Figure 4.

Somatic mutations in V_H ³¹⁵ are essential for the ability of DC-targeted DNA vaccines to induce protection against MM cells. (A) Overview of neoepitopes predicted using NetMHCpan4.0. Strong binders containing a V_H ³¹⁵ mutation are shown. Mutations present in V_H ³¹⁵ are highlighted in orange. B) Overview of mutant V_H used in scFv constructs used for immunization. Germline V_H residues are shown in black, V_H ³¹⁵-specific residues in orange. All scFv constructs included V_L ³¹⁵. Below, the constructs are abbreviated as Mut1 etc. (C, D) BALB/c mice were immunized i.m./EP with 50 µg DNA or NaCl i.m. and challenged 14 days later intravenous with (2×10⁵) MOPC315.BM.Luc.IgAλ2 (C) or MOPC315.BM.Luc (D), n=4–6 mice/group. Shown are survival curves (left) and M315 levels in sera at end point (right). (E) Summary of the effects of the different V_H mutations in Exp 1 (figure 4C), Exp 2 (figure 4D) and Exp 3 (online supplemental figure 8) at end point (either day at paraplegia or day 100). Statistics: Mantel Cox log-rank test compared with NaCl group. *p<0.05, **p<0.01, ***p<0.001. MM, multiple myeloma; ND, not detected; ns, not significant.