Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients

Figure 4

Effect of CR1 clustering on BCR-induced phosphorylation of Syk and MAPKs in human B cells. (a) 10⁶ PBMCs isolated from healthy donors were activated for 10 minutes with 5 μg/mL F(ab’)₂ fragment of anti-human IgG+M+A and treated or not with 40 μg/mL heat-aggregated C3. Effect of CR1 clustering on phosphorylation of Syk (a), ERK (b), and JNK (c) was investigated by the Phosphoflow method. Dot plots show percentage (%) of p-Syk, p-ERK, or p-JNK positive B cells and are representative of three independent experiments with similar results. (d) Results showing percent of inhibition mediated by aggregated C3 are mean % of inhibition ± SEM of three independent experiments and correlated with the CR1-agonist untreated sample (see Section 2, Permutation-test; and ).

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