B- and T-lymphocyte counts. (A) B lymphocyte counts. PBMC were isolated at the time points (days post-infection (p.i.)) indicated on the x-axis, and stained with anti-IgG H+L Ab to analyse the B cell numbers. The absolute B cell counts were calculated and expressed as ×103 cells/ml. Individual animals are represented by the open and filled symbols, with the mean values for the groups shown by the continuous line. (B) T lymphocyte counts. The above PBMC were stained for CD3a expression, to analyse the T lymphocyte counts. These counts are given as × 103 cells/ml for the individual animals (open and filled symbols), with the group mean values shown as the continuous line. *P < 0.05.