Default development of cloned human naive CD4 T cells into interleukin‐4‐ and interleukin‐5‐producing effector cells

Abstract

It was recently demonstrated that naive human and mouse CD4 T cells release low but sufficient levels of interleukin (IL)-4 at priming to support their development into IL-4 producers. To determine whether this IL-4 is produced by a minor subset of cells, freshly isolated human naive CD4 T cells were directly cloned by limiting dilution in the absence of exogenous IL-4. More than 95% of neonatal and 60% of adult naive T cells seeded in single-cell cultures could be expanded upon stimulation with anti-CD3 mAb immobilized on CD32-B7.1 L cell transfectants in the presence of IL-2. All 171 clones derived from four neonates and two adults produced IL-4 and IL-5 at generally high levels. Like the allergen-specific human Th2 clones described in the literature, these T cell clones produced little or no interferon-gamma upon stimulation via their T cell receptor/CD3 complex, whereas they released high levels of this cytokine when activated with phorbol 12-myristate 13-acetate+ionomycin. Cells cloned and expanded in the presence of anti-IL4 + anti-IL-4R mAb produced much lower levels of IL-4 and IL-5. It is concluded that almost every single naive human CD4 T cell primed and expanded in the absence of exogenous IL-4 releases sufficient autocrine IL-4 to support its clonal expansion into high IL-4/IL-5 producers.

Identification of Novel Genes Regulated by IL-12, IL-4, or TGF-β during the Early Polarization of CD4+ Lymphocytes

“…Briefly, the priming was performed in the presence of 100 ng/ml PHA (Murex Diagnostics, Chatillon, France) and irradiated CD32-B7 transfected fibroblasts (20). The feeder cells were added in the final density of 1 ϫ 10 6 cells/ml.…”

CD45 isoform expression is associated with different susceptibilities of human naive and effector CD4+ T cells to respond to IL‐4

“…Although IL-4-independent signaling pathways have been described [2], IL-4 is the most critical parameter for the development of Th2 cells in mice, as well as in humans [1,2]. Studies in mice and humans indicate that naive T cells might produce IL-4 at very low levels [12][13][14][15][16][17][18][19]; however, it is not well understood how these T cells can utilize IL-4 so efficiently.…”

“…Nonetheless, like in the murine system, IL-4 seems to be the major factor required for the development of Th2 cells [11,12]. Despite the fact that human naive T cells, like their murine counterparts [13], produce either no or very low levels of IL-4 [12,[14][15][16][17][18][19], they sufficiently utilize these minute amounts of IL-4, suggesting that their IL-4R signaling machinery is highly efficient. On the other hand, murine T cells, once committed to the Th2 pathway, do produce high amounts of IL-4, but are resistant to respond to IL-4 to increase their IL-4 production [20][21][22].…”

Bordetella pertussisInfection in 2-Month-Old Infants Promotes Type 1 T Cell Responses

“…IFN-␥ secretion in response to PHA has been shown to be barely detectable in infants Ͻ2 mo old and to be still significantly lower in 2-to 12-mo-old infants than in older children (7,15). Based on these in vitro findings and on results obtained with cloned naive neonatal CD4 ϩ T cells (27), it has been concluded that newborns are unable to develop efficient Th1-mediated responses in vivo and are instead heavily biased toward Th2 responses. Information on the in vivo development of Ag-specific Th function in infants is limited and virtually nonexistent for very young infants (around 2 mo).…”