BASES FOR THE EARLY IMMUNE-RESPONSE AFTER RECHALLENGE OR COMPONENT VACCINATION IN AN ANIMAL-MODEL OF ACUTE MYCOPLASMA-PNEUMONIAE PNEUMONITIS

The pathology of Mycoplasma pneumoniae pulmonary infection for a hamst er model was examined after whole bacterium rechallenge or component v accination. Animals which, after an initial infection, were rechalleng ed with either live or heat-killed M. pneumoniae inocula developed sev ere early recall lesions in the first 3 days. In contrast, animals inf ected once develop maximum histopathology at approximately 10-14 days. A severe perivascular inflammatory cellular infiltrate developed in t he rechallenged groups, and pulmonary pathology could also be elicited by rechallenge with bacterial growth medium components. Component vac cination with protein P1 did not reduce disease in comparison to once- infected controls, and vaccination promoted art early immune recall re sponse as well. We conclude that art early immune response needs to be sought in all future experiments of challenge/rechallenge or vaccinat ion. Vaccine studies will require an understanding of both protective and harmful immunogens.