Specific antibodies to soluble alpha-synuclein conformations in intravenous immunoglobulin preparations

Abstract

SummaryAlpha-synuclein is the major protein in Lewy bodies, the hallmark pathological finding in Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Although normally intracellular, it also can be secreted, so extracellular alpha-synuclein may contribute to neuronal injury. Serum antibodies to alpha-synuclein could exert protective effects by increasing alpha-synuclein's movement out of the brain and, if they cross the blood-brain barrier, by inhibiting its neurotoxic effects. The objective of this study was to measure antibody concentrations to alpha-synuclein monomer and soluble oligomers in three intravenous immunoglobulin (IVIG) preparations, Gamunex (Talecris Biotherapeutics), Gammagard (Baxter Healthcare) and Flebogamma (Grifols Biologicals). Antibodies were measured in native IVIG preparations and after antibody-antigen complex dissociation. IVIG's non-specific binding was subtracted from its total binding to alpha-synuclein to calculate specific anti-alpha-synuclein antibody concentrations. Specific antibodies to alphasynuclein monomer and/or soluble oligomers were detected in all IVIG products. In native IVIG preparations, the highest anti-monomer concentrations were in Gammagard and the highest anti-oligomer concentrations were in Gamunex; the extent to which lot-to-lot variation may have contributed to these differences was not determined. Antibody-antigen complex dissociation had variable effects on these antibody levels. The IVIG preparations did not inhibit alpha-synuclein oligomer formation, although they changed the distribution and intensity of some oligomer bands on Western blots. The presence of antibodies to soluble alpha-synuclein conformations in IVIG preparations suggests that their effects should be studied in animal models of synucleinopathies, as a first step to determine their feasibility as a possible treatment for PD and other synucleinopathies.

Influence of 6‐Hydroxydopamine Toxicity on α‐Synuclein Phosphorylation, Resting Vesicle Expression, and Vesicular Dopamine Release

“…Western blot analysis showed an increase in monomeric a-synuclein at 10 and 40 mM treatment of 6-OHDA but appearance of distinct oligomeric bands of a-synuclein was noticed from 75 mM concentration of 6-OHDA. This is in alignment with earlier studies, where an increase in oligomeric bands of a-synuclein has been noticed under oxidative stress [Cappai et al, 2005;Hunya et al, 2008;Patrias et al, 2010;Lee and Kamitani, 2011]. Since phosphorylation of a-synuclein at serine 129 has been related to PD (based on data from post mortem studies) [Fujiwara et al, 2002;Anderson et al, 2006], we looked into the expression of pSyn-129 in SH-SY5Y cells under 6-OHDA toxicity.…”

“…Densitometric analysis represented in Figure 4D, indeed showed a significant increase in the 19 kDa a-synuclein band at the 10 and 40 mM 6-OHDA treatment (P < 0.05) in comparison to control. As depicted in Figure 4C, the Western blot analysis of cells, treated with higher concentrations (75, 100, and 150 mM) of 6-OHDA showed an additional band at $24 kDa for a-synuclein which refers to a covalently modified isoform of the protein [Cappai et al, 2005;Hunya et al, 2008;Patrias et al, 2010;Lee and Kamitani, 2011]. Densitometric analysis for the 19 kDa (Fig.…”

Effects of intravenous immunoglobulin on alpha synuclein aggregation and neurotoxicity

“…IVIG administration to patients with DLB and MSA has also been reported [39,40] but little is known of its effects on α-synuclein. In our previous study [34], as shown by western blots of reducing/denaturing gels, IVIG preparations did not prevent short-term (four-day) development of α-synuclein soluble oligomers, although alterations were seen in the distribution of the oligomer bands. The objectives of the present study were to further examine the effects of IVIG on α-synuclein aggregation, by determining its effects on the formation of longer-term (nine-day) α-synuclein soluble oligomers and amorphous aggregates as well as preformed α-synuclein oligomers, and to determine its possible protective effects against α-synuclein oligomer neurotoxicity.…”

“…The objectives of the present study were to further examine the effects of IVIG on α-synuclein aggregation, by determining its effects on the formation of longer-term (nine-day) α-synuclein soluble oligomers and amorphous aggregates as well as preformed α-synuclein oligomers, and to determine its possible protective effects against α-synuclein oligomer neurotoxicity. The IVIG preparation Gammagard (Baxter Healthcare) was chosen for this study because in our earlier investigation [34] it appeared to contain the highest specific antibody levels to α-synuclein monomer among three IVIG preparations examined.…”

“…We previously reported the presence of antibodies to α-synuclein monomer and soluble oligomers in intravenous immunoglobulin (IVIG) preparations [34]. These products consist of purified plasma immunoglobulins from thousands of healthy subjects and are used, often off-label, to treat many autoimmune, infectious, and idiopathic disorders [35].…”