Relationships between cell-mediated immunity and the IgE antibody response: I. Lymphotoxin production to DNP-Ascaris conjugates

The purpose of this paper is to present evidence for the suitability of a lymphotoxin (LT) assay as an in vitro correlate of cell-mediated immunity (CMI) to a hapten-carrier conjugate known to stimulate a high IgE antibody response. This would be used in a study of the factors influencing the relationship(s) between CMI and IgE antibody responses to the same antigen. Antigen-induced LT was assayed on actinomycin-inhibited, chromium-51-labeled L929 fibroblasts, using supernatants obtained from spleen and lymph node cells of animals immunized with 2,4-dinitrophenyl-Ascaris conjugates. Although LT was present at all times tested, beginning at Day 10, its concentration varied with time after immunization, adjuvant used, and cell type assayed. The induction of LT was T-cell dependent and conjugate specific. LT was produced by nonadherent cells. Adherent cells from immunized animals produced L-cell cytotoxin in the absence of antigen stimulation when tested before Day 10.