Plasmodium falciparum: in vitro characterization and human infectivity of a cloned line.
The culture-adapted NF54 isolate of Plasmodium falciparum was subjected in vitro to three sequential limiting dilution titrations and the resulting clone was given the designation CVD1. DNA sequence analysis of the gene encoding the circumsporozoite (CS) protein revealed differences between CVD1 and the published NF54 CS gene. CVD1 had 1191 bp, 397 amino acids, and 42 repeat units while NF54 had 1218 bp, 405 amino acids, and 44 repeat units. The CVD1 clone was more sensitive to chloroquine than was the parental line, in vitro. Anopheles stephensi mosquitoes were infected equally by the cloned and uncloned parasites. Volunteers were readily infected by NF54 and CVD1 following infectious mosquito bites. The availability of a well-characterized, chloroquine-sensitive clone which safety infects humans should facilitate performance of experimental challenge studies to assess vaccine efficacy.
Department of Medicine, University of Maryland School of Medicine, Baltimore 21201.
J R
JR
Davis
J F
JF
Cortese
D A
DA
Herrington
J R
JR
Murphy
D F
DF
Clyde
A W
AW
Thomas
S
S
Baqar
M A
MA
Cochran
J
J
Thanassi
M M
MM
Levine
D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D000953:Antigens, Protozoan / Q000235:genetics; D000954:Antigens, Surface / Q000235:genetics; D001483:Base Sequence; D002738:Chloroquine / Q000494:pharmacology; D002999:Clone Cells; D016054:DNA, Protozoan / Q000235:genetics; D005260:Female; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D008297:Male; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D016054:DNA, Protozoan; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan; C065974:merozoite surface protein 2, Plasmodium; D002738:Chloroquine