ANTI-CD5 THERAPY DECREASES SEVERITY OF ESTABLISHED DISEASE IN COLLAGEN TYPE II-INDUCED ARTHRITIS IN DBA 1 MICE/

Collagen-induced arthritis has been widely used as an animal model of rheumatoid arthritis. We have used this model with a view to determini ng potential therapeutic targets for the treatment of human disease. T o do this we have attempted to modulate the progression of established arthritis over a 10-day time period following the first appearance of disease, by i.p, injection of one of three different MoAbs. These con sist of a rat IgG2a specific for the CD5 antigen expressed on all T ce lls and a subpopulation of B cells, a mouse IgG2b recognizing the CD72 antigen, and a rat IgM specific for the B220 molecule, CD72 and B220 both being expressed on all B cells. None of the three MoAbs had deple ting activity in vivo. The progression of arthritis was monitored both clinically, and histologically. The effects of treatment with anti-CD S and anti-CD72 antibodies were compared with control antibodies of th e same species class and subclass. In the case of anti-B220 antibodies , the effects of treatment were compared with administration of PBS. O f these MoAbs, only treatment with anti-CDS resulted in disease amelio ration with significant decrease in disease severity in 60% of the ani mals. These changes became apparent 6 days after initiation of treatme nt. There were no significant differences in serum levels of IgG antib odies to native bovine collagen type II between the groups of treated and control mice. Possible mechanisms underlying the modification of d isease expression following treatment with anti-CDS MoAb are discussed .