That is, in view of the large differentials in C3b deposition and cell killing for OFA versus RTX-opsonized CLL cells, these findings again support the idea that the threshold for C3b deposition required for generation downstream of sufficient amounts of the MAC to effectively permeabilize ARH77 cells and promote Ca2+ entry is not reached for RTX-reacted ARH77 cells. The gene discussed is C3; the disease is B-cell chronic lymphocytic leukemia.