Production of Immunity to Poliomyelitis Virus in Motor Cells of the Monkey's Spinal Cord. ∗

The following experiments constitute a demonstration that, as in the case of the olfactory bulbs already reported, 1 certain motor cells in the spinal cord of the rhesus monkey may be rendered resistant to the effects of invasion by poliomyelitis virus by means of procedures which produce alterations in their normal metabolism. Eighteen animals were subjected to section of the sciatic nerve in the sciatic notch at intervals varying between 3 and 57 days previous to the induction of complete leg paralysis by intranasal inoculation of poliomyelitis virus. A series of 6 uninoculated controls were operated upon in a similar fashion and sacrificed at intervals between 6 and 30 days.

These animals may be grouped under two headings. The first includes those monkeys in which the nerve section either produced no effect upon the susceptibility of the cells involved, or may have slightly enhanced it. This situation was found in 3 cases where nerve section had preceded leg paralysis by 3-4 days. In this group the cells of the operated and control sides were completely destroyed and it appeared that the destruction of the former had preceded that of the control cells.

Exactly the opposite effects were observed in the second group of 15 animals in which nerve section had been carried out 6-57 days previous to leg paralysis. In these cases the entire anterior horn of the control side was destroyed wrhile on the operated side the vast majority of the cells giving rise to the sciatic nerve were spared. In the cases of longest duration of nerve section (13-57 days) the differences between the two sides were most striking (Figs. 1 and 2). As might be expected from the analysis of the cases in the first group, showing the opposite effect, the sparing was less extensive in those animals where nerve section was of shorter duration (6-8 days).