Fig 4.

Memory T cell responses are lower and more restricted than those observed during acute infection in BAL fluid samples. BAL fluid cells from latently infected young RM (2 to 4 years of age) were stimulated with overlapping peptide libraries covering all 70 SVV ORFs and T cell responses assessed using IFN-γ–ELISpot technology. Each peptide was tested in triplicate, and average numbers of spot-forming cells (SFC) per ORF per 200,000 cells with the background subtracted are shown. (A) Representative profile of one latently infected animal. (B) Average SFC responses ± SEM from all 12 latently infected animals. (C) Numbers of animals that generated a positive response to each ORF. Horizontal lines indicate the threshold above which a response is defined as positive.