FIGURE 2.

Xmv45 induction during in vitro and in vivo murine B cell stimulation. Expression pattern of the 31 includible LTR elements identified in Figure 1B in three independent datasets. Significantly induced LTR elements were identified in each study separately (≥2-fold change; p < 0.05, and the elements shared with in vitro stimulated cells (Figure 1B) are shown. (A) Transcriptional analysis of purified splenic follicular B cells before and after 2-h in vitro stimulation with a-IgM (10 μg/ml) or LPS (25 μg/ml) (GSE61608), depicting the significantly induced LTR elements. (B) Transcriptional analysis of purified splenic follicular B cells before and after in vitro stimulation with LPS for 3 days or a combination of CD40L, IL-4 and IL-5 for 4 days (GSE60927). Also included in the comparison are ex vivo analyzed splenic germinal center B cells, marginal zone B cells and plasma cells. The heat map depicts the significantly induced LTR elements and unsupervised hierarchical clustering of samples according to their expression. (C) Mice were primed by intramuscular injection of inactivated influenza A/New Caledonia/20/99 virus and were boosted with intramuscular injection of seasonal (2006–2007) trivalent inactivated influenza vaccine 30 days later (GSE68769). The figure shows the transcriptional analysis of purified lymph node B cells, pooled from 3 mice for each of the indicated time-points after boost, depicting the significantly induced LTR elements. In (A–C) each column is an independent pool and the underlined element is Xmv45. (D) Normalized counts for the 6 LTR elements with the highest expression in dataset described in Figure 1A. Symbols represent the mean values of triplicate samples. The underlined element is Xmv45. (E) Normalized counts of the indicated proviruses in the same dataset described in Figure 1A. Each symbol is an independent sample.