For spot size measurements, fresh heparinized blood was spotted onto sheets of Whatman no 1, Whatman 3 MM (Whatman, Maidstone, UK) or glass fibre (Printed Filtermat A, Perkin Elmer, Beaconsfield, UK) filter paper in volumes from 1 μl to 45 μl. For antibody stability and recovery studies, reconstituted blood was prepared by mixing individual African malaria-hyperimmune plasma samples or a hyperimmune plasma pool or a European (non-exposed) negative control pool (all containing heparin) 1:1 by volume with washed European blood group O erythrocytes and immediately spotting 10 μl of this mixture onto Whatman 3 MM or glass fibre filter paper. Spots were allowed to dry at ambient temperature and relative humidity (RH) overnight.
Laboratory-generated blood spots and blood spots from Uganda were stored in individual self-sealing plastic bags (25 cm × 25 cm approx), which were then combined into sets and stored within three further successive plastic bags, the innermost of which contained approximately 3 g of self-indicating silica desiccant gel type III (Sigma). The bags were inspected regularly to confirm that the desiccant remained blue (RH < 20%), and the desiccant replaced if necessary.
Fingerprick blood samples from lower Moshi were collected into EDTA-coated microtainers and as blood spots on Whatman 3 MM paper and transported daily to the laboratory at Kilimanjaro Christian Medical College. Filter papers were refrigerated (2–8°C) in individual plastic bags with silica gel. Plasma was separated from packed red blood cells after centrifugation and stored at -20°C. All samples were assayed within 8 weeks of collection.
Laboratory-generated blood spots and blood spots from Uganda were stored in individual self-sealing plastic bags (25 cm × 25 cm approx), which were then combined into sets and stored within three further successive plastic bags, the innermost of which contained approximately 3 g of self-indicating silica desiccant gel type III (Sigma). The bags were inspected regularly to confirm that the desiccant remained blue (RH < 20%), and the desiccant replaced if necessary.
Fingerprick blood samples from lower Moshi were collected into EDTA-coated microtainers and as blood spots on Whatman 3 MM paper and transported daily to the laboratory at Kilimanjaro Christian Medical College. Filter papers were refrigerated (2–8°C) in individual plastic bags with silica gel. Plasma was separated from packed red blood cells after centrifugation and stored at -20°C. All samples were assayed within 8 weeks of collection.
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