Exploring the Association of Surface Plasmon Resonance with Recombinant MHC:Ig Hybrid Protein as a Tool for Detecting T Lymphocytes in Mice Infected with Leishmania (Leishmania) amazonensis

A surface plasmon resonance- (SPR-) based recognition method applying H-2 L(d):Ig/peptides complexes for ex vivo monitoring cellular immune responses during murine infection with Leishmania (Leishmania) amazonensis is described. Lymphocytes from lesion-draining popliteal lymph nodes were captured on a carboxylated sensor chip surface previously functionalized with H-2 L(d):Ig (DimerX) protein bound to synthetic peptides derived from the COOH-terminal region of cysteine proteinase B of L. (L.) amazonensis. In computational analysis, these peptides presented values of kinetic constants favorable to form complexes with H-2 L(d) at neutral pH, with a Gibbs free energy ΔG° < 0. The assayed DimerX:peptide complexes presented the property of attaching to distinct T lymphocytes subsets, obtained from experimentally infected BALB/c mice, in each week of infection, thus indicating a temporal variation in specific T lymphocytes populations, each directed to a different COOH-terminal region-derived peptide. The experimental design proposed herein is an innovative approach for cellular immunology studies of a neglected disease, providing a useful tool for the analysis of specific T lymphocytes subsets.