Influence of DNA priming on the MPER-specific antibody response after the VLP boost.

<p>(A) Mice (n = 5–6/group) were immunized with VLPs containing different MPER display mutant either with or without prior DNA immunization with plasmids encoding the same MPER display mutants. (B) MPER-specific antibody levels in the sera of immunized mice three weeks after the last VLP immunization are presented as Log values of the relative light units (Log RLU) obtained in an MPER antibody ELISA. Mean and single values for each of the animals are shown. Statistically significant differences between the groups treated with the different DNA and VLP vaccines were determined by one way analysis of variance followed by Bonferroni’s multiple comparison test and are indicated by horizontal bars with “a” indicating a p-value of <0.05. T-tests were performed to determine whether DNA priming enhances antibody levels for each of the different immunogens. Statistically significant differences are marked by dashed horizontal bars with “b” indicating a p-value of <0.05. Filled symbols are used for non-primed mice and opened symbols for DNA-primed mice. (C) Time course of MPER-specific antibodies in sera of individual mice (MPER42-1 to MPER42-5) immunized with MPER42 DNA and VLP vaccines.