Figure 4.

Percentage of MN immunostained for (a) CD4 and (b) CD8 in the three types of lesion. At 2 days, the reinfection BCG lesions and tuberculin reactions contained a higher percentage of CD8 cells per mm² than did the primary lesions (P < 0·05), suggesting that tuberculin sensitivity favours the production of cytotoxic T lymphocytes. Note that CD4 cells are much more numerous than CD8 cells (compare the scales on the y-axes). Each point represents the mean of four lesions with its standard error: for reinfection BCG lesions versus primary BCG lesions: *P < 0·05 and **P < 0·01; for tuberculin reactions versus primary BCG lesions: †P < 0·05; and for reinfection BCG lesions versus tuberculin reactions: ‡P < 0·05 and ‡‡P < 0·01.