Helminths host immune systems

One likely reason for the prevalence of helminths is their undoubted ability to down-regulate the host immune system at both the antigen-specific and polyclonal levels [3], In many chronic diseases, such as schistosomiasis and lymphatic filariasis, peripheral blood T cells show dramatically impaired parasite antigen-specific responsiveness [4], as discussed in more detail below. Moreover, from early reports of immunosuppression in animal models of infection, to studies in Africa linking vaccine failure to heavy helminth infection, there is clear evidence that infections can diminish reactivity to bystander antigens, particularly with increasing intensity of... 

Recent advances by molecular and immunological helminthologists have indicated that helminths are a rich source of interesting molecules that could lead to innovation for many aspects of biomedicine. Parasites can produce different molecules which interfere with the host immune system at different levels (regulatory and effector responses). Some of them have been weU characterised and purified or, in some cases, the corresponding cDNA was cloned. 

FIGURE 6.17.1 Helminths, or parasitic worms, have the ability to cakti the host immune system. 

Helminths alter immune responses by releasing factors. Many of these specific molecules are discussed in this book. Perhaps treatment with modified helminth-derived components or small molecule mimics could obviate the need fi>r actual helminth exposure. On the other hand, each helminth may exude many immune modulating factors. Helminths are complex organisms with large diverse genomes. They adapt to their environments. It is quite probable that the immune effects of a viable helminth will be greater than that provided by one or more of its molecular components. Moreover, a viable helminth will continuously interact with the host immune system. Administered components would require frequent administration. If viable helminths prove... 

---