Vaccination with BCG induces an early CD4⁺ T cell response in the DLN of <i>M. ulcerans</i>-infected mice.

<p>Mice were either non-immunized (•) or immunized with BCG (○) two months before challenge. All mice were infected in the footpad with 4 log₁₀ CFU of <i>M. ulcerans</i> 98–912. At different time points post-infection, the total number of leukocytes in the popliteal lymph node of the infected footpad was counted (A) and the number of CD4⁺ (B), and CD8⁺ (C) cells was determined by flow cytometry. The data points represent the mean ± SEM (<i>n</i> = 5–8). Statistical significance was calculated with Student's <i>t</i> test (*<i>p</i><0.05; **<i>p</i><0.01).