Comparative activation response of splenocytes oxidized by periodic acid and selenium dioxide

Murine splenocytes were activated by selenium dioxide (SeO2) oxidation of cell membranes, as evidenced by increased tritiated thymidine (3H-TdR) incorporation. In contrast to splenocyte activation by periodic acid (H5IO6), the SeO2-induced response was not inhibited by neuraminidase degradation of cell membranes prior to oxidation, nor by the prior hydroxylamine (NH2OH) addition reaction. However, reduction by borohydride (NaBH4), as a preliminary step to the oxidation by SeO2 and H5IO6, inhibited the subsequent cell activation. Sequential oxidation by H5IO6 and SeO2 increased the cell stimulation index versus the response elicited after one step oxidation by SeO2 or H5IO6. The reverse order of the sequential oxidation depressed the stimulation index relative to oxidation solely by H5IO6, but not by SeO2. It is concluded that the activation of splenocytes by SeO2 is triggered primarily by the conversion of cell membrane carbonyls into corresponding dicarbonyls.