ABSTRACT
Protamine sulphate/DNA complexes have been shown to protect DNA from DNase digestion in a lipid system for gene transfer. A DNA-based vaccine complexed to protamine sulphate was used to induce an immune response against Schistosoma mansoni anchored-glycosylphosphatidylinositol tegumental antigen in BALB/c mice. The protection elicited ranged from 33 to 44 percent. The spectrum of the elicited immune response induced by the vaccine formulation without protamine was characterized by a high level of IgG (IgG1> IgG2a). Protamine sulphate added to the DNA vaccine formulation retained the green fluorescent protein encoding-plasmid longer in muscle and spleen. The experiments in vivo showed that under protamine sulphate effect, the scope of protection remained unchanged, but a modulation in antibody production (IgG1= IgG2a) was observed.
Subject(s)
Animals , Female , Mice , Antibodies, Helminth/immunology , Antigens, Helminth/immunology , Glycosylphosphatidylinositols/immunology , Heparin Antagonists/immunology , Protamines/immunology , Schistosoma mansoni/immunology , Vaccines, DNA/immunology , Antibodies, Helminth/blood , Antigens, Helminth/administration & dosage , Glycosylphosphatidylinositols/administration & dosage , Heparin Antagonists/administration & dosage , Immunoglobulin G/immunology , Mice, Inbred BALB C , Protamines/administration & dosage , Schistosomiasis mansoni/prevention & control , Time Factors , Vaccines, DNA/administration & dosageABSTRACT
The 18-kDa protein from Mycobacterium leprae is a major target for the immune response in leprosy. We have developed a system to express this antigen in yeast as a fusion protein with the C-terminal region of the yeast membrane protein GAS1, which would render the recombinant protein anchored to the plasma membrane by a glycosylphosphatidylinositol (GPI) anchor. Cells lacking the GAS1 gene and transformed with the hybrid 18-kDa-GAS1 construct express a polypeptide that reacts with an 18-kDa-specific monoclonal antibody. In addition, these cells react with an alpha-CRD antibody after GPI-PLC treatment. The non-transformed cells are negative. These data indicate that our system may be suitable for the expression of foreign proteins in yeast in a GPI-anchored form