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Developmentally regulated expression and secretion of a polymorphic antigen by Onchocerca infective-stage larvae
A E Bianco1, B D Robertson, Y M Kuo
1Department of Pure and Applied Biology, Imperial College of Science, Technology and Medicine, London, U.K.
Molecular and Biochemical Parasitology
|March 1, 1990
Summary
Researchers developed a novel protein labeling method for parasitic worms like Onchocerca. This technique identified a key 23 kDa protein crucial for larval development in insect vectors.
Area of Science:
- Parasitology
- Molecular Biology
- Developmental Biology
Background:
- Understanding the developmental biology of parasitic nematodes like Onchocerca is crucial for identifying novel therapeutic targets.
- Filarial worms, such as Onchocerca lienalis and Onchocerca volvulus, undergo complex life cycles involving arthropod vectors and vertebrate hosts.
- Identifying parasite-specific molecules expressed during specific developmental stages can aid in controlling these pathogens.
Purpose of the Study:
- To develop a novel method for analyzing protein synthesis in parasitic larvae within their vectors.
- To identify and characterize developmentally regulated proteins in Onchocerca spp.
- To investigate the expression and secretion patterns of a specific 23 kDa larval protein.
Main Methods:
- Micro-injection of [35S]methionine into blackflies (vectors) for pulse labeling of Onchocerca lienalis larvae.
- Analysis of synthesized proteins using gel electrophoresis and immunological techniques.
- Investigating protein secretion triggered by temperature changes simulating transmission to the vertebrate host.
Main Results:
- A novel protein labeling technique was successfully developed for studying parasitic nematode gene expression in arthropods.
- A major acidic 23 kDa protein was identified, predominantly expressed in infective third-stage larvae of O. lienalis.
- This 23 kDa protein is antigenically conserved between O. lienalis and O. volvulus, showing size polymorphisms.
- Protein secretion was observed 24-72 hours after a temperature shift from 26°C to 37°C, mimicking host transmission.
Conclusions:
- The developed labeling technique is a powerful tool for studying endoparasite gene expression within arthropod vectors.
- The 23 kDa protein is a developmentally regulated molecule, specifically expressed during the infective larval stage.
- Temperature-induced secretion of the 23 kDa protein suggests its role in parasite transmission and early development in the vertebrate host.