Isolation of Clq-binding virus-antibody immune complexes from lactic dehydrogenase virus (LDV)-infected mice.

A Sepharose-IgG-Clq sorbent has been successfully used to isolate circulating virus-antibody (virus Ab) complexes from serum of lactic dehydrogenase virus (LDV)-infected mice. The chronological study demonstrated that although circulating LDV in persistently infected mice was complexed with IgG antibody, the virus-Ab complexes bound to the Clq sorbent only early during the infection. Inactivation of these Clq-isolated virus Ab complexes was accomplished with rabbit anti-mouse IgG but not anti-IgM. The critical time period for the demonstration of Clq-binding LDV-Ab complexes in serum was between 10 and 18 days postinoculation. The reasons for the apparent shift from Clq-binding virus-Ab complexes to non-Clq binding are not clear, however, possible explanations and implications in immune complex tissue injury are discussed.