Distribution of Immunoglobulin-producing Cells in Lungs with Swine Enzootic Pneumonia

Immune responses in lungs with swine enzootic pneumonia (SEP) were evaluated by the demonstration of histological distribution of immunoglobulin-positive cells (Ig positive cells) by immunoperoxidase stain employing avidin-biotin complex method and pyroninophilic cells (plasma cells) by methylgreen-pyronin stain. In mild SEP lesions, IgA positive cells were prominent in bronchial mucosa and peribronchiolar portion. As increased the severity of SEP lesions, numerous IgA positive cells appeared in the bronchial mucosa. In chronic SEP lesions, many IgG positive cells accompaneid by the increases of IgA positive cells localized at the bronchial mucosa and alveoli. These finding indicated that IgA, and IgA and IgG play major roles on local humoral immune responses in SEP lesions. In lymph nodules formed in the SEP lungs, the number of plasma cells increased much more than that of Ig positive cells. Accordingly, Ig positive cells/plasma cells ratio extensively decreased, suggesting that Ig positive cells generate and proliferate in lymph nodules and infiltrate to the peribronchiolar portions, bronchial mucosa and alveoli. In this experiment, it was concluded that a combined demonstration of Ig positive cells and plasma cells could be useful aids to precisely evaluate the stages of SEP lesions.