Polyclonal antibodies to Paracoccidioides brasiliensis are able to recognise antigens from different strains from Paracoccidioides species complex, including Paracoccidioides lutzii LDR2.

Since the new species Paracoccidioides lutzii emerged in 2009, much has been researched on strains previously considered atypical. Still, there is no consensus about recognition of antigens from P. lutzii by antibodies directed to other Paracoccidioides species, which can have great impact on Paracoccidioidomycosis (PCM) diagnosis. Current research investigated soluble protein/carbohydrate epitopes from P. lutzii LDR2, Paracoccidioides restrepiensis B339 and Paracoccidioides americana LDR3 recognised by IgG directed to Paracoccidioides brasiliensis. Cell free antigens (CFA) were analysed by: (a)silver and periodic acid-Schiff staining of SDS-PAGE; (b)immunoblot (IB) with rabbit IgG anti-P. brasiliensis Pb18; (c)IB and ELISA with a pool of PCM patients' sera before and after treatment with sodium metaperiodate (SMP) to oxidise carbohydrate epitopes. Both rabbit and human immune sera recognised several antigens of P. lutzii LDR2, P. restrepiensis B339 and P. americana LDR3. P. lutzii's gp43 was not observed in IB or silver/PAS staining. SMP treatment affected reactions with all 3 CFAs, but more intensely with antigens from P. lutzii LDR2. In conclusion, antibodies directed to P. brasiliensis recognised antigens from P. lutzii LDR2. The use of any of the recognised antigens in a broad spectrum diagnostic model for Paracoccidioides species complex needs to be further investigated.