CD99 and infection: More interestingly, for the first time, we observed a reduction in CD99 and CD99L2 on THP-1 and Jurkat cells after strain ATCC 33277 infection, and these results suggested that P. gingivalis gingipains can reduce CD99 and CD99L2 expression on both endothelial cells and multiple types of leukocytes, which in turn affects TEM capacity.