Quantification of antigen‐reactive cells among human T lymphocytes

Abstract

The number of antigen-reactive cells among human peripheral blood T lymphocytes was estimated by a limiting dilution analysis. Antigen-induced lymphocyte activation was measured by means of incorporation of tritiated thymidine [3H]dThd. We have studied the frequency of memory T cells for the bacterial antigens tuberculin PPD and tetanus toxoid in immune donors, as well as the frequency of alloantigen-reactive T cells. In 11 different donors, the observed frequencies of the antigen-reactive T cell ranged between 1:300 and 1:16 000 for PPD; for tetanus toxoid values, between 1:750 and 1:11 500 were obtained in 5 different donors. The frequency of alloantigen-reactive T cells was found to be higher: between 1:200 and 1:600 (n = 10). For 3 donors, the estimated frequencies proved to be reproducible over a period of several months. Finally, a correlation could be demonstrated between the frequency of PPD-reactive T cells and the [3H]dThd incorporation of 4 X 10(4) PPD-stimulated lymphocytes.

Immunological significance of Mycobacterium leprae cell walls.

“…Reactivity to CWC correlated with the cellmediated reactivity of patients-i.e., positive in patients with tuberculoid leprosy, but not in patients with lepromatous leprosy. Cell wall antigens represent the major proportion of the T-cell repertoire committed to M. leprae in sensitized individuals; 1/6000 peripheral T cells and 1/60 CD4 + cells obtained from tuberculoid lesions can proliferate to intact organisms, consistent with previous studies (28,29), or cell walls (ref. 14 and Fig.…”

“…Although this approach has been useful in murine systems (15, and has been used in man, [28][29][30] it has had only limited application in humans because of a larger number of cells proliferating to growth factors independently of antigen recognition. We recently developed a limiting-dilution assay to estimate the frequency of antigen-reactive T-cell precursors that virtually eliminates the background of antigenindependent proliferation, thus rendering the assay more sensitive and accurate (12).…”

Response of Human Newborn Lymphocytes to Alloantigen: Lack of Evidence for Suppression Induction

“…Although there is some disagreement in the literature as to whether human newborn's lymphocytes respond better (4) or less well (3) than adult cells in MLC, our present results suggest that the two populations have very similar precursor frequencies of cells which proliferate in MLC. Our own estimate of 1:150 responders in healthy adults is close to the 1 :200-1 :600 estimated by van Oers et al (19) and to the 1:240-1:468 estimated by Singal (24). Accurate estimation of responder cell frequencies in man is made difficult by uncertainty as to the number of antigenic differences between the stimulator and responder.…”

“…Wells were pulsed for 6 h on the 9th d of culture [this was the optimal duration of culture found by van Oers et ul. (19) and in our own experience] with 0.25 pCi tritiated thymidine (TRA 6 1, 5 Ci/mmol, Radiochemical Centre, Amersham) and then harvested onto glass fiber discs. Background counts were determined from unstimulated wells containing responder cells only and their log mean + 3 SD calculated.…”

The nature and kinetics of a delayed immune response to purified protein derivative of tuberculin in the skin of lepromatous leprosy patients.

“…From studies in small animals, few of the emigrated cells are specifically sensitized to the evoking antigen (24) . One suspects, therefore, that a minor fraction of cells initially responds to antigen.…”