Excretory/secretory antigens of Strongyloides venezuelensis applied to IgG detection in human strongyloidosis.

Strongyloidosis is a neglected disease that affects millions of people around the world. The cases that particularly deserve attention are those related to hyperinfection, mainly in immunocompromised patients. In this sense, there is a need to improve the serological diagnosis of this helminth. The objective of this study was therefore to produce and characterize excretory/secretory (E/S) antigens of Strongyloides venezuelensis infective larvae (L3) for use as a heterologous antigen in the diagnosis of human strongyloidosis and other parasitic infection groups. Soluble antigenic preparations were produced as total saline extract (SE), E/S in Roswell Park Memorial Institute 1640 (RPMI) and E/S in phosphate buffered saline (PBS). The three antigenic preparations showed similar protein bands. An ELISA showed that the E/S antigens were profitable, easy to use, and more sensitive and specific than SE, eliminating cross-reactivity with other parasites in serum samples. The detection of anti-Strongyloides stercoralis in the sera of patients with strongyloidosis and those with immunosuppressive conditions using S. venezuelensis L3 larvae E/S antigens was satisfactory. RPMI and PBS E/S antigens were also superior in terms of specificity than SE.