Experimental Models Poster Presentation

P0987 - Pathological effects of primary progressive MS cerebrospinal fluid are antibody-mediated (ID 1021)

Speakers
  • J. Wong
Authors
  • J. Wong
  • T. Shue
  • J. Beaty
  • J. Vernejoul
  • J. Lin
  • S. Sadiq
Presentation Number
P0987
Presentation Topic
Experimental Models

Abstract

Background

Primary progressive multiple sclerosis (PPMS) is characterized by unremitting disease progression from disease onset and afflicts 10-15% of MS patients. We previously reported that intrathecal delivery of PPMS cerebrospinal fluid (CSF) from PPMS, but not relapsing-remitting (RRMS) or secondary progressive (SPMS) patients, in mice can induce significant forelimb motor deficits along with demyelination, reactive astrogliosis, and axonal damage in the spinal cord. We also showed that CSF filtration with a 5 kDa molecular weight cutoff (MWCO) filter attenuated the pathology-inducing capacity of PPMS CSF. The PPMS CSF factor(s) responsible for inducing these pathological outcomes have yet to be identified.

Objectives

To identify the factor(s) present in PPMS CSF responsible for inducing motor deficits and spinal cord pathology in mice.

Methods

CSF derived from PPMS patients was pumped through a tangential flow filtration system with 100 kDa MWCO filters for 3 filtration cycles. 8-10 week old female mice underwent laminectomies at cervical levels 4 and 5, then received 3µl injections into the subarachnoid space of either PPMS CSF, filtered PPMS CSF, or filtered PPMS CSF spiked with recombinant IgG antibodies (rAbs) produced from B-cells in PPMS CSF. Control mice were injected with saline. Functional deficits were evaluated by measuring forelimb grip strength, reaching accuracy and tail rigidity at 1 day post injection (DPI), then mice were immediately perfused for histological analyses of the cervical spinal cord.

Results

At 1 DPI, PPMS CSF-injected mice exhibited significantly impaired forelimb function and grip strength compared to saline controls and mice injected with filtered PPMS CSF. Luxol fast blue staining, GFAP and SMI-32 immunostaining showed demyelination, reactive astrogliosis and axonal damage in the dorsal column of PPMS CSF-injected mice, respectively. These pathological changes were not observed in controls or mice injected with filtered PPMS CSF. Mice injected with filtered PPMS CSF spiked with a PPMS rAb developed significant motor deficits at 1 DPI.

Conclusions

Attenuation of the pathology-inducing capacity of PPMS CSF using 100 kDa MWCO filters indicates that the target CSF component is larger than 100 kDa. The addition of PPMS rAbs (150 kDa) into filtered PPMS CSF was able to restore the pathological effects in vivo, suggesting that the induction of motor deficits and pathology by PPMS CSF is antibody-mediated.

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