Figure 2.

After treatment with human Abs, chronically TMEV-infected mice demonstrate significant OL remyelination. Light photomicrographs of representative areas of spinal cord white matter pathology of different treatment groups. Treatment with IVIg resulted in significant OL remyelination (A). Almost complete OL remyelination, characterized by densely packed thin myelin sheaths in relation to axon diameter (B, arrowhead), was observed in sections from the spinal cords of mice after treatment with polyclonal human IgM (B) and human mAbs sHIgM 22 (F) and sHIgM46 (G). In contrast, after treatment with human mAbs sHIgM1 (C), sHIgM2 (D), sHIgM14 (E), or PBS (H) mice demonstrated white matter pathology without significant OL remyelination. Infiltrating inflammatory cells, macrophages ingesting myelin debris (A, arrowhead), and signs of active myelin destruction were also evident. Spinal cord cross sections in four of eight animals treated with sHIgM22 and five of five animals treated with sHIgM46 contained at least one area of nearly confluent OL remyelination, a rare event indicating significant tissue repair. In contrast, the 10 spinal cord cross sections from each mouse treated with sHIgM1, sHIgM2, sHIgM14, or PBS contained none. (Scale bar is 20 μm.)