Invasion of brain endothelia by M. tuberculosis is reduced by anti-PknD serum. M. tuberculosis CDC1551 were pre-incubated with naïve or custom anti-PknD serum, washed, and used to infect brain endothelial cells. Following 90 minutes of infection, cells were lysed and CFU enumerated. It was observed that incubation with anti-PknD serum, but not naïve serum, significantly reduced the number of bacilli able to successfully invade HBMEC (P = 0.01). *Statistically significant difference.