Diagnostics of autoimmune neurodegeneration using fluorescent probing

Abstract

The discovery of antibody-mediated catalysis was a breakthrough that showed antibody function is not limited to specific binding interactions, and that immunoglobulins (Igs) may also chemically transform their target antigens. Recently, so-called “natural catalytic antibodies” have been intimately linked with several pathologies, where they either protect the organism or contribute to the development of autoimmune abnormalities. Previously, we showed that myelin-reactive autoantibodies from patients with multiple sclerosis (MS) and mice with experimental autoimmune encephalomyelitis (EAE) exhibit the ability to recognize and hydrolyse distinct epitopes within myelin basic protein (MBP). Further, the antibody-mediated cleavage of encephalitogenic MBP peptide 81–103, flanked by two fluorescent proteins, can serve as a novel biomarker for MS. Here, we report the next generation of this biomarker, based on the antibody-mediated degradation of a novel chemically synthesized FRET substrate, comprising the fluorophore Cy5 and the quencher QXL680, interconnected by the MBP peptide 81–99: Cy5-MBP81–99-QXL680. This substrate is degraded upon incubation with either purified antibodies from MS patients but not healthy donors or purified antibodies and splenocytes from EAE but not from non-immunized mice. Data presented herein suggest the elaboration of potential specific, rapid, and sensitive diagnostic criteria of active progressive MS.

Immunoglobulin Go: Synergy of Combinatorics for Catalysis

“…During the last two decades, immunoglobulins (Ig) have emerged as one of the favorite templates for drug development. For some therapeutic antibodies the catalytic properties may be very beneficial [10f,19b,24a,b,33a] …”

Multiple Sclerosis Is Associated with Immunoglobulin Germline Gene Variation of Transitional B Cells

“…Despite the long history of MS research, its exact etiology still remains elusive. Molecular mimicry, epitope spreading, and cross-reactivity are believed to underlie the mechanisms of viral induction of the disease [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. The immunoglobulin repertoire of MS patients contains cross-reactive antibodies capable of simultaneously binding the human myelin basic protein and components of the Epstein–Barr virus [ 15 , 16 ]…”

“…В основе механизмов вирусной индукции заболевания могут лежать молекулярная мимикрия и перекрестная реактивность с последующим увеличением числа узнаваемых эпитопов (epitope spreading) между Т-и В-клетками [5,[8][9][10][11][12][13]. У пациентов с РС повышен титр аутореактивных антител, специфически связывающих компоненты миелиновой оболочки, у них обнаружены также каталитические иммуноглобулины, гидролизующие основной белок миелина -один из характерных аутоантигенов при РС [14][15][16].…”

Deconvolution of B cell receptor repertoire in multiple sclerosis patients revealed a delay in tBreg maturation

“…However, it is evident now that B cells are crucial for MS pathogenesis as well ( 42 , 43 ). Autoreactive B cells in MS may produce catalytic antibodies, hydrolyzing myelin basic protein ( 13 , 44 , 45 ), and cause humoral cross-reactivity between myelin and viral antigens ( 46 – 50 ). Still, the existing studies on Bregs functioning in MS are controversial and far from conclusive.…”