Fig. 1. Gene expression profiling of Plasmodium falciparum gametocytes by microarray identified Pf77 and PfMDV-1 as candidate transmission-blocking vaccine antigens.

Identification of gametocyte-enriched transcripts by gene expression profiling was used as a first screen for selection of transmission-blocking vaccine candidates. cRNA microarray was used to compare cRNA prepared from stage V gametocytes versus asynchronous blood-stage parasites. A total of 56 genes were transcriptionally up-regulated by >50-fold across four replicates (P < 0.01) in the P. falciparum gametocyte and were plotted by differential gene expression (fold change) and transcriptional abundance within the gametocyte (cy5 signal). Selection of a subset of these 56 genes for further evaluation as transmission-blocking vaccine candidates was guided by two-layered criteria of strong fold up-regulation and high cy5 intensity to ensure that selected transmission-blocking vaccine candidates were not only highly differentially expressed (increased fold change) by the gametocyte but also transcriptionally abundant (increased cy5 signal) within the gametocyte. Asterisk (*) denotes genes selected for recombinant expression and efficacy studies to determine transmission-reducing activity. One additional P. falciparum gametocyte gene, PF3D7_120400 (not in this dataset), was also selected for recombinant expression.