Tissue expression patterns of Schistosoma mansoni Venom Allergen-Like proteins 6 and 7

[Display omitted] ► WISH was used to investigate the tissue localisation of Schistosoma mansoni VAL genes. ► SmVAL6 demonstrated a discrete expression pattern in oral and ventral suckers. ► SmVAL7 revealed a distinct staining pattern in the oesophageal gland. ► The diversity of SmVAL6 transcripts is translated to the protein level. The Schistosoma mansoni Venom Allergen-Like proteins (SmVALs) are members of the SCP/TAPS (Sperm-Coating Protein/Tpx-1/Ag5/PR-1/Sc7) protein superfamily, which may be important in host–pathogen interactions. Whole mount in situ hybridisation demonstrated a distinct expression pattern in oral and ventral suckers of adult worms for SmVAL6 and in the oesophageal gland for SmVAL7 transcripts, respectively. Additionally, immunocytochemistry analysis corroborated SmVAL7 expression in the oesophageal gland. Analysis of protein expression across the parasite’s life cycle revealed that the SmVAL6 protein is upregulated in cercariae and adult male worms. Furthermore, SmVAL6 protein was identified by mass spectrometry in tegument fractions of adult worms. Finally, we speculate on possible functions of these two SmVALs at the host–parasite interface.