<p>(A) Size exclusion chromatography and Western Blot (inset) of lysates of BHK21 cells (ATCC CCL-10) transfected with, either, wild type (wt, dashed line) or N-terminally truncated ΔβGal (ΔN, solid line); fractions analyzed for βGal by ELISA. (B) Enzymatic βGal activity of serially diluted lysates of transfected cells (from samples shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102280#pone-0102280-g003" target="_blank">fig. 3A</a> inset) as determined by luminescence and expressed as kilo-photon counts (kpc) per second. (C) in-vivo CTL activity in B6 mice (n = 5) 14 d after 2 gene gun immunizations with pCI-ΔβGal or the full length wild type sequence (WT βGal). (D,E) Serum IgG isotypes of individual mice, 2 weeks after two gene gun immunizations with pCI-βGal (D) or pCI-ΔβGal (E).</p