Figure 7.
Analysis of IL-4 and IFN-γ mRNA expression in lung tissue (a and c) and isolated thoracic lymph nodes (b and d). Expression of mRNA was semiquantitatively analysed 18 hr after the last of three repeated exposures of aerosolized OVA in presensitized γδ T-cell deficient (TCRγδ KO) or wild-type C57BL/6 mice. For comparison, the IL-4 and IFN-γ expression in lung tissue of untreated wild-type control mice is also shown. Thoracic lymph nodes could not be dissected from untreated healthy mice. The residual cycle threshold value (CT) was determined for each amplified transcript (see Materials and methods) and the relative levels of IL-4 and IFN-γ mRNA was calculated in relation to the expression of the housekeeping GAPDH gene (a and b). The residual CT ratio of IL-4/IFN-γ was used as a marker for a shift in the Th2/Th1 balance (c and d). *P < 0·05; **P < 0·01