TABLE 1

Attenuation of gene knockout P. yoelii preerythrocytic stages in BALB/c mice

Parasite name or genotypeNo. of sporozoites used for inoculationaMouseNo. of mice patentbNo. of days to patencyc
1971cl1d1,000BALB/cJ3/33 (3)
1971cl1d10,000BALB/cJ3/33 (3)
lisp21,000BALB/cJ6/85 (4)
7 (2)
lisp210,000BALB/cJ7/74 (2)
5 (4)
6 (1)
plasmei250,000BALB/cByJ0/10
200,000BALB/cByJ3/305 (2)
6 (1)
500,000BALB/cByJ4/305 (2)
6 (1)
7 (1)
plasmei2 lisp250,000BALB/cJ0/30
50,000BALB/cByJ0/10
200,000BALB/cByJ0/29
500,000BALB/cByJ0/26
fabb/f500,000BALB/cJ0/10
500,000BALB/cByJ0/20
  • a Salivary gland sporozoites were isolated from infected Anopheles stephensi mosquitoes, and mice were i.v. challenged with the listed number of sporozoites.

  • b The number of patent mice per number of mice challenged is indicated. Detection of blood stage patent parasitemia was carried out by Giemsa-stained thin blood smear. Attenuation was considered complete if mice remained blood stage negative for 21 days.

  • c If mice became blood stage patent, the day to patency is listed, with the number of mice that became patent in parentheses.

  • d The marker-free GFP-luciferase-expressing 1971cl1 parasite has a wild-type phenotype in all aspects of the life cycle, including sporozoite infectivity, and was used for the creation of all of the gene knockouts.