Immunologic events in pigeon breeders'' disease

The immunologic and physiologic status of a group of symptomatic and asymptomatic pigeon breeders was studied in an attempt to define the immunologic events occurring in pigeon breeders' disease. Antibody activity to antigen(s) present in pigeon dropping extract (PDE) and pigeon serum (PS) was detected in the serum of both symptomatic and asymptomatic breeders. Antibody activity, however, tended to be greater in the symptomatic pigeon breeders. When subjects were challenged with PS via aerosol, serum complement activity became depressed only in asymptomatic patients. Cellular hypersensitivity to antigens present in PDE was detected in vitro in peripheral lymphocyte populations of 4 of 5 symptomatic breeders and in none of the asymptomatic breeders; cellular hypersensitivity to antigens in PS was not demonstrated in any of the individuals tested. These findings indicate that cell-mediated hypersensitivity, as well as humoral immunologic processes, may be involved in the pathogenesis of the hypersensitivity pneumonitis found in pigeon breeders.     

Development of chronic pulmonary inflammation in immunized guinea pigs by aerosol challenge with antigen: relationship of immune complex disease and cell-mediated hypersensitivity

Immunized guinea pigs develop immune complex disease (ICD) in the lungs after a single aerosol challenge with specific antigen. In the current study, immunized guinea pigs developed chronic pulmonary inflammation and cellular immunity (CI) in the lungs when aerosol challenged daily with specific antigen for 2 wk. When immune serum was passively transferred to normal recipients that were then aerosol challenged with specific antigen for 2 wk, chronic pulmonary inflammation and CI did not develop. These results suggest that ICD produced by passive transfer of serum and subsequent aerosol exposure to antigen was inadequate to cause chronic pulmonary inflammation and CI. The development of chronic pulmonary inflammation by aerosol challenge with antigen was suppresed with cobra venom factor. However, because of other studies, we attribute this suppression to the diminution of complement (C) factors in the alternative C pathway that affect macrophage mobility rather than to the depletion of C5a, which is important in the development of ICD.     

Passive transfer of experimental hypersensitivity pneumonitis with lymphoid cells in the rabbit

Although precipitating antibody is associated with human hypersensitivity pneumonitis, there is evidence that cell-mediated hypersensitivity may be involved in disease pathogenesis. In this study, alveolar, interstitial, and peribronchial lesions were produced by respiratory challenge of rabbits passively sensitized with ovalbumin-sensitive lymph node cells. Ovalbumin sensitivity of donor rabbits and lymph node cells was demonstrated by skin testing, migration inhibition factor (MIF) production using alveolar wash cells as migrating cells, and lymphocyte stimulation. Passive cell transfer was accomplished by intraperitoneal injection with all lymph node cells obtained from one donor transferred to one recipient. Recipients were challenged by aerosol or intratracheal injection of antigen immediately or 24 hr after passive sensitization and were killed 48 hr after challenge. Lesions in rabbits passively sensitized by lymph node cells and challenged with antigen by intratracheal inoculation consisted of focal pneumonitis with intra-alveolar edema and infiltrates of mononuclear cells in alveoli and alveoli septa. Aerosol challenge of passively sensitised animals produced similar changes, but peribronchial lymphoid tissue containing macrophages and germinal centers was prominent in this group. Antiovalbumin serum recipients challenged by intratracheal injection demonstrated only mild peribronchial mononuclear cell infiltrates, without pneumonitis. Control animals receiving lymph node cells only or challenge only demonstrated no changes in lung histology.     

Carrier requirement for development of acute experimental hypersensitivity pneumonitis in the rabbit

Fluorescein isothiocyanate (FITC) conjugated to protein carriers was used to explore carrier dependence in an established rabbit model of acute hypersensitivity pneumonitis (HSP). Rabbits were immunized via toepads with either FITC-ovalbumin (OA) or FITC-human gamma-globulin (HGG) in complete Freund's adjuvant, and were aerosol challenged with homologous or heterologous conjugates 30 days later. Only those rabbits challenged with the homologous carrier developed acute HSP, despite the presence of comparable levels of anti-FITC antibodies in the sera of all groups. These findings indicate a strict carrier dependence in the pathogenesis of HSP in this model and provide further evidence that the mechanism of inflammation depends upon a cellular immune response.     

III. Mediators of allergic reactions. Endogenous and exogenous stimulating or suppressor substances. Mediators of experimental hypersensitivity pneumonitis.

Using a physiologic model of hypersensitivity pneumonitis where depressions of arterial oxygen tension in unimmunized rabbits are monitored following aerosol challenge with Aspergillus terreus spores, attempts were made to assess the nature of the cellular and pharmacologic mediators of the impairment. Unlike normal animals no PaO2 depressions were obtained following aerosol challenge in either rabbits deficient in C6 or in rabbits made thrombocytopenic with antiplatelet serum. Such aerosols were also shown to produce platelet count depressions of up to 45% in normal rabbits. Finally, in vitro evidence of histamine release was obtained following incubation of Aspergillus extract, platelets and autologous serum from unimmunized rabbits. It was concluded that Aspergillus-induced pulmonary disease may be initiated by platelet release of mediators such as histamine stimulated by nonspecific complement activation.     

Zymosan-induced experimental hypersensitivity pneumonitis in rabbits.

An experimental model of hypersensitivity pneumonitis is presented. New Zealand white rabbits, previously immunized against yeast-derived zymosan, reacted to intratracheal challenge developing extensive pneumonitis. The lesions healed in a few weeks. Control animals challenged with inert particulate material (latex beads) or suspending fluid (PBS-Mg++) did not show pulmonary inflammation. Nonimmunized rabbits developed only transient pneumonitis after zymosan challenge. This reaction was clearly different from that seen in the group of immunized animals. The model reveals that biologically active substances such as zymosan, which is able to activate the alternate pathway of complement and mononuclear phagocytes, requires an active immune state in order to cause significant tissue damage. Isolated exposure to this kind of substance may not be sufficient to cause lung disease.     

Analysis of rabbit lung lavage immunoglobulins during the course of pulmonary inflammation induced with aerosolized antigen

Lung lavage fluids (LLF) from rabbits with pigeon dropping extract (PDE)-induced granulomatous pulmonary inflammation were studied for protein and immunoglobulin (Ig) G and A levels. It was found that the protein levels of the lung fluids of rabbits increased to a maximum after 2-3 weeks of aerosol treatment with PDE during which time inflammation of the lung increases. This is followed by a gradual decrease in protein content as the inflammation wanes and the lung returns to normal. These variations primarily reflect changes in IgG and IgA levels. IgG and IgA levels follow different courses. IgA reaches a maximum in the first week of inflammation and then gradually decreases. In contrast, IgG reaches a maximum level (2-3 weeks) and stays at an elevated level throughout the 12 week period of aerosol treatment with PDE. Antibodies to PDE in these two classes of immunoglobulins do not entirely reflect the immunoglobulin class levels. IgA antibody levels reach a maximum after extended aerosol challenge while IgG antibody reaches a maximum early and then declines to background levels. The specificity of the non-PDE antibody IgG is unknown at present. The distribution of IgA subclass producing cells in the lung is different than in the gut. In the lung the major subclass is g while in the gut it is f. The distribution of subclasses of IgA in the LLF, however, does not appear to reflect the cellular distribution. The reason for this is not clear.     

A study of the effects of systemic administration of adrenal glucocorticoids in an experimental model of hypersensitivity pneumonitis

To study the effects of steroids on the pulmonary lesions in experimental hypersensitivity pneumonitis, rabbits were sensitized to ovalbumin (OA) by injections of OA into footpads and 3 weeks later they were subjected to two successive aerosol challenges with OA at an interval of 48 hr. Injections of hydrocortisone sodium succinate 10 mg twice daily (but not at the reduced dosage of 5 mg twice daily) or methylprednisolone acetate 5 mg twice daily beginning 30 min before the first challenge and continued to the time of killing reduced the extent and intensity of vasculitis in both the treated groups and showed less alveolar septal thickening in the hydrocortisone treated group and less alveolar consolidation in the methylprednisolone treated group compared to the pulmonary lesions in the rabbits which were sensitized and then subjected to OA aerosol challenges, but received no treatment. In view of the observation that even in a steroid sensitive species like the rabbit, extensive pulmonary changes like alveolar consolidation, septal thickening and vasculitis persisted in spite of treatment with relatively large doses of these steroids, it was felt that in human hypersensitivity pneumonitis steroids might only suppress the warning symptoms without substantially affecting the progress of the pulmonary lesions.     

Immunization with extracellular proteins of Mycobacterium tuberculosis induces cell-mediated immune responses and substantial protective immunity in a guinea pig model of pulmonary tuberculosis.

We have studied the capacity of a selected fraction of Mycobacterium tuberculosis extracellular proteins (EP) released into broth culture by mid-logarithmic-growth-phase organisms to induce cell-mediated immune responses and protective immunity in a guinea pig model of pulmonary tuberculosis. Guinea pigs infected with M. tuberculosis by aerosol but not uninfected control guinea pigs exhibit strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. Guinea pigs immunized subcutaneously with EP but not sham-immunized control guinea pigs also develop strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. EP is nonlethal and nontoxic to guinea pigs upon subcutaneous immunization. Guinea pigs immunized with EP and then challenged with aerosolized M. tuberculosis exhibit protective immunity. In five independent experiments, EP-immunized guinea pigs were consistently protected against clinical illness, including weight loss. Compared with EP-immunized guinea pigs, sham-immunized control guinea pigs lost 12.9 +/- 2.0% (mean +/- SE) of their total weight. EP-immunized guinea pigs also had a 10-fold reduction in viable M. tuberculosis bacilli in their lungs and spleens (P = 0.004 and 0.001, respectively) compared with sham-immunized control animals. In the two experiments in which some guinea pigs died after aerosol challenge, EP-immunized animals were protected from death. Whereas all 12 (100%) EP-immunized guinea pigs survived challenge with aerosolized M. tuberculosis, only 6 of 12 (50%) sham-immunized control guinea pigs survived challenge (P = 0.007, Fisher exact test). This study demonstrates that actively growing M. tuberculosis cells release immunoprotective molecules extracellularly, that a subunit vaccine against tuberculosis is feasible, and that extracellular molecules of M. tuberculosis are potential candidates for a subunit vaccine.     

Hypersensitivity pneumonitis resulting from community exposure to Canada goose droppings: when an external environmental antigen becomes an indoor environmental antigen.

BACKGROUND: In the past, hypersensitivity pneumonitis has been attributed to occupational, agricultural, or home environmental exposure. OBJECTIVE: This report describes the first case of hypersensitivity pneumonitis due to community exposure to droppings from Canada geese migrating through a suburban environment. METHOD: Clinical and serologic information was used in making the diagnosis of hypersensitivity pneumonitis. RESULTS: Serologic analysis demonstrated precipitating antibodies against goose droppings and against an extract made from washings from a filter taken from the patient's office. These studies also showed that the antigens in the office filter were goose dropping antigens. CONCLUSION: Hypersensitivity pneumonitis can result from exposure to goose dropping antigens in the community that enter buildings through ventilation systems. This represents a new form of an old disease.     

Detection of antigen-specific antibodies on lung tissue in a patient with hypersensitivity pneumonitis

Summary A patient with hypersensitivity pneumonitis showed positive Ouchterlony's immunodiffusion tests against pigeon faecal extract, Cephalosporium and Pullularia antigens. Deposits of immunoglobulins - IgG and IgM antibodies - were detected in a subendothelial position in arterial and venous vessels and on alveolar macrophages in the lung tissue. The IgG desposits in blood vessels belonged to IgG₁, IgG₂ and IgG₃ subclasses and the absorbed IgG on alveolar macrophages to all IgG subclasses. The detection of allergen specific antibodies in lung tissue was made by indirect immunofluorescent staining with FITC conjugated antigen extracts from pigeon faeces and demonstrated the aetiology of this hypersensitivity pneumonitis.Abbreviation HP hypersensitivity - FITC fluorescein-isothiocyanate - PBS phosphate buffered saline     

Alveolar macrophage catabolism of Micropolyspora faeni

Pulmonary histologic abnormalities resolve despite continuing intratracheal injections of Micropolyspora faeni in a rabbit model of hypersensitivity pneumonitis. We examined in vitro alveolar macrophage (AM) metabolism to determine if increased efficiency of M. faeni degradation by AMs was associated with resolution of pulmonary abnormalities. Rabbits were exposed to M. faeni with three sensitizing and two, four, or eight weekly intratracheal challenge injections. Bronchoalveolar cells (BAC) were obtained by lavage 4 to 6 days after the last intratracheal injection. We determined the fate of 125I-labeled M. faeni added to 48-hour cultures of BAC derived from naive and M. faeni-exposed animals. Label was transported from the pellet to the supernatant fraction of BAC cultures, and the proportion of supernatant label that was precipitated by trichloroacetic acid decreased. These phenomena were dependent on time, viable cells, and temperature. They were not altered by puromycin and were caused by AM. BAC from M. faeni-treated rabbits were slightly more effective in transport of label from pellet to supernatant than BAC from naive rabbits during the first 4 hours of culture but not thereafter. There was no difference between BAC from rabbits challenged two, four and eight times. We conclude that resolution of pulmonary histologic abnormalities in this model of hypersensitivity pneumonitis is not associated with evidence of enhanced AM particulate M. faeni catabolism.     

Naturally occurring double-stranded RNA and immune responses. III. Immunogenicity and antigenicity in animals.

Naturally occurring, double-stranded RNA (ds-RNA)) was immunogenic when injected into mice, rats, guinea-pigs, rabbits, dogs and baboons. The response to native material administered intravenously (i.v.) was strongest in rabbits and mice, and weakest in baboons. Mice, guinea-pigs and baboons injected with ds-RNA complexed with methylated BSA emulsified in Freund's complete adjuvant all gave high antibody responses. When ds-RNA was given in aerosol form to mice and guinea-pigs the response was weaker than that following i.v. injection, and baboons did not respond to antigen given as an aerosol. In most species the immune response obtained was predominantly IgM in nature, and there was no evidence for cell-mediated immunity in any species. The only evidence of an adverse reaction associated with repeated administration of ds-RNA was a systemic anaphylactic-type response in a small group of mice given ds-RNA repeatedly in aerosol form and challenged with ds-RNA i.v.     

Vaccination against Legionella pneumophila: serum antibody correlates with protection induced by heat-killed or acetone-killed cells against intraperitoneal but not aerosol infection in guinea pigs.

An aerosol model of Legionella infection has been established in guinea pigs. Infected animals showed growth of Legionella in their lungs, dissemination of organisms to the spleen, development of pneumonia and fever, and weight loss. Vaccination studies using heat-killed or acetone-killed cells were carried out, and guinea pigs were challenged intraperitoneally or by using the aerosol model of infection. Both vaccines were shown to give moderately high levels of protection against intraperitoneal challenge (28 to 145 50% lethal doses). Protection was found to be dose dependent and correlated with antibody levels as measured by enzyme-linked immunosorbent assay to an outer membrane antigen and by indirect immunofluorescence to heat-killed cells. In contrast, the same vaccination regimens that protected against intraperitoneal challenge failed to protect guinea pigs against aerosol challenge with comparable doses of Legionella, despite the presence of serum antibody. The results are discussed in terms of the possible requirements for immunity to aerosolized Legionella, including secretory immunoglobulin or cell-mediated immunity.     

Antibodies against purified pigeon IgA in pigeon breeders' disease.

It is demonstrated that previously described PDF1-A antigens from pigeon dropping extract contain pigeon IgA. The sera of patients with pigeon breeders' disease contain precipitating antibodies against pigeon IgA, in contrast to the sera of pigeon breeders suffering from unrelated forms of pulmonary dysfunction. The degree of complement consumption by PDF1A antigens, pigeon serum, and pigeon IgA turned out to be correlated. No correlation was found between precipitating anti-pigeon IgA antibodies and complement consumption by pigeon IgA in patients' sera.     

Down regulation in hypersensitivity pneumonitis

Levels of soluble interleukin-2 receptor (sol-IL-2R) in the bronchoalveolar lavage fluid (BALF) of pigeon breeders with hypersensitivity pneumonitis were compared with BALF levels in asymptomatic pigeon breeders who had been exposed to pigeon allergens for an equivalent length of time. No mean difference in sol-IL-2R levels was detected when these levels were expressed per milliliter BALF, epithelial lining fluid, or per T-lymphocyte. In sarcoidosis, the availability of sol-IL-2R per T cell was significantly higher for the group with inactive sarcoidosis compared with the group with active sarcoidosis. The results do not support the hypothesis that down regulation, in subjects exposed to allergens causing hypersensitivity pneumonitis, is a function of cell-free sol-IL-2R levels in BALF. In the dynamic situation, however, the hypothesis appears tenable.     

Tumor necrosis factor plays an essential role in determining hypersensitivity pneumonitis in a mouse model

We examined the importance of the cytokine tumor necrosis factor-alpha (TNF-alpha) in a mouse model of hypersensitivity pneumonitis (HP). Mice of the C57BL/6 strain were instilled intranasally 3 days/wk for 3 wk with 150 micrograms of the actinomycete Faenia rectivirgula (Micropolyspora faeni) to induce HP as a model of farmer's lung. This experimental model was associated with a progressive inflammation in the lungs of challenged mice, seen histologically as cellular infiltrates of large quantities of macrophages and lymphocytes and some neutrophils. The disease in challenged mice treated with a control rabbit serum was also associated with a substantial release of tumor TNF-alpha (up to 80 U/ml of TNF-alpha in the bronchoalveolar lavage [BAL] at 3 wk after beginning of treatment) and interleukin-1, which peaked at 1 wk (approximately 300 U/ml) and diminished thereafter. A very large increase in BAL cell number (11-fold increase versus saline controls) and an enhanced release potential for TNF-alpha by alveolar macrophages was also seen. Lung fibrosis was also evident in challenged animals, as demonstrated by a 2-fold increase in hydroxyproline levels. Infusion of challenged mice with a rabbit polyclonal antibody against TNF-alpha (2 mg/wk) completely abrogated the disease, as mice so treated had normal lung histology. Anti-TNF-alpha blocked cellular recruitment in the lungs (only a 2-fold increase at week 3); it also completely abolished TNF-alpha secretion in the BAL and drastically reduced interleukin-1 levels in this fluid. Anti-TNF-alpha also abolished lung index increases and lung fibrosis, with both parameters similar to that of saline-instilled mice.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cross reactions to antigens causing hypersensitivity pneumonitis

The sera of patients with asthma, aspergillosis, pigeon breeder's disease, farmer's lung, and a hypersensitivity pneumonitis in textile plant workers were screened by gel diffusion against a variety of fungal antigens and dust extracts. Patients with hypersensitivity pneumonitis were especially prone to develop precipitating antibody to numerous airborne antigens. From the results it was concluded that patients with hypersensitivity pneumonitis form precipitating antibodies to definite groups of antigens in their environment. Most of the patients had precipitins to house dust that formed lines of identity with fungi and thermophilic actinomycetes.     

The effect of complement depletion on hypersensitivity pneumonitis lesions induced by Micropolyspora faeni antigen

Animals sensitized by intratracheal administration of particulate Micropolyspora faeni antigen and subsequently challenged with the antigen intratracheally developed lesions of hypersensitivity pneumonitis histologically similar to those observed in man with this disease. Animals sensitized with antigen but depleted of complement with cobra venom factor prior to challenge with the antigen manifested a significant reduction in mean lesion indices when compared to a group of control animals that were not complement-depleted. These data indicate that complement is necessary for the development of pulmonary lesions of experimental hypersensitivity pneumonitis in the rabbit.