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Vaccine efficacy of recombinant cathepsin D aspartic protease from Schistosoma japonicum
Author(s) -
Verity Christiana K.,
McManus Donald P.,
Brindley Paul J.
Publication year - 2001
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1046/j.1365-3024.2001.00369.x
Subject(s) - biology , schistosoma japonicum , antibody , recombinant dna , immunology , immune system , vaccination , virology , protease , immunogenicity , microbiology and biotechnology , humoral immunity , helminthiasis , schistosomiasis , helminths , enzyme , biochemistry , gene
Mice were vaccinated with recombinant Schistosoma japonicum cathepsin D aspartic protease, expressed in both insect cells and bacteria, in order to evaluate the vaccine efficacy of the schistosome protease. Mean total worm burdens were significantly reduced in vaccinated mice by 21–38%, and significant reductions in female worm burdens were also recorded (22–40%). Vaccination did not reduce fecundity; rather, we recorded increased egg output per female worm in vaccinated animals, suggesting a crowding effect. Vaccinated mice developed high levels of antibodies (predominantly IgG1, IgG2a and IgG2b isotypes), but there was no correlation between antibody levels and protective efficacy. Immune sera from vaccinated mice did not inhibit the degradation of human haemoglobin by the recombinant protease, and passive transfer of serum or antibodies from vaccinated animals, before and after parasite challenge, did not significantly reduce worm or egg burdens in recipient animals. These results suggest that antibodies may not play a key role in the protective effect elicited, and that protection may be due to a combination of humoral and cell‐mediated responses