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Altered proliferative response by T lymphocytes of Ly-6A (Sca-1) mice.

Stanford WL, Haque S, Alexander R, Liu X, Latour AM, Snodgrass HR, Koller BH, Flood PM - J. Exp. Med. (1997)

Bottom Line: To better understand the function of Ly-6A, we used gene targeting to produce Ly-6A mice which are healthy and have normal numbers and percentages of hematopoietic lineages.However, T lymphocytes from Ly-6A-deficient animals proliferate at a significantly higher rate in response to antigens and mitogens than wild-type littermates.This enhanced proliferation is not due to alterations in kinetics of response, sensitivity to stimulant concentration, or cytokine production by the T cell population, and is manifest in both in vivo and in vitro T cell responses.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7455, USA.

ABSTRACT
Ly-6A is a murine antigen which is implicated in lymphocyte activation and may be involved in activation of hematopoietic stem cells. Antibody cross-linking studies and antisense experiments have suggested that Ly-6A is a lymphocyte coactivation molecule. To better understand the function of Ly-6A, we used gene targeting to produce Ly-6A mice which are healthy and have normal numbers and percentages of hematopoietic lineages. However, T lymphocytes from Ly-6A-deficient animals proliferate at a significantly higher rate in response to antigens and mitogens than wild-type littermates. In addition, Ly-6A mutant splenocytes generate more cytotoxic T lymphocytes compared to wild-type splenocytes when cocultured with alloantigen. This enhanced proliferation is not due to alterations in kinetics of response, sensitivity to stimulant concentration, or cytokine production by the T cell population, and is manifest in both in vivo and in vitro T cell responses. Moreover, T cells from Ly-6A-deficient animals exhibit a prolonged proliferative response to antigen stimulation, thereby suggesting that Ly-6A acts to downmodulate lymphocyte responses.

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Absence of cell surface Ly-6A expression in Ly-6A−/− mice.  Splenocytes were stained with the PE-conjugated anti–Ly-6A antibody  D7 (12). Stainings of wild-type, heterozygous, and homozygous mutant  splenocytes from littermates were determined. No expression of Ly-6A  on mutant lymphocytes was detected using two other anti–Ly-6A antibodies (data not shown). 16,000 gated events were collected with the  FACScan®. Negative control staining was determined with PE-conjugated anti–rat IgG.
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Figure 2: Absence of cell surface Ly-6A expression in Ly-6A−/− mice. Splenocytes were stained with the PE-conjugated anti–Ly-6A antibody D7 (12). Stainings of wild-type, heterozygous, and homozygous mutant splenocytes from littermates were determined. No expression of Ly-6A on mutant lymphocytes was detected using two other anti–Ly-6A antibodies (data not shown). 16,000 gated events were collected with the FACScan®. Negative control staining was determined with PE-conjugated anti–rat IgG.

Mentions: Analysis of Lymphoid and Myeloid Subpopulations. Flow cytometry was used to verify the absence of Ly-6A expression in homozygous mutant mice (Fig. 2). Approximately 60% of wild-type splenocytes express Ly-6A. Splenocytes from heterozygous animals show a slight decrease in Ly-6A expression intensity; however, splenocytes from homozygotes do not stain with any of three antibodies to Ly-6A (Fig. 2). In addition, phenotypic analysis was performed to determine if the absence of Ly-6A expression in homozygous mutant mice altered the differentiation of various cell populations. Although there are minor variations between littermates, as a population Ly-6A animals (as old as 8 mo) contain normal percentages of B220, TCR-α/β, TCR-γ/δ, CD3, CD4, CD8, Mac-1, and Ly-6G (Gr-1) positive cells in the bone marrow, lymph nodes, spleen, and thymus (data not shown). In addition to Ly-6G, antibodies to other members of the Ly-6 gene family were used to determine if the lack of phenotypic changes is due to compensation by other family members. Ly-6C, Sca-2 (TSA-1), and ThB do not appear to be overexpressed in any hematopoietic tissues (data not shown).


Altered proliferative response by T lymphocytes of Ly-6A (Sca-1) mice.

Stanford WL, Haque S, Alexander R, Liu X, Latour AM, Snodgrass HR, Koller BH, Flood PM - J. Exp. Med. (1997)

Absence of cell surface Ly-6A expression in Ly-6A−/− mice.  Splenocytes were stained with the PE-conjugated anti–Ly-6A antibody  D7 (12). Stainings of wild-type, heterozygous, and homozygous mutant  splenocytes from littermates were determined. No expression of Ly-6A  on mutant lymphocytes was detected using two other anti–Ly-6A antibodies (data not shown). 16,000 gated events were collected with the  FACScan®. Negative control staining was determined with PE-conjugated anti–rat IgG.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199024&req=5

Figure 2: Absence of cell surface Ly-6A expression in Ly-6A−/− mice. Splenocytes were stained with the PE-conjugated anti–Ly-6A antibody D7 (12). Stainings of wild-type, heterozygous, and homozygous mutant splenocytes from littermates were determined. No expression of Ly-6A on mutant lymphocytes was detected using two other anti–Ly-6A antibodies (data not shown). 16,000 gated events were collected with the FACScan®. Negative control staining was determined with PE-conjugated anti–rat IgG.
Mentions: Analysis of Lymphoid and Myeloid Subpopulations. Flow cytometry was used to verify the absence of Ly-6A expression in homozygous mutant mice (Fig. 2). Approximately 60% of wild-type splenocytes express Ly-6A. Splenocytes from heterozygous animals show a slight decrease in Ly-6A expression intensity; however, splenocytes from homozygotes do not stain with any of three antibodies to Ly-6A (Fig. 2). In addition, phenotypic analysis was performed to determine if the absence of Ly-6A expression in homozygous mutant mice altered the differentiation of various cell populations. Although there are minor variations between littermates, as a population Ly-6A animals (as old as 8 mo) contain normal percentages of B220, TCR-α/β, TCR-γ/δ, CD3, CD4, CD8, Mac-1, and Ly-6G (Gr-1) positive cells in the bone marrow, lymph nodes, spleen, and thymus (data not shown). In addition to Ly-6G, antibodies to other members of the Ly-6 gene family were used to determine if the lack of phenotypic changes is due to compensation by other family members. Ly-6C, Sca-2 (TSA-1), and ThB do not appear to be overexpressed in any hematopoietic tissues (data not shown).

Bottom Line: To better understand the function of Ly-6A, we used gene targeting to produce Ly-6A mice which are healthy and have normal numbers and percentages of hematopoietic lineages.However, T lymphocytes from Ly-6A-deficient animals proliferate at a significantly higher rate in response to antigens and mitogens than wild-type littermates.This enhanced proliferation is not due to alterations in kinetics of response, sensitivity to stimulant concentration, or cytokine production by the T cell population, and is manifest in both in vivo and in vitro T cell responses.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7455, USA.

ABSTRACT
Ly-6A is a murine antigen which is implicated in lymphocyte activation and may be involved in activation of hematopoietic stem cells. Antibody cross-linking studies and antisense experiments have suggested that Ly-6A is a lymphocyte coactivation molecule. To better understand the function of Ly-6A, we used gene targeting to produce Ly-6A mice which are healthy and have normal numbers and percentages of hematopoietic lineages. However, T lymphocytes from Ly-6A-deficient animals proliferate at a significantly higher rate in response to antigens and mitogens than wild-type littermates. In addition, Ly-6A mutant splenocytes generate more cytotoxic T lymphocytes compared to wild-type splenocytes when cocultured with alloantigen. This enhanced proliferation is not due to alterations in kinetics of response, sensitivity to stimulant concentration, or cytokine production by the T cell population, and is manifest in both in vivo and in vitro T cell responses. Moreover, T cells from Ly-6A-deficient animals exhibit a prolonged proliferative response to antigen stimulation, thereby suggesting that Ly-6A acts to downmodulate lymphocyte responses.

Show MeSH
Related in: MedlinePlus