Characterization of the allergen Sol gem 2 from the fire ant venom, Solenopsis geminata

Sukprasert S (1), Uawonggul N (2), Jamjanya T (3), Thammasirirak S (1), Daduang J (4), Daduang S (1)

(1) Protein and Proteomics Research Group, Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand; (2) Faculty of Liberal Arts and Science, Nakhon Phanom University, Nakhon Phanom, Thailand; (3) Department of Entomology, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand; (4) Department of Clinical Chemistry, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.

Abstract: Sol i 2 is a potent allergen in Solenopsis invicta venom, and most humans exhibit reactivity to it. The Sol gem 2 allergen found in the venom of the Thai tropical fire ant Solenopsis geminata was analysed in the present study. The protein was present in higher amounts than other proteins, as determined by SDSPAGE, and presumably has allergenic properties similar to those of Sol i 2. Sol gem 2 molecular weight is 28 and 15 kDa, respectively, under non-reducing and reducing conditions, indicating that its native form is a dimer. LC-MS/MS analysis confirmed its similarity to Sol i 2. The mono/dimeric form of Sol gem 2 was determined to be relevant by proteomic approach and immunoblotting. An anti-Sol gem 2 antibody was produced in mice, with a titer greater than 1:800 according to the Western blotting analysis. The Sol gem 2-neutralising activity of this antibody was determined in crickets. The paralytic dose 50 (PD50) of crude S. geminata venom was elevated from 0.18 mg/g of body weight to more than 0.90 mg/g of body weight after preincubation with antibody at a ratio of 1:1. These results suggest that Sol gem 2 plays an important role in mediating the effects of the piperidine derivatives in the venom.

Key words: allergy, ant venom, hymenoptera, immunoreactivity.

ACKNOWLEDGMENTS

This work was supported by the "TRF-CHE Research Grant for Mid-Career University Faculty", jointly funded by the Thailand Research Fund (TRF) and the Commission on Higher Education (CHE), Ministry of Education, fiscal years 2007-2009, with additional support from the "CHE grant fund under the program Strategic Scholarships for Frontier Research Network for the Ph.D. Program Thai Doctoral degree (CHEPhD-THA-SUPV)" to S.S. from the office of the Commission on Higher Education, Thailand, with additional support from the Khon Kaen University Research Fund, fiscal years 2007-2010.

COPYRIGHT

© CEVAP 2012

SUBMISSION STATUS

Received: May 15, 2012.

Accepted: July 24, 2012.

Abstract published online: August 7, 2012.

Full paper published online: August 31, 2012.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

FINANCIAL SOURCE

TRF-CHE, CHE-PhD-THA-SUPV from the office of the Higher Education Commission, and Khon Kaen University, Thailand, provided the financial grants.

ETHICS COMMITTEE APPROVAL

The present study was approved by the Animal Ethics Committee of Khon Kaen University based on the Ethics for Animal Experimentation of the National Research Council of Thailand (reference n. 0514.1.12.2/1).

CORRESPONDENCE TO

Sakda Daduang, Protein and Proteomics Research Group, Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand. Phone/fax: +66 43 342911. E-mail: sakdad@kku.ac.th.