Rantes and MCP-1 expression in antigen challenged guinea-pig airways

Allergic asthma is associated with a pronounced accumulation of eosinophils and mononuclear cells in the airways. In this study we have examined the expression of CC chemokine mRNA in the lungs of sensitised guinea-pigs following challenge with aerosolised antigen. Northern blot analysis of total lung mRNA expression indicated that MCP-1 was markedly upregulated 2, 6 and 12h after antigen challenge of sensitised, but not naive, animals, whilst RANTES mRNA expression did not exhibit marked changes in either group at these time points. Semiquantitative RT-PCR of whole lung mRNA demonstrated a 4 fold increase in MCP-1 mRNA expression (p<0.01, n=6 per group) at 2 and 24h following antigen challenge, while RANTES expression was not significantly changed. In situ hybridisation with antisense RANTES riboprobe indicated basal expression of RANTES mRNA by mononuclear cells. Following challenge expression was slighly increased, and weak epithelial expression was also seen. These results indicate that RANTES mRNA expression is relatively insensitive to antigen challenge in guinea-pig airways, in contrast with MCP-1, which is markedly upregulated.