FIG. 6.

Synthesis of immunoglobulin G (IgG) in the injured spinal cord at 2 weeks after cervical spinal cord injury (cSCI). (A) IgG+ antibody-secreting cells (ASCs) were detected in the lesioned spinal cord at 2 weeks post-SCI. Spinal cord sections were stained for rat IgG, IgM, and 4′,6-diamidino-2-phenylindole (DAPI) to assess presence of ASCs. IgG+ ASCs (arrows) were detected in the anterior white matter of the spinal cord, as shown in the schematic on the right corner of panel (A). IgM+ ASCs were not detected in the lesioned spinal cord. Scale bar: 20 μm. (B) Confocal microscope image taken close to the developing cavity distinguishing IgG+ ASCs (arrowhead) from IgG+ astrocytes (arrow) and lack of CD45RA expression in the IgG+ ASCs. (C) Rat spleen stained for CD45RA and IgG as a positive control for the detection of CD45RA+ cells. Of note, IgG+ ASCs (arrowhead) are negative for CD45RA staining (arrow). Scale bar (B, C): 10 μm. (D) Rat spleen stained for IgG and IgM immunoglobulins as a positive control for the detection of rat IgG+ (cyan arrowhead) and IgM+ (white arrowhead) ASCs. Scale bar: 100 μm. (E-F) High-power confocal image of splenic IgM+ and IgG+ ASCs. Scale bar: 10 μm. (G) Quantification of IgG and IgM immunoglobulins in cerebrospinal fluid (CSF) of SCI or sham rats at 2 weeks post-injury. Levels of immunoglobulins were not statistically different between the groups. Mann-Whitney test, n = 5-8/group; bars indicate mean. Color image is available online at www.liebertpub.com/neu