John Radcliffe Hospital

About: John Radcliffe Hospital is a healthcare organization based out in Oxford, Oxfordshire, United Kingdom. It is known for research contribution in the topics: Population & Antigen. The organization has 14491 authors who have published 23670 publications receiving 1459015 citations.

Insulin-IGF2 region on chromosome 11p encodes a gene implicated in HLA-DR4-dependent diabetes susceptibility

Abstract: A class of alleles at the VNTR (variable number of tandem repeat) locus in the 5' region of the insulin gene (INS) on chromosome 11p is associated with increased risk of insulin-dependent diabetes mellitus (IDDM), but family studies have failed to demonstrate linkage. INS is thought to contribute to IDDM susceptibility but this view has been difficult to reconcile with the lack of linkage evidence. We thus investigated polymorphisms of INS and neighbouring loci in random diabetics, IDDM multiplex families and controls. HLA-DR4-positive diabetics showed an increased risk associated with common variants at polymorphic sites in a 19-kilobase segment spanned by the 5' INS VNTR and the third intron of the gene for insulin-like growth factor II (IGF2). As INS is the major candidate gene from this region, diabetic and control sequence were compared to identify all INS polymorphisms that could contribute to disease susceptibility. In multiplex families the IDDM-associated alleles were transmitted preferentially to HLA-DR4-positive diabetic offspring from heterozygous parents. The effect was strongest in paternal meioses, suggesting a possible role for maternal imprinting. Our results strongly support the existence of a gene or genes affecting HLA-DR4 IDDM susceptibility which is located in a 19-kilobase region of INS-IGF2. Our results also suggest new ways to map susceptibility loci in other common diseases.

Enhanced Immunogenicity and Protective Efficacy Against Mycobacterium tuberculosis of Bacille Calmette-Guérin Vaccine Using Mucosal Administration and Boosting with a Recombinant Modified Vaccinia Virus Ankara

Abstract: Heterologous prime-boost immunization strategies can evoke powerful T cell immune responses and may be of value in developing an improved tuberculosis vaccine. We show that recombinant modified vaccinia virus Ankara, expressing Mycobacterium tuberculosis Ag 85A (M.85A), strongly boosts bacille Calmette-Guerin (BCG)-induced Ag 85A specific CD4(+) and CD8(+) T cell responses in mice. A comparison of intranasal (i.n.) and parenteral immunization of BCG showed that while both routes elicited comparable T cell responses in the spleen, only i.n. delivery elicited specific T cell responses in the lung lymph nodes, and these responses were further boosted by i.n. delivery of M.85A. Following aerosol challenge with M. tuberculosis, i.n. boosting of BCG with either BCG or M.85A afforded unprecedented levels of protection in both the lungs (2.5 log) and spleens (1.5 log) compared with naive controls. Protection in the lung correlated with the induction of Ag 85A-specific, IFN-gamma-secreting T cells in lung lymph nodes. These findings support further evaluation of mucosally targeted prime-boost vaccination approaches for tuberculosis.

HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells.

Abstract: Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.