Multi-Epitope Protein as a Tool of Serological Diagnostic Development for HTLV-1 and HTLV-2 Infections

Abstract

A multi-epitope protein expressed in a prokaryotic system, including epitopes of Env, Gag, and Tax proteins of both HTLV-1 and HTLV-2 was characterized for HTLV-1/2 serological screening. This tool can contribute to support the implementation of public policies to reduce HTLV-1/2 transmission in Brazil, the country with the highest absolute numbers of HTLV-1/2 infected individuals. The chimeric protein was tested in EIA using serum/plasma of HTLV-infected individuals and non-infected ones from four Brazilian states, including the North and Northeast regions (that present high prevalence of HTLV-1/2) and Southeast region (that presents intermediate prevalence rates) depicting different epidemiological context of HTLV-1/2 infection in our country. We enrolled samples from Pará (n = 114), Maranhão (n = 153), Minas Gerais (n = 225) and São Paulo (n = 59) states; they are from blood donors' candidates (Pará and Minas Gerais), pregnant women (Maranhão) and HIV+/high risk for sexually transmitted infection (STI; São Paulo). Among the HTLV-1/2 positive sera, there were co-infections with viral (HTLV-1 + HTLV-2, HIV, HCV, and HBV), bacterial (Treponema pallidum) and parasitic (Trypanosoma cruzi, Schistosma mansoni, Strongyloides stercoralis, Entamoeba coli, E. histolytica, and Endolimax nana) pathogens related to HTLV-1/2 co-morbidities that can contribute to inconclusive diagnostic results. Sera positive for HIV were included among the HTLV-1/2 negative samples. Considering both HTLV-1 and HTLV-2-infected samples from all states and different groups (blood donor candidates, pregnant women, and individuals with high risk for STI), mono or co-infected and HTLV-/HIV+, the test specificity ranged from 90.09 to 95.19% and the sensitivity from 82.41 to 92.36% with high accuracy (ROC AUC = 0.9552). This multi-epitope protein showed great potential to be used in serological screening of HTLV-1 and HTLV-2 in different platforms, even taking into account the great regional variation and different profile of HTLV-1 and HTLV-2 mono or co-infected individuals.

Design, development, and validation of multi-epitope proteins for serological diagnosis of Zika virus infections and discrimination from dengue virus seropositivity

“…Additionally, the combination of epitopes derived from several distinct viral proteins with low reactivity among flaviviruses is clearly advantageous when compared to the use of full-length proteins. The successful use of multi-epitope chimeric proteins has been increasingly documented in the literature, and includes chimeric proteins for the diagnosis of Trypanosoma cruzi [ 47 ], Burkholderia pseudomallei [ 48 ], Human T-cell lymphotropic virus [ 49 , 50 ], Brucella [ 51 ], Leishmania braziliensis [ 52 ], among others. These publications also demonstrate the reliability and feasibility of a multi-epitope recombinant approach for diagnosis.…”

Bioprospecting by Phage Display of Mimetic Peptides of Chlamydia trachomatis for Use in Laboratory Diagnosis

“…The approach used to select different epitopes in different proteins of the infectious agent has also been successfully attempted using other selection methods for HTLV as a novel opportunity for diagnosis. 60 …”

“…The approach used to select different epitopes in different proteins of the infectious agent has also been successfully attempted using other selection methods for HTLV as a novel opportunity for diagnosis. 60 In the present study, the phage display method showed the importance of using CPAF for diagnosis, but this protein has already been used in a murine model as a sufficient immunizer against C. muridarum, inducing protective CD4 + T lymphocytedependent immunity and IFN-γ production. 61 The description of clones G1, H5, C6 and H7 and the conserved structure of CPAF indicate the presence of four epitopes that are also conserved, a finding that can be tested for the production of future vaccines with universal use for human primates and other animals infected by Chlamydia species.…”

Recombinant multiepitope proteins expressed in Escherichia coli cells and their potential for immunodiagnosis

“…coli BL21(λDE3) cells ELISA 22 rubella-positive serum samples/11 rubella-negative serum samples Sensitivity: 100% Specificity: 90.91% [ 114 ]/Brazil Human HTLV-1 and HTLV-2/human T-lymphotropic viruses 1 and 2 HTLV-1/HTLV-2 E . coli Rosetta-gami 2(DE3) cells ELISA 162 HTLV-positive serum samples/297 serum samples from healthy individuals/92 serum samples from non-HTLV disease HTLV-1 and HTLV-2 samples Sensitivity: 82.41 to 92.36% Specificity: 90.09% to 95.19% HTLV-1 samples Sensitivity: 99.19% Specificity: 92.55% HTLV-2 samples Sensitivity: 57.14% Specificity: 94.61% [ 115 ]/Brazil Human chikungunya/chikungunya virus MULTREC Binary system insect cell/baculovirus ELISA 161 chikungunya-positive serum samples/22 serum samples from healthy individuals/312 serum sample from non-chikungunya diseases Sensitivity: 86.36% Specificity: 100% [ 116 ]/Brazil “–”: information not provided by the study …”

“…In addition to the bioinformatics tools mentioned below, there are specific E. coli strains developed to mitigate those potential issues. In this regard, an E. coli Rosetta-derived lineage was used to express RMPs designed for T. cruzi, W. bancrofti, and human HTLV detection [ 10 , 115 , 126 ]. This lineage harbors extra copies of genes encoding rare tRNAs, including for AUA, AGG, AGA, CUA, CCC, and GGA codons [ 142 ].…”