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Biomedical subjects

A L Notkins

Publications and source records attributed to A L Notkins.

At least 145 records · Page 8Linked to original sources

Human lymphocytes making rheumatoid factor and antibody to ssDNA belong to Leu-1+ B-cell subset.

B lymphocytes bearing the Leu-1 cell-surface antigen (Leu-1+), the human equivalent of mouse Ly-1+ B lymphocytes, have been detected in human peripheral blood, but there is little information on their frequency and properties. Analysis by fluorescence-activated cell sorter and double immunofluorescence showed that Leu-1+ B cells are consistently present in the peripheral blood and spleens of healthy subjects and constitute 17.0 +/- 5.0% (mean value +/- standard deviation) and 17.3 +/- 3.9%, respectively, of total B cells. When purified Leu-1+ and Leu-1- B lymphocytes were transformed into immunoglobulin-secreting cells by infection with Epstein-Barr virus and the culture fluids were tested for reactivity with self-antigens, at least two important autoantibodies, antibody to the Fc fragment of human immunoglobulin G (rheumatoid factor) and antibody to single-stranded DNA, were found to be made exclusively by Leu-1+ B cells. It is concluded that the Leu-1+ lymphocytes represent a major subset of the normal human B cell repertoire and include the B cells capable of making autoantibodies similar to those found in systemic lupus erythematosus and rheumatoid arthritis.

Antibodies, Anti-Idiotypic↗

Pancreatic islet cell surface glycoproteins containing Gal beta 1-4GlcNAc-R identified by a cytotoxic monoclonal autoantibody.

To investigate the autoimmune pathogenesis of spontaneously occurring diabetes mellitus in BB rats, spleen cells of newly diagnosed diabetic BB rats were fused with mouse myeloma cells. Hybridoma supernatants were screened for antibodies by indirect immunofluorescence and by 51Cr-release assays using the RINm5F rat insulinoma cell line. One clone, E5C2, produced an IgM kappa antibody that was cytotoxic for RINm5F cells, but not for other rat cell lines nor for primary rat islet cells. However, treatment of primary rat islet cells with neuraminidase exposed surface antigens and rendered the cells susceptible to complement-mediated lysis by antibody E5C2. Using immunostaining of glycolipids separated by thin-layer chromatography, hapten inhibition assays with defined carbohydrates, and Western blots, the antigens recognized by E5C2 on RINm5F cells were identified as glycoproteins with molecular weights of 60,000 and 68,000. The antibody recognizes a carbohydrate antigen containing the sequence Gal beta 1-4GlcNAc-R, which on RINm5F cells is predominantly hidden by covalently bound sialic acid. These studies raise the possibility that hidden antigenic determinants on islet cells exposed by a variety of means may be the target of autoimmune attack.

Animals↗

Viral and host genetic factors influence encephalomyocarditis virus-induced polymyositis in adult mice.

Recent research findings implicate picornaviruses in the etiology of human polymyositis/dermatomyositis and suggest that genetic factors play a role in susceptibility to these diseases. We compared 2 variants of encephalomyocarditis (EMC) virus for their ability to induce polymyositis in adult mice, and evaluated what role the genetic background of the host plays in the degree of myositis induced. While BALB/c mice developed minimal myositis when infected with a diabetogenic variant (EMC-D), the same strain inoculated with a newly isolated myopathic variant (EMC-221A) developed viral dose-dependent elevations in muscle-associated enzymes, bilateral limb muscle weakness, and the histopathologic changes of severe polymyositis. Mice with different genetic backgrounds showed significantly different susceptibilities to EMC-221A. These data suggest that the severity of polymyositis induced by EMC virus is influenced by both the viral and host genomes.

Animals↗

Reactivation of latent herpes simplex virus infection by ultraviolet light: a human model.

Infection with herpes simplex virus often results in a latent infection of local sensory ganglia and a disease characterized by periodic viral reactivation and mucocutaneous lesions. The factors that trigger reactivation in humans are still poorly defined. In our study, five patients with documented histories of recurrent herpes simplex virus infection on the buttocks or sacrum were exposed to three times their minimal erythema dose of ultraviolet light. Site-specific cutaneous herpes simplex virus infection occurred at 4.4 +/- 0.4 days after exposure to ultraviolet light in 8 of 13 attempts at reactivation. We conclude that ultraviolet light can reactivate herpes simplex virus under experimentally defined conditions. This model in humans should prove useful in evaluating the pathophysiology and prevention of viral reactivation.

Adult↗

Expression of herpes simplex virus 1 glycoprotein B by a recombinant vaccinia virus and protection of mice against lethal herpes simplex virus 1 infection.

The herpes simplex virus 1 (HSV-1) strain F gene encoding glycoprotein gB was isolated and modified at the 5' end by in vitro oligonucleotide-directed mutagenesis. The modified gB gene was inserted into the vaccinia virus genome and expressed under the control of a vaccinia virus promoter. The mature gB glycoprotein produced by the vaccinia virus recombinant was glycosylated, was expressed at the cell surface, and was indistinguishable from authentic HSV-1 gB in terms of electrophoretic mobility. Mice immunized intradermally with the recombinant vaccinia virus produced gB-specific neutralizing antibodies and were resistant to a lethal HSV-1 challenge.

Animals↗

Continued expression of a poly(A)+ transcript of herpes simplex virus type 1 in trigeminal ganglia of latently infected mice.

Radioactively labeled cDNAs were prepared by using as the template poly(A)+ mRNA from trigeminal ganglia of mice latently infected with herpes simplex virus type 1. These cDNAs were used as hybridization probes for Southern blots of cloned herpes simplex virus type 1 DNA fragments. Specific hybridization to fragments from the terminal repetition of the L segment was detected with probes derived from mRNAs obtained as early as 3 weeks and as late as 17 months postinoculation. Fine mapping of the region of hybridization showed that the viral transcripts originated from DNA sequences coding for the immediate-early gene IE-1 (alpha-0). These results indicate that IE-1, or an as yet unidentified gene colinear with it, is continuously expressed during latency.

Animals↗

Human monoclonals from antigen-specific selection of B lymphocytes and transformation by EBV.

Hybridoma technology has made it possible to prepare monoclonal antibodies with the use of murine lymphocytes. Attempts to extend this technology to the human level, however, have met with difficulties. A method has been developed for making human monoclonal antibodies of predetermined specificity. Biotinylated antigens (human thyroglobulin or tetanus toxoid) were incubated with human B lymphocytes from peripheral blood. The lymphocytes to which the antigens bound were selected by fluorescence-activated cell sorting. Positively selected (high fluorescence) and negatively selected (low fluorescence) cells were then transformed with Epstein-Barr virus (EBV) and grown in microculture wells. All wells from the positively selected fraction produced antigen-specific antibody (95 to 1800 nanogram-equivalents per milliliter), whereas fewer than 6% of the wells from negatively selected fraction made any detectable antibody (less than 10 nanogram-equivalents per milliliter). When the positively selected EBV-transformed cells were cultured in limiting dilution, clones were obtained that made antigen-specific monoclonal antibodies. By this method, monoclonal antibodies to both foreign antigens and autoantigens can be prepared from the normal human B-cell repertoire.

Antibodies, Monoclonal↗

Multiple organ-reactive IgG antibody induced by an antiidiotypic antibody to a human monoclonal IgM autoantibody.

MOR-h1 is a human multiple organ-reactive (MOR) monoclonal autoantibody (Ab1) that reacts with human growth hormone (hGH) and a 35 kD protein found in the anterior pituitary, thyroid, stomach, and pancreas. 4E6 is a mouse monoclonal anti-idiotypic antibody (Ab2) that reacts with the paratope of MOR-h1 and is ligand inhibitable. In the present study, we immunized a rabbit with 4E6 and purified an IgG fraction (anti-4E6) from the sera. Competitive inhibition experiments showed that anti-4E6 (Ab3) binds to the same epitope on 4E6 and to the same antigens (i.e., hGH and 35 kD protein) as does MOR-h1. By immunofluorescence, anti-4E6, an IgG antibody, shows the same multiple organ reactivity with tissues as does MOR-h1, an IgM antibody. From these and other studies, we conclude that the 4E6 paratope (Ab2) has a conformational resemblance to an epitope on hGH and the 35 kD protein. This raises the possibility that antibodies made in response to certain anti-idiotypic antibodies may be one of the mechanisms for triggering an autoimmune response.

Antibodies, Anti-Idiotypic↗

Anti-idiotypic antibodies to monoclonal antibodies that neutralize coxsackievirus B4 do not recognize viral receptors.

We have made anti-idiotypic antibodies in rabbits against three mouse monoclonal neutralizing antibodies with specificities for independent epitopes on Coxsackievirus B4. Each of these anti-idiotypic antibodies was found to react specifically with the immunizing monoclonal antibody in radioimmunoassays and did not react with the other monoclonal antibodies. In addition, the anti-idiotypic antibodies specifically inhibited the function (i.e., virus neutralization) of the immunizing antibody. These anti-idiotypic antibodies were tested for their ability to recognize receptors for Coxsackievirus B4 as measured by their ability to inhibit the attachment of radiolabeled virus to cellular receptors. The anti-idiotypic antibodies did not block the binding of Coxsackievirus B4 to monkey kidney cells. Moreover, when tested for their ability to bind to other receptor positive cells, none of the anti-idiotypic antibodies bound above control levels. Anti-idiotypic antibodies did induce a small anti-anti-idiotypic antibody response in mice when tested by radioimmunoassay; however, little if any virus neutralizing activity was found in the sera of these mice. Our results contrast to those reported for anti-idiotypic antibodies in several other virus systems and suggest that not all anti-idiotypic antibodies made against neutralizing antibodies are capable of eliciting an antiviral immune response or binding to viral viral receptors on cells.

Animals↗

Monoclonal autoantibodies that react with multiple organs. Basis for reactivity.

We have been able to make monoclonal MOR antibodies in several different ways. First, we have been able to prepare MOR antibodies from mice with autoimmune disease and from humans with autoimmune disease. Second, we have prepared MOR antibodies from normal mice without autoimmune disease and from healthy humans without evidence of autoimmune disease. Third, we have prepared MOR antibodies by hybridoma technology and by transformation of lymphocytes with EBV. We have shown that MOR antibodies are common and are part of the host's normal B-cell repertoire. Our studies raise the possibility that most monoclonal autoantibodies, when extensively screened, will to a greater or lesser degree be of the MOR type.

Animals↗

Molecular mimicry: frequency of reactivity of monoclonal antiviral antibodies with normal tissues.

More than 600 monoclonal antiviral antibodies made against 11 different viruses were screened against 14 different organs from normal uninfected mice. Of these antiviral antibodies, 21, or approximately 3.5%, reacted with specific cells in these organs. Several of these antibodies were of the multiple-organ-reactive type and recognized antigens in more than one organ. It was concluded that the reactivity of monoclonal antiviral antibodies with normal tissues is a common phenomenon.

Animals↗

Human monoclonal autoantibodies that react with both pancreatic islets and thyroid.

Transformation of human peripheral blood lymphocytes with Epstein-Barr virus and rapid screening on rat insulinoma cells by an enzyme-linked immunosorbent assay were used to identify monoclonal autoantibodies that reacted with human pancreatic islets. Six such monoclonal autoantibodies were isolated and cloned. All six also were found to react with human thyroid. It is concluded that lymphocytes able to make autoantibodies that react with both the pancreas and thyroid are common in the human B cell repertoire.

Animals↗

Coxsackie virus B4 produces transient diabetes in nonhuman primates.

Cynomolgus, rhesus, and Cebus monkeys failed to show glucose tolerance or insulin secretion abnormalities after infection with encephalomyocarditis virus or Coxsackie virus B4. Patas monkeys also showed no abnormalities after infection with encephalomyocarditis virus. However, patas monkeys infected with Coxsackie virus B4 or treated first with a subdiabetogenic dose of streptozocin and then infected sequentially with Coxsackie viruses B4 and B3 showed transient elevation of glucose tolerance tests, depressed insulin secretion, and glucose in the urine. Our experiments in nonhuman primates support earlier studies in mice and humans that under certain circumstances, Coxsackie viruses can cause abnormalities in glucose homeostasis.

Animals↗

Detection of conserved and nonconserved epitopes on Coxsackievirus B4: frequency of antigenic change.

A sensitive microneutralization assay was used to detect antigenic variants of Coxsackievirus B4. Analysis of 47 clinical isolates with 16 monoclonal neutralizing antibodies revealed highly conserved, moderately conserved, and poorly conserved epitopes. Upon passage of Coxsackievirus B4 in tissue culture, certain epitopes disappeared and others appeared in the apparent absence of selective pressure. Changes in epitopes often exceeded a frequency of 10(-2). Despite considerable variation in individual epitopes, the overall antigenic composition of Coxsackievirus B4, as measured by the capacity of hyperimmune serum to neutralize clinical isolates, remains fairly constant.

Antibodies, Monoclonal↗

Triad of markers for identifying children at high risk of developing insulin-dependent diabetes mellitus.

A longitudinal investigation was conducted from 1977 to 1984 on 178 families in which one or more of the children had insulin-dependent diabetes mellitus. Of 351 nondiabetic sibs followed up for an average of 54 months, ten have, thus far, become diabetic. Eight sibs were HLA identical to their diabetic proband and nine had HLA-DR3 and/or HLA-DR4. Islet cell surface antibody and islet cell cytoplasmic antibody were found from two to 74 months before the onset of clinical diabetes in 100% and 90%, respectively, of the children. A decrease in insulin secretion was observed in all of these children on entry into the study and was detected in the absence of elevated plasma glucose concentrations. The data suggest that the triad of HLA identity, pancreatic islet cell antibodies, and depressed insulin secretion identifies those sibs who are at high risk of developing insulin-dependent diabetes mellitus.

Adolescent↗