In silico identification of B-cell epitopes of Leishmania infantu | 56381
Journal of Clinical and Cellular Immunology

Journal of Clinical and Cellular Immunology
Open Access

ISSN: 2155-9899

In silico identification of B-cell epitopes of Leishmania infantum recombinant histone shared with human sera stably living in area where Leishmania species does perpetuate

Joint Conference 9th World Congress and Expo on Immunology, Immunity Inflammation & Immunotherapies

November 02-03, 2017 | Atlanta, USA

Sami Lakhal and Malcolm S Duthie

Veterinary Research Institute of Tunisia, Tunisia
Infectious Disease Research Institute, USA

Posters & Accepted Abstracts: J Clin Cell Immunol

Abstract :

Visceral leishmaniasis (VL) can initially be misdiagnosed because its presentation is similar to many autoimmune diseases such as systemic lupus erythematosus (SLE), autoimmune hepatitis and dermatomyositis. Furthermore, serum antibodies from VL patients have been shown to strongly react against proteins that are conserved between the causative agent, L. infantum, and humans themselves. Some of these proteins, like histone, have also been described as immunogenic in several auto-immune syndromes, and the detection of antibodies against them is considered to be indicative of immune system disorders. The potential overlap of autoimmune diseases and VL presents a situation of confounding diagnoses if cross-reactive tests are used. To explore this possibility, we screened sera from three Tunisian populations for the presence, and relative quantity, of antibodies against a panel of L. infantum antigens comprising crude extract or recombinant molecules, with special attention being given to evolutionarily conserved histones. Our data indicate that antibodies in many of the SLE at-risk individuals recognized crude soluble Leishmania antigen (SLA). This compromised the specificity of SLA-based ELISA, providing many results falsely indicating L. infantum infection. Examination of the crude Florentina Berianu, Olga Pinkston and Benjamin Wang histone (CLH) mixture, which is expected to contain nucleosomal Leishmania histones H2A, H2B and H4, as well as recombinant versions of these Leishmania histones, suggested these to be a source of the cross-reactivity. For the purposes of diagnosing VL, it is therefore important to note that the rK39 antigen was found to be more specific and not conflicting with autoimmune presentations. In silico prediction data validate and indicate that the human histones are immunologically cross-reactive with Leishmania histones.