[Study on invasibility and multiplication of Toxoplasma strains with different virulence toward Vero-cells].
OBJECTIVE
To investigate the pathogenic mechanisms of Toxoplasma strains with different virulence.


METHODS
Tachyzoites from 3 strains, Viz. RH, B36 and Fukaya strains, were challenged to in vitro cultivated Vero-cells. Systematic examinations on the earliest invasion time, the invasion rate and intracellular multiplication were performed under different cultivation conditions.


RESULTS
The tachyzoites of all the 3 strains invaded the host cells within a short period after inoculation. Invasion rates were all increased along with the prolonged duration of infection. The intracellular multiplication was found to be most active in RH strain, moderate in B36, and comparatively slow in Fukaya strains. Using purified tachyzoites freed from host debris and proteins and adding sufficient FCS in the medium may facilitate the invasion and subsequent multiplication of the parasite.


CONCLUSIONS
Strain differences in pathogenicity to the host may be correlated to the genetically predetermined multiplication capabilities of the parasites after being invaded to the host cell, and that environmental factors may give certain impact on the invasibility of the parasite.
Yang
H
H
Department of Parasitology, Shanghai Second Medical University, Shanghai 200025.
Zhang
A
A
Yang
Y
Y
Qian
Z
Z
D000818:Animals; D002522:Chlorocebus aethiops; D008297:Male; D051379:Mice; D013045:Species Specificity; D014122:Toxoplasma / Q000145:classification / Q000254:growth & development / Q000472:pathogenicity*; D014709:Vero Cells / Q000469:parasitology; D014774:Virulence