CYTOKINE GENE-EXPRESSION IN THE LUNGS OF BALB C MICE DURING PRIMARY AND SECONDARY INTRANASAL INFECTION WITH MYCOPLASMA-PNEUMONIAE/

Cytokine gene expression was determined in vivo in the lungs and splee ns of Mycoplasma pneumoniae-infected BALB/c mice by means of qualitati ve and semiquantitative PCR-mediated mRNA amplification. During the ac ute phase of both primary and secondary infections, cytokines commonly associated with innate resistance, TNF alpha, IFN gamma, IL-1 beta an d IL-6, were expressed. In contrast. early expression of the genes for IL-2 and IL-2 receptor was detected only during reinfection. Expressi on was greater in the lungs than in the spleen, attesting to the rapid accumulation of lymphocytes at the infected site. interestingly. IL-2 mRNA expression declined rapidly and was no longer detectable after 2 4 h, whereas IL-10 mRNA levels rose sharply during the same period. Du ring reinfection, mRNAs for TNF alpha and IL-6 were 10-fold and for IF N gamma about 50-fold higher than during primary challenge. The result s suggest that the pathogenesis of M. pneumoniae diseases may be assoc iated with elevated expression of proinflammatory cytokines.