Antibody Formation Initiated in Vitro

Abstract

Previous reports (1, 2) have described a system in which a culture of lymph node cells from non-immunized rats was stimulated, in vitro, to produce specific antibody. This stimulus was provided by a cell-free homogenate of peritoneal exudate ceils, consisting mainly of macrophages, which had been incubated with the antigen in question. The observations that both streptomycin and ribonuclease rendered the system ineffective directed attention to the possibility that nucleic acid was an essential factor. The experiments to be presented show that the specific stimulatory activity resides in a purified ribonucleic acid fraction of the cell-free homogenate.Tests for activity of the purified material were conducted with the aid of diffusion chambers. Such chambers, charged with non-immune rat lymph node ceils and the material to be tested, were inserted intraperitoneally into x-irradiated rats. In some experiments the material alone was placed into the chambers which were then inserted into non-irradiated recipients. Activity was measured by titrating the sera of the recipient rats for specific antibody. Material and MethodsAnimals.--200 to 250 gm Wistar rats were used as recipients for the diffusion chambers, and as the source of exudate cells, hereafter referred to as macrophages. 60 to 80 gm rats served as lymph node donors. The procedures for obtaining both macrophages and lymph node cells have been described in a previous paper (2).X-Irradiation Factors.--Rats were exposed to 500 r total body irradiation through the facilities of the Brookhaven National Laboratories. The x-ray factors were 250 KVP, 15 ma, 0.5 mm Cu -4-1.0 mm A1; distance from target to skin, 40 inches; roentgens in air per minute, 28.0. Macrophage-A ntigenInteraction.--The procedure for obtaining sterile cell-free homogenates of macrophage-bacteriophage T2 mixtures has been described (2). In brief, the macrophages

Relationship between Immunity and Interferon Production in Macrophages

“…Glasgow [10] presented the results that antiserum-treated cells had only a low capacity of IF production and neutralized [2,5] and that macrophages have a specific receptor for this antibody [12]. Mitsuhashi et al [16] have discussed that the macrophages have three functions in defense mechanism; the first function is phagocytosis, the second being production of transfer agent which transfers immunogenic information to immunocompetent cells [9,13], and the third is for the production of cellular antibody [14]. The mechanism of enhancement of IF production in macrophages will be also analyzed from the point of view of cytophilic antibody and cellular antibody.…”

Cells as Antigen Carriers and as Immunoglobulin Producers

“…The size may affect the period within the body during which an antigen may retain its configuration and may also affect the rate at which it is phagocytized. Whether such phagocytosis is itself an active step in the initiation of the immune response (37,38) it simply serves to reduce the ambient antigen concentration in the immediate surroundings of antibody-forming cells must remain open. Promoting capacity of cells does not solely depend on size of the antigen: the promoting capacity of red blood corpuscles and nucleated cells shows considerable differences.…”

Studies on Artificial Antigens

“…The observations with the polylysine hapten conjugates and the copolymers of GA and GL strongly suggest that besides the recognition of the antigenic determinant capable of inducing specific antibody synthesis, an earlier step of metabolism of the antigen molecule must take place, presumably at the level of the macrophages, for the inducer to be made (9,10). Recent observations of Maurer (11) and Gill et o2.…”