Production of auto-anti-idiotypic antibody during the normal immune response to TNP-ficoll. II. Hapten-reversible inhibition of anti-TNP plaque-forming cells by immune serum as an assay for auto-anti-idiotypic antibody

Sera taken from AKR/J mice 7 d after the intravenous injection of 2,4,6-trinitrophenyl-lys-Ficoll (TNP-F) caused a specific inhibition of anti- trinitrophenol (TNP) plaque-forming cells (PFC) in vitro. This inhibition was reversed by the incorporation of 10(-8)-10(-7) M 2,4,6-trinitrophenyl- ε-amino-n-caproic acid (TNP-EACA) into the agar during the PFC assay. The factor responsible for the hapten-reversible PFC inhibition was removed from serum by passage through an anti-immunoglobulin column or through a 2,4,-dinitrophenyl-human-serum-albumin-bromoacetylcellulose plus anti-TNP- antibody column, but not by DNP-HSA-BAC alone. It was concluded that this immunoglobulin-like substance, lacking anti-TNP activity but reacting with anti-TNP antibody of AKR/J origin, was most likely an auto-anti-idiotypie antibody that had been produced during the normal course of the response of AKR/J mice to TNP-F. Pools of anti-idiotypic-antibody-containing antisera inhibited anti-TNP plaque formation to varying degrees when tested on d-4 PFC from different mice of the same inbred strain, suggesting a variability in idiotype expression. 4 d after transfer of immune (7 d after 10 μg TNP-F, administered intravenously) AKR/J spleen cells plus 10 μg TNP-F into syngeneic mice, the number of PFC detectable in the recipients' spleens could be markedly augmented by the inclusion of TNP-EACA in the agar during the PFC assay. Incubation of spleen cells containing such hapten-augmentable PFC with TNP- EACA yielded a factor in the supernate that caused a specific, in vitro, hapten-reversible inhibition of anti-TNP PFC. Studies with immunoadsorbents indicated that this PFC-inhibiting factor was antigenically immunoglobulin- like, lacked anti-TNP-antibody activity, but reacted with anti-TNP antibody of AKR/J origin. The results are consistent with the view that this PFC inhibitor is auto-anti-idiotypic antibody that is involved in the normal regulation of the immune response. It is proposed that hapten-reversible inhibition of plaque formation can be employed as an assay for anti-idiotypic antibody and the conditions for such an assay are described. It is further proposed that the detection of hapten-augmentable PFC suggests the presence of auto-anti-idiotypic antibody

Adult murine T cells activated in vitro by alpha-fetoprotein and naturally occurring T cells in newborn mice: identity in function and cell surface differentiation antigens.

Murine alpha-fetoprotein (alphaFP) has been shown to suppress T cell-dependent antibody responses in vitro but not T cell-independent responses. Our earlier preliminary findings indicated that such inhibitory effects are mediated via activated T cells. In this study, using alphaFP as the inducing agent, we have analyzed cells generated in vitro from adult spleen cells with regard to function and surface markers and compared the cells to the naturally occurring splenic T cells of newborn mice, in which there are high intrinsic concentrations of alphaFP. Both types of T lymphocytes were found to effectively inhibit T cell-dependent antibody responses in vitro but not T cell-independent responses. Moreover, both groups of T cells were found to express the identical differentiation antigen phenotype,Ly 1 + 2-. Thus alphaFP-induced inhibitory T cells from adults could be shown to have the same functional properties and Ly phenotype as splenic T lymphocytes from newborn mice. These findings support the concept that alphaFP might function as an important immunoregulatory agent in vivo during ontogenetic development