The interaction between viruses and the immune system is known to be varied and complex. In particular, viruses may develop survival tactics to diminish the immune system, causing the protective immunity response to become deleterious to the host. A dynamic model is developed to depict the interaction between viruses and immune system response under this scenario. Rather general and nonlinear specifications are allowed in the growth rate of the antibodies and antibodiesí kill rate. Some stylized prognosis possibilities are generated by the model. It also yields the interesting outcome in which the slightly infected may die of the disease while the seriously infected may survive. Treatment simulation is also considered.