Lymphocyte targeting with 111In-labelled monoclonal antibodies.

In vitro tests were conducted using human T and B cell lines, as well as whole blood, to establish the usefulness of 2 murine monoclonal antibodies (MAbs), an anti-CD5 (Pan T) and a Pan B, for potential radioimmunolocalization and therapy. Both MAbs showed specificity for the cell line in question as tested by indirect immunofluorescence and radioimmunoassay. Assays carried out on whole blood showed 40-70% of the added activity of 111In-labelled Pan B antibody binding to B cells and 20-24% of 111In-Pan T antibody binding to T cells. The amount of internalised 111In-labelled Pan B was 6% of total amount at 24 hr indicating a slow internalisation process. These results should allow for in vivo targeting of normal and neoplastic B and T cells.