Identification of immunogenic proteins of the cysticercoid of Hymenolepis diminuta

Abstract

Background: A wide range of molecules are used by tapeworm metacestodes to establish successful infection in the hostile environment of the host. Reports indicating the proteins in the cestode-host interactions are limited predominantly to taeniids, with no previous data available for non-taeniid species. A non-taeniid, Hymenolepis diminuta, represents one of the most important model species in cestode biology and exhibits an exceptional developmental plasticity in its life-cycle, which involves two phylogenetically distant hosts, arthropod and vertebrate.

Results: We identified H. diminuta cysticercoid proteins that were recognized by sera of H. diminuta-infected rats using two-dimensional gel electrophoresis (2DE), 2D-immunoblotting, and LC-MS/MS mass spectrometry. Proteomic analysis of 42 antigenic spots revealed 70 proteins. The largest number belonged to structural proteins and to the heat-shock protein (HSP) family. These results show a number of the antigenic proteins of the cysticercoid stage, which were present already in the insect host prior to contact with the mammal host. These are the first parasite antigens that the mammal host encounters after the infection, therefore they may represent some of the molecules important in host-parasite interactions at the early stage of infection.

Conclusions: These results could help in understanding how H. diminuta and other cestodes adapt to their diverse and complex parasitic life-cycles and show universal molecules used among diverse groups of cestodes to escape the host response to infection.

Keywords: Hymenolepis diminuta; Immunogenic proteins; Mass spectrometry; Two-dimensional electrophoresis.

Fig. 1

Silver-stained 2-DE protein maps of Hymenolepis diminuta cysticercoid protein spots. Cysticercoid proteins were separated on a linear pH range of 4–7 by using IEF in the first dimension and 12% SDS-PAGE in the second dimension. Antigenic protein spots are indicated by red colour

Fig. 2

Recognition pattern of H. diminuta cysticercoid antigens by antibodies of H. diminuta-infected rats. The nitrocellulose membrane shows cysticercoid immunogenic protein spots visualized using SuperSignal West Pico Chemiluminescent Substrate (ThermoFisher Scientific, USA) combined with Quantity One 1-D Analysis Software (Bio-Rad, USA)

Fig. 3

Identified cysticercoid antigenic proteins categorized by their molecular functions according to gene ontology (GO) information obtained from UniProtKB and QuickGO databases

Fig. 4

Identified cysticercoid antigenic proteins categorized by their biological processes according to gene ontology (GO) information obtained from UniProtKB and QuickGO databases

Fig. 5

Identified cysticercoid antigenic proteins categorized by their cellular component category according to gene ontology (GO) information obtained from UniProtKB and QuickGO databases