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J L Strominger

Publications and source records attributed to J L Strominger.

At least 217 records · Page 12Linked to original sources
PubMed1990

Promoter switching in Epstein-Barr virus during the initial stages of infection of B lymphocytes.

Transcription of the genes encoding the six viral nuclear antigens present in Epstein-Barr virus latently infected lymphocytes can be initiated from one of two promoters (Cp and Wp) mapping near the left end of the viral genome. These promoters are used in a mutually exclusive manner in clonal cell lines established from either Burkitt lymphoma tumors or in vitro infection of peripheral B lymphocytes. In this paper the role of Cp and Wp during viral latency is investigated. Cp appears to be the promoter normally employed during established latent infection. Analysis of two cell lines that use Wp revealed a deletion spanning Cp in the endogenous viral genomes, suggesting that cell lines exhibiting Wp activity harbor mutated viral genomes with a nonfunctional Cp. However, in contrast to the preferred usage of Cp exhibited by established Epstein-Barr virus-infected cell lines, Wp was shown to be exclusively utilized during the initial stages of viral infection. In addition to Wp activity, Cp usage was apparent by 6 days post-infection. A model is proposed involving B-lymphocyte differentiation-driven promoter switching during the establishment of viral latency.

Adult↗
PubMed1990

A gene pair from the human major histocompatibility complex encodes large proline-rich proteins with multiple repeated motifs and a single ubiquitin-like domain.

A large number of genes has been identified previously between the class I and class II gene families within the class III region of the human major histocompatibility complex. The complete sequences of two of these genes, BAT2 and BAT3 (where BAT is HLA-B-associated transcript), which are closely linked, were determined from cDNA clones. The putative BAT2 and BAT3 proteins are 228 and 110 kDa, respectively, and do not appear to be members of any known family of proteins. However, BAT3 contains an amino-terminal ubiquitin-like domain. Both BAT2 and BAT3 are very rich in proline and include short tracts of polyproline, polyglycine, and charged amino acids. In addition, these proteins contain several unrelated families of similar repeated segments. BAT2 and BAT3 are similar to other proteins with large proline-rich domains, such as some nuclear proteins, collagens, elastin, and synapsin. BAT2 also contains four Arg-Gly-Asp (RGD) motifs typical of the integrin receptor family.

Amino Acid Sequence↗
PubMed1990

Restriction fragment length polymorphism (RFLP) of two HLA-B-associated transcripts (BATs) genes in healthy Danes.

The restriction fragment length polymorphism (RFLP) of the two human HLA-B-associated transcripts (BATs) genes, BAT1 and BAT2, was investigated using 5 different restriction enzymes and two human BAT1 and BAT2 cDNA probes. Two of the enzymes, NcoI and RsaI, revealed polymorphic patterns which were investigated in healthy Danes. The cDNA/restriction enzyme combination BAT1/NcoI identifies polymorphic bands at 12 kb, 8 kb, 2.5 kb, and 1.1 kb, while the BAT2/RsaI combination identifies polymorphic bands at 3.3 kb, 2.7 kb, 2.3 kb, and 0.9 kb. The frequencies of these markers were determined in 90 unrelated Danes. Co-dominant segregation and allelic behavior was seen for the BAT1/NcoI 12 kb and 8 kb bands and the BAT2/RsaI 2.7 kb and 2.3 kb bands, respectively. It is possible that the BAT2/RsaI 3.3 kb band represents a rare allele of the BAT2/RsaI system. The BAT2/RsaI 2.3 kb marker was strongly negatively associated with HLA-B8 and HLA-DR3 while there were no strong associations between the BAT1 and BAT2 markers, but the BAT2/RsaI 2.7 kb marker was strongly positively associated with the TNF alpha/NcoI 5.5 kb marker, which in turn is positively associated with HLA-B8 and HLA-DR3. The negative associations between the BAT2/RsaI 2.3 kb marker and HLA-B8 and HLA-DR3 raise the question as to whether this BAT allele may play a role in protecting against certain autoimmune diseases.

DNA Probes, HLA↗
PubMed1989

Comparison between two peptide epitopes presented to cytotoxic T lymphocytes by HLA-A2. Evidence for discrete locations within HLA-A2.

An influenza B virus nucleoprotein (BNP) peptide, residues 82-94, defined by limited sequence homology with an HLA-A2-restricted peptide from influenza A matrix protein, was recognized by HLA-A2-restricted CTL. Reciprocal inhibition of T cell recognition by the two peptides suggest that the BNP peptide may have lower avidity for HLA-A2 molecules than the matrix peptide. The interaction between this peptide and HLA-A2 was explored by studying the CTL recognition of BNP 82-94 presented by mutant HLA-A2 molecules. Mutations at residues 9, 99, 70, 74, 152 and 156 were found to abolish T cell recognition of the BNP peptide. These results were compared with results previously obtained with the influenza A matrix peptide and suggest that the two peptides bind differently in the peptide binding site.

Amino Acid Sequence↗
PubMed1989

Specificity pockets for the side chains of peptide antigens in HLA-Aw68.

We have determined the structure of a second human histocompatibility glycoprotein, HLA-Aw68, by X-ray crystallography and refined it to a resolution of 2.6 A. Overall, the structure is extremely similar to that of HLA-A2 (refs 1, 2; and M.A.S. et al., manuscript in preparation), although the 11 amino-acid substitutions at polymorphic residues in the antigen-binding cleft alter the detailed shape and electrostatic charge of that site. A prominent negatively charged pocket within the cleft extends underneath the alpha-helix of the alpha 1-domain, providing a potential subsite for recognizing a positively charged side chain or peptide N terminus. Uninterpreted electron density, presumably representing an unknown 'antigen(s)', which seems to be different from that seen in the HLA-A2 structure, occupies the cleft and extends into the negatively charged pocket in HLA-Aw68. The structures of HLA-Aw68 and HLA-A2 demonstrate how polymorphism creates and alters subsites (pockets) positioned to bind peptide side chains, thereby suggesting the structural basis for allelic specificity in foreign antigen binding.

Amino Acid Sequence↗
PubMed1989

Developmental biology of T cell receptors.

T cell receptors are the antigen-recognizing elements found on the effector cells of the immune system. Two isotypes have been discovered, TCR-gamma delta and TCR-alpha beta, which appear in that order during ontogeny. The maturation of prothymocytes that colonize the thymic rudiment at defined gestational stages occurs principally within the thymus, although some evidence for extrathymic maturation also exists. The maturation process includes the rearrangement and expression of the T cell receptor genes. Determination of these mechanisms, the lineages of the cells, and the subsequent thymic selection that results in self-tolerance is the central problem in developmental immunology and is important for the understanding of autoimmune diseases.

Animals↗
PubMed1989

Human lymphocytes bearing T cell receptor gamma/delta are phenotypically diverse and evenly distributed throughout the lymphoid system.

A direct quantitative and phenotypic cytofluorographic analysis of TCR-gamma/delta+ lymphocytes as well as an immunohistologic study of their tissue distribution and microanatomy was made possible by the availability of two mAbs (anti-TCR-delta 1 and anti-C gamma M1) specific for framework determinants on human TCR gamma and delta chains, respectively. TCR-gamma/delta+ lymphocytes, ranging between greater than 0.5 and 16% of CD3+ cells, were found in fetal and postnatal thymus, fetal and adult peripheral lymphoid organs, and adult peripheral blood. While TCR-gamma/delta+ lymphocytes comprised a small subpopulation of T cells (mean, approximately 4%) occasionally greater than 10-16% of CD3+ cells expressed TCR-gamma/delta. Virtually all TCR-gamma/delta+ thymocytes/lymphocytes expressed CD7, CD2, and CD5 but were heterogeneous with respect to their expression of CD1, CD4, CD8, CD28, CD11b, CD16, and Leu-7. Human TCR-gamma/delta+ cells populate both organized lymphoid tissues (thymus, tonsil, lymphnode, and spleen) as well as the gut- and skin-associated lymphoid systems at similar frequencies without obvious tropism for epithelial microenvironments. TCR-gamma/delta+ lymphocytes tend to be located within a given organ wherever TCR-alpha/beta+ lymphocytes are found. This study shows that TCR-gamma/delta+ lymphocytes constitute a small but numerically important, phenotypically diverse T cell population distributed throughout the body. These results support the concept that TCR-gamma/delta+ cells comprise a distinct, functionally heterogeneous, mature T cell sublineage that may substantially broaden the T cell repertoire at all immunologically relevant sites.

Antibodies, Monoclonal↗
PubMed1989

A new cluster of genes within the human major histocompatibility complex.

A 435-kilobase (kb) DNA segment, which is centromeric to HLA-B in the human major histocompatibility complex, was isolated by chromosome walking with overlapping cosmids. Within the cloned region, the genes for the tumor necrosis factors (TNFs) alpha and beta and HLA-B were 210 kb apart. The human homolog of a mouse gene, B144, was located next to TNF alpha. Moreover, the presence of additional genes was suggested by a large cluster of CpG islands. With cosmid probes, several distinct transcripts were detected in RNA samples from a variety of cell lines. Altogether, five novel genes were identified by isolation of corresponding complementary DNA clones. These "HLA-B-associated transcripts" (BATs) were mapped to different locations within a 160-kb region that includes the genes for TNF alpha and TNF beta. The presence of the genes for BAT1 and BAT5 in the vicinity of HLA-B again raises the question of which gene in this region determines susceptibility to ankylosing spondylitis.

Animals↗
PubMed1989

Modulation of HLA class II antigen expression by transfection of sense and antisense DR alpha cDNA.

In the human there are three isotypic forms of MHC class II gene products (HLA-DR, -DQ, and -DP). The isotype-matched alpha-beta dimers are predominant but isotype-mismatched dimers can also be expressed (DR alpha-DQ beta). Here it is shown that the expression of the DR alpha-DQ beta dimer can be correlated to a high ratio of DR alpha/DR beta mRNA. The DR alpha chain expression was modulated by transfection of a sense and antisense DR alpha cDNA. Overexpression of DR alpha promoted the appearance of the DR alpha-DQ beta dimer. On the other hand, pre-existing DR alpha-DQ beta dimer expression was suppressed after antisense DR alpha cDNA transfection. Therefore, imbalanced expression of the alpha and beta chain from a given isotype could lead to the modification of HLA class II phenotype.

B-Lymphocytes↗
PubMed1989

Identification of murine complement receptor type 2.

A rabbit antiserum reactive with the human complement component C3d/Epstein-Barr virus receptor (complement receptor type 2, CR2) immunoprecipitates a Mr 155,000 murine B-cell surface antigen. The apparent molecular weight and cellular distribution of this murine antigen are similar to those of human CR2. Cells expressing the murine protein bind sheep erythrocytes coated with antibody and murine C1-C3d but do not bind Epstein-Barr virus at all. The monospecific antiserum to human CR2 together with goat F(ab')2 anti-rabbit IgG blocks attachment of the C3d-coated erythrocytes to receptor-bearing murine B lymphocytes. To further characterize murine CR2, a lambda gt11 library from the murine late pre-B-cell line 70Z/3 was screened with human CR2 cDNA. A partial cDNA clone of 3.5 kilobases with 79% amino acid sequence identity to human CR2 in the unique intracytoplasmic region and 63% identity to the sixth human CR2 repeat was obtained. Blot hybridization with the murine cDNA clone identified an RNA species of approximately 4.7 kilobases, similar in size to human CR2 mRNA, from a murine B-cell line but not from a murine T-cell line.

Amino Acid Sequence↗
PubMed1989

Double-negative (CD4-CD8-) lymphocytes bearing T-cell receptor alpha and beta chains in normal human skin.

Double-negative (CD4-CD8-) T-cell receptor alpha- and beta-chain (TCR alpha beta)-expressing lymphocytes have been identified in human skin. Two skin-derived lymphocyte cell lines (II-1 and II-2) expressing this phenotype were obtained. They each expressed full-length TCR alpha- and beta-chain transcripts and lacked TCR gamma- and delta-chain as well as CD4 and CD8 mRNAs. These polyclonal cell lines shared one predominant TCR beta-chain gene rearrangement. The CD3/TCR alpha beta complexes were functionally competent as evidenced by their capacity to transduce activation signals resulting in cell proliferation, lymphokine secretion, and cytolytic activity. The demonstration of CD4-CD8-TCR alpha beta lymphocytes as a subpopulation of the skin-associated immune system should contribute to understanding the biologic potential of this cell population as well as of this organ-specific immune system.

Adult↗
PubMed1989

Mutually exclusive use of viral promoters in Epstein-Barr virus latently infected lymphocytes.

Of the eight viral antigens known to be expressed during Epstein-Barr virus latency, six are transcribed from a major rightward transcriptional unit, which gives rise to mRNAs containing common 5' exons. Analysis of cDNA clones has identified the use of two different promoters (Wp and Cp), located near the left-hand end of the viral genome, in generating these viral messages. Characterization of the activities of these two viral promoters in a number of Burkitt lymphoma and lymphoblastoid cell lines has revealed exclusive usage of only one of these promoters in all cell lines examined. Transfection of reporter constructs containing Wp and/or Cp linked to the bacterial chloramphenicol acetyltransferase gene into several different Epstein-Barr virus-infected cell lines generally supports a model in which the mutually exclusive use of Cp or Wp is determined by cellular factors and not by viral strain variation.

Base Sequence↗
PubMed1989

Alloreactivity studied with mutants of HLA-A2.

Based on the crystal structure of HLA-A2.1 and the recognition of a panel of mutant HLA-A2.1 molecules by a large number of alloreactive cytotoxic T lymphocyte clones, a model to explain alloreactivity is described. In this model recognition of an allogeneic major histocompatibility complex molecule by a self-restricted T-cell receptor occurs as the result of accommodation by the receptor of a few amino acid differences in the major histocompatibility complex molecule--i.e., cross-recognition. Alloreactivity is the result of the presence in the foreign antigen binding site of the allogeneic major histocompatibility complex molecule of unusual self-peptides, reactivity to which could not have been eliminated by negative thymic selection.

Antibodies, Monoclonal↗
PubMed1989

Human major histocompatibility complex contains a minimum of 19 genes between the complement cluster and HLA-B.

A 600-kilobase (kb) DNA segment from the human major histocompatibility complex (MHC) class III region was isolated by extension of a previous 435-kb chromosome walk. The contiguous series of cloned overlapping cosmids contains the entire 555-kb interval between C2 in the complement gene cluster and HLA-B. This region is known to encode the tumor necrosis factors (TNFs) alpha and beta, B144, and the major heat shock protein HSP70. Moreover, a cluster of genes, BAT1-BAT5 (HLA-B-associated transcripts) has been localized in the vicinity of the genes for TNF alpha and TNF beta. An additional four genes were identified by isolation of corresponding cDNA clones with cosmid DNA probes. These genes for BAT6-BAT9 were mapped near the gene for C2 within a 120-kb region that includes a HSP70 gene pair. These results, together with complementary data from a similar recent study, indicated the presence of a minimum of 19 genes within the C2-HLA-B interval of the MHC class III region. Although the functional properties of most of these genes are yet unknown, they may be involved in some aspects of immunity. This idea is supported by the genetic mapping of the hemopoietic histocompatibility locus-1 (Hh-1) in recombinant mice between TNF alpha and H-2S, which is homologous to the complement gene cluster in humans.

Cell Line↗
PubMed1989

Comparison of the secondary structures of human class I and class II major histocompatibility complex antigens by Fourier transform infrared and circular dichroism spectroscopy.

We have examined the secondary structures of human class I and class II histocompatibility antigens in solution by Fourier transform infrared spectroscopy and circular dichroism in order to compare the relative amounts of alpha-helix, beta-sheet, and other structures, which are crucial elements in the comparison of the protein structures. Quantitation of infrared spectra of papain-solubilized HLA-A2, HLA-B7, and DR1 in phosphate buffer gave alpha-helix contents of 17%, 8%, and 10% and beta-sheet contents of 41%, 48%, and 53%, respectively. By circular dichroism, papain-solubilized HLA-A2, HLA-B7, and DR1 were also found to have comparable alpha-helix contents (e.g., 8%, 20%, and 17%, respectively). Circular dichroism analysis for beta-sheet gave 29% for papain-solubilized HLA-B7 and 42% for papain-solubilized DR1. The value for papain-solubilized HLA-A2 (74%) was anomalous. It is proposed that Trp-107 of HLA-A2, missing in both HLA-B7 and DR1, may be responsible for much of the anomaly. Due to the uncertainties inherent in quantitation of the amounts of secondary structures by both spectral methods, the differences in the contents of alpha-helix and beta-sheet in the three proteins are not considered significant. However, differences in the nature of the beta-sheet structures are suggested by infrared spectroscopy. These results provide physical evidence for an overall structure of class II antigens modeled on that of class I antigens.

Buffers↗
PubMed1989

Constitutive endocytosis of HLA class I antigens requires a specific portion of the intracytoplasmic tail that shares structural features with other endocytosed molecules.

HLA class I antigens present in the human leukemia T-cell line HPB-ALL are shown to be endocytosed in the absence of specific antibodies. In 1 hr, approximately 10% of class I molecules initially present at the cell surface are found intracellularly. Genetically engineered mutants of the HLA-A2 gene lacking exon 6 or 7 or both were used to analyze whether the cytoplasmic region contributes to the internalization. The results indicate that amino acids encoded by exon 7 (spanning amino acid residues 323-340) are required for internalization, while deletion of exon 6 had no effect. In addition, a comparison of the cytoplasmic sequences of receptors that are known to be internalized via coated pits and the present data revealed that they share a structural feature that could constitute a specific signal required for endocytosis.

Antigen-Antibody Complex↗