This thesis considers the interaction between adult male and female Schistosoma mansoni and their host in a mouse model in order to identify targets for new therapies and treatment strategies. Therefore, this work focused on the outer surface of adult schistosomes, the tegument. On the one hand, the influence of the host on the tegument of the adult worms was analysed. As a result of incubation in host serum, adult male and female schistosomes exhibited marked surface enlargement, and females showed a repulsion of their outer surface. Next, the tegument proteome was analysed using a new, highly sensitive protocol. Male and female worms differed significantly in the number and composition of proteins detected on the outer surface. On the other hand, the effect of circulating antigens from male and female schistosomes on the host's immune response was investigated. For this purpose, the spleens of unisexually infected mice were analysed via transcriptomic analyses. Male and female Schistosoma mansoni elicited an egg-independent, non-polarised Th1/Th2 immune response in the host, with males showing a significantly greater influence on gene regulation in the spleen and thus on the host. The results of the thesis provide promising approaches for the elucidation of new metabolic pathways and immunomodulatory mechanisms of the adult worms and may thus contribute to the development of new drugs or a vaccine against schistosomiasis.