Production of interferon-gamma and interleukin-4 by splenocytes in mice infected with Paragonimus westermani.

The TH cytokine responses of spleen cells stimulated with Con A from mice infected with Paragonimus westermani were examined. The spleen cell culture supernatants were assayed for TH1-specific IFN-gamma and TH2-specific IL-4. Cytokine responses for IL-4 peaked at three days (410 +/- 60.9 pg/ml), persisted at a high level until the second week (343 +/- 59.0 pg/ml), and then decreased slowly four and six weeks after infection. IFN-gamma production by splenocytes only increased during the first week (151 +/- 32.3 pg/ml) and declined abruptly after the second week of infection. IFN-gamma production by splenocytes of infected mice was not observed during the sixth week of infection. In addition, serum IL-4 and IFN-gamma were measured. Serum IL-4 was not detected in substantial quantity until four to six weeks after infection. The time course of serum IL-4 was not correlated with that of IL-4 production by splenocytes. Serum IFN-gamma was undetectable during the entire course of infection. These results suggest that TH2 cytokine responses, rather than TH1, predominate in mice infected with P. westermani.