C3 and arthritic joint disease: Furthermore, when two mice from each of the critical groups (C3 -/- BMC into wild-type, and wild-type BMC into C3 -/-) continued to receive injections of K/B×N serum for a total of 4 weeks and arthritis was evaluated until day 42, the wild-type recipients continued to show severe inflammation, while the C3-deficient recipients never developed disease (not shown).