Article Text

A6.36 Characterisation of anti-JO1 autoantibodies in myositis
  1. C Fernandes-Cerqueira,
  2. I Lundberg,
  3. PJ Jakobsson
  1. Unit of Rheumatology, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden


Background and objectives Anti-histidyl tRNA synthetase (Jo1) autoantibodies are the most common type of myositis specific autoantibodies, being present in 15%–30% of the patients. When myositis patients develop simultaneous interstitial lung disease the percentage of patients positive for anti-Jo1 autoantibodies can reach approximately 70%. These individuals are generally characterised by a condition called anti-synthetase syndrome known to present a particular clinical phenotype affecting the muscles, lungs, joints and skin. Little is known about the functional role of anti-Jo1 autoantibodies. The aim of this study was to purify anti-Jo1 IgG from blood of myositis patients, determine the proportion in circulation and further characterise any molecular effects of these autoantibodies.

Materials and methods Sera (n = 42) samples from anti-Jo1 positive myositis patients were collected and used to affinity purify anti-Jo1 IgG. Recombinant human Jo1 (rJo1) was over-expressed in E.coli competent cells, purified from the cytosolic fraction using hydroxyapatite followed by strong anion exchange chromatography and coupled to an NHS activated pre-packed sepharose column. Anti-Jo1 IgGs were isolated from total IgGs extracted from pooled myositis sera using a ProteinG column and further purified using the Jo1 column. The abundance of anti-Jo1 IgG in serum from myositis patients was estimated by measuring the absorbance at 280 and 595 nm. Recovery/purity and reactivity against rJo1 was analysed by SDS-PAGE and western blot, respectively.

Results Anti-Jo1 IgGs were successfully purified from myositis serum using an in-house developed Jo1 affinity column. Among the total percentage of IgG 1.5% were Jo1 reactive (anti-Jo1 IgG). The total concentration of anti-Jo1 IgG in myositis serum was estimated to be 180 μg/ml. Anti-Jo1 IgG recognised both the monomer and the dimer structure of the enzyme.

Conclusions Anti-Jo1 IgGs were efficiently purified from myositis serum and the proportion and concentration was estimated. Affinity purified anti-Jo1 autoantibodies are currently being used as molecular tools in in vivo and in vitro experiments for the characterisation of functional effects and antigen/autoantibody dynamics in myositis.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.