Phytomonas serpens, a tomato parasite, shares antigens with Trypanosoma cruzi that are recognized by human sera and induce protective immunity in mice

Abstract

The immune cross-reactivity between Trypanosoma cruzi, the protozoan that causes Chagas' disease, and Phytomonas serpens, a trypanosomatid that infects tomatoes, was studied. Sera from patients with Chagas' disease presented a strong reactivity with P. serpens antigens by conventional serological assays such as indirect immunofluorescence (IIF) and direct agglutination test (DAT), confirmed after cross-absorption experiments. The results show that this protozoan is highly immunogenic and that rabbit and mouse hyperimmune serum raised against T. cruzi or P. serpens was able to recognize both T. cruzi and P. serpens antigens in immunofluorescence and agglutination assays. The antigenic cross-reactivity between T. cruzi and P. serpens was also demonstrated in vivo. BALB/c mice immunized by the intraperitoneal or oral route with P. serpens and later challenged with a lethal inoculum of T. cruzi blood forms showed a significant decrease in parasitemia and increase in survival compared to controls. A practical implication of these findings is that the ingestion by humans or animals of living plant trypanosomatids present in naturally infected edible fruits could potentially prime the immune response to T. cruzi antigens and interfere with the development of T. cruzi infection.