Internal Medicine

Proc. Nati. Acad. Sci. USA Vol. 88, pp. 4538-4542, May 1991 Immunology ... Allergen-and bacterial antigen-specific T-cell clones established from atopic donors show a different profile of cytokine production ... PAOLA PARRONCHI*, DONATELLA MACCHIA*, MARIE-PIERRE ...

IL-17A is associated with different asthma phenotypes as virus-associated or steroid-resistant asthma. Invariant natural killer T (iNKT) cells play an important role in the pathogenesis of asthma. The aim of the study was to evaluate the activity of polyinosinic-polycytidylic acid [poly(I:C)] on IL-17A production by CD1d-activated iNKT cells. We analysed the in vitro effect of poly(I:C) on the release of IL-17A by spleen and lung CD1d-activated iNKT cells with α-galactosylceramide (α-GalCer). Its activity was also investigated in an α-GalCer-induced murine models, including lung inflammation. The inhibition of IL-17A by Toll-like receptor (TLR) 7 agonists in the same in vitro and in vivo models has been analysed. Poly(I:C) upregulated the in vitro IL-17A production by CD1d-activated NK1.1- CD4- iNKT subset, without modifying type 1 and type 2 cytokines. The two stimuli selectively upregulated IL-17A serum levels in vivo. Their intratracheal administration resulted in increased airway hyper-reactivity (AHR), neutrophilia in bronchoalveolar lavage and airway inflammation, which were inhibited by anti-IL-17A antibody. Poly(I:C) effects were attributable to IL1β and IL-23 release from dendritic cells, as showed by inhibition with neutralizing antibodies. TLR7 agonists inhibited the IL-17A production by poly(I:C) plus α-GalCer in the same models. Such effect was associated with the increased production by DC of IL-17A-inhibiting cytokines and the dampening of IL-1β and IL-23. Synthetic dsRNA selectively expand a CD1d-driven IL-17A-producing iNKT cell subset, thus explaining the worsening of airway inflammation by some viral infections. TLR3- and TLR7-triggering viral sequences can exert variable and opposite effects on adaptive immune response.

Phenotypic markers, localization, functional activities, and mechanisms of action in vitro of CD4 + CD25 + T cells, purified from postnatal human thymuses, were investigated. These cells showed poor or no proliferation in mixed lymphocyte culture (MLC), and suppressed in a dose-...

In addition to T helper type 1 (Th1) and Th2 cells, Th17 cells are a third arm of effector CD4(+) T cells. Human Th17 cells express RORC and CD161 and originate from RORC-expressing CD161(+) precursors, which migrate to lymphoid tissue and differentiate into mature Th17 cells in response to interleukin (IL)-1β and IL-23. Human Th17 cells are rare in inflammed tissues for two reasons: (1) Th17 cells do not produce IL-2 and, therefore, do not proliferate in response to TCR signaling, mainly because of RORC-dependent IL-4I1-mediated mechanisms that interfere with IL-2 gene activation; and (2) Th17 cell shift to a Th1 phenotype in the presence of IL-12; such Th17-derived Th1 cells are considered to be nonclassical Th1 cells and can be distinguished from classical Th1 cells. The possible role of Th17 cells in human tumors is still unclear and even controversial.

T-cell clones generated from both CD4+CD25+ and CD8+CD25+ human thymocytes were assessed for their ability to suppress the proliferative response to allogeneic stimulation of type 1 T-helper (Th1) or type 2 T-helper (Th2) clones derived from autologous CD4+CD25- thymocytes. Both CD4+ and CD8+ T-regulatory (Treg) cells completely suppressed the proliferation of Th1 clones but exhibited significantly lower suppressive activity on the proliferation of Th2 clones. The partial suppressive effect on Th2 cells was further reduced by the addition in culture of interleukin-4 (IL-4), whereas it was increased in the presence of an anti–IL-4 monoclonal antibody (mAb). The suppressive activity on Th2 clones was also completely inhibited by the addition of IL-7, IL-9, and IL-15 but not of IL-2, whereas the suppressive effect on Th1 clones was only reverted by the addition of IL-15. Of note, Th2 clones expressed significantly higher amounts of mRNA for IL-4 receptor (IL-4R) and IL-9R α chains than...

The administration of biological agents is potentially affected by IgE-mediated infusion reactions. The aim of the study was to evaluate the utility of skin testing in patients who have experienced infliximab (IFX)-related reactions. Thirty patients with previous immediate hypersensitivity reaction to IFX, 20 disease-matched non exposed subjects, 15 IFX-treated disease-matched tolerant patients and 15 IFX non-responder patients were enrolled. Non-isotype-specific and IgE anti-drug antibodies (ADAs) were measured by a double-capture ELISA kit and ImmunoCAP assay, respectively. Prick and intra-dermal tests were carried out with the commercial IFX preparation serially diluted. Skin testing, performed in 23 of 30 reactive patients, resulted positive in 7 of them (30.4%), whereas no positivity was found in other groups of patients. The majority of reactive patients displayed non-isotype-specific ADAs (23/30, 76.6%) and the presence of anti-IFX IgE antibodies was detected in 6 of them (26%). All 6 IgE-positive reactive patients showed skin testing positivity. One reactive ADAs-positive patient who resulted skin test positive, with no detectable serum IFX-specific IgE ADAs, was also found. Skin testing positivity was associated with severe and early reactions (within the 3rd dose). No unexpected adverse reactions to skin testing were recorded. This study shows that about 30% of reactive patients display skin testing positivity. They usually develop severe reactions, mainly during the first administrations of IFX. The specificity and the safety of skin testing procedure for this biological agent are also confirmed.

Polarized human type 1 and type 2 T helper cells not only produce different sets of cytokines, but they also preferentially express certain activation markers, such as lymphocyte activation gene-3 (LAG-3) and CD30, respectively. In this study we have examined the LAG-3 and CD30 expression in relation to the lineage commitment of human naive CD4+ T cells, as assessed at the single-cell level of committed T cells. Purified CD45RA+ umbilical cord blood T lymphocytes were activated with phytohemagglutinin and interleukin (IL)-2 in the absence or presence of interleukin IL-4 or IL-12 and assessed for CD30 and LAG-3 expression, as well as for intracellular cytokine synthesis. Significant numbers of CD30+ cells were only found in CD4+ and CD8+ T lymphocytes of cultures primed with IL-4, which developed into cells able to produce IL-4 and IL-13 in addition to interferon (IFN)-gamma. By contrast, LAG-3 expression was strongly up-regulated in CD4+ and CD8+ T cells from cultures primed with IL-12, which developed into high numbers of IFN-gamma producers. The addition of a neutralizing anti-IFN-gamma antibody to IL-12-primed CD4+ T cell cultures virtually abolished the development of LAG-3-expressing CD4+ T cells. Taken together, these data suggest that CD30 expression is dependent on the presence of IL-4, whereas LAG-3 expression is dependent on the production of IFN-gamma during the lineage commitment of human naive T cells.

We have previously shown that human Th17 lymphocytes are characterized by the selective expression of IL-23 receptor (IL-23R), CCR6, CD161, and the transcription factor retinoic acid-related orphan receptor C (RORC), and originate from a CD161(+)CD4(+) naïve T-cell precursor in response to the combined activity of IL-1β and IL-23. We show here that not only CD4(+)TCRαβ(+), but also CD8(+)TCRαβ(+), CD4(-)CD8(-) TCRαβ(+), and CD4(-)CD8(-) TCRγδ(+) circulating lymphocytes that produce IL-17 express the distinctive marker CD161 on their surface. In addition, we demonstrate that CD161 expression identifies CD8(+) and CD4(-)CD8(-) umbilical cord blood T cells that already express RORC and IL-23R mRNA and that can be induced to differentiate into IL-17-producing cells in the presence of IL-1β and IL-23. Finally, we provide evidence that umbilical cord blood naïve CD4(+)CD161(-) T cells, upon lentivirus-mediated transduction with RORC2 can acquire the ability to express IL-23R, IL-1RI, and CD161, as well as to produce IL-17. Taken together, these data allow to conclude that T-cell subsets able to produce IL-17, as well as precursors of IL-17-producing T cells, exhibit surface expression of CD161, and that this feature is at least in part RORC2-dependent.