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A T cell receptor-specific blockade of positive selection.

Baldwin KK, Reay PA, Wu L, Farr A, Davis MM - J. Exp. Med. (1999)

Bottom Line: One of these antibodies (G35) specifically blocks the positive selection of transgenic thymocytes expressing a T cell receptor that is reactive to this peptide- MHC complex.Furthermore, G35 does not block the differentiation of transgenic T cells bearing receptors for a different I-Ek-peptide complex.This antibody recognizes a subset of endogenous I-Ek-peptide complexes found on a significant fraction of thymic antigen-presenting cells, including cortical and medullary epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, and the Department of Microbiology and Immunology, Stanford University, Stanford, California 94305, USA.

ABSTRACT
To investigate the influence of endogenous peptides on the developmental processes that occur during thymocyte selection, we have used monoclonal antibodies that preferentially recognize the major histocompatibility complex (MHC) molecule I-Ek when it is bound to the moth cytochrome c peptide (88-103). One of these antibodies (G35) specifically blocks the positive selection of transgenic thymocytes expressing a T cell receptor that is reactive to this peptide- MHC complex. Furthermore, G35 does not block the differentiation of transgenic T cells bearing receptors for a different I-Ek-peptide complex. This antibody recognizes a subset of endogenous I-Ek-peptide complexes found on a significant fraction of thymic antigen-presenting cells, including cortical and medullary epithelial cells. The sensitivity of G35 to minor alterations in peptide sequence suggests that the thymic peptide-MHC complexes that mediate the positive selection of a particular class II MHC-restricted thymocyte are structurally related to the complexes that can activate it in the periphery.

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Related in: MedlinePlus

Effect of G35 on the  selection of 5C.C7 transgenic  thymocytes. (A) Distribution of  5C.C7-α chain and KJ25 (Vβ3)  determinants on thymocytes derived from transgenic (left) or  nontransgenic (right) pups. (B)  Distribution of CD4 and CD8  on separate populations of cells  derived from transgenic or nontransgenic pups exposed in utero  to G35, PBS, or D4 as indicated.  Numbers refer to the percentage  of total live transgenic or nontransgenic thymocytes that fall  within each boxed population.
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Figure 1: Effect of G35 on the selection of 5C.C7 transgenic thymocytes. (A) Distribution of 5C.C7-α chain and KJ25 (Vβ3) determinants on thymocytes derived from transgenic (left) or nontransgenic (right) pups. (B) Distribution of CD4 and CD8 on separate populations of cells derived from transgenic or nontransgenic pups exposed in utero to G35, PBS, or D4 as indicated. Numbers refer to the percentage of total live transgenic or nontransgenic thymocytes that fall within each boxed population.

Mentions: To address this question, we injected mice with G35, D4, and PBS and analyzed the effects of these antibodies on the development of I-Ek–MCC-specific thymocytes that express the TCR transgene 5C.C7. To provide nontransgenic internal controls, 5C.C7 TCR transgenic males were crossed to nontransgenic females to generate litters in which 50% of the progeny were transgenic. The pregnant females were injected intraperitoneally each day (from day 15 of gestation until birth) with either 1 mg of antibody or PBS. On day 21, thymuses were harvested from the neonates and four-color flow cytometry was used to determine the transgenic status and CD4 versus CD8 profile of each mouse (Fig. 1 A). In transgenic pups, the percentage of identified transgene-positive cells was ∼80% in all treatment groups; the rest of the cells were presumably immature cells that lacked detectable TCR expression or thymic APCs.


A T cell receptor-specific blockade of positive selection.

Baldwin KK, Reay PA, Wu L, Farr A, Davis MM - J. Exp. Med. (1999)

Effect of G35 on the  selection of 5C.C7 transgenic  thymocytes. (A) Distribution of  5C.C7-α chain and KJ25 (Vβ3)  determinants on thymocytes derived from transgenic (left) or  nontransgenic (right) pups. (B)  Distribution of CD4 and CD8  on separate populations of cells  derived from transgenic or nontransgenic pups exposed in utero  to G35, PBS, or D4 as indicated.  Numbers refer to the percentage  of total live transgenic or nontransgenic thymocytes that fall  within each boxed population.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1887687&req=5

Figure 1: Effect of G35 on the selection of 5C.C7 transgenic thymocytes. (A) Distribution of 5C.C7-α chain and KJ25 (Vβ3) determinants on thymocytes derived from transgenic (left) or nontransgenic (right) pups. (B) Distribution of CD4 and CD8 on separate populations of cells derived from transgenic or nontransgenic pups exposed in utero to G35, PBS, or D4 as indicated. Numbers refer to the percentage of total live transgenic or nontransgenic thymocytes that fall within each boxed population.
Mentions: To address this question, we injected mice with G35, D4, and PBS and analyzed the effects of these antibodies on the development of I-Ek–MCC-specific thymocytes that express the TCR transgene 5C.C7. To provide nontransgenic internal controls, 5C.C7 TCR transgenic males were crossed to nontransgenic females to generate litters in which 50% of the progeny were transgenic. The pregnant females were injected intraperitoneally each day (from day 15 of gestation until birth) with either 1 mg of antibody or PBS. On day 21, thymuses were harvested from the neonates and four-color flow cytometry was used to determine the transgenic status and CD4 versus CD8 profile of each mouse (Fig. 1 A). In transgenic pups, the percentage of identified transgene-positive cells was ∼80% in all treatment groups; the rest of the cells were presumably immature cells that lacked detectable TCR expression or thymic APCs.

Bottom Line: One of these antibodies (G35) specifically blocks the positive selection of transgenic thymocytes expressing a T cell receptor that is reactive to this peptide- MHC complex.Furthermore, G35 does not block the differentiation of transgenic T cells bearing receptors for a different I-Ek-peptide complex.This antibody recognizes a subset of endogenous I-Ek-peptide complexes found on a significant fraction of thymic antigen-presenting cells, including cortical and medullary epithelial cells.

View Article: PubMed Central - PubMed

Affiliation: Howard Hughes Medical Institute, and the Department of Microbiology and Immunology, Stanford University, Stanford, California 94305, USA.

ABSTRACT
To investigate the influence of endogenous peptides on the developmental processes that occur during thymocyte selection, we have used monoclonal antibodies that preferentially recognize the major histocompatibility complex (MHC) molecule I-Ek when it is bound to the moth cytochrome c peptide (88-103). One of these antibodies (G35) specifically blocks the positive selection of transgenic thymocytes expressing a T cell receptor that is reactive to this peptide- MHC complex. Furthermore, G35 does not block the differentiation of transgenic T cells bearing receptors for a different I-Ek-peptide complex. This antibody recognizes a subset of endogenous I-Ek-peptide complexes found on a significant fraction of thymic antigen-presenting cells, including cortical and medullary epithelial cells. The sensitivity of G35 to minor alterations in peptide sequence suggests that the thymic peptide-MHC complexes that mediate the positive selection of a particular class II MHC-restricted thymocyte are structurally related to the complexes that can activate it in the periphery.

Show MeSH
Related in: MedlinePlus