Immunomorphological reactivity of the intrapulmonary lymphoid tissue.

Young albino rats were repeatedly stimulated by a pulverized suspension of living pneumococci and others by intramuscular injection of killed microbes emulsified in complete Freund adjuvant. The bronchus associated lymphoid nodules increase in size and number; the proximal nodules contain one more follicle with germinal centers formed of pyroninophilic lymphoblasts and plasma cells at the periphery. The follicular organization and the pyronine - plasma cells differentiation point out the ability of these nodules to elaborate a local immune response to antigenic stimulation.