A synthetic dengue virus antigen elicits enhanced antibody titers when linked to, but not mixed with, Mycobacterium tuberculosis HSP70 domain II

Domain II of Mycobacterium tuberculosis (Mtb) heat shock protein 70 (HSP70), spanning amino acid residues 161-370, was covalently linked to a recently described synthetic dengue virus antigen to study the influence of the former on the immunogenicity of the latter. Using an enzyme-linked immunosorbent assay, dengue antigen-specific antibody titers elicited by the fusion protein in Balb/c mice were an order of magnitude higher than those elicited by either the synthetic dengue antigen alone or a physical mixture of the dengue antigen plus Mtb HSP70 domain II protein. Our data demonstrate that (i) Mtb HSP70 domain II is capable of potentiating B-cell response and (ii) it should be covalently linked to the target antigen to do so.