Figure 2

Principal component (PC) analysis. (A) Depicts variability in gene expression of native hearts from allograft (BN) and isograft recipients (DA), and of transplanted hearts from allograft (DA) and isograft recipients (DA). Principal component 1 (PC1) on the x-axis, and PC2 on the y-axis, accounted for 42.5% (p < 0.05), and 7.9% of total variability in gene expression, respectively. The samples visually separate into 3 main groups based on their immunological status: (1) rejecting transplanted hearts from allograft recipient (DA allograft); (2) non-rejecting transplanted hearts from isograft recipient (DA isograft); (3) and native hearts (DA and BN). (B) Depicts variability in gene expression of peripheral blood mononuclear cells (PBMC) from transplanted and untransplanted animals. Transplanted and untransplanted animal samples were processed in two batches, and the results as shown were batch-corrected for this nuisance factor. PC1 (x-axis) and PC2 (y-axis) accounted for 17% (p < 0.05) and 8% of the total variability in gene expression, respectively. Samples visually separate into 2 main groups: (1) PBMC from untransplanted DA animals and isograft recipients (DA); and (2) PBMC from untransplanted BN animals and allograft recipients (BN). The separation of animals primarily into two groups based on strain, and not ACR, indicates that most of the gene expression variability in PBMC during rejection was due to strain.