Macrophage stimulation using a group B-streptococcus exotoxin (CM101) leads to axonal regrowth in the injured optic nerve.

Purpose: A group B-streptococcus exotoxin (CM101) was administered following optic nerve injury in adult rats in order to analyze putative effects on macrophages, glial scar formation and regrowth of axons in the lesioned optic nerve.

Methods: After a standardized intraorbital optic nerve crush, animals were randomized to treatment with CM101 (30 microm/kg body weight, iv, repeated every other day) or vehicle alone. Morphology (semithin sections) and immunohistochemistry directed towards macrophages (ED1), neurofilament (NF), astrocytes (GFAP) and regenerative sprouts (GAP43) were employed at different time-points up to 28 dpi.