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Biomedical subjects

M B Oldstone

Publications and source records attributed to M B Oldstone.

At least 163 records · Page 9Linked to original sources
PubMed1991

Role of viral strains and host genes in determining levels of immune complexes in a model system: implications for HIV infection.

Virus-antibody immune complexes form during infection with most RNA and DNA viruses, including those with human immunodeficiency virus (HIV). Yet a subset of individuals so infected apparently does not mount such responses. To understand the principles involved, we studied the formation and deposition of virus-antibody immune complexes in the circulation in a model system utilizing mice persistently infected with lymphocytic choriomeningitis virus (LCMV). Although mice of several genetic haplotypes could be persistently infected with LCMV, mount anti-LCMV antibody responses, and form immune complexes levels varied among murine strains. Earlier, genetic analysis of high and low immune complex formers, their F1 crosses, and appropriately selected recombinant inbred strains located the ability to mount heightened immune responses in genes within the MHC. Further, variations among LCMV strains in the capacity to incite high levels of immune complex formation were found. Persistent infection with LCMV Armstrong (ARM) strain was associated with high levels of complexes in the circulation and marked deposits in the glomeruli of high-responder SWR/J mice. In contrast, persistent infection of SWR/J mice with LCMV Traub strain led to very low levels of circulating complexes and minimal immune complex deposition in tissues. The amount of virus carried during both infections was roughly equivalent indicating that the genetics of both the host and the virus play essential roles in whether or not immune complexes develop. Antibody responses in SWR/J mice persistently infected with LCMV ARM were 5- to 10-fold higher than responses of age- and sex-matched mice infected with LCMV Traub.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Viral persistence and disease: cytopathology in the absence of cytolysis.

Realising that viruses could persist and thereby cause chronic disease has been one of the major accomplishments in virology. In this review we will discuss the principles by which viruses can persist and how such persistence can lead to disease. Our focus will be on the ability of certain viruses to interfere subtly with the cell's ability to produce specific differentiated products as hormones, neurotransmitters, cytokines and immunoglobulins, etc., in the absence of their ability to lyse the cell they infect. By this means viruses can replicate in histologically normal appearing cells and tissues. Despite viral replication the infected cell maintains its normal anatomic architecture and yet the virus disorders the differentiated or luxury function of the cell leading to disturbances in homeostasis and disease. Viruses by this means likely underline a wide variety of clinical illnesses, currently of unknown aetiology, that affect the endocrine, immune, nervous and other differentiated systems.

Animals↗
PubMed1991

Common immunologic determinant between human immunodeficiency virus type 1 gp41 and astrocytes.

Monoclonal antibodies against a synthetic 12-amino-acid peptide that comprises the immunodominant domain of human immunodeficiency virus type 1 gp41 (amino acids 598 through 609) reacted with astrocytes found in human and rodent central nervous system tissue. The monoclonal antibodies bound to a 43-kDa protein found in central nervous system tissue preparations. These results indicate that human immunodeficiency virus type 1 gp41 contains a common epitope with astrocytes and that an immune response to human immunodeficiency virus type 1 gp41 could generate antibodies that are cross-reactive to astrocytes. Furthermore, anti-astrocyte antibodies, which were directed at a common epitope with the gp41 sequence, were found to be present in cerebrospinal fluid from some AIDS patients with central nervous system complications. Astrocytes regulate the environment for appropriate neuronal function, and astrocyte hyperactivity (astrocytosis) is known to be the common and early pathologic event in brains from patients with central nervous system AIDS. We suggest that antibody-induced effect(s) on astrocytes could lead to the physiologic neuronal dysfunctions observed in AIDS patients.

Animals↗
PubMed1991

Mapping the anatomy of the immunodominant domain of the human immunodeficiency virus gp41 transmembrane protein: peptide conformation analysis using monoclonal antibodies and proton nuclear magnetic resonance spectroscopy.

Thirty-six monoclonal antibodies from mice and three from rats were raised against a peptide corresponding to the immunodominant domain of the transmembrane gp41 protein of human immunodeficiency virus (HIV) type 1 (LGLWGCSGKLIC; amino acid residues 598 to 609). Of these, three monoclonal antibodies from the mice and one from a rat also reacted with the corresponding peptide derived from the HIV type 2 transmembrane gp41 protein (amino acid residues 593 to 603; NSWGCAFRQVC). Immunochemical studies using a variety of synthetic peptides indicated that the cross-reactivity was due to antibody binding to CSGKLIC of HIV type 1 or CAFRQVC of HIV type 2. Single amino acid substitutions for a cysteine at either the amino or the carboxy end of the peptide interrupted antibody binding, indicating that the site recognized was the Cys-XXXXX-Cys loop. Similar results were obtained when the 11-mer HIV type 2 gp41 peptide (amino acids 593 to 603) was inoculated into mice to raise monoclonal antibodies. In this instance, of 30 monoclonal antibodies developed, 4 reacted with both HIV type 1 and HIV type 2 peptides. The conformation of a seven-residue peptide, CSGKLIC, corresponding to residues 603 to 609 of the gp41 immunodominant epitope of HIV-1 was investigated by proton nuclear magnetic resonance spectroscopy. The immunologically active form of CSGKLIC contains an intramolecular disulfide bond and maintains a preference for a folded conformation, apparently including a type I reverse turn about the residues SGKL. No such preference is observed for the reduced form of the peptide, which contains two thiol groups. The presence of the disulfide bond is thus integral to the formation of the structure of the loop in solution. In agreement with this finding, elimination of the possibility of loop formation by substitution of S for C at the amino or carboxy termini of the 7-mer is accompanied by the failure of antibody binding to this peptide.

Amino Acid Sequence↗
PubMed1991

Molecular basis of viral persistence: a single amino acid change in the glycoprotein of lymphocytic choriomeningitis virus is associated with suppression of the antiviral cytotoxic T-lymphocyte response and establishment of persistence.

Isolates of lymphocytic choriomeningitis virus (LCMV) that elicit a cytotoxic T-lymphocyte response (CTL+) have been compared with isolates that suppress the CTL response (CTL-) in an effort to map this phenotype. A single amino acid change in the glycoprotein of the LCMV Armstrong (ARM) strain is consistently associated with the CTL- trait and the ability of the virus to persist (P+). The CTL+ P- parental strain spontaneously gives rise to CTL- P+ variants within lymphoid tissues of mice persistently infected from birth. To map the structural basis of the phenotype, the complete RNA sequence of LCMV ARM 53b (CTL+) was compared with that of its variant ARM clone 13 (CTL-). Differences in 5 of 10,600 nucleotides were found. Three changes are noted in the large L RNA segment, and two are noted in the small S RNA segment. Only two of the changes distinguishing CTL+ from CTL- isolates affect amino acid coding: lysine to glutamine at amino acid 1079 of the polymerase protein, and phenylalanine to leucine at amino acid 260 of the envelope glycoprotein (GP). We also analyzed two additional CTL- variants and four spontaneous CTL+ revertants. All three CTL- variants differ from the original CTL+ parental strain at GP amino acid 260, indicating that this amino acid change is consistently associated with the CTL- phenotype. By contrast the other four mutations in LCMV are not associated with the CTL- phenotype. Sequence analysis of the coding regions of four CTL+ revertants of ARM clone 13 did not reveal back mutations at the GP 260 locus. This finding indicates that the GP 260 mutation is necessary but not sufficient for a CTL- P+ phenotype and that the reversion to CTL+ P- is likely either due to secondary mutations in other regions of the viral genome or to quasispecies within the revertant population that make significant contributions to the phenotype.

Amino Acid Sequence↗
PubMed1991

An HLA-C-restricted CD8+ cytotoxic T-lymphocyte clone recognizes a highly conserved epitope on human immunodeficiency virus type 1 gag.

A unique epitope on the gag protein of human immunodeficiency virus type 1 (HIV-1), located at amino acid 145 to 150, has been mapped by using a CD8+ cytotoxic T-lymphocyte (CTL) clone. This epitope is highly conserved among 18 HIV-1 strains. The HIV-1 gag-specific human leukocyte antigen (HLA) class I-restricted CD8+ CTL clone was generated from fresh peripheral blood mononuclear cells of an HIV-seropositive donor by stimulation with gamma-irradiated allogeneic peripheral blood mononuclear cells in the presence of an anti-CD3 monoclonal antibody and recombinant interleukin-2. This gag-specific CTL clone killed autologous target cells infected with a recombinant vaccinia virus containing the gag gene of HIV-1 and target cells pulsed with an authentic p24gag construct expressed in Escherichia coli. Fine specificity was determined by using a panel of overlapping 30-amino-acid-long synthetic peptides and subsequently using smaller peptides to precisely map the CTL domain on p24. The epitope is on a highly conserved region, and it overlaps with a major B-cell epitope of gag. This CD8+ T-cell epitope is restricted by HLA-Cw3, which has not been previously identified as a restricting element for human CTL responses.

Amino Acid Sequence↗
PubMed1991

Rapid activation of astrocyte-specific expression of GFAP-lacZ transgene by focal injury.

Astrocytes form a key cellular component of the central nervous system. They respond vigorously to diverse neurologic insults by undergoing hypertrophy and increasing expression of the glial fibrillary acidic protein (GFAP) gene, but their functions are largely unknown. To analyze astrocytes in vivo we constructed a transgenic vector from GFAP gene sequences and monitored its efficiency by fusing it to lacZ. Injection of the GFAP-lacZ hybrid gene into the germline of mice yielded six different lines of transgenic mice. In all lines the expression of lacZ was astrocyte-specific. In unmanipulated transgenic animals beta-galactosidase activity was much more prominent in astrocytes of the hippocampal formation, selected white matter tracts, and glial limitans than in astrocytes of other areas. This pattern of expression illustrates the physiologic heterogeneity of astrocytes and probably reflects differences in functional demands placed on these cells in different brain regions. Upmodulation of transgene expression was used to determine the time frame within which astroglial activation and increased GFAP gene expression occur following a neurologic insult. Induction of GFAP-lacZ expression was detectable within 1 hour after focal mechanical trauma. This demonstrates that the response of astrocytes to neurologic injury is very rapid and implies that these cells could fulfill important early functions in wound healing within the central nervous system.

Animals↗
PubMed1990

Detection of cytomegalovirus nucleic acid sequences in pancreas in type 2 diabetes.

Nucleic acid sequences specific for human cytomegalovirus (CMV) were found in samples of pancreatic tissue from patients with non-insulin-dependent (type 2) diabetes mellitus. RNA extracted from paraffin-embedded or fresh-frozen specimens from 14 of 32 (44%) diabetic patients but from none of 49 non-diabetic controls reacted with 10 kb (pJN201) or 6.6 kb (pCM3) probes of human CMV immediate-early or late gene products, respectively. The RNA from the 32 diabetic patients did not react with nucleic acid probes for mumps, rubella, or coxsackie B viruses. In-situ nucleic acid hybridisation on tissues from 5 randomly selected human-CMV-positive patients showed that the human CMV signal was localised primarily in the islets of Langerhans and not in exocrine cells. Despite the clear viral nucleic acid signal in tissues of human-CMV-positive patients, there were no morphological injuries to the islets, no inflammatory cells in the islets, and no perivascular inflammatory cell cuffing. These findings suggest a possible association of human CMV with type 2 diabetes in human beings.

Aged↗
PubMed1990

Viruses as therapeutic agents. I. Treatment of nonobese insulin-dependent diabetes mice with virus prevents insulin-dependent diabetes mellitus while maintaining general immune competence.

A situation in which virus can be used as a therapeutic agent to prevent a lethal autoimmune disease is explored. Nonobese insulin-dependent diabetes (NOD) mice spontaneously develop insulin-dependent diabetes mellitus (IDDM), characterized by lymphocytic infiltration into the islets of Langerhans and beta cell destruction, resulting in hypoinsulinemia, hyperglycemia, ketoacidosis, and death. Infection of NOD mice with lymphocytic choriomeningitis virus (LCMV) aborts the autoimmune manifestations and resultant IDDM. The viruses' effect is on a subset of CD4+ lymphocytes. Ablating this autoimmune diabetes does not significantly alter immune responses to a variety of non-LCMV antigens that require CD4+ lymphocyte participation. The prevention of IDDM associated with viral therapy is maintained throughout the life spans of NOD mice.

Animals↗
PubMed1990

Viruses as therapeutic agents. II. Viral reassortants map prevention of insulin-dependent diabetes mellitus to the small RNA of lymphocytic choriomeningitis virus.

Nonobese diabetic (NOD) mice are the experimental prototype of type 1 insulin-dependent diabetes mellitus (IDDM). These mice develop a characteristic autoimmune lesion in the pancreatic islets of Langerhans, where infiltrating lymphocytes destroy beta cells, resulting in hypoinsulinemia, hyperglycemia, ketoacidosis, and death. This IDDM, which closely resembles that in humans, is prevented by infecting NOD mice with particular strains of lymphocytic choriomeningitis virus (LCMV), including Armstrong 53b, Traub, WE, and Pasteur. In contrast, the LCMV Armstrong 53b variant, Clone 13, fails to abort IDDM. Hence, although Clone 13 establishes a persistent infection that endures throughout the life spans of NOD mice, their hyperglycemia, hypoinsulinemia, and lymphocytic infiltration into the islets of Langerhans still occur. Genetic reassortant viruses generated between the IDDM therapeutic strain of LCMV Pasteur and the nontherapeutic variant, LCMV Clone 13, were used to treat NOD mice. By using such reassortants and both parental strains of virus to infect NOD mice, the prevention of IDDM was mapped to the S RNA segment of LCMV Pasteur.

Amino Acid Sequence↗
PubMed1990

Viral persistence and immune dysfunction.

Viruses can persist for years without provoking an effective host immune response or otherwise causing the cell destruction characteristic of an acute viral infection. Clinically relevant principles, generalizable to many persistent viruses, are exemplified by measles and lymphocyte choriomeningitis viruses. The LCMV model indicates that viral persistence and the anergic state are reversible.

Animals↗
PubMed1990

Vaccination and protection from a lethal viral infection: identification, incorporation, and use of a cytotoxic T lymphocyte glycoprotein epitope.

The outcome of infection by lymphocytic choriomeningitis virus (LCMV) is determined largely by the cytotoxic T lymphocyte (CTL) response of the host. In H-2b mice, the anti-glycoprotein (GP) response is directed to at least two epitopes, one located at GP aa 272-286 and a second in GP-1. Here we show that the second epitope can be minimally identified by amino acid residues GP 34-40 (AVYNFAT). The epitope is restricted by the Db class I glycoprotein. Characterization of these CTL epitopes allowed us to address the role(s) played by each epitope when expressed singly in the control of a lethal challenge with LCMV. Here we show that a single immunization with a recombinant vaccinia virus (VV) vaccine expressing LCMV GP aa 1-59 confers protection to H-2b mice from lethal LCMV infection. In contrast, a VV expressing LCMV GP aa 272-293, although recognized by CTL, does not protect. We show that the success or failure of protective immunization is determined by the ability of the immunizing sequences to prime for CTL in vivo. Although the GP 278-286 epitope when contained as a "minigene" fails to induce CTL, when incorporated in the normal GP "backbone" it successfully elicits CTL. These observations suggest that the "minimal" recognition sequence alone may not be sufficient to induce a protective CTL response in vivo. Thus a single CTL epitope can protect against a lethal virus infection, but to achieve an effective vaccine, the immunizing sequences must be carefully selected.

Amino Acid Sequence↗
PubMed1990

A selective defect in tissue factor mRNA expression in monocytes from AIDS patients.

Expression of tumor necrosis factor (TNF alpha), tissue factor (TF), and interleukin 1-beta (IL-1 beta) mRNA was evaluated in monocytes isolated from patients infected with human immunodeficiency virus (HIV). There was a significant depression (66%) of the induced level of TF mRNA expression in response to lipopolysaccharide. Conversely, the response of TNF alpha and IL-1 beta, following LPS induction, was "normal." TF mRNA reduction was also observed to a lesser degree in AIDS-related complex patients (20%) but not in asymptomatic seropositives. TF is necessary for initiation of the coagulation protease cascade, leading to thrombin production and fibrin deposition, which play a role in inflammatory responses. Its selective reduction may be a factor in the diminished resistance to secondary infections observed in AIDS. Further, since the TF defect increases as patients progress toward AIDS, it may serve as a marker for disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Immunological cross-reactivity between mimicking epitopes on a virus protein and a human autoantigen depends on a single amino acid residue.

Recently we identified a novel autoantigenic region in the alpha chain of the human acetylcholine receptor (HuAChR), residues 160-167 (P. L. Schwimmbeck, T. Dyrberg, D. B. Drachman, and M. B. A. Oldstone, J. Clin. Invest., in press). Antibodies to that sequence appeared in the sera of a subset of patients with myasthenia gravis (MG) and affinity-purified antibody was biologically active for an in vitro assay of the HuAChR. Sequence homology between the autoantigen and two separate regions of herpes simplex virus glycoprotein D (HSV-GpD) have been identified. These components are, respectively, the HuAChR, residues [160-167] (PESDQPDL), and residues [286-293] (PNATQPEL) and [381-388] (PEDDQPSS) of HSV-GpD. Antisera from rabbits immunized with synthetic peptides representing HSV-GpD [286-293] bound strongly to the AChR peptide. In contrast, antiserum to HSV-GpD [381-388] bound minimally, if at all, even though both virus peptides shared four amino acids with the receptor sequence. To investigate the molecular basis for the differential binding, we tested the reactivity of the HSV-GpD antisera to analogs of the [381-388] virus peptide containing single amino acid substitutions. The results demonstrated that the cross-reactivity between HuAChR [160-167] and HSV-GpD [286-293] predominantly depends on a single residue, the C-terminal leucine in HSV-GpD, position 293.

Amino Acid Sequence↗
PubMed1990

Cytotoxic T lymphocytes do not control lymphocytic choriomeningitis virus infection of BB diabetes-prone rats.

BioBreeding Worcester diabetes-prone (BBdp) rats develop insulin-dependent autoimmune-driven diabetes mellitus spontaneously and intravenous administration of 1 x 10(7) p.f.u. of lymphocytic choriomeningitis virus (LCMV) to young adult mice prevents disease. The virus is lymphotropic, binding to and replicating in such cells. BBdp rats fail to generate virus-specific major histocompatibility complex-restricted cytotoxic T lymphocyte (CTL) responses when challenged with this dose or other doses of LCMV, Pichinde virus or vaccinia virus. Yet such rats clear virus effectively and show no evidence of persistent infection. Associated with this clearance of virus and establishment of immunity is the production of neutralizing antibodies. In contrast, diabetes-resistant (BBdr) rats generate virus-specific CTL responses. Furthermore LCMV binds to fewer lymphoid cells of BBdr rats (in comparison to those of BBdp rats) and replicates in fewer lymphocytes (by one order of magnitude) from these rats. Thus, unlike mice in which CTLs play a dominant role in the control of LCMV infection, BBdp rats do not overcome this infection via CTLs. In addition, both the BBdp rats and their BBdr counterpart may provide useful models for determining whether or how individual lymphocyte subsets function in the induction of CTL responses, for the analysis of virus-induced immunosuppression and for the use of viruses or their products as therapeutic modalities.

Animals↗