Podoplanin (PDPN), a transmembrane receptor, has been shown to be upregulated in inflammation and expressed on inflammatory macrophages. Thus, targeting PDPN may be a potential approach in reducing inflammation. This study aimed to examine PDPN expression in THP-1 cells during infection and to investigate the effects of antibody-mediated PDPN blockade in inflamed THP-1 cells. THP-1 cells were infected with Chlamydia trachomatis or Helicobacter pylori, and podoplanin expression was examined using flow cytometry. Following infection, cells were treated with anti-human PDPN antibody (clone NC-08) for 16 h, and the concentrations of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were measured. C. trachomatis and H. pylori-infected THP-1 cells exhibited a threefold increase of cell surface PDPN in flow cytometrical analysis, but PDPN expression was not downregulated with the increasing anti-PDPN treatment. Unexpectedly, the anti-PDPN antibody increased the proinflammatory cytokines in a dose-dependent manner, suggesting that clone NC-08 antibody acts as an agonist, rather than antagonist, in promoting the secretion of proinflammatory cytokines. In conclusion, the PDPN blockade using clone NC-08 antibody did not limit the inflammation, but further study can be done using different clones of blocking antibody.