FIGURE 3.

Effects of immune education splenic size and splenic germinal center formation 24 h post-CLP. C57Bl/6 laboratory mice underwent education or treatment with isotype control antibody. Thirty-five days later mice were euthanized (T₀) or subjected to CLP. Mice subjected to CLP were euthanized 24 h later. Spleens were weighed immediately ex vivo and normalized to pre-CLP body weight. Spleens were fixed and stained with hematoxylin and eosin and analyzed for germinal center formation by blinded pathologists. Each point represents results in an individual animal, central horizontal line indicates mean, upright and inverted Ts indicate standard deviation, data representative of two independent experiments. Filled circles – T₀ in control mice; Filled square – T₀ in immune educated mice; Open circle – 24 h post-CLP in control mice; Open square – 24 h post-CLP in immune educated mice. Data analyzed using two-way ANOVA with Sidak’s post hoc correction for multiple comparisons. ***p < 0.001, significantly different from value in control mice at same time point; ^#p < 0.05, slope of line connecting T0 mean and mean 24 h post-CLP significantly different than slope of line for control mice. (A) Splenic weight normalized to pre-CLP body weight. N = 3/group. (B) Germinal centers per high power field. N = 6/group. (C) Hematoxylin and eosin stain of the spleen visualized at 100× or 200× revealing germinal centers. Representative of 6 slides each. (D) Percent area covered by germinal centers in the spleen. N = 6/group.