One minute ultraviolet exposure inhibits Toxoplasma gondii tachyzoite replication and cyst conversion without diminishing host humoral-mediated immune response

• T. gondii tachyzoites exposed to UV for 1 min still have intact membranes.
• With 1 min UV exposure, tachyzoites are unable to replicate in vitro or produce parasite cysts in vivo.
• UV-inactivated tachyzoites can stimulate an IgG response but not cytokine response in vivo.

We developed a protocol to inactivate Toxoplasma gondii (T. gondii) tachyzoites employing 1 min of ultraviolet (UV) exposure. We show that this treatment completely inhibited parasite replication and cyst formation in vitro and in vivo but did not affect the induction of a robust IgG response in mice. We propose that our protocol can be used to study the contribution of the humoral immune response to rodent behavioral alterations following T. gondii infection.