The Demonstration of Pneumococcal Antigen in Tissues by the Use of Fluorescent Antibody

Abstract The object of this investigation has been to determine the feasibility of using chemically labelled antibodies as reagents for the detection and orientation of antigenic material in mammalian tissue. Such a method requires the retention of specificity by the antibody-molecule during and after the necessary chemical manipulation, a stable chemical linkage between the antibody and its label, and a label that can be detected when present in minute quantities. A further important requirement demands the separation of the labelled-antibody solution from unconjugated tracer-material. In addition a method of this sort would obviously be more useful for many studies if it were possible to determine not only those organs, but those cells which contain the antigen in question. Accordingly we investigated the possibility of employing materials for labelling that could be detected by optical rather than by analytic or radiographic methods.