Genetic immunization of mice with DNA encoding the 23 kDa transmembrane surface protein of Schistosoma japonicum (Sj23) induces antigen‐specific immunoglobulin G antibodies

Abstract

The 23 kDa transmembrane surface protein of schistosomes is of recognized interest in studies of immune responsiveness in schistosomiasis. To examine the immunogenicity of the 23 kDa antigen of Schistosoma japonicum, Sj23, when delivered by genetic immunization, mice were immunized using a DNA construct containing the Sj23 cDNA under the control of a CMV promotor. Serological analysis of peripheral blood from immunized mice demonstrated that this construct was able to induce the production of antigen-specific IgG antibodies that recognized a schistosome antigen of 23 kDa in Western blots. Despite inducing antigen-specific antibodies, the Sj23 DNA vaccine was unable to confer protection in immunized mice subjected to challenge with S.japonicum cercariae. Appropriate engineering of the unique structure of the Sj23 kDa transmembrane protein of schistosomes may provide a novel vehicle for expressing foreign epitopes from other infectious agents or, possibly, cancer antigens, anchored to the surface of transfected cells.

Protective immunity of single and multi-antigen DNA vaccines against schistosomiasis

“…Several DNA-vaccine constructions encoding for S. japonicum paramiosine did not induce protective immunity after challenge, despite inducing the production of specific antibodies IgG1, IgG2a and IgG2b (Waine et al 1997). Serological reactivity for IgG was also observed after DNA immunizations of the 23kDa tegumental protein albeit no protection was detected after challenge (Waine et al 1999a). The comparison of the genetic immunization with a plasmid coding either a secreted or nonsecreted form of S. japonicum 22 kDa tegumental protein demonstrated the influence of the plasmid construction on the capability to induce specific IgG response, being superior in animals inoculated with the secreted form, however neither group induced protection to challenge (Waine et al 1999b).…”

Biochemical Characterization and Differential Expression of a 16.5-Kilodalton Tegument-Associated Antigen from the Liver Fluke Fasciola hepatica

“…Interestingly, some of these proteins have been localized at the tegument of S. japonicum (44), and a recent proteomic study of the F. hepatica tegument revealed uncharacterized proteins with DM9 motifs to be associated with the tegumental membrane of the parasite (72), which supports our findings. On the other hand, numerous tegumental proteins lacking the DM9 motif have been identified and purified from F. gigantica (5)(6)(7)64), S. japonicum (69,70), S. mansoni (31,39,55), C. sinensis (18,74), Echinococcus granulosus (56), and Taenia spp. (40,42,54), and none of these proteins shares homology with FhTP16.5.…”

Current status and future prospects for a vaccine against schistosomiasis

“…A degree of protective immunity against S. mansoni was achieved with an ovalbumin (OVA)-coupled peptide antigen from Sm37 glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (TABLE 2) when coadministered with granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-12 [61] and with a multi-antigen peptide (MAP) carrying peptides from two S. mansoni antigens coadministered with GM-CSF [62]. Most efforts have been aimed at trying to achieve immune responses to schistosome antigens that are skewed towards Th1 either by the use of recombinant cytokines as described previously, or by the use of DNA vaccines which tend to give rise to Th1 skewed responses [63][64][65][66][67][68][69][70]. Others have used DNA vaccines in combination with cytokines encoded on coimmunized DNA [70].…”