the observed cross-reactive hypersensitivity might be due to shared antigens of viral or substrate origin in the influenza, mumps and measles preparations. The present findings in guinea pigs suggest that the adverse effects, attributed in whole or in part to induced hypersensitivity, observed in man following injection of killed influenza, mumps and measles vaccines could be due to cross-reactive delayed hypersensitivity resulting from the use of these preparations.     

Differing mechanisms of tolerance and desensitization to dinitrochlorobenzene in guinea pigs

In the present paper the mechanisms of tolerance and desensitization to dinitrochlorobenzene (DNCB) contact sensitivity in guinea pigs were investigated using the methods of adoptive sensitization of tolerant and normal syngeneic recipients and cyclophosphamide-treatment of tolerant animals known to selectively inactivate suppressor lymphocytes. It was shown that desensitization of presensitized animals is caused by the direct effect of the intravenously injected hapten on the effector cells in the peripheral compartment. The immediate onset of unresponsiveness and its very short duration almost exclude the possible involvement of enhancing antibodies or suppressor cells. In the case of tolerance induced by pretreatment with dinitrobenzenesulfonic acid, suppressor cell activity is enhanced, preventing normal specific immunocompetent cells from recognizing the antigen and/or proliferating in the draining lymph nodes. Whether suppressor lymphocytes are of the B or T type is not yet known.     

Role of amines in anaphylactic contraction of guinea pig isolated smooth muscle

The possible role of acetylcholine (ACh,) histamine (His), and 5-hydroxytryptamine (5-HT) in the contractile response to ovalbumin (Oval) of ileal and tracheal muscle from sensitized guinea pigs was examined. Antagonists to these agents (atropine, mepyramine and methysergide, 5-benzyloxygramine, or 5-HT tachyphylaxis, respectively) were employed singly or in combinations. Care was always taken to ensure specificity of blockade. Results indicate that about half of the peak magnitude of the oval-induced contraction is absent in the presence of a specific inhibitory concentration of mepyramine. This finding suggests that His plays a considerable role in the oval-induced contraction. Contrary to previous reports, similar evidence was not obtained of a role for ACh and 5-HT in the Oval-induced contraction. The source of the agonists released by Oval was also investigated. Pretreatment with compound48/80 almost completely eliminated the Oval-induced contraction of ileal muscle while reducing the tracheal contraction about one-half. It would appear that the Oval-induced ileal contraction involves primarily agonists released from mast cells in the preparation whereas tracheal contraction is only partly dependent on mediators from mast cells.     

Influence of epithelium on beta-adrenoceptor desensitization of guinea pig tracheal smooth muscle

The effect of tissue incubation with a beta2-agonist of denuded and intact epithelium trachea on the responsiveness to isoprenaline and beta-receptor blocked by propranolol (CR-1) was examined in this study. We examined the effect of epithelium removal on the beta-adrenoceptor desensitization resulting from incubation of guinea pig trachea in the beta-adrenergic agonist isoprenaline (10 microM). Desensitization was measured as the change in EC50, the concentration of beta-agonist that produced 50% relaxation of tracheal rings contracted with methacholine. As a second measure of desensitization, we measured the shift in EC50 resulting from incubation of tracheal rings with the beta-adrenoceptor antagonist propranolol (20 nM), expressed as CR-1 ([post-propranolol EC50/baseline EC50]-1). Initially, we measured desensitization immediately after incubation in isoprenaline; subsequently, we repeated the protocol and allowed a 30 min rest between the end of incubation and the measurement. The sensitivity of denuded epithelium trachea to isoprenaline and (CR-1) was significantly higher than that of intact epithelium only in non-incubated preparations (p<0.05 to p<0.001). Incubation to isoprenaline caused a significant reduction in the tracheal response to isoprenaline in both the denuded groups (p<0.005 for both cases) and intact epithelium groups (p<0.05 for both cases). Incubation to isoprenaline also caused a significant reduction in (CR-1) value in both the denuded groups (p<0.005 for group 2 and p<0.001 for group 4) and intact epithelium only in group 1 (p<0.05). However, the changes in EC50 due to tissue incubation with isoprenaline were significantly greater in denuded than intact epithelium trachea (p<0.05 for all cases) and for CR-1 value only in groups 1 and 2 (p<0.05). These results indicate decrease in both tracheal response to beta-agonist (tolerance) and CR-1 (due to incubation of tissues with isoprenaline), which were greater in denuded epithelium groups.     

Role of immunoglobulins G1 and G2 in anaphylactic shock in the guinea pig

Heating serum from actively sensitised guinea pigs did not remove its ability to sensitise recipient animals in vivo and parenchymal lung strips in vitro to anaphylaxis. Thermoresistant antibodies should thus account for the transferable sensitising effect, which persists for at least 9 days. IgG1 and IgG2, contained in the serum, were separated by affinity chromatography to determine the importance and the participation of these subclasses in passive anaphylactic shock. IgG1, present in smaller amounts than IgG2, was more effective in sensitising isolated lung strips. The intravenous administration of ovalbumin to guinea pigs, which had been injected with 0.8 mg/kg of IgG1 or 2 mg/kg of IgG2 9 days beforehand, induced an intense bronchoconstriction with leucopenia and moderate thrombopenia, suggesting an as yet undescribed role for IgG2 in passive tissue sensitisation. The use of mepyramine, an antagonist of the histamine H1 receptor, WEB 2086, an antagonist of platelet-activating factor, and nordihydroguaiaretic acid, a dual inhibitor of cyclooxygenase and lipooxygenase, alone or associated, demonstrated that the anaphylactic contraction of lung strips from guinea pigs sensitised by IgG1 is mediated by histamine and arachidonate derivatives, whereas that of lung strips from guinea pigs sensitised with IgG2 is mostly mediated by histamine. In addition, the association of the three potential antagonists slightly reduced the anaphylactic contraction of lung strips provided by guinea pigs sensitised by serum. Our results, using a sensitisation procedure considered until now to involve exclusively IgE antibodies, indicate that IgG1 and IgG2 are in fact the essential antibodies for passive anaphylactic shock in the guinea pig.     

Immunoregulatory mechanisms involved in elicitation of allergic contact hypersensitivity

Although the pathophysiology of contact hypersensitivity (CHS) might appear to be well understood, this only applies to the sensitization phase. Little is known about the elicitation phase, and fundamental differences exist between CHS and other forms of delayed-type hypersensitivity responses. Here, Stephan Grabbe and Thomas Schwarz summarize the role of different cellular components and soluble mediators in the inflammatory tissue response during CHS elicitation.     

Ultrastructural development of guinea pig cytomegalovirus in cultured guinea pig embryo cells.

The ultrastructural development of guinea pig cytomegalovirus (GPCMV) in guinea pig embryo cells was studied using electron microscopy. Tubular structures were found in nuclei of virus infected cells, followed by the appearance of intranuclear inclusions containing virus nucleocapsids. While some nucleocapsids were enveloped at the inner nuclear membrane, others were released into the cytoplasm where they were associated with, or within, dense matrix which was subsequently enveloped by cytoplasmic membranes to form enveloped dense virions. Dense bodies without virus capsids were formed in the cytoplasm and enveloped in a similar manner. An involvement of the nuclear pores in the release of unenveloped virus capsids from the nucleus to the cytoplasm was postulated. Evidence that the enveloped dense virions and dense bodies shared common envelope antigen(s) was obtained by immunoelectron microscopy. The similarities and differences in the ultrastructural development of GPCMV and other cytomegaloviruses are discussed.