Immune Responses in Rats Sensitized with Aerosolized Antigen

Abstract

Rats of BN × Wi/Fu strain were immunized by aerosol exposure to 0.001–1% of ovalbumin (OA) without using any adjuvant for 2- or 1-week periods with 4-week intervals. The immunization, particularly with the highest dose, induced antibody formation of IgE, measured with RAST, and of IgG and IgA, measured with ELISA. Regional lymph node cells from immunized animals showed spontaneous proliferation which was suppressed by syngeneic spleen cells. The cell mixture could be stimulated by addition of specific antigen or mitogen, while cultures of peripheral lymph node cells showed a less consistent increase in lymphoblast formation. Histological examination of the lungs of immunized animals revealed a rapid onset of inflammation with accumulations of mononuclear cells and also increased numbers of mast cells. There was some dose-response relationship between antigen concentration and cell accumulations. The immunization also seemed to induce differentiation of epithelial cells to mucous cells. Intravenous provocation of animals immunized with 0.01–1% OA aerosol resulted in clinical bronchial reactivity assessed as increased transpulmonary pressure. This airway response was attenuated by pretreatment with indomethacin. Animals immunized with 1% OA did, however, not respond to challenge. These animals showed a decreased response to serotonin compared with nonimmunized controls. In summary, the described animal model seems to provide a tool for studies of the asthmatic reaction.

Distribution and Histochemical Characterization of Pulmonary Mast Cells in the Rat and Guinea Pig

“…In con trast, in the rat, the mast cell density rapidly decreased along the bronchial tree with a very low value in the small bronchi; moreover, mast cells were not detected in the interalveolar septa. These findings are in agree ment with those of Ahlstedt et al [16] and Goto et al [17], but are opposite to those of Williams et al [18] and Bienenstock et al [19] who described mast cells in the alveolar septa of the rat lung. This different mast cell distribution in the rat and guinea pig could ex plain some different responses after sensitization in these two species and in particular, the alveolitis ob served after antigenic challenge in the guinea pig [unpubl.…”

Detection, pathogenesis, and therapy of respiratory syncytial virus infections

“…Another mechanism by which proliferating lymphocytes might cause pulmonary pathology is suggested by experiments in rats sensitized with aerosolized ovalbumin (1 (30). Since most infants with RSV infection will stabilize and improve rapidly upon hospitalization and after being given supple- Table 7.…”

“…With the immunofluorescence technique, diagnostic increases in titer were observed in 75% of infants aged 1 to 3 or 4 to 6 months at the time of RSV infection and in 100% of infants older than VOL. 1,1988 on April 29, 2019 by guest http://cmr.asm.org/ Downloaded from 6 months ( Table 2). RSV-specific IgM responses, which also would be indicative of acute infection, were observed in 13% of infants between 1 and 3 months of age and in >50% of infants who were more than 3 months of age at the time of primary RSV infection.…”

“…A statistically significant correlation of the magnitude of the RSV IgE response and of the VOL. 1,1988 on April 29, 2019 by guest http://cmr.asm.org/ Downloaded from Cell-Mediated Immunity Cell-mediated immune function is generally believed to be critical to the containment of viral infection within the respiratory tract. In the specific case of RSV, when cotton rats are infected with this agent, leukocytes that can cause significant chromium release from RSV-infected cells in cytotoxicity assays appear in their lungs.…”