• Vaccine Name: CTLVECNS
• Target Pathogen: Toxoplasma gondii
• Target Disease: Toxoplasmosis
• Type: Inactivated or "killed" vaccine
• Status: Research
• Host Species for Licensed Use: Human
• Antigen: Toxoplasma lysate: Tachyzoites were collected from previously infected mice and were sedimented by centrifugations and sonications. The supernatant material (the lysated antigen of Toxoplasma) was collected. (El et al., 2016)
• Immunization Route: Intraperitoneal injection (i.p.)
• Description: Crude Toxoplasma lysate vaccine encapsulated chitosan nanospheres (El et al., 2016)

Mouse Response

• Host Strain: Swiss strain albino mice (El et al., 2016)
• Host gender: male (El et al., 2016)
• Vaccination Protocol: Mice were divided into two main groups, Group I control group (100 mice) which was further subdivided into five equal subgroups (20 mice): Ia: normal non infected; Ib: chitosan delivery control subgroup, received 20 µg of BCNS in 100 µl of PBS/mouse/dose; Ic: FIA control subgroup, received 100 µl of FIA/mouse/dose, Id & Ie: non vaccinated groups for further challenge. Group II experimental vaccinated group (100 mice) was further subdivided into two equal subgroups (50 mice). Subgroup IIa, received CTLVECNS suspended in PBS while subgroup IIb received CTLV + FIA. All vaccinated mice received three doses 2 weeks apart. (El et al., 2016)
• Immune Response: Higher ratio of IgG2a to IgG1; Higher level of IFN-γ and IL-2 (El et al., 2016)
• Challenge Protocol: RH: Group Id (20 mice) were infected with 2,500 tachyzoites of RH strain without immunization, serving as RH infected control group. 25 mice from group IIa and 25 mice from group IIb were challenged by 2,500 viable tachyzoites of virulent RH strain. 10 mice out of 25 were sacrificed 5 days post infection and the remaining mice were observed daily to record mortality. (El et al., 2016)
  Me49: Group Ie (20 mice) were perorally inoculated by 10 cysts of Me49 strain without immunization, serving as Me49 infected control group. The other 25 mice from group IIa and 25 mice from group IIb were challenged orally by 10 cysts of Me49 strain. 10 mice out of 25 were sacrificed 60 days post infection and the remaining were observed daily to record mortality. (El et al., 2016)
  Serum samples were collected from RH and Me49 infected control subgroups mice before being sacrificed simultaneously with their corresponding experimental subgroups. (El et al., 2016)
• Efficacy: RH: None of the mice of RH infected control subgroup remained alive beyond the seventh day post infection with a mean survival time of 5.9 ± 0.88 days. Mice vaccinated with CTLV either in chitosan nanospheres or in combination with FIA and challenged with RH strain showed significant increase in their survival time. (BCNS: maximum survival time of 80 days with a mean of 35.73 ± 31.82; FIA: 57 days with a mean of 33.67 ± 18.30 days). There was a statistically significant reduction in parasitic count in all studied organs in vaccinated animals. The reduction in the mean tachyzoites count was more evident in the subgroup receiving encapsulated chitosan vaccine in comparison to the subgroup receiving the vaccine in combination with FIA .(El et al., 2016)
  Me49: The mean survival time in the control group was 60.7 ± 8.11 days with only one mouse which lived for 120 days post infection. Only mice vaccinated with CTLV in combination with FIA showed a statistically significant increase in the survival time (a mean of 120.53 ± 33.13 days). There was a statistically significant difference between mice vaccinated with CTLV whether in chitosan nanospheres (a mean of 79.20 ± 17.91 days) or in combination with FIA. A statistically significant reduction in the mean cyst count of the brain was found in both experimental subgroups. The difference between vaccinated subgroups was statistically significant with the highest reduction in the subgroup receiving the vaccine in combination with FIA. (El et al., 2016)