In vivo tissue distribution of CD4 lymphocytes in mice determined by radioimmunoscintigraphy with an (111)In-labeled anti-CD4 monoclonal antibody

Abstract

The tissue distribution of CD4 lymphocytes in normal C57/BL mice and CD4 knockout mice was determined by biodistribution measurements and gamma camera imaging with an In-111-labeled rat IgG(2b) monoclonal antibody directed against the murine CD-4 antigen. In normal mice, high concentrations of antibody accumulated in the spleen and lymph nodes, at 45 hr after injection, the concentrations of radiolabel in the spleen and lymph nodes of normal mice were 10- to 20-fold greater than in the corresponding tissues of the CD4 knockout mice and nonlymphoid tissues of both types of mice. At 24 and 45 hr, gamma camera images showed high concentrations of radiolabeled antibody in lymph nodes and spleen of normal but not knockout mice. These results indicate that radioimmunoscintigraphy with In-111-anti-CD4 is an excellent method for studying tissue distribution of CD4 lymphocytes in mice. Using an equivalent anti-human CD4 antibody, this method might be useful for studying the pathophysiology of conditions in which these cells play a critical role and for monitoring therapies for these disorders.