<sup dir="En3t9"></sup> "VSports手机版" Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The . gov means it’s official. Federal government websites often end in . gov or . mil VSports app下载. Before sharing sensitive information, make sure you’re on a federal government site. .

Https

The site is secure V体育官网. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. .

. 2007 Sep;27(3):493-504.
doi: 10.1016/j.immuni.2007.07.019.

"VSports最新版本" Nonself-antigens are the cognate specificities of Foxp3+ regulatory T cells

Rafal Pacholczyk  1 , Joanna Kern, Nagendra Singh, Makio Iwashima, Piotr Kraj, Leszek Ignatowicz
Affiliations

Nonself-antigens are the cognate specificities of Foxp3+ regulatory T cells

Rafal Pacholczyk et al. Immunity. 2007 Sep.

Abstract

The majority of regulatory Foxp3+CD4+ T cells naturally arises in the thymus VSports手机版. It has been proposed that T cell receptors (TCRs) on these cells recognize self-MHC class II-peptide complexes with high or higher affinity and that their specificities mirror specificities of autoreactive T cells. Here, we analyzed hundreds of TCRs derived from regulatory or nonregulatory T cells and found little evidence that the former population preferably recognizes self-antigens as agonists. Instead, these cells recognized foreign MHC-peptide complexes as often as nonregulatory T cells. Our results show that high-affinity, autoreactive TCRs are rare on all CD4+ T cells and suggest that selecting self-peptide is different from the peptide that activates the same regulatory T cells in the periphery. .

PubMed Disclaimer

"V体育ios版" Figures

Figure 1
Figure 1. Overlap of TCRs between naïve T and Treg populations
(A) The maximum frequency (ϕmax) of a CDR3α transcript whose sequence did not appear after accumulation of n sequences, with 95% confidence, was computed based on equation 1. Upper and lower limits of the 95% confidence interval for a clone with ϕmax frequency were calculated based on equation 2. Both equations are shown in Experimental Procedures. (B) Observed frequency of most dominant naive and Treg clones found in TCRmini or TCRminiEp mice. Percentage of overlap was calculated by dividing shared clones by a total number of dominant clones of a given population. Shown amino acid sequences represent fragments of CDR3 regions including amino acids beginning with the third amino acid after the invariant C residue in all TCRAV genes (Y-L/F-C-A-X-1) and spanning the amino acid immediately preceding the TCRAJ motif (2-F/W-G-X-F-G-T). Clones shared between populations are highlighted by grey box. Table below the graphs shows at what frequency dominant clones of one population were found at least once in second population (for both type of mice).
Figure 2
Figure 2. Relative extrathymic proliferation of dominant T cell clones from TCRmini mice
The proportions of peripheral proliferation of most frequent T cell clones (shown in Fig. 1) was calculated by dividing the peripheral frequency of a given clone by its thymic frequency. CDR3α sequences are aligned from the most expanded to the least proliferated clones. Clones shared between populations are highlighted by grey box.
Figure 3
Figure 3. TCRs on T cell hybridomas derived from expanded Treg blasts accurately represent TCRs found on Treg cells
(A) Expression of Foxp3 by Treg cells isolated from lymph nodes of TCRminiEp mice and 7−10 days after in vitro culture of these cells. Cells were surface-stained with antibodies against CD4, CD8, and CD25 molecules, followed by intracellular staining with Foxp3 antibody. (B) 2D-F-SSCP revealed extensive (82%) overlap of CDR3 regions of TCRα chains from freshly sorted and expanded Treg cells. cDNA was synthesized from isolated RNA of both types of cells. Run-off PCR was done with primer specific for TCRVα2, coupled with Cy3 (fluorescent dye). First, fluorescent PCR products were run in the first dimension using capillary electrophoresis in denaturing PAGE. The second dimension was run in a non-denaturing SSCP slab gel. Resulting 2D gels show diversity, distribution, and frequency of dominant CDR3α regions from indicated populations. The intensity of individual dots corresponds to the real frequency of a particular rearrangement in the original sample. Spots migrating with different speed on the second dimension SSCP gel represent different VαJα rearrangements. (C) TCR CDR3α sequences retrieved from Treg-derived hybridomas (Hyb) were compared with the most abundant CDR3α sequences found in Treg cells in TCRminiEp mice (Treg). (D) Hybridomas derived from naïve T or Treg cells of TCRminiEp mice, were co-cultured with splenocytes from C57BL/6 mice. Responding hybridomas were compared for the ability to produce IL-2. Production of IL-2 secreted by activated hybridomas was measured by HT-2 proliferation using MTT assay. Results are shown as arithmetical mean ± SD.
Figure 4
Figure 4. Treg-derived hybridomas from TCRminiEp mice frequently recognize foreign but not self MHC-peptide complexes
(A) Hybridomas were co-cultured overnight with splenocytes or bone marrow derived dendritic cells (BMDC's) from C57BL/6 (Ab), Ii-, or AbEpIi− (AEp) mice. Production of IL-2 secreted by activated hybridomas was measured by HT-2/MTT assay. In each experiment, all hybridomas were separately tested for response to anti-CD3 stimulation in the presence of autologous APCs, to determine the percentages of hybridomas able to respond to activation. The box beneath the bar graph shows number of hybridomas (n) used in each test. (B) Twelve dominant Treg TCRs identified by single-cell RT-PCR were compared with TCRs found on T cell hybridomas. Based on reactivities of these hybridomas, antigenic specificity was assigned to the particular CDR3α sequence.
Figure 5
Figure 5. Hybridomas derived from naïve T and Treg cells respond with the same frequency to stimulation with allogeneic APCs but not autologous APCs
(A) Hybridomas derived from naive and Treg cells from TCRmini or C57BL/6 mice, were stimulated by splenocytes or BMDC's derived from autologous C57BL/6 (Ab), allogenic CBA Ca/J (AkEk) or bm12 (Abm12) mice. All hybridomas were tested for response to anti-CD3 stimulation in the presence of autologous APCs. Production of IL-2 was measured by HT-2 proliferation using MTT assay. To determine percentages of hybridomas responding to APCs, only hybridomas that responded to the anti-CD3 stimulation were considered. The box beneath the bar graph shows number of hybridomas (n) used in each test. (B) The CDR3α regions of autoreactive TCRs identified in TCRmini repertoire. TCRs on TCRminiEp Treg-derived hybridomas reactive to Ab were compared against database containing CDR3α sequences retrieved by single-cell RT-PCR from T cells in TCRmini mice. Of the six CDR3 sequences identified so far, five were expressed on Foxp3+ Treg cells and two were found on Foxp3− T cells.
Figure 6
Figure 6. The CD4+CD45RBhi T cells isolated from TCRmini but not TCRminiEp mice cause wasting disease upon adoptive transfer into autologous lymphopenic hosts
T cells isolated from lymph nodes were FACS sorted using CD4 and CD45RB antibodies. 4×105 of CD4+CD45RBhi T cells (purity above 99%) from TCRmini or TCRminiEp mice were injected intraperitoneally to AbWT TCRα−/− or AbEp TCRα−/− lymphopenic hosts, respectively. The ratio of the starting weight of recipient mice is shown. Data are representative of two independent experiments with 2 or 3 mice per group. Weight loss was associated with colon inflammation, prolapse, bowel wall thickening, and typical hunched-back appearance (data not shown).
See this image and copyright information in PMC

Comment in

References

    1. Apostolou I, Sarukhan A, Klein L, von Boehmer H. Origin of regulatory T cells with known specificity for antigen. Nat. Immunol. 2002;3:756–763. - "VSports" PubMed
    1. Aschenbrenner K, D'Cruz LM, Vollmann EH, Hinterberger M, Emmerich J, Swee LK, Rolink A, Klein L. Selection of Foxp3(+) regulatory T cells specific for self antigen expressed and presented by Aire(+) medullary thymic epithelial cells. Nat. Immunol. 2007;8:351–358. - PubMed
    1. Baron V, Bouneaud C, Cumano A, Lim A, Arstila TP, Kourilsky P, Ferradini L, Pannetier C. The repertoires of circulating human CD8(+) central and effector memory T cell subsets are largely distinct. Immunity. 2003;18:193–204. - PubMed
    1. Belkaid Y, Piccirillo CA, Mendez S, Shevach EM, Sacks DL. CD4+CD25+ regulatory T cells control Leishmania major persistence and immunity. Nature. 2002;420:502–507. - PubMed
    1. Bill J, Ronchese F, Germain RN, Palmer E. The contribution of mutant amino acids to alloantigenicity. J Exp. Med. 1989;170:739–750. - PMC - PubMed

"VSports在线直播" Publication types

MeSH terms

LinkOut - more resources (V体育平台登录)