<i>In vitro</i> and <i>in vivo</i> activities of the monoclonal antibody (mAb) VSX targeting <i>P</i>. <i>aeruginosa</i> core LPS.

(A)In vitro killing of P. aeruginosa PAO1 in the presence of PMN and complement (OPKA) by VSX. The lot#-472 is representative of mAbs able to bind P. aeruginosa but without any detectable OPKA activity. C = complement. HIC = heat inactivated complement. PMN = polymorphonuclear leukocytes. Abs = antibodies. (B) Acute lung infection model. Challenge dose: 2x106 CFU. Inoculation: intranasal, 106 CFUs in each nostril. Mice = 10 per group (two experiments with 5 animals per group each time). mAbs were injected IP 4 hours post-infection. Dose of the mAbs: VSX = 15 mg/kg. Control mAb (against Clostridioides difficile) = 15 mg/kg. P-value = 0.04, measured in a log-rank test.