Immunodiagnosis of Parasitic Diseases with Synthetic Peptides

Abstract

Parasitic diseases remain as a major public health problem worldwide, not only based on their historically high morbidity and mortality rates, but also because risk factors associated with their transmission are increasing. Laboratory diagnosis and particularly immunodiagnosis is a basic tool for the demonstration, clinical management and control of these infections. Classically, the serological tests for the detection of antibodies or antigens are based on the use of crude and purified antigens. Synthetic peptides have opened a new field and perspectives, as the source of pure epitopes and molecules for diagnosis of malaria, Chagas' disease, leishmaniasis, schistosomiasis, hidatidosis, cysticercosis and fasciolosis based on the detection of antibodies and circulating antigens. Herein, are critically reviewed the relevant advances and applications of the synthetic peptides on immunodiagnosis of parasitic diseases. A variety of sequences, constructs (monomers, polymers, MAPs), immunological methods and samples have been used, demonstrating their diagnostic potential. However, in most parasitic infections it is necessary to use more than a single peptide in order to avoid the genetic restriction against certain epitopes, as well as to test them in well characteized groups of patients, in order to confirm their sensitivity and specificity. The concept of multidiagnosis with synthetic peptides, using a novel multi-dot blot assay is introduced. Finally, the chemical imitation of antigens, offers a tremendous posibilities in the diagnosis of parasitic infections in developing countries since this strategy is cheaper, simpler, reproducible, useful for large scale testing and in most cases, specific and sensitive.

Sensitive and Specific Serodiagnosis of Leishmania infantum Infection in Dogs by Using Peptides Selected from Hypothetical Proteins Identified by an Immunoproteomic Approach

“…In canine epidemiological screening, a test with high sensitivity and specificity is desirable. The performance observed for the synthetic antigens in this work is consistent with the performance of many antigens (mainly recombinant proteins) that have been developed in recent years for CVL diagnosis by ELISA (23,24), with the advantages of being cheaper, simpler, reproducible, useful for large-scale testing and, in most cases, more specific and sensitive (26). Our results show an improvement in the sensitivity of the synthetic antigen ELISA, compared to the indirect immunofluorescence assay, in asymptomatic dogs, due to the fact that the IFAT shows a lack of sensitivity for the detection of specific antibodies in asymptomatic dogs (20) and in healthy dogs, due to the large number of false-positive IFAT reactions (18).…”

“…These antigens are relatively simpler and cheaper to produce than recombinant proteins. It also has been reported that the use of synthetic peptides (individually or in a mixture format), in comparison with the use of recombinant proteins, is able to increase the sensitivity and/or specificity of immunoassays for the serodiagnosis of parasitic diseases (26), such as canine and human visceral leishmaniasis (27,28).…”

Application of an Improved Enzyme-Linked Immunosorbent Assay Method for Serological Diagnosis of Canine Leishmaniasis

“…Total soluble antigens derived from the promastigote stage of different Leishmania species are the most commonly used antigens in ELISA. These ELISAs have demonstrated sensitivities and specificities of 80 to 100% and 85 to 95%, respectively (20). Nevertheless, the use of total soluble antigens is limited due to problems of reproducibility and manufacturing.…”

Peptide synthesis: chemical or enzymatic

“…It is also a fundamental tool for understanding the structure-function relationship in proteins and peptides, the discovery of novel therapeutic and diagnosis agents and the production of synthetic vaccines (Noya et al 2003). Recently it has been used for the design of synthetic biocatalysts, which is a very promising area of research (Kaplan and DeGrado, 2004;Carrea et al 2005).…”