U. Wendling et al., ANTIRHEUMATIC ESCHERICHIA-COLI EXTRACT OM-89 INDUCES T-CELL RESPONSESTO HSP60 AND HSP70, International journal of immunopharmacology, 19(9-10), 1997, pp. 565-568
Oral administration of E. coli extract OM-89 is used in treating RA. I
t has been shown that immune reactivity to heat-shock proteins (hsp) i
s involved in immunomodulation of arthritis. We evaluated the postulat
ed presence and immunogenicity of hsp's in OM-89. The effects of OM-89
in experimental arthritis were analyzed. Proliferative T cell respons
es to bacterial hsp60 and hsp70 were found in rats immunized with OM-8
9. And conversely, immunization with hsp antigens induced OM-89-specif
ic T cell responses. Hsp70 (DnaK) was found to be a major immunogenic
constituent of OM-89. Parenteral immunization with OM-89 reduces resis
tance to adjuvant arthritis (AA), whereas oral administration protects
against AA. Given the arthritis inhibitory effect of oral OM-89 in AA
our findings suggest peripheral tolerance induced by hsp-specific reg
ulatory T cells as a mode of action for OM-89 as an arthritis suppress
ive oral drug. (C) 1998 Published by Elsevier Science Ltd on behalf of
the International Society for Immunopharmacology.