The p1 Protein of the Yeast Transposon Ty1 Can Be Used for the Construction of Bi-Functional Virus-Like Particles

Virus-like particles (VLPs) containing heterologous proteins are often used as vaccines. Two approaches for the construction of bi-functional VLPs using hybrid protein pl-380 of the Ty1 transposon of Saccharomyces yeast are described. We have shown that both C- and N-termini of p1–380 can be used for the expression of heterologous peptides. Peptides from A. fumigatus Asp f 2, expressed at the C- and/or N-termini of p1–380, did not interfere with VLP self-assembling, were accessible for antibodies and hence were exposed at the VLP surface. Another way to obtain bivalent VLPs is the formation of mixed particles, which co-express two hybrid pl proteins with different heterologous protein fragments at the C-terminus. To do it the yeast cells were transfected with a mixture of two recombinant DNA coding Asp f 2 peptide and green fluorescent protein (Gfp). We have shown that both Asp f 2 peptide and Gfp are expressed within the same particle. To evaluate biological activity of bi-functional VLP a construction containing peptides representing dominant T- and B-cell epitopes of Asp f 2 was produced. Bi-functional particles were more potent in stimulating memory immune responses. These results demonstrate new possibilities of pl-380 based expression system to produce multifunctional VLPs.