SUPPRESSIVE EFFECTS OF THE ORAL-ADMINISTRATION OF LACTOBACILLUS-CASEION TYPE-II COLLAGEN-INDUCED ARTHRITIS IN DBA 1 MICE/

We investigated the effects of the oral administration of the viable b acterium Lactobacillus casei strain Shirota (LcS), on the development of type II collagen (CII)induced arthritis (CIA) in DBA/1 mice. Male D BA/1 mice were immunized with an emulsion of 100 mu g of CII and compl ete Freund's adjuvant (CFA). The mice were then given orally a suspens ion of LcS or distilled water (DW) during the experiment. We observed the development of CIA in the mice, and determined the in vivo and ex vivo CII-specific immune responses in the control and LcS-administered mice. In the control mice, we observed the onset of arthritis at the 27th day after the CII-immunization, and then the severity of CIA deve loped gradually. In the tested mice, the LcS-treatment reduced the inc idence and the development of CIA and the levels of antibody to CII in serum compared with the control mice. The CII-specific IgG2a and IgG2 b antibodies in serum were also down regulated in the tested mice. The administration of this bacterium also inhibited delayed-type hypersen sitivity response to CII in DBA/1 mice immunized with CII and CFA. The orally administered-LcS suppressed the CII-specific secretion of inte rferon-gamma from splenocytes ex vivo. From these results, we conclude d that the oral administration of LcS was able to modify the humoral a nd cellular immune responses to CII, and these modifications could res ult in the reduction of the development of CIA in DBA/1 mice.