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A monoclonal antibody that tracks endospore formation in the microsporidium Nosema bombycis
Yanhong Li1, Meiling Tao2, Fuping Ma3
1State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, P.R. China; College of Animal Science and Technology, Southwest University, Chongqing 400715, P.R. China.
Abstract:
Nosema bombycis, the first identified microsporidium, is a destructive pathogen of the silkworm Bombyx mori and causes severe worldwide economic losses in sericulture. Major microsporidian structural proteins, such as the spore wall protein (SWP), are known to be involved in host invasion. In this study, the reactivity of the monoclonal antibody 2B10 was tested against an endospore protein of N. bombycis with a molecular weight size at 50-kDa, using Western blotting. The antigen was purified after immunoprecipitation and was further identified as EOB13320 according to MALDI-TOF MS assay. We found that EOB13320 locates to the surface of the different developmental stages of the parasite, mostly the sporoblast stage and the mature spore after immunoelectron microscopy examination. EOB13320 was also widely distributed in the developing endospore, especially at the sporoblast stage. This endospore protein also accumulated in the cytoplasm of both the merogony and sporoblast stages. These results imply that EOB13320 detected by monoclonal antibody 2B10 is expressed throughout the life cycle of the parasite, notably during the stage when the endospore is formed, and that this protein is important for spore-coat formation and parasite maintenance. Our study could be instrumental in the understanding of spore wall formation and will help to gain greater insight into the biology of this parasite.
Insights
Nosema bombycis, a silkworm pathogen, has a key spore protein, EOB13320, identified using monoclonal antibody 2B10. This protein is crucial for spore formation and parasite survival throughout its life cycle.
Area of Science:
- Parasitology
- Microbiology
- Molecular Biology
Background:
- Nosema bombycis is a microsporidian pathogen impacting silkworm Bombyx mori, causing significant economic losses in sericulture.
- Spore wall proteins (SWPs) are implicated in microsporidian host invasion, highlighting the need to understand their structure and function.
Purpose of the Study:
- To identify and characterize a 50-kDa endospore protein of Nosema bombycis recognized by monoclonal antibody 2B10.
- To investigate the localization and expression of this protein during the parasite's life cycle.
Main Methods:
- Western blotting was used to test the reactivity of monoclonal antibody 2B10 against the 50-kDa protein.
- Immunoprecipitation and MALDI-TOF MS assay were employed for antigen purification and identification as EOB13320.
- Immunoelectron microscopy was utilized to determine the protein's subcellular localization.
Main Results:
- The 50-kDa endospore protein, identified as EOB13320, was recognized by monoclonal antibody 2B10.
- EOB13320 was localized to the surface of sporoblasts and mature spores, and within the developing endospore.
- The protein also accumulated in the cytoplasm during merogony and sporoblast stages.
Conclusions:
- EOB13320 is expressed throughout the Nosema bombycis life cycle, particularly during endospore formation.
- This protein plays a significant role in spore-coat formation and parasite maintenance.
- Understanding EOB13320's function provides insights into microsporidian spore wall development and parasite biology.
