Trypanosoma cruzi serinecarboxypeptidase is a sulfated glycoprotein, and a minor antigen in human Chagas disease infection.

L. L. SOPRANO ; J. E. PARENTE; M. LANDONI; A. S. COUTO; V. G. DUSCHAK

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedades de Biociencias

In this work, the presence of sulfated N-glycans was studied in a high mannose type glycoprotein of Trypanosoma cruzi with serinecarboxypeptidase (SCP) activity. Taking advantage that the latter co-purifies with cruzipain (Cz) from Concanavalin-A affinity columns and after the obtainment of rabbit sera specific for SCP and Cz, respectively, by immunizations with each of the T. cruzi glycoproteins, we evaluated the immune-crossreactivity between both molecules. In addition, the Cz-SCP mixture was desulfated finding that the cross-reactivity seemed to be due to the presence of sulfate groups in both molecules. Therefore, knowing that Cz was the first sulfated glycoprotein described and considering the antigenicity of these groups, SCP was excised from SDS-PAGE and the N-glycosidic chains were analyzed by MALDI-TOF mass spectrometry confirming the presence of short chain sulfated high mannose type oligosaccharides. Besides, we analyzed the presence of sulfated epitopes in lysates of the different stages of the parasite demonstrating that in trypomastigotes a band with apparent molecular weight similarly to SCP was highly recognized. On the other hand, SCP was confronted with sera of infected people with different degree of cardiac dysfunction. Although most sera recognized the protein in the different groups, no statistical association could be found between the presence of sera antibodies specific for SCP and the severity of the disease. In summary, our findings demonstrate i) the presence of sulfate groups in the N-glycosidic chains of TcSCP, ii) the involvement of these sulfated epitopes in the immune cross-reactivity between SCP and Cz, in epimastigotes, and iii) an enhanced presence of sulfated epitopes in trypomastigotes, probably involved in parasite-host relationship and/or infection. Interestingly, our results showed for the first time that SCP is a minor antigen recognized by most of chronic Chagas disease patients.