Figure 2

Immunization of DBA/1 mice with glucose-6-phosphate-isomerase-derived peptides induces arthritis. (a) Mice were immunized with either 400 μg glucose-6-phosphate-isomerase (G6PI), 50 μg G6PI_85–99, 50 μg G6PI_325–339 or 50 μg G6PI_469–483 in complete Freund's adjuvant. Shown is the clinical severity of disease in arthritic mice in a representative experiment (n = 5 per group). Each peptide was tested in at least two independent experiments (Table 1). (b) The animals immunized with G6PI showed a strong synovialitis (circles) and inflammation of the adjacent skeletal muscle (star), which was dominated by neutrophilic granulocytes (small arrow) as a sign of acute inflammation and exhibited activation of synovial fibroblasts to a lesser extent (broad arrow). The synovial tissue was enlarged due to the dense inflammatory infiltrate; however, bone destruction was only focally observed. Similar but markedly less intense alterations could be observed in the animals immunized with G6PI_85–99, whereas immunization with peptide G6PI_469–483 resulted in an inflammation that was as strong as when using whole G6PI. (H & E; original magnification: upper row, 50×; lower row, 200×). Results show representative data from at least nine individual mice from two typical experiments.