Aim/background: CD99 participate in neutrophil infiltration after inflammatory events; however, despite the important role of inflammation in ischemic stroke, the role of CD99 in ischemic stroke remains unclear. Method: In the present study, we detected the protein expression of CD99, ICAM-1, and CD31 (PECAM-1) in oxygen-glucose deprivation (OGD)-induced bEnd.3 cells and neutrophils and explored the influence of HIF-1 alpha and IL-1 beta on their expression. We also explored the role of CD99 in the OGD-induced transmigration of neutrophils. Results: Our results showed that OGD induction upregulated CD99 in bEnd.3 cells and that this effect could be abolished by the preadministration of IL-1 beta and was not mediated by HIF-1 alpha. However, the activation of ICAM-1 by OGD remained activated with IL-1 beta treatment. No significant influence of IL-1 beta on OGD-induced CD31. Finally, we found a significant increase in infiltrated neutrophils after OGD induction compared with the control and OGD + anti-CD99 groups. Conclusion: Our results indicated that CD99 mediates neutrophil infiltration and transmigration via OGD induction and thus constitutes a potential therapeutic target for anti-inflammatory treatment after ischemic stroke. (C) 2020 Elsevier Inc. All rights reserved.