High level expression, purification and characterization of recombinant CCR5 as a vaccine candidate against HIV

• We highly expressed and purified recombinant CCR5 vaccines from Escherichia coli.
• The immunogenicity of PADRE-rCCR5 and rCCR5 was stronger than that of GST-C1 and GST-C2.
• PADRE-rCCR5 can induce a high titer (1:100,000) CCR5-specific antibodies.
• The induced polyclonal antibody can specifically bind with CCR5+ U937 cells.

Cysteine–cysteine chemokine receptor type 5 (CCR5) is an important co-receptor for human immunodeficiency virus (HIV) infection and CCR5 neutralizing agents have proven efficient in patients suffering from HIV infection. Here, we expressed and purified various CCR5 vaccines named rCCR5, PADRE-rCCR5, GST-C1 and GST-C2 composed of different epitopes of CCR5. Results showed that vaccines containing multiple epitopes (rCCR5 and PADRE-rCCR5) induced stronger immune responses than single-epitope ones (GST-C1 and GST-C2). In addition, the elicited antibodies can specifically bind CCR5+ U937 but not CCR5− Wish cells. These results demonstrate that the CCR5 vaccines are useful for further research, especially for the in vitro preclinical evaluation of their potential as biological CCR5 neutralizing agents.