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Full-Text Articles in Life Sciences

Cell Surface Expression Of A Peptide Encoded By The Unrearranged Tcr-Vβ8.2 Gene, Janice Abbey, Mark Hulett, Helen O'Neill Dec 2005

Cell Surface Expression Of A Peptide Encoded By The Unrearranged Tcr-Vβ8.2 Gene, Janice Abbey, Mark Hulett, Helen O'Neill

Helen O'Neill

Germline transcription of T-cell receptor (TCR) genes has been described in early lymphoid cells. The most common explanation for this phenomenon is that transcription of unrearranged Vβ genes directs gene usage during the rearrangement event. Germline transcription of the TCR-Vβ8.2 gene has been detected in a precursor T-cell line, C1-V13D, which shows no rearrangement at any of the TCR gene loci. This cell line also shows weak binding of specific anti-V 8.2 antibody to the cell surface, consistent with expression of a truncated TCR chain. RT-PCR has been used to confirm expression of spliced germline transcripts of TCR-Vβ8.2 in C1-V13D …


Lack Of Antigen-Specific Tissue Remodeling In Mice Deficient In The Macrophage Galactose-Type Calcium-Type Lectin 1/Cd301a., Thandi M. Onami, K. Sato, Y. Imai, N. Higashi, Y. Kumamoto, S. M. Hedrick, T. Irimura Jan 2005

Lack Of Antigen-Specific Tissue Remodeling In Mice Deficient In The Macrophage Galactose-Type Calcium-Type Lectin 1/Cd301a., Thandi M. Onami, K. Sato, Y. Imai, N. Higashi, Y. Kumamoto, S. M. Hedrick, T. Irimura

Thandi M. Onami

Macrophage galactose-type C-type lectins (MGLs), which were recently named CD301, have 2 homologues in mice: MGL1 and MGL2. MGLs are expressed on macrophages and immature dendritic cells. The persistent presence of granulation tissue induced by a protein antigen was observed in wild-type mice but not in mice lacking an endogenous, macrophage-specific, galactose-type calcium-type lectin 1 (MGL1) in an air pouch model. The anti-MGL1 antibody suppressed the granulation tissue formation in wild-type mice. A large number of cells, present only in the pouch of MGL1-deficient mice, were not myeloid or lymphoid lineage cells and the number significantly declined after administration of …


The Immunogenicity Of Dendritic Cell-Derived Exosomes, Ben Quah, Helen O'Neill Dec 2004

The Immunogenicity Of Dendritic Cell-Derived Exosomes, Ben Quah, Helen O'Neill

Helen O'Neill

Exosome production represents an alternate endocytic pathway for secretion. Multivesicular endosomes (MVE) fuse with the plasma membrane expelling internal vesicles or exosomes from cells. Exosome production has been recently described for immune cells including B cells, dendritic cells (DC), mast cells, macrophages and T cells. Exosomes derived from some DC populations stimulate T lymphocyte proliferation in vitro and have potent capacity to generate anti-tumour immune responses in vivo. These reported studies have involved in vitro grown mature DC expanded from precursors with cytokines. However, immature DC produce higher numbers of exosomes than mature DC and this is thought to be …


Cd43 Modulates Severity And Onset Of Experimental Autoimmune Encephalomyelitis., Thandi M. Onami, M. L. Ford, A. Sperling, R. Ahmed, B. D. Evavold Dec 2003

Cd43 Modulates Severity And Onset Of Experimental Autoimmune Encephalomyelitis., Thandi M. Onami, M. L. Ford, A. Sperling, R. Ahmed, B. D. Evavold

Thandi M. Onami

Experimental autoimmune encephalomyelitis (EAE) is a mouse model of multiple sclerosis characterized by infiltration of activated CD4(+) T lymphocytes into tissues of the CNS. This study investigated the role of CD43 in the induction and progression of EAE. Results demonstrate that CD43-deficient mice have reduced and delayed clinical and histological disease severity relative to CD43(+/+) mice. This reduction was characterized by decreased CD4(+) T cell infiltration of the CNS of CD43(-/-) mice but similar numbers of Ag-specific T cells in the periphery, suggesting a defect in T cell trafficking to the CNS. The absence of CD43 also affected cytokine production, …


Primary And Secondary Immunocompetence In Mixed Allogeneic Chimeras, Thandi M. Onami, M. A. Williams, A. B. Adams, M. B. Walsh, N. Shirasugi, T. C. Pearson, R. Ahmed, C. P. Larsen Mar 2003

Primary And Secondary Immunocompetence In Mixed Allogeneic Chimeras, Thandi M. Onami, M. A. Williams, A. B. Adams, M. B. Walsh, N. Shirasugi, T. C. Pearson, R. Ahmed, C. P. Larsen

Thandi M. Onami

Targeted disruption of T cell costimulatory pathways, particularly CD28 and CD40, has allowed for the development of minimally myeloablative strategies for the induction of mixed allogeneic chimerism and donor-specific tolerance across full MHC barriers. In this study we analyze in depth the ability of mixed allogeneic chimeras in two strain combinations to mount effective host-restricted and donor-restricted antiviral CD4 and CD8 responses, as well as the impact of development of mixed chimerism on the maintenance of pre-existing memory populations. While antiviral CD8 responses in mixed chimeras following acute viral infection with lymphocytic choriomeningitis virus Armstrong or vaccinia virus are largely …


Tcr Signal Transduction In Antigen-Specific Memory Cd8 T Cells, Thandi M. Onami, Ellen N. Kersh, Susan M. Kaech, Miriana Moran, E. John Wherry, M. Carrie Miceli, Rafi Ahmed Jan 2003

Tcr Signal Transduction In Antigen-Specific Memory Cd8 T Cells, Thandi M. Onami, Ellen N. Kersh, Susan M. Kaech, Miriana Moran, E. John Wherry, M. Carrie Miceli, Rafi Ahmed

Thandi M. Onami

Memory T cells are more responsive to Ag than naive cells. To determine whether memory T cells also have more efficient TCR signaling, we compared naive, effector, and memory CD8 T cells of the same antigenic specificity. Surprisingly, initial CD3 signaling events are indistinguishable. However, memory T cells have more extensive lipid rafts with higher phosphoprotein content before TCR engagement. Upon activation in vivo, they more efficiently induce phosphorylation of-LAT (linker for activation of T cells), ERK (extracellular signal-regulated kinase), JNK (c-Jun N-terminal kinase), and p38. Thus, memory CD8 T cells do not increase their TCR sensitivity, but are better …


Iodinated Feed Reduces Stress In Steelhead Trout., Ahmed Mustafa Dec 2002

Iodinated Feed Reduces Stress In Steelhead Trout., Ahmed Mustafa

Ahmed Mustafa Dr.

No abstract provided.


Cutting Edge: Persistent Viral Infection Prevents Tolerance Induction And Escapes Immune Control Following Cd28/Cd40 Blockade-Based Regimen, Thandi M. Onami, M. A. Williams, A. B. Adams, M. M. Durham, T. C. Pearson, R. Ahmed, C. P. Larsen Nov 2002

Cutting Edge: Persistent Viral Infection Prevents Tolerance Induction And Escapes Immune Control Following Cd28/Cd40 Blockade-Based Regimen, Thandi M. Onami, M. A. Williams, A. B. Adams, M. M. Durham, T. C. Pearson, R. Ahmed, C. P. Larsen

Thandi M. Onami

A continuing concern with CD28 and/or CD40 blockade-based strategies to induce tolerance and mixed chimerism is their potential to disrupt protective immunity to preexisting infections. In this report, we find that preexisting persistent infection with lymphocytic choriomeningitis virus (LCMV) clone 13 prevents the induction of tolerance, mixed chimerism, and donor-reactive T cell deletion. Mice continue to be refractory to tolerance induction even after viremia has been resolved and virus is present only at very low levels in peripheral tissues. Conversely, we find that the full tolerance regimen, or costimulation blockade alone, specifically inhibits already ongoing antiviral immune responses, leading to …


Molecular Cloning And Characterization Of A Novel Mouse Macrophage C-Type Lectin, Mmgl2, Which Has A Distinct Carbohydrate Specificity From Mmgl1, Thandi M. Onami, M. Tsuiji, M. Fujimori, Y. Ohashi, N. Higashi, S. M. Hendrick, T. Irimura Aug 2002

Molecular Cloning And Characterization Of A Novel Mouse Macrophage C-Type Lectin, Mmgl2, Which Has A Distinct Carbohydrate Specificity From Mmgl1, Thandi M. Onami, M. Tsuiji, M. Fujimori, Y. Ohashi, N. Higashi, S. M. Hendrick, T. Irimura

Thandi M. Onami

A novel mouse macrophage galactose-type C-type lectin 2 (mMGL2) was identified by BLAST analysis of expressed sequence tags. The sequence of mMGL2 is highly homologous to the mMGL, which should now be called mMGL1. The open reading frame of mMGL2 contains a sequence corresponding to a type II transmembrane protein with 332 amino acids having a single extracellular C-type lectin domain. The 3'-untranslated region included long terminal repeats of mouse early transposon. The Mgl2 gene was cloned from a 129/SvJ mouse genomic library and sequenced. The gene spans 7,136 base pairs and consists of 10 exons, which is similar to …


Generation Of Mice Deficient For Macrophage Galactose- And N-Acetylgalactosamine-Specific Lectin: Limited Role In Lymphoid And Erythroid Homeostasis And Evidence For Multiple Lectins, Thandi M. Onami, M. Y. Lin, D. M. Page, S. A. Reynolds, C. D. Katayama, J. D. Marth, T. Irimura, A. Varki, N. Varki, S. M. Hedrick Jul 2002

Generation Of Mice Deficient For Macrophage Galactose- And N-Acetylgalactosamine-Specific Lectin: Limited Role In Lymphoid And Erythroid Homeostasis And Evidence For Multiple Lectins, Thandi M. Onami, M. Y. Lin, D. M. Page, S. A. Reynolds, C. D. Katayama, J. D. Marth, T. Irimura, A. Varki, N. Varki, S. M. Hedrick

Thandi M. Onami

Macrophage receptors function in pattern recognition for the induction of innate immunity, in cellular communication to mediate the regulation of adaptive immune responses, and in the clearance of some glycosylated cells or glycoproteins from the circulation. They also function in homeostasis by initiating the engulfment of apoptotic cells. Evidence has suggested that macrophage receptors function to recognize cells that are destined for programmed cell death but not yet overtly apoptotic. We have examined the function of a macrophage receptor specific for unsialylated glycoproteins, known as the mouse macrophage galactose- and N-acetylgalactosamine-specific lectin (mMGL) (Ii et al., J. Biol. Chem. 265:11295-11298, …


Dynamic Regulation Of T Cell Immunity By Cd43, Thandi M. Onami, L. E. Harrington, M. A. Williams, M. Galvan, C. P. Larsen, T. C. Pearson, N. Manjunath, L. G. Baum, B. D. Pearce, R. Ahmed Jun 2002

Dynamic Regulation Of T Cell Immunity By Cd43, Thandi M. Onami, L. E. Harrington, M. A. Williams, M. Galvan, C. P. Larsen, T. C. Pearson, N. Manjunath, L. G. Baum, B. D. Pearce, R. Ahmed

Thandi M. Onami

During a viral response, Ag-specific effector T cells show dramatically increased binding by the mAb 1B11 and the lectin peanut agglutinin (PNA). We investigated the contribution of CD43 expression to 1B11 and PNA binding as well as its role in generation and maintenance of a CD8 T cell response. Analysis of CD43(-/-) mice revealed no increased 1B11 binding and reduced PNA binding on virus-specific CD8 T cells from -/- mice compared with +/+ mice. Furthermore, we examined the role of CD43 in the kinetics of an immune response. We show that CD43 expression modestly effects generation of a primary virus-specific …