Experimental glomerulonephritis induced by immune complexes of monoclonal antibodies produced by immunoglobulin class-switch variants.

Experimental glomerulonephritis was induced in mice by injecting performed antigen-antibody complexes composed of monoclonal anti-dansyl antibody of switch-variant origin and dansyl-conjugated bovine serum albumin. A comparison was made of the ability of two kinds of monoclonal antibodies, IgE and IgG2a, of the same variant origin to induce glomerulonephritis. Both types of immune complexes (IC), (IgE-IC and IgG2a-IC), given daily elicited exudative proliferative glomerulonephritis accompanied by proteinuria. Significant glomerular hypercellularity including invasion by polymorphonuclear leukocytes was observed as early as 2 days and was prominent at 14 days after the start of daily injections. Deposits of IgE-IC and IgG2a-IC plus the third complement component were observed mainly in mesangial areas early in the experiment (3 to 8 days) and additionally along peripheral loops at a later stage (9 to 14 days). By electron microscopic examination, immune deposits were detected in the mesangial areas as well as in the subepithelial aspect of the peripheral loops. These results reveal that the isotype of the antibody used to prepare IC does not influence the form or severity of glomerulonephritis.