T Cell Zones of Lymphoid Organs Constitutively Express Th1 Cytokine mRNA: Specific Changes during the Early Phase of an Immune Response

Abstract

The cytokine milieu of the T cell zones in lymphoid organs is involved in the activation of naive T cells. Quantitative data regarding the local expression of cytokines are lacking. Therefore, the expression of Th1 (IL-2, IL-12p40, IFN-γ), Th2 (IL-4, IL-10), as well as TGFβ1 and IL-15 mRNA was studied after laser microdissection in the steady state and during an immune response in rats. Our results show that Th1 cytokines are preferentially found in lymphoid tissues and in the T cell zones, whereas Th2 cytokines are expressed throughout the organs and especially in the B cell zones. After injection of sheep RBC, IL-2 and IFN-γ mRNA are significantly increased in the T cell zone only, a change not seen by analyzing the whole spleen. Studying the spatial and temporal expression of genes will reveal new insights into the regulation of immune responses.

Nonoverlapping Expression of IL10, IL12p40, and IFNγ mRNA in the Marginal Zone and T Cell Zone of the Spleen after Antigenic Stimulation

“…Cryosections, 10 m in thickness, were mounted on membrane-covered slides (Palm Membrane Slides, PEN membrane, 1 mm; PALM Microlaser Technologies) for laser microdissection or on usual glass slides for histology and stored at Ϫ80°C. The staining with toluidine blue was performed as described (16). To visualize the T and B cell compartments in the spleens, the sections were stained immunohistologically with either mAbs R73 (␣␤ T cells) or mAbs G35-2238 (B cells, both BD Biosciences).…”

“…To visualize the T and B cell compartments in the spleens, the sections were stained immunohistologically with either mAbs R73 (␣␤ T cells) or mAbs G35-2238 (B cells, both BD Biosciences). To identify proliferating cells, the tissue sections were stained for the rat homolog of the Ki-67 Ag (MIB-5; DakoCytomation) as described (16). The TUNEL assay was used to detect apoptotic cells using an anti-mousedigoxigenin-peroxidase Ab, digoxigenin-11-UTP and the TdT (Roche Diagnostics) as described (17).…”

“…After treatment with DNase I (SigmaAldrich) for 15 min, the RNA was heated 70°C for 10 min and immediately cooled on ice. cDNA synthesis was performed as described (16).…”

“…The optimal primer concentrations used were 900 nM each for the forward and reverse primers and 200 nM for the TaqMan probe (IBA). The primer sequences, the exon localizations, amplicon sizes, and gene accession numbers are shown in Table I or were published earlier (16). The same batch of cDNA (20 l) was used to determine the cycles of threshold (ct), and the amounts of the cytokine cDNA copies were normalized to the housekeeping gene MLN51 as described (see Refs.…”

Differential expression of SMAD3 transcripts is not regulated by cis-acting genetic elements but has a gender specificity

“…[1][2][3][4][5][6] Under steady-state conditions, TGF-b is the cytokine expressed at highest levels in lymphoid and nonlymphoid organs where constitutive TGF-b signaling is required to maintain self-tolerance. [7][8][9] Ablation of TGF-b receptor II causes aggressive earlyonset, multiorgan, autoimmune-associated lesions with 100% mortality. 10,11 TGF-b blocks T-cell proliferation, inhibits differentiation of Th1 cells and CTLs, and promotes expansion as well as maintenance of CD4 regulatory T cells.…”