Antibody-Mediated Suppression of the Immune Response in Vitro

Abstract

Antibody-mediated suppression of the in vitro immune response to polymerized flagellin of Salmonella adelaide and to sheep erythrocytes was studied at the cellular level. Normal mouse spleen cells, preincubated in vitro with mixtures of antigen and antibody for short periods of time before being washed, did not respond to an optimal antigenic challenge in vitro, whereas similar cells treated with antibody alone gave a normal response. The degree of immune suppression was found to depend on the time of preincubation. Significant immune suppression could be induced in as short a time as 15 min, whereas profound suppression (90%) required the incubation of cells with mixtures of antigen and antibody for 4–6 hr. Mouse spleen cells treated similarly were also unable to respond subsequently to the antigen upon transfer to lethally irradiated hosts, as measured at both the level of the antigen-reactive cell and that of serum antibody production. These results were taken as evidence that in vitro an effect of antibody-mediated suppression occurred at the level of the immunocompetent cell. Similarities between immune tolerance and antibody-mediated suppression in vitro were described, and the significance of the findings discussed in the light of current concepts of the mechanism of antibody-mediated suppression.

Antibody-Mediated Suppression of the Immune Response in Vitro

“…The experimental results described above and previously (6) are in accordance with this hypothesis. We have suggested that in vitro immune complexes may form on the surface of immunocompetent cells.…”

“…The data presented in this paper augment those of an earlier publication in which we reported for the first time the induction, in vitro and in vivo, of immunological tolerance mediated by low doses of antigen in the presence of specific antibody (6). In close analogy to the in vitro induction of tolerance to Salmonella adelaide tt antigens by the brief exposure of dispersed mouse spleen cells to high concentrations of a polymerized form of these antigens (10,14), tolerance may also be induced by the in vitro treatment of spleen cells for 6 hr with an immunogenic dose of the antigen together with low concentrations of the relevant antibody.…”

“…This is similar to the situation in vivo where antibody adherent to the dendritic processes of the reticular cells of lyznphoid follicles may enable the antigen to form a similar immunosuppressive lattice. This concept may explain the tolerogenic effect of antigen and antibody that we have recently described in vivo (6).…”

“…Any change in this ratio in favor of either the concentration of the antigen or the antibody prevents the induction of tolerance. It is important to remember that, an antibody concentration too high to favor tolerance induction under the described experimental conditions of preincubation of cells with antigen and antibody for only 6 hr, prior to culture and antigenic challenge, is readily immunosuppressive when present during the entire culture period (6). This leads to the conclusion that antibody-mediated immune suppression must be effective either at the central level (i. e. the level of the immunocompetent cells), in which case it represents the induction of immunological tolerance, or, alternatively, at the peripheral level by altering the antigenic stimulus that is necessary for immune performance.…”

Induction of Immunity and Tolerance in Vitro by Hapten Protein Conjugates

“…To circumvent this and other difficulties, the competitive inhibition experiments were modified. The DNP inhibitors, and the immunogen were only present for a brief period of time (2-21/4 hr), in the cold (004°C), conditions under which B cell tolerance is much less likely to occur (5,14). These modifications were possible since brief incubation with DNP POL immunizes spleen cells (16).…”