PLASMODIUM-FALCIPARUM - GENETIC DIVERSITY OF SEVERAL STRAINS INFECTIOUS FOR THE SQUIRREL-MONKEY (SAIMIRI-SCIUREUS)

The squirrel monkey, Saimiri sciureus, is a useful experimental host f or the human malaria parasite Plasmodium falciparum. Twelve strains of P. falciparum, including monkey-adapted strains, culture-derived stra ins, and one human isolate were injected into naive, splenectomized Sa imiri monkeys of karyotype 14-7. Several parameters were recorded foll owing inoculation such as parasitemia, body temperature, standard hema tological parameters, gametocytemia, rosette formation, autoagglutinat ion, as well as HRPI and PfEMP3 expression. Each strain was injected i nto two to four monkeys and induced a reproducible course of infection . Four distinct patterns of parasite development were observed, For ea ch strain, a multilocus genotype was established by PCR using several polymorphic (Pf60, RESA, RESA2, MSA1, MSA2, Pf332, TRAP, GLURP, CSP, a nd HRPI) or conserved (EBA175, GARP, MDR1, and RNA POL III) markers. R FLP analysis was conducted for the Pf11.1 locus. This genotyping appro ach showed that 3 strains presented strictly similar patterns, typical of FUP/SP parasites. A group of 7 other strains presented a highly si milar FUP/CP (FCR3-like) genetic background, while 4 other strains sho wed unique patterns. Infectiousness did not depend on a RESA deletion, as several strains developed successfully while presenting a wild-typ e RESA gene. Conversely, an interesting correlation was found between allelic diversity at the HRPI locus and the course of blood stage infe ction. The data presented here provide the first precise genotyping of several monkey-adapted strains, allowing a more rational approach in the study of the role of parasite diversity on host/parasite interacti ons. (C) 1996 Academic Press, Inc.