Immunological findings in amyotrophic lateral sclerosis

Generalization of the prion hypothesis to other neurodegenerative diseases: an imperfect fit

Protein misfolding diseases have been classically understood as diffuse errors in protein folding, with misfolded protein arising autonomously throughout a tissue due to a pathologic stressor. The field of prion science has provided an alternative mechanism whereby a seed of pathologically misfolded protein, arising exogenously or through a rare endogenous structural fluctuation, yields a template to catalyze misfolding of the native protein. The misfolded protein may then spread intercellularly to communicate the misfold to adjacent areas and ultimately infect a whole tissue. Mounting evidence implicates a prion-like process in the propagation of several neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's, amyotrophic lateral sclerosis, and the tauopathies. However, the parallels between the events observed in these conditions and those in prion disease are often incomplete. The aim of this review was to examine the current state of knowledge concerning the mechanisms of protein misfolding and aggregation for neurodegeneration-associated proteins. In addition, possible methods of intercellular spread are described that focus on the hypothesis that released microvesicles function as misfolded protein delivery vehicles, and the therapeutic options enabled by viewing these diseases from the prion perspective.

Transgenic mice for interleukin 3 develop motor neuron degeneration associated with autoimmune reaction against spinal cord motor neurons

Interleukin 3 (IL-3) stimulates the proliferation and differentiation of various haematopoietic progenitor cells. Recently, IL-3 and other cytokines were reported to exert a neurotrophic activity and to be associated with neurological disorders, suggesting their complex role in the central nervous system. We now show that overexpression of IL-3 in transgenic mice causes a motor neuron disease with several features of amyotrophic lateral sclerosis and progressive muscular atrophy. These animals exhibit hind limb paralysis at 7 months of age, associated with dendritic and axonal degeneration, loss of motor neurons in the spinal cord, and autoimmune reaction against these cells. We examined the effect of IL-3 on embryonic motor neurons survival in mixed spinal cord cultures. Our results suggest that motor neuronal degeneration is not directly triggered by the high level of expression of IL-3.

Antibodies to chondroitin sulfate C: a new detection assay and correlations with neurological diseases

Antibodies to chondroitin sulfate C (ChS C) have been previously associated with sensory axonal neuropathy. Investigation of these antibodies has, however, been limited by the lack of a sensitive and reliable test for their detection. We developed a new enzyme-linked immunoassorbent assay (ELISA), where biotinylated ChS C was made to adhere to avidin-coated microwells. The new ELISA showed a much greater sensitivity than other currently available ELISAs for detection of anti-ChS C antibodies. A total of 480 sera (466 patients and 14 normal volunteers) were tested at increasing dilutions for anti-ChS C antibody activity. Normal subjects had IgM anti-ChS C antibody titers of up to 3,200 and mildly elevated titers of 6,400 were seen in a variety of diseases. Eleven patients had titers of 12,800 or higher. These included seven patients with sensory axonal neuropathy, three with amyotrophic lateral sclerosis and one with corticobasal ganglionic degeneration. These studies indicate that anti-ChS antibodies do occur in patients with axonal sensory neuropathy, but are not limited to that disease.