T-lymphocyte colonies in malignant disease

Abnormal in vitro proliferation and differentiation of T cell colony-forming cells in patients with tropical spastic paraparesis/human T lymphocyte virus type I (HTLV-I)-associated myeloencephalopathy and healthy HTLV-I carriers

T cell colonies were generated from the peripheral blood mononuclear cells (PBMC) of 10 patients with tropical spastic paraparesis/human T lymphocyte virus type I (HTLV-I)-associated myeloencephalopathy (TSP/HAM), two healthy HTLV-I carriers, and 17 healthy HTLV-I-seronegative subjects. PBMC were cultured in methylcellulose in the absence of added growth factors (spontaneous T cell colonies), or in the presence of phorbol myristate acetate and interleukin 2 (induced T cell colonies). PBMC T cell colony-forming cells (T-CFC) from all TSP/HAM patients and HTLV-I carriers were able to grow in the absence of added growth factors and/or mitogenic stimulation. Pooled spontaneous and induced colonies were composed of cells bearing CD3+, CD4+, CD8+, and CD1+ antigens. Colonies from normal HTLV-I-seronegative subjects displayed mature cells bearing the CD3+, CD4+, CD8+, and CD1- surface phenotype. In addition, spontaneous and induced T cell colonies expressed HTLV-I antigens in 18-38% of the cells from TSP/HAM patients and HTLV-I carriers. These results demonstrate that HTLV-I infection is associated with an abnormal proliferation and differentiation of T cell progenitors in vitro and that the T-CFC from HTLV-I-seropositive individuals are infected, suggesting that T-CFC abnormalities may play a predominant role in the pathophysiology of HTLV-I.

Peripheral blood adherent cells from AIDS patients inhibit normal T-colony growth through decreased expression of interleukin 2-receptors and production of interleukin 2

Adherent cells display an important accessory role on normal T-cell colony formation. Since the in-vitro proliferation of T colony-forming cells (T-CFC) from AIDS patients is extremely impaired we studied the effect of patients' adherent cells on T-CFC growth. Patients' peripheral blood mononuclear cells (PBMC) were fractionated on the basis of rosette formation with sheep red blood cells and complement-mediated cytotoxicity with OKT3 monoclonal antibody (E-T3-). Both mature (E+) T cells and E-OKT3- cell fractions failed to generate T-cell colonies although colony growth could be obtained from unfractionated PBMC. In five out of 12 AIDS patients, adherent cell-depletion of PBMC enhanced the plating efficiency. Moreover, patients' but not normal adherent cells could inhibit normal T-cell colony growth in a dose-dependent manner. Media conditioned by patients' unstimulated adherent cells (LCM-A+p) also inhibit normal T-cell colony formation. In addition, LCM-A+p were capable of inhibiting interleukin 2-receptor (IL2-R) expression and interleukin 2 (IL2) production by normal mitogen-stimulated T cells. These LCM-A+p did not contain detectable reverse transcriptase activity nor could they infect the CEM T-cell line which is permissive to human immunodeficiency virus (HIV). Conversely, this adherent cell-derived inhibitory activity could be abrogated by heating or treatment with proteolytic enzymes. These findings indicate that the low T-cell colony formation in some AIDS patients could be due to adherent cell-derived inhibitory activity(ies).

Unaltered immunocompetence in patients with non-disseminated breast cancer at the time of diagnosis

Immunologic parameters were examined preoperatively in 104 patients with breast cancer, staged according to the TNM classification and in 95 age-matched healthy women. The immunologic evaluation in the peripheral blood included lymphocyte and monocyte counts, determination of E-rosette-forming T-lymphocytes (SER+) and B-lymphocytes (MER+), T-lymphocyte subsets defined with monoclonal antibodies (Leu-1, Leu-2a, Leu-3a) and with lectin fractionation (soybean agglutinin), lymphocyte transformation test with phytohemagglutinin (PHA) and concanavalin A (ConA), and colony formation of T-lymphocytes in agar (T-lymphocyte colony-forming cells, [TL-CFC]). Two age groups (Group A: 30-50 years; Group B: 51-70 years) and the different tumor stages (Stage I-IV) were analyzed. Patients and controls did not differ in the absolute numbers of lymphocytes, T- and B-cells. In patients of Group B, the absolute number of monocytes was increased slightly in Stage II and III and significantly in Stage IV (P less than 0.05). Similarly, the lymphocyte response to PHA was significantly reduced in Stage IV Group B only (P less than 0.05). ConA-induced lymphocyte proliferation and TL-CFC capacity were not different in patients and controls. In the small number of patients and age-matched controls in whom T-lymphocyte subsets were determined, the absolute numbers of T-cells with helper or suppressor phenotype as defined with Leu-3a, Leu-2a, or lectin fractionation with soybean agglutinin were similar. This study demonstrates that in patients with early breast cancer (Stage I-III), immunocompetence as defined by either functional in vitro studies or surface marker analysis is not significantly altered at the time of diagnosis. In contrast, patients with advanced disease (Stage IV) show a significant increase in the absolute number of monocytes and a depressed PHA responsiveness of mononuclear cells.

Functional characterization of T lymphocytes grown in semisolid agar

T lymphocyte colony forming cells (TL-CFC) grown in agar in the presence of PHA were assayed for their capacity to induce or suppress polyclonal PWM dependent B lymphocyte differentiation into plasma cells. This was measured by identifying cells containing intracytoplasmatic immunoglobulins by direct immunofluorescence. To validate the helper and suppressor system used in this paper, the inductive capacity of unfractionated T lymphocytes and their subpopulations bearing Fc-receptors for IgM (TM) and for IgG (TG) was measured. The unfractionated T cells and the TM fraction showed helper activity, whereas the TG cells expressed suppressor activity. The TL-CFC grown in agar in the presence of PHA manifested helper activity at low cell concentration. However, increasing the TL-CFC concentration finally caused suppression of B cell differentiation. The suppressor effect could be abolished by prior irradiation of the TL-CFC before seeding them in agar. These results indicate that T cells grown in agar have the functional capacity of T helper and T suppressor cells to induce and suppress polyclonal PWM dependent B lymphocyte differentiation into plasma cells.

Impaired T-lymphocyte colony formation by cord blood mononuclear cells

When compared to adult mononuclear cells, cord blood mononuclear cells demonstrated significantly decreased T-lymphocyte colony formation (1351 +/- 643 vs 592 +/- 862, P less than 0.01). This diminished colony-forming activity did not appear to be associated with impaired responsiveness to the stimulant phytohemagglutinin or with excessive suppressor-cell activity. Irradiation reduced the colony-forming capacity of cord blood mononuclear cells more than it did that of adult mononuclear cells. Depletion of adherent cells reduced cord blood mononuclear-cell colony-forming capacity by 40%, while similar treatment reduced adult colony formation by 10%. Lymphocyte proliferation in liquid culture of cord and adult cells was minimally affected by these procedures. The colony-forming capacity of cord blood could be enhanced by the addition of irradiated adult cells (284 +/- 72 vs 752 +/- 78, P less than 0.01). This enhancement was demonstrated to be due to a soluble factor produced by a population of irradiated adult cells depleted of the OKT8+ subpopulation of lymphocytes. These results indicate that the progenitor cells of T-lymphocyte colonies in cord blood have distinct biologic characteristics when compared to colony progenitors present in adult blood. This assay may prove to be useful in our efforts to understand the differentiation of T-cell function in man.