Regulation of B/T segregation. (A) Low-magnification confocal images of spleen sections. CD3 is shown in red and IgM in green. Yellow shows colocalization of B and T cells. (i) Wild-type (WT) mice. (ii) LTα^−/− mice. (iii) Organization of the spleens of LTα^−/− mice 10 days after transfer of normal splenocytes. (iv) Organization of the spleens of RAG^−/− mice 10 days after transfer of LTα^−/− splenocytes. (v) Organization of the spleens of LTα^−/− mice 10 days after transfer of CD11c⁺-enriched population (DCs and pDCs). (vi) Organization of the spleens of LTα^−/− mice 10 days after transfer of CD4⁺CD3⁻ cells. (B) CCL21 expression. CD3 is shown in red, IgM in green, and CCL21 in white. Single staining for CCL21 is shown in the adjacent box. Scale bars represent 100 μm. Results representative of at least 2 separate experiments.