RP105 and TLR4/MD-2 expression in splenocytes and A20 cell lines. (A) Splenocytes from wild-type and CD19^–/– mice were examined by 2-color immunofluorescence staining with flow cytometry analysis. Quadrant gates indicate negative and positive populations of cells as determined using isotype-matched unreactive control mAbs. These results are representative of those obtained with four to seven 2-month-old mice of each genotype. (B) RP105 and TLR4/MD-2 expression by parental A20 (bold line) and CD19^– A20 cells (thin line). Cell surface molecule expression was detected with flow cytometry analysis. Immunofluorescence staining with an unreactive, isotype-matched, control mAbs is also shown (dashed line). These results are representative of those obtained in 4 experiments.