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1.
PLoS One ; 7(8): e41466, 2012.
Article in English | MEDLINE | ID: mdl-22870225

ABSTRACT

Noncognate or self peptide-MHC (pMHC) ligands productively interact with T-cell receptor (TCR) and are always in a large access over the cognate pMHC on the surface of antigen presenting cells. We assembled soluble cognate and noncognate pMHC class I (pMHC-I) ligands at designated ratios on various scaffolds into oligomers that mimic pMHC clustering and examined how multivalency and density of the pMHCs in model clusters influences the binding to live CD8 T cells and the kinetics of TCR signaling. Our data demonstrate that the density of self pMHC-I proteins promotes their interaction with CD8 co-receptor, which plays a critical role in recognition of a small number of cognate pMHC-I ligands. This suggests that MHC clustering on live target cells could be utilized as a sensitive mechanism to regulate T cell responsiveness.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , Histocompatibility Antigens Class I/immunology , Models, Immunological , Peptides/immunology , Receptors, Antigen, T-Cell/immunology , Self Tolerance/physiology , Signal Transduction/physiology , CD8-Positive T-Lymphocytes/cytology , Cells, Cultured , Humans
2.
PLoS One ; 7(4): e34433, 2012.
Article in English | MEDLINE | ID: mdl-22514633

ABSTRACT

The AID/APOBEC family (activation induced deaminase/apolipoprotein B mRNA editing cytokine deaminase) in B cells play important roles in adaptive and innate immunity. Whereas APOBEC3G has been studied in CD4+ T cells and myeloid cells its functional potential in B cells has received little attention. AID combines two critical functions of antibodies, class switching and affinity maturation and may serve as a functional surrogate of protection. These functions were studied following systemic immunization of rhesus macaques with recombinant HLA constructs, linked with HIV and SIV antigens and HSP70 to dextran. The results showed significant upregulation of AID in CD20+ B cells, APOBEC 3G in CD27+ memory B cells and CD4+ effector memory T cells. After immunization the upregulated APOBEC 3G and AID were directly correlated in B cells (p<0.0001). Following challenge with SHIV SF162.P4 the viral load was inversely correlated with AID in B cells and APOBEC 3G in B and T cells, suggesting that both deaminases may have protective functions. Investigation of major interactions between DC, T cells and B cells showed significant increase in membrane associated IL-15 in DC and CD40L in CD4+ T cells. IL-15 binds the IL-15 receptor complex in CD4+ T and B cells, which may reactivate the DC, T and B cell interactions. The overall results are consistent with AID inhibiting pre-entry SHIV by eliciting IgG and IgA antibodies, whereas APOBEC 3G may contribute to the post-entry control of SHIV replication and cellular spread.


Subject(s)
Adaptive Immunity/immunology , Cytidine Deaminase/metabolism , HIV Infections/immunology , HIV/immunology , Immunity, Innate/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Animals , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , Female , HIV Infections/metabolism , Humans , Immunization , Interleukin-15/metabolism , Macaca mulatta , Receptors, Interleukin-15 , Simian Acquired Immunodeficiency Syndrome/metabolism
3.
J Gen Virol ; 93(Pt 7): 1506-1518, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22492918

ABSTRACT

Genetic, epidemiological and experimental evidence suggest that the major histocompatibility complex (MHC) is critical in controlling human immunodeficiency virus (HIV) infection. The objectives of this study were to determine whether novel recombinant Mamu MHC constructs would elicit protection against rectal challenge with heterologous simian-human immunodeficiency virus (SHIV) strain SF162.P4 in rhesus macaques. Mamu class I and II gene products were linked together with HIV gp140, simian immunodeficiency virus (SIV) p27 and heat-shock protein 70 to dextran. The vaccine was administered to two groups, each consisting of nine macaques, either subcutaneously (SC), or rectally and boosted by SC immunization. The controls were untreated or adjuvant-treated animals. Repetitive rectal challenges with up to ten doses of SHIV SF162.P4 showed a significant decrease in the peak and sequential viral RNA concentrations, and three macaques remained uninfected, in the nine SC-immunized animals, compared with infection in all nine controls. Macaques immunized rectally followed by SC boosters showed a less significant decrease in both sequential and peak viral loads compared with the SC-immunized animals, and all were infected following rectal challenge with SHIV SF162.P4. Plasma and mucosal IgG and IgA antibodies to Mamu class I alleles and HIV gp120, as well as to RANTES (regulated upon activation, normal T-cell expressed, and secreted; CCR5) were increased, and showed significant inverse correlations with the peak viral load. These results suggested that allo-immunization with recombinant MHC constructs linked to HIV-SIV antigens merits further investigation in preventing HIV-1 infection.


Subject(s)
Histocompatibility Antigens Class II/immunology , Histocompatibility Antigens Class I/immunology , SAIDS Vaccines/immunology , Simian Acquired Immunodeficiency Syndrome/prevention & control , Simian Immunodeficiency Virus/immunology , env Gene Products, Human Immunodeficiency Virus/immunology , Administration, Rectal , Animals , Antibodies, Viral/blood , Disease Models, Animal , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Injections, Subcutaneous , Macaca mulatta , SAIDS Vaccines/administration & dosage , Vaccination/methods , Viral Load
4.
Biol Blood Marrow Transplant ; 18(3): 381-7, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22062805

ABSTRACT

HY-specific T cells are presumed to play a role in acute graft-versus-host disease (aGVHD) after female-to-male stem cell transplantation (SCT). However, infiltrates of these T cells in aGVHD-affected tissues have not yet been reported. We evaluated the application of HLA-A2/HY dextramers for the in situ detection of HY-specific T cells in cryopreserved skin biopsy specimens. We applied the HLA-A2/HY dextramers on cryopreserved skin biopsy specimens from seven male HLA-A2(+) pediatric patients who underwent stem cell transplantation with confirmed aGVHD involving the skin. The dextramers demonstrated the presence of HY-specific T cells. In skin biopsy specimens of three male recipients of female grafts, 68% to 78% of all skin-infiltrating CD8(+) T cells were HY-specific, whereas these cells were absent in biopsy specimens collected from sex-matched patient-donor pairs. Although this study involved a small and heterogeneous patient group, our results strongly support the hypothesis that HY-specific T cells are actively involved in the pathophysiology of aGVHD after sex-mismatched stem cell transplantation.


Subject(s)
Graft vs Host Disease/immunology , Hematopoietic Stem Cell Transplantation/methods , Skin/immunology , T-Lymphocytes/immunology , Adolescent , Child , Child, Preschool , Cryopreservation , Fluorescent Antibody Technique , Graft vs Host Disease/pathology , Humans , Male , Microscopy, Confocal , Skin/pathology , T-Lymphocytes/pathology
5.
J Virol ; 85(13): 6442-52, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21490092

ABSTRACT

Major histocompatibility complex (MHC) molecules expressed on the surface of human immunodeficiency virus (HIV) are potential targets for neutralizing antibodies. Since MHC molecules are polymorphic, nonself MHC can also be immunogenic. We have used combinations of novel recombinant HLA class I and II and HIV/simian immunodeficiency virus (SIV) antigens, all linked to dextran, to investigate whether they can elicit protective immunity against heterologous simian/human immunodeficiency virus (SHIV) challenge in rhesus macaques. Three groups of animals were immunized with HLA (group 1, n = 8), trimeric YU2 HIV type 1 (HIV-1) gp140 and SIV p27 (HIV/SIV antigens; group 2, n = 8), or HLA plus HIV/SIV antigens (group 3, n = 8), all with Hsp70 and TiterMax Gold adjuvant. Another group (group 4, n = 6) received the same vaccine as group 3 without TiterMax Gold. Two of eight macaques in group 3 were completely protected against intravenous challenge with 18 50% animal infective doses (AID(50)) of SHIV-SF162P4/C grown in human cells expressing HLA class I and II lineages represented in the vaccine, while the remaining six macaques showed decreased viral loads compared to those in unimmunized animals. Complement-dependent neutralizing activity in serum and high levels of anti-HLA antibodies were elicited in groups 1 and 3, and both were inversely correlated with the plasma viral load at 2 weeks postchallenge. Antibody-mediated protection was strongly supported by the fact that transfer of pooled serum from the two challenged but uninfected animals protected two naïve animals against repeated low-dose challenge with the same SHIV stock. This study demonstrates that immunization with recombinant HLA in combination with HIV-1 antigens might be developed into an alternative strategy for a future AIDS vaccine.


Subject(s)
AIDS Vaccines/administration & dosage , Gene Products, gag/administration & dosage , HIV Infections/prevention & control , Histocompatibility Antigens Class II/administration & dosage , Histocompatibility Antigens Class I/administration & dosage , Simian Acquired Immunodeficiency Syndrome/prevention & control , env Gene Products, Human Immunodeficiency Virus/administration & dosage , Animals , Female , Gene Products, gag/genetics , Gene Products, gag/immunology , HIV Infections/immunology , HIV-1/immunology , HIV-1/pathogenicity , Histocompatibility Antigens Class I/genetics , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class II/genetics , Histocompatibility Antigens Class II/immunology , Humans , Immunization , Macaca mulatta/immunology , Molecular Sequence Data , Recombination, Genetic , SAIDS Vaccines/administration & dosage , Sequence Analysis, DNA , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus/immunology , Simian Immunodeficiency Virus/pathogenicity , Treatment Outcome , env Gene Products, Human Immunodeficiency Virus/genetics , env Gene Products, Human Immunodeficiency Virus/immunology
6.
J Immunol Methods ; 360(1-2): 1-9, 2010 Aug 31.
Article in English | MEDLINE | ID: mdl-20542039

ABSTRACT

The objective of this study was to produce and evaluate the immunogenic potential of a recombinant HLA-class I antigen linked to dextran. The HLA-A*0201 heavy chain and beta2 microglobulin were cloned by PCR amplification of overlapping oligonucleotides and produced in E. coli. These were assembled with a CMV binding peptide motif, the HLA complex was biotinylated and bound by streptavidin coated dextran at a ratio of 24 HLA to 1 dextran molecule (termed Dextramer). Allostimulation of human PBMC in vitro and in vivo immunization of Balb c mice with the HLA-A*0201 construct elicited CD4+ and CD8+ T cell proliferative responses, IgG specific antibodies in mice and in human T cell proliferation and APOBEC3G mRNA. These adaptive and innate immune responses induced by a novel recombinant HLA construct in human cells and mice suggest their application as a potential vaccine candidate against HIV infection.


Subject(s)
AIDS Vaccines , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , Dextrans/pharmacology , HLA-A Antigens/metabolism , Recombinant Proteins/pharmacology , Adaptive Immunity/drug effects , Animals , Antibody Formation/drug effects , CD4-Positive T-Lymphocytes/drug effects , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/pathology , CD8-Positive T-Lymphocytes/drug effects , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/pathology , Cell Proliferation/drug effects , Cells, Cultured , Cloning, Molecular , Dextrans/genetics , Dextrans/metabolism , HLA-A Antigens/genetics , HLA-A Antigens/pharmacology , HLA-A2 Antigen , Humans , Immunity, Innate/drug effects , Immunization , Immunoglobulin G/blood , Lymphocyte Activation , Mice , Mice, Inbred BALB C , Protein Binding , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
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