Immunoglobulin E-binding reactivities of natural pollen grain extracts from selected grass species in the Philippines

Abstract

Background: Pollen grains have been reported to be present in the Philippine atmosphere but studies regarding their allergenicity are limited.

Objective: The present study aimed to profile the sensitization of allergic individuals to selected grass pollen species and to characterize the pollen proteins that may be responsible for this allergenic response.

Methods: The protein profile of the grass pollen extracts from Cynodon dactylon, Saccharum spontaneum, Sporobulus indicus, Chloris barbata, Oryza sativa, Imperata cylindrica, and Zea mays was analyzed by Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis. The specific-IgE profile of the allergic individuals and the allergenic potential of the pollen extracts were evaluated through Enzyme-linked Immunosorbent Assay and IgE immunoblotting.

Results: Sensitization of the allergic individuals to the pollen extracts was detected with I. cylindrica and O. sativa to be the most frequently recognized with more that 92% reactivity, whereas for C. dactylon and Z. mays, were found to have less than 25% reactivity.

Conclusion: Multiple IgE-binding proteins from S. indicus, S. spontaneum and C. barbata that were detected may be responsible for the allergic reactions among Filipino subjects.

Keywords: Grass pollen allergy; IgE binding reactivity.

Fig. 1

Sex distribution of subjects according to their allergic symptoms.

Fig. 2

Sodium dodecyl sulfate polyacrylamide gel electrophoresis profile of the selected grass pollen extracts resolved using a 20% reducing gel and was stained with silver nitrate.

Fig. 3

Specific-IgE levels of symptomatic subjects to the natural extracts from Cynodon dactylon (Cd), Saccharum spontaneum (Ss), Sporobulus indicus (Si), Chloris barbata (Cb), Oryza sativa (Os), Imperata cylindrica (Ic), and Zea mays (Zm). Broken lines indicate the cut-off value (mean + 2 SD of the control sera) used in determining positive IgE reactivity among the allergic subjects.

Fig. 4

Correlation of specific-IgE levels between and among the grass species.

Fig. 5

IgE Immunoblot of selected sera from allergic patients against Sporobulus indicus (A), Saccharum spontaneum (B) and Chloris barbata (C) pollen extracts.