Although not tested here, the injection of bacterial components as essential part of the AnExIL formulation may pose problems of reactogenicity. S30 extract derived from E. coli is an essential component of AnExILs and which is likely to contain the pyrogenic endotoxin LPS. Visual inspection of the mice after i.m. administration of the AnExILs did not show any discomfort or illness. Nevertheless, alternative sources of IVTT mixes that are free of endotoxins should be tested. For example, extracts prepared from gram-positive bacteria, wheat germ or the synthetic PURExpress system (Shimizu et al. 2001 ) may be substituted for the E. coli-based extract.