In Vitro Survival and Retention of Infectivity of Plassmodium yoelii SporozoitesOver Extended Periods of Time

摘要

The ability to maintain sporozoites in vitro should render the biologicalmechanism of sporozite infectivity amenable to experimental analysis. With this in mind, Plasmodium yoelii Py17X(NL) clone 1.1 sporozoites were incubated at 4, 24, or 37 C for 0.8, or 24 hr in tissue culture medium M199 with 5% normal mouse serum and penicillin-streptomycin. BALB/c mice were challenged intravenously with 5,000 in vitro-incubated sporozoites and then evaluated daily for parasitemia beginning on day 3 postinoculation. Sporozoites held at 24 C remained infective up to 24 hr unlike sporozoites incubated at 4 and 37 C. We observed 100% infection in mice challenged with a minimum of 200, 40, and 1,000 sporozoites that were in vitro incubated at 24 C at times 0,24, and 36 hr respectively. Infectivity was also maintained for 24 hr at 24 C in RPMI-1640 with 5% normal mouse serum and penicillin-streptomycin.