Activation and proliferation of normal resting human T lymphocytes in serum-free culture: role of IL-4 and IL-6.
Purified human T lymphocytes, completely depleted of accessory cells [i.e. monocytes, large granular lymphocytes (LGL) and B lymphocytes], have been grown in serum-free culture in presence of a mitogenic lectin (phytohaemagglutinin, PHA) and different recombinant cytokines. Only IL-2 and IL-4 induced a marked stimulation of [3H] thymidine ([3H]TdR) uptake, cell proliferation and expression of activation markers [transferrin receptor (TrfR), IL-2R]. The other cytokines (IL-1 alpha, IL-1 beta, IFN-gamma, GM-CSF, TNF-alpha) had no significant effect, except for a moderate, but significant, stimulation of [3H]TdR uptake induced by IL-3. Simultaneous addition of IL-4 and anti-IL-2 neutralizing monoclonal antibodies (mAb) did not modify the effects induced by IL-4 alone. Furthermore, IL-2 was not detected in the supernatant of T cells grown in the presence of PHA and IL-4. Thus, our results indicate that IL-4 acts on T lymphocytes independently of IL-2. We also observed that IL-6 moderately activates DNA synthesis in PHA-stimulated T lymphocytes, but markedly potentiates the proliferative effect of suboptimal amounts of IL-2. In conclusion, the present study suggests that B-cell growth factors, in addition to IL-2, control the proliferation of normal circulating T lymphocytes.
Habetswallner
D
D
Istituto Superiore di Sanità, University La Sapienza, Rome, Italy.
Pelosi
E
E
Bulgarini
D
D
Camagna
A
A
Samoggia
P
P
Montesoro
E
E
Giannella
G
G
Lazzaro
D
D
Isacchi
G
G
Testa
U
U
D002478:Cells, Cultured; D003470:Culture Media; D006801:Humans; D015847:Interleukin-4; D015850:Interleukin-6; D007378:Interleukins / Q000276:immunology*; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000276:immunology*
D003470:Culture Media; D015850:Interleukin-6; D007378:Interleukins; D015847:Interleukin-4