Early Priming Minimizes the Age-Related Immune Compromise of CD8+ T Cell Diversity and Function
Figure 7
Comparison of TCRβ diversity, and inter-individual sharing and similarity for the DbNP366+Vβ8.3+CD8+ and DbPA224+Vβ7+CD8+ repertoires.
Shown are the relative measures of TCRβ repertoire diversity, (A–D) the number of different clonotypes and (E–H) Simpson's diversity index, and (I–L) % of repertoire comprised of shared clonotypes, and (M–P) inter-individual TCR repertoire similarity, as measured by the Morisita-Horn similarity index. The Simpson's diversity and Morisita-Horn similarity indices account for the clonal dominance hierarchy among the different clonotypes and vary between 0 (minimum diversity/similarity) and 1 (maximum diversity/similarity). Each of the diversity, inter-individual sharing and similarity measures were estimated for a standard sample size of 22 TCR sequences per individual mouse repertoire. The repertoire diversities were calculated for each mouse per age/priming group for primary (A, E) and secondary (B, F) DbNP366+Vβ8.3+CD8+ TCR repertoires and for primary (C, G) and secondary (D, H) DbPA224+Vβ7+CD8+ TCR repertoires. The repertoire similarities were assessed between pairs of primary (M) and secondary (N) DbNP366+Vβ8.3+CD8+ TCR repertoires and between pairs of primary (O) and secondary (P) DbPA224+Vβ7+CD8+ TCR repertoires within the same age/priming group. To evaluate TCR sharing, clonotypes were first defined as shared or non-shared across all DbNP366-specific or DbPA224-specific TCRβ repertoires. The proportions of the 22 TCRβ sequences per DbNP366+Vβ8.3+CD8+ TCR repertoire (I, J) or DbPA224+Vβ7+CD8+ TCR repertoire (K, L) that were comprised of shared clonotypes were then estimated. A Mann-Whitney test was used to compare between young and aged mice for the primary responses and between young mice, aged mice primed young and aged mice primed old for the secondary responses. For the comparison between age/priming groups for the secondary responses, the statistical significance for each pairwise comparison was determined at p<0.0167 (*), using Bonferroni correction for multiple pairwise comparisons.