An appropriate in vitro culture condition for the induction of human TCR gamma delta + cells by heat-killed bacteria

Localization of T cell receptor (TCR)-gamma delta + T cells into human colorectal cancer: flow cytometric analysis of TCR-gamma delta expression in tumour-infiltrating lymphocytes

We analysed TCR-gamma delta expression in tumour-infiltrating lymphocytes (TIL) obtained from 13 patients with colorectal cancer and simultaneously isolated the T lymphocytes from normal intestinal tissue (IL) to compare the frequencies of TCR-gamma delta expression in TIL, IL, and peripheral blood lymphocytes (PBL) in the same patient. Flow cytometric analysis showed that the frequency of TCR-gamma delta expression in TIL (2.75 +/- 1.84%) was significantly lower than that in IL (15.28 +/- 9.45%, P < 0.01). However, a larger quantity of TIL was separated than IL per unit weight of specimen, so the total number of gamma delta T cells obtained per unit weight was not different between tumour tissue and normal intestine. In addition, phenotypic analysis revealed that about half of the TCR-gamma delta + TIL were CD8+ (CD4+, 3.0 +/- 3.1%; CD8+, 54.7 +/- 19.9%, mean +/- s.d. of five patients), and a very similar result was obtained in TCR-gamma delta + IL (CD4+, 2.7 +/- 2.4%; CD8+, 53.1 +/- 17.4%). In contrast, most TCR-gamma delta + PBL were double-negative (CD4+, 3.2 +/- 3.0%; CD8+, 20.6 +/- 7.4%). These results indicated that TCR-gamma delta + CD8+ T cells selectively and consistently localized in colorectal tumour tissue, similarly to normal intestinal epithelium.

An in vitro model for the expansion of V gamma 9 delta 2 T lymphocytes during development

The gamma/delta T lymphocytes represent a minority of T lymphocytes in human peripheral blood. Although there have been reports of reactivity against (myco-) bacterial antigens and heat shock proteins, their function and antigen specificity remain ill defined. The biological role of gamma/delta T cells has been related to functions within the 'first line of defense'. Similar to gamma/delta T lymphocytes in the T-cell compartment, CD5 positive B cells represent a small subset of B lymphocytes, which is thought to be involved in the maintenance of natural immunity and autoimmunity. We provide evidence for the cooperation of gamma/delta T cells and CD5 positive B cells in the proliferative response of gamma/delta T cells to bacterial antigens. Our data indicate a strong proliferation of V gamma 9 delta 2 T cells in response to gram-negative bacteria, which is dependent upon the presence of CD5 positive B-CLL or activated normal B lymphocytes. The selective stimulation of the V gamma 9 delta 2 subpopulation by gram-negative bacteria is also confirmed by analysis of different gamma/delta T-cell clones. The interaction of gamma/delta T cells with activated B cells and gram-negative bacteria may prove to be a useful model similar to the expansion of the V gamma 9 delta 2 subpopulation during development. In addition, our in vitro system should provide new insights in the interaction of CLL B cells with the immune system and the antigens recognized by gamma/delta T cells.