Monoclonal antibody analysis of responder and stimulator cells in the human autologous mixed lymphocyte reaction

Autologous mixed lymphocyte reaction in human neonatal lymphocytes

Human neonatal mononuclear cells were examined to determine their ability to participate in an autologous mixed lymphocyte reaction (AMLR). Stimulator cells were isolated by plastic adherence and nylon wool adherence. The nylon wool-nonadherent cells were used as responder cells. In 10 of 10 neonatal samples and 6 of 7 adult samples, a significant AMLR was present when plastic-adherent cells were used as stimulators. Neonatal blood showed a mean increase in proliferation of 7.6 (3.6-14.9), while adult cultures showed a mean stimulation index of 11.8 (1.0-39.0). When nylon wool-adherent cells were used as stimulator cells, only 2 of 7 neonatal blood samples and 1 of 5 adult blood samples showed a significant AMLR. When recombinant interleukin 2 (IL-2) was added to AMLR cultures of plastic-adherent cells and nylon wool-nonadherent cells, a mean augmentation of 12.0 was seen in the neonatal AMLR, while the adult cultures were augmented by a mean response of 4.1. Addition of IL-2 to nylon wool-nonadherent cells alone produced a 5.9-fold increase in adult cells, while neonatal cells showed an 85.8-fold mean increase in proliferation. The results suggest that autoreactive T cells are present in neonatal blood and that these cells can be activated by plastic-adherent autologous cells. However, neonatal and adult nylon wool-adherent cells do not consistently activate autoreactive T cells.

Heterogeneity of human T-lymphocyte clones generated from autologous mixed-lymphocyte cultures

To assess the heterogeneity of T cells activated during the autologous mixed-lymphocyte reaction (AMLR), a cloning procedure based on the soft agar colony assay was developed. Supernatants of allogeneic MLR cultures were used as a source of interleukin 2 (IL-2) to generate two types of colonies: upper and lower colonies. Both types of colonies were expanded in long-term cultures using supernatants of phytohemagglutinin (PHA)-activated lymphocyte cultures. Cloned cells underwent secondary proliferation when stimulated by autologous monocytes, although certain clones also responded to autologous B cells. Most autoactivated clones expressed the serological determinants of HLA-DR, MB, and MT and were OKT3+, OKT4+, OKT8-. They did not induce cytolysis of autologous monocytes, B lymphoblasts, or PHA blasts nor did they express natural killer-like activity toward K562 cells. Several autoactivated clones (irradiated with 500 R) expressed helper activity, shown by an enhancing effect on AMLR proliferation. Furthermore, many irradiated clones were capable of inducing proliferation of autologous T cells in the absence of accessory cells. These observations suggest that autoactivated clones generated from soft agar colonies may interact with autologous T lymphocytes.