Preliminary observations on the efficacy of a recombinant multistage Plasmodium falciparum vaccine in Aotus nancymai monkeys.

A vaccine trial was conducted to determine the efficacy of a multicomponent candidate vaccine, FALVAC-1, against Plasmodium falciparum in Aotus nancymai monkeys. After two immunizations, animals were challenged intravenously with parasites of the Vietnam Oak Knoll (FVO) strain of P. falciparum. The primary outcome was to determine the protective response of the monkeys to immunization with the FALVAC-1 antigen produced in baculovirus when combined with different adjuvants (alum, QS-21, ASO2a, CRL1005/oil, and CRL1005/saline) as compared with FALVAC-1 with FCA/FIA and antigen alone. When compared with the monkeys immunized with FALVAC-1 alone, FALVAC-1 with FCA/FIA reduced the mean parasite count (to Day 11), reduced the mean accumulated parasitemia (through Day 11), and extended the number of days to treatment. None of the other 5 antigen-adjuvant combinations were able to provide discernable levels of protection based on log(parasitemia) and log(cumulative parasitemia) to Day 11.

Development of a rapid method for simultaneous recovery of diverse microbes in drinking water by ultrafiltration with sodium polyphosphate and surfactants.

The ability to simultaneously concentrate diverse microbes is an important consideration for sample collection methods that are used for emergency response and environmental monitoring when drinking water may be contaminated with an array of unknown microbes. This study focused on developing a concentration method using ultrafilters and different combinations of a chemical dispersant (sodium polyphosphate [NaPP]) and surfactants. Tap water samples were seeded with bacteriophage MS2, Escherichia coli, Enterococcus faecalis, Cryptosporidium parvum, 4.5-microm microspheres, Salmonella enterica serovar Typhimurium, Bacillus globigii endospores, and echovirus 1. Ten-liter tap water samples were concentrated to approximately 250 ml in 12 to 42 min, depending on the experimental condition. Initial experiments indicated that pretreating filters with fetal bovine serum or NaPP resulted in an increase in microbe recovery. The addition of NaPP to the tap water samples resulted in significantly higher microbe and microsphere recovery efficiencies. Backflushing of the ultrafilter was found to significantly improve recovery efficiencies. The effectiveness of backflushing was improved further with the addition of Tween 80 to the backflush solution. The ultrafiltration method developed in this study, incorporating the use of NaPP pretreatment and surfactant solution backflushing, was found to recover MS2, C. parvum, microspheres, and several bacterial species with mean recovery efficiencies of 70 to 93%. The mean recovery efficiency for echovirus 1 (49%) was the lowest of the microbes studied for this method. This research demonstrates that ultrafiltration can be effective for recovering diverse microbes simultaneously in tap water and that chemical dispersants and surfactants can be beneficial for improving microbial recovery using this technique.