The induction and suppression of in vitro IgG anti-tetanus toxoid antibody synthesis by human lymphocytes stimulated with tetanus toxoid in the absence of in vivo booster immunizations.

Abstract

This report presents a new approach that by-passes booster immunizations with tetanus toxoid (TT) before in vitro studies of antibody (Ab) production. The methodology for optimal TT-induced synthesis of specific IgG anti-tetanus toxoid Ab (IgG anti-TT) by peripheral blood mononuclear cells (PBMC) from randomly selected TT immune individuals without recent booster immunizations is described. PBMC from most normal immune subjects could be repeatedly induced to produce in vitro IgG anti-TT; PBMC from subjects with high TT titers are not required for this new approach. This approach uses high cell concentrations in multiple replicate microcultures and TT washout to obtain optimal IgG anti-TT synthesis. Washed cultures produced more Ab than nonwashed cultures (p less than or equal to 0.005). The readdition of TT (2.5 to 250 ng/ml) to the culture media after washout of TT on day 4 suppressed specific Ab formation, whereas diphtheria toxoid added at comparable doses did not inhibit specific Ab formation. Suppression of antibody synthesis mediated by T cells could be induced by TT per se, and was not due to binding of synthesized Ab to TT in the latter 8 days of culture. In addition, suppression could not be induced in the first 4 days of culture by IgG anti-TT, IgG, or IgM. This approach permits the analysis of antigen-specific regulatory circuits in the steady and activated immune states, and the evaluation of in vivo and in vitro effects of biologic response modifiers on specific Ab production.

Mathematical Model to Predict Polyclonal T-Cell-Dependent Antibody Synthesis Responses

“…In Vitro Experimental Data Supporting the Model. The in vitro model was used as a guide for establishing the range of immune response variables [18,60,61]. Individual I g G-secreting B-cells were measured by B-cell ELISpots in cultures of PBMC, CD4 + Tcells + non-T-cells (B-cells, monocytes, and NK cells), or CD8 + T-cells + non-T-cells in co-cultures stimulated with PWM (Figure 2B).…”

“…Individual I g G-secreting B-cells were measured by B-cell ELISpots in cultures of PBMC, CD4 + Tcells + non-T-cells (B-cells, monocytes, and NK cells), or CD8 + T-cells + non-T-cells in co-cultures stimulated with PWM (Figure 2B). The data from individuals published by Lum et al [18,60,61] were reanalyzed and presented in the context of this study. Similarly, purified CD4 + or CD8 + T-cell subsets were evaluated for enhancement or suppression of control culture containing a fixed number of T + B-cells (Figure 2C).…”