Cje. Watson et al., CD4 AND CD8 MONOCLONAL-ANTIBODY THERAPY - STRATEGIES TO PROLONG RENAL-ALLOGRAFT SURVIVAL IN THE DOG, British Journal of Surgery, 80(11), 1993, pp. 1389-1392
The value of CD4 and CD8 monoclonal antibody therapy in tolerance indu
ction has been demonstrated in rodent transplant models. In this paper
the immunosuppressive potential of CD4 and CD8 monoclonal antibodies
for dog renal allografts was evaluated as a preliminary fo tolerogenic
studies in this large animal model. Monoclonal antibodies were given
for a maximum of 10 days after transplantation. Therapy was stopped pr
ematurely following adverse reactions associated with the recipient de
veloping an antibody response against the foreign (rat) therapeutic mo
noclonal antibody. Blood trough levels of CD4 and CD8 antibodies indic
ated that saturating doses were achieved. Although neither CD4 nor CD8
alone prolonged allograft survival (rejection by day 7), combination
of CD4 and CD8 antibodies resulted in good graft function for a median
of 14 days. The effect of removing circulating T lymphocytes was also
assessed using a lytic Thy-1 monoclonal antibody. Alone Thy-1 had lit
tle effect but, when combined with CD4, the median allograft survival
time was increased to 15.5 days. Reduction of the number of circulatin
g T lymphocytes appears complementary to blockade of CD4 for immunosup
pression, while blockade of CD4 combined with removal of CD8 also favo
urs allograft survival.