Production of Epithelioid Cells in Lymph Glands by Injection of Non-Tuberculous Substances.

Abstract

Until the introduction of certain dyes permitting the staining of cells in the living condition, the epithelioid cell was a rather vague cytological entity. However, it is now possible to define it morphologically (as seen supra-vitally stained with neutral red) as a relatively large cell having a great number of very fine granules or vacuoles, arranged in a rosette, which assume with this vital dye a salmon pink to a brownish red tint. Such an appearance furnishes neither definite nor conclusive evidence regarding the origin or function of this cell, but does, on the other hand, very clearly define it as a cell of distinctive characteristics. This specific characteristic staining quality was first noted by Sabin (1923) in cells obtained from tuberculous lymph nodes, and similar cells have since been observed by other investigators in tuberculous tissues generally. As it had been found that epithelioid cells are very numerous in tuberculous involvement of the lymph nodes, it seemed that these structures would be a favorable location for the study of the possible effect of non-tuberculous substances.

Rabbits were used for these experiments. They were subjected to laparotomy and the mesenteric lymph nodes were exposed. By means of small glass pipettes, material was removed from various parts of the nodes, the experimental materials were then injected into the substance of the nodes, and the incision closed. The substance used in these experiments have been sterile macerated rabbits'brain, olive oil (with and without phosphorous), cod liver oil (unphosphorated), and mineral oil. All of the aspirated material was studied on supra-vitally stained slides.

In the material from the normal nodes, a few monocytes were usually, but not invariably, found, but in none of them were any epithelioid cells seen.∗ The animals were sacrificed 72-120 hours after the injection of the experimental material and many supra-vital preparations were carefully studied. In the rabbits which had been given macerated brain, examination brought to light an abundance of typical epithelioid cells and a large number of monocytes.