Relevance of I133T mutation to Y135F and its impact on CTL responses. (A) The cross-sectional analysis of the co-variation relationship between Nef codons 133 and 135. Nef codons containing gaps or amino acid mixtures were excluded from analysis, leaving 941 and 924 sequences for analysis of codon pairs 135F/133T and 135Y/133I, respectively. (B) Kaplan-Meier plot of the emergence of Y135F and I133T mutations in a multicenter longitudinal acute/early infection cohort comprising 16 HLA-A*24:02-expressing persons. (C) Within 24 patients who harboring 133I/135F or 133T/135F mutant, correlation between the magnitude of peptide-specific response and pVL was examined. Peptide-specific response was determined by using ex vivo IFN-γ ELISpot assay with frozen PBMCs. Each point is plotted according to the average SFU of duplicate wells and the measured pVL at the sampling point. Statistical significance of the correlation between the magnitude and pVL was calculated by Spearman’s rank correlation.