Normal numbers of sporozoites are formed that are infective to cultured hepatocytes. Parasites arrest during development in hepatocytes after a period of growth. In most parasites no merozoites are formed as shown by the low level of MSP1 expression. After intravenous injection of sporozoites, 1 out of 60 mice developed a blood stage infection

Mutant sporozoites showed normal gliding motility and WT-levels of hepatocyte invasion. Mice infected with either 1 or 5x104 Pbsequestrin sporozoites, intravenously, had a 2-3 day delay in blood-stage patency when compared to WT sporozoites infections and 4 out of 11 mice did not develop a blood-stage infection after inoculation with 1x104 sporozoites. These observations show that liver stage development is strongly affected in the absence of sequestrin and the 2-3 day prolonged prepatent period is indicative of a >99% reduction in liver-stage development. Pbsequestrin liver stages have normal morphology, with respect to cell division, size and PVM formation at 24hpi. However at 48hpi, as determined by staining with anti-MSP1 antibodies, all liver-stage parasites were MSP1 negative. To investigate the maturation of these parasites, 54hpi parasites were examined using anti-MSP1 and anti-EXP1 antibodies. Over 60% WT parasites at this time point were strongly MSP1 positive, whereas the majority of Pbsequestrin parasites were MSP1 negative, with only around 7% of parasites exhibiting similar MSP1 staining.

Mutant sporozoites showed normal gliding motility and WT-levels of hepatocyte invasion. Mice infected with either 1 or 5x104 Pbsequestrin sporozoites, intravenously, had a 2-3 day delay in blood-stage patency when compared to WT sporozoites infections and 4 out of 11 mice did not develop a blood-stage infection after inoculation with 1x104 sporozoites. These observations show that liver stage development is strongly affected in the absence of sequestrin and the 2-3 day prolonged prepatent period is indicative of a >99% reduction in liver-stage development. Pbsequestrin liver stages have normal morphology, with respect to cell division, size and PVM formation at 24hpi. However at 48hpi, as determined by staining with anti-MSP1 antibodies, all liver-stage parasites were MSP1 negative. To investigate the maturation of these parasites, 54hpi parasites were examined using anti-MSP1 and anti-EXP1 antibodies. Over 60% WT parasites at this time point were strongly MSP1 positive, whereas the majority of Pbsequestrin parasites were MSP1 negative, with only around 7% of parasites exhibiting similar MSP1 staining.

Sporozoites show normal hepatocyte traversal and invasion Strongly reduced liver stage development. In mice a delay of the prepatent period of 1.5 days after inoculation of sporozoites. Normal livers stage development up to 24 hour after invasion of hepatocytes. Maturing liver stage schizonts show abberrant morphology and merozoite formation is impaired (see also 'Additional Information')