Asian pear pectin administration during presensitization inhibits allergic response to ovalbumin in BALB/c mice.

Objective: A type of respiratory disorder resembling some aspects of human allergic asthma can be induced in mice using ovalbumin. The factors that influence the etiology of asthma are poorly understood even though cytokines are known to play a pivotal role. The purpose of this study was to test the hypothesis whether an administration of Asian pear pectin during presensitization could suppress allergic response to ovalbumin in BALB/c mice.

Design: High-dose (100 microg) of pectin-sol was used and values were compared to those from the control. Ovalbumin and aluminum hydroxide were utilized for sensitization while ovalbumin aerosol was used for provocation 2 weeks later. The bronchoalveolar lavage (BAL) and assessment of tracheal smooth muscle responsiveness to electrical field stimulation or acetylcholine were performed 1 day after ovalbumin provocation. Two main cytokines of interferon (IFN)-gamma and interleukin (IL)-5, and serum immunoglobulin E (IgE) were assayed.

Settings: Laboratory of the Chosun University Medical School

Subject: Male BALB/c mice

Results: Antigen dose of 5 microg for sensitization generated TH1 type cytokines in the lungs with a high level of IFN-gamma and a low level of IL-5. In contrast, TH2 type cytokines were produced in splenocytes including a high level of IL-5 and a low level of IFN-gamma. Asian pear pectin-sol administration during presensitization significantly inhibited (p < 0.05) sensitivity of airway smooth muscle to electrical field stimulation and acetylcholine. Further, IFN-gamma production significantly decreased (p < 0.05) in BAL fluids while it significantly increased (p < 0.05) in splenic cells. On the other hand, IL-5 production significantly increased (p < 0.05) in BAL fluids while it was a significant decrease (p < 0.05) in splenic cells. For the histopathologic changes in the lung, pear pectin-sol recovered ovalbumin (OVA)-induced abnormal signs to an almost normal state. As a correlate, IgE production significantly decreased (p < 0.05) in pectin-sol-treated animals compared to the control.

Conclusions: It is possible from these data that BALB/c mice have different susceptibilities to different doses of OVA regulated by pulmonary TH1 and TH2 type cytokines, independent of splenic TH1 and TH2 type cytokines production. These results also indicate that administration of Asian pear pectin-sol in presensitized mice suppresses allergic asthmatic reaction.