PROTECTION AGAINST MURINE CYSTICERCOSIS USING CDNA EXPRESSION LIBRARYIMMUNIZATION

Genetic or DNA-based immunization, including genomic immunization, has shown to be a viable alternative approach to induce protective immuni ty against a number of pathogens in several disease models. Here we de scribe a new method, cDNA expression library immunization (cDELI), bas ed on the use of a large number of cDNA clones. This immunization stra tegy was tested in experimental murine Taenia crassiceps cysticercosis model. A partial cDNA expression library of 2 x 10(4) members was con structed in eukaryotic expression vector pcDNA3 and used to immunize B ALB/c female mice subcutaneously (s.c.) and intramuscularly (i.m.). In both cases significant reduction of parasite load (up to 65%) was obt ained. We were unable to directly measure T. crassiceps-specific humor al immune response in any of the immunized mice, although the expressi on of pathogen proteins in vitro in macrophages transfected with cDNA expressing plasmids was demonstrated. Also, in three out of five rando mly selected immunized mice detectable levels of interferon-gamma (IFN -gamma) were obtained, cDELI has additional advantages compared with r ecently developed single gene or genomic immunization approaches becau se a cDNA population represents only those genes that are being expres sed in the pathogen cells and the selection of stage-specific antigens is possible. The use of cDELI could be particularly attractive for th e pathogens with complicated life cycles and large genomes. (C) 1998 E lsevier Science B.V. All rights reserved.