RESUMEN
In this work, the changes in expression of the costimulatory molecules [B7-2/CD28] were studied at 6, 8 and 16 weeks p.i. on immuno-inflammatory cells of livers in S. mansoni-infected and SEA-sensitized mice model by immunohistochemistry. Both B7-2 and CD28 were only expressed positively at 6 weeks p.i. in both groups with significantly lower cell counts in SEA group compared to infected control group. The distribution of B7-2 was concentrated towards the periphery of the granulomas, while that of CD28 was homogeneously distributed all through the granulomas. The present data showed that repeated i.v. injection of SEA before infection resulted in the drop of B7-2/CD28 to lower levels than its expected natural course. This drop may explain the decrease of host immunopathological reaction to S. mansoni eggs in the SEA group than infected control group