Non-infected human blood was treated in the same manner as for experimental infections of malaria vectors by DMFA using natural isolates of P. falciparum and using gametocyte heat inactivation in parallel
[17 (link),18 (link)]. The blood was first centrifuged at 2,000 rpm at 37°C for three min, and the serum was replaced by the same volume of European AB serum. In experimental infections, this step limits the effect of human transmission blocking immunity
[24 (link)]. To mimic gametocyte heat inactivation, half of the reconstituted blood was placed in a thermo-mixer and heated at 43°C for 15 min and 900 rpm while the remaining blood was maintained at 37°C. Five hundred μl of blood (heated or not) were distributed in membrane feeders maintained at 37°C by water jackets. At least two different feeders were used for each group (blood donor and heat treatment) in order to limit potential feeder effects. Cups containing 50 mosquito females were placed under the feeders to allow blood feeding through Parafilm membranes for 30 min. Fed females were sorted and placed in individual 30 ml plastic tubes for subsequent measures of life history traits. Because of logistic limitations, the blood feeding with the different blood donors had to be carried out at different days and using different mosquito batches from the same colony and therefore constituted different experimental blocks. In the statistical analyses the effect “blood donor” could thus be due to either differences in the “quality” of the blood of the various donors, intrinsic differences of the different mosquito batches, date effects, or a combination of the above.
[17 (link),18 (link)]. The blood was first centrifuged at 2,000 rpm at 37°C for three min, and the serum was replaced by the same volume of European AB serum. In experimental infections, this step limits the effect of human transmission blocking immunity
[24 (link)]. To mimic gametocyte heat inactivation, half of the reconstituted blood was placed in a thermo-mixer and heated at 43°C for 15 min and 900 rpm while the remaining blood was maintained at 37°C. Five hundred μl of blood (heated or not) were distributed in membrane feeders maintained at 37°C by water jackets. At least two different feeders were used for each group (blood donor and heat treatment) in order to limit potential feeder effects. Cups containing 50 mosquito females were placed under the feeders to allow blood feeding through Parafilm membranes for 30 min. Fed females were sorted and placed in individual 30 ml plastic tubes for subsequent measures of life history traits. Because of logistic limitations, the blood feeding with the different blood donors had to be carried out at different days and using different mosquito batches from the same colony and therefore constituted different experimental blocks. In the statistical analyses the effect “blood donor” could thus be due to either differences in the “quality” of the blood of the various donors, intrinsic differences of the different mosquito batches, date effects, or a combination of the above.
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