Mass spectrometry-based identification of allergens from Curvularia pallescens, a prevalent aerospore in India

• CP was found to be a major allergenic trigger in the population of Kolkata, India.
• In vivo and in vitro allergenicity tests confirmed its allergenic potency.
• 11 potent allergens were identified from CP by using proteomic tools.
• This study presents allergenic proteins from CP for the first time.

The worldwide prevalence of fungal allergy in recent years has augmented mining allergens from yet unexplored ones. Curvularia pallescens (CP) being a dominant aerospore in India and a major sensitiser on a wide range of allergic population, pose a serious threat to human health. Therefore, we aimed to identify novel allergens from CP in our present study. A cohort of 22 CP-sensitised patients was selected by positive Skin prick grade. Individual sera exhibited elevated specific IgE level and significant histamine release on a challenge with antigenic extract of CP. First gel-based profiling of CP proteome was done by 1- and 2-dimensional gel. Parallel 1- and 2-dimensional immunoblot were performed applying individual as well as pooled patient sera. Identification of the sero-reactive spots from the 2-dimensional gel was found to be challenging as CP was not previously sequenced. Hence, mass spectrometry-based proteomic workflow consisting of conventional database search was not alone sufficient. Therefore, de novo sequencing preceded homology search was implemented for further identification. Altogether 11 allergenic proteins including Brn-1, vacuolar protease, and fructose-bis-phosphate aldolase were identified with high statistical confidence (p < 0.05). This is the first study to report on any allergens from CP. This kind of proteome-based analysis provided a catalogue of CP allergens that would lead an improved way of diagnosis and therapy of CP-related allergy.

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