The Reticulo-endothelial system in relation to antibody formation.

The general lines of inquiry to determine the seat of antibody formation have been to seek the tissue where a given antigen is fixed; to determine the locality where the corresponding antibody may first be detected; or to prevent the formation of antibody either by specific injury (benzol, x-ray) or by extirpation of an organ. It has also been claimed that antibodies may be produced in tissue culture. With the evidence obtained by these methods it has been variously concluded that the essential antibody formers are the leucocytes; the leucocyte forming organs, spleen, bone marrow and lymph nodes; the liver; and the capillary endothelium.

We have probably been led astray by the expectation that some particular organ like the spleen, or some strictly localized cell group, rather than a more universal tissue, is responsible. Many of the phenomena of general immunity can be better explained on the assumption that some widely distributed cell-type is the essential antibody producer. The condition of strictly local immunity in various parts of the body, which we believe has now been proved to exist, can be understood only on such an assumption.

The reticulo-endothelial system of cells (Aschoff) fulfills this criterion of wide distribution throughout the body including as it does one of the constituent elements of connective tissue and the capillary and lymph space endothelium, and being related to adult endothelium and the monocytes of the blood. It includes, moreover, the most markedly phagocytic and resistant cells of the body; indeed its differentiation depends on its ability to take up rapidly and to retain particulate matter and colloidal substances. The undoubted importance of spleen, lymph nodes and liver in the disposal of foreign cells and in antibody-formation, that has already been mentioned, would depend on their content of elements that make up the reticulo-endothelial system; and the failure of removal of one of these organs (e. g. spleen) to prevent antibody formation entirely would depend on the vicarious or increased functioning of other parts of the same system.