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F Vartdal

Publications and source records attributed to F Vartdal.

At least 91 records · Page 5Linked to original sources
PubMed1986

Immunofluorescence staining of agarose-embedded cells. A new technique developed for immunological characterization of markers on a small number of cells.

A simple new method for the immunofluorescence staining of small numbers of cells is described: cell suspensions are mixed with low-temperature-gelling agarose at 37 degrees C and 2 microliter samples of agarose containing cells are dispensed onto multitest microslides precoated with agarose. The cells are subsequently stained by immunofluorescence techniques. Alternatively, the cell slides can be stored in liquid nitrogen until immunofluorescence staining is carried out. Since cells are entrapped within the agarose matrix, cell loss is prevented during staining and washing procedures. The method permits staining of as few as 250 cells for each marker, thus enabling simultaneous characterization of several separate cell markers in cerebrospinal fluid or other body compartments from which comparatively few cells are obtainable.

Antigens, Surface↗
PubMed1986

Characterization of human mononuclear cells after positive selection with immunomagnetic particles.

We have investigated the possibility to employing magnetic monodisperse polymer particles for positive selection of human peripheral blood mononuclear cell populations. By carefully titrating the ratio between particles and cells we succeeded in isolating a number of cell populations that could be cultivated subsequently in vitro for functional studies. The success of the procedure is partly dependent on the properties of the monoclonal antibodies used to sensitize the cells. Provided these antibodies do not react with membrane structures involved in the transduction of activating signals, highly purified, quiescent cell populations can be recovered in a single fractionation step. In most instances particles will detach from the isolated cells by overnight culture, and the particles can then be removed from the system by a suitable magnet. T lymphocytes, subpopulations of T lymphocytes, and B lymphocytes have been isolated in this way and studied in a variety of functional assay systems. Comparison with cells obtained after negative selection clearly demonstrates the usefulness of this technique, especially if the membrane marker selected for it is not directly engaged in the activation processes.

Antibodies, Anti-Idiotypic↗
PubMed1986

HLA class I and II typing using cells positively selected from blood by immunomagnetic isolation--a fast and reliable technique.

This paper describes a new cell isolation and HLA typing technique, which permits cell separation and HLA class I or class II typing to be performed in 70 min. Magnetic monodisperse microspheres (Dynabeads TM) were coated with monoclonal antibodies (MAbs) specific for the CD8 T cell antigen or for HLA class II monomorphic epitopes. They could then be used to obtain HLA class I or class II positive cells directly from ACD blood in approximately 15 min by the use of magnetic separation. The cells (attached to the microspheres) were subsequently used in microcytotoxic HLA typing (total incubation time of 55 min) using acridin orange/ethidiumbromide to stain viable (yellow) and dead (red) cells. It was found that this immunomagnetic (IM) HLA typing technique was specific, has a sensitivity superior to that observed for conventional microcytotoxicity assays and gave low background staining. IM HLA-ABC typing of 50 healthy donors and 10 patients and IM HLA-DR typing of 25 healthy donors and 30 patients gave results corresponding well with that obtained independently by conventional HLA typing (concordancy rates 92-100%). Furthermore, the IM HLA typing technique permitted reliable HLA class II typing of blood cells from six patients where conventional HLA class II typing was impossible. The IM HLA typing technique also enables HLA class I and II typing to be quickly and reliably performed on cells from ACD blood of cadaveric donors.

Antibodies, Monoclonal↗
PubMed1986

Hereditary thrombocytopenia with excessively prolonged bleeding time, corrected by infusions of platelet poor plasma.

In a family with hereditary thrombocytopenia, transfused normal platelets as well as their own platelets had a shortened survival in the patients' circulation (11). On the other hand, the patients' platelets survived normally when transfused to a normal recipient. Platelet-associated immunoglobulins or circulating platelet antibodies were not detected (immunofluorescence method). About 200 ml platelet poor plasma (PPP) from each of 4 normal donors was infused daily for 5 consecutive d to 1 afflicted family member, causing a rise of platelet count from 65 X 10(9)/l to 163 X 10(9)/l and a decrease of bleeding time from 28 to 11 min 7 d after the PPP was discontinued. The platelet count then gradually decreased and was 65 X 10(9)/l with a bleeding time of 30 min 16 d after the PPP was discontinued. In a repeated PPP infusion experiment a similar response was evoked. It is concluded that the afflicted family members must have a deficiency of some plasma principle necessary to keep platelets fit and circulating.

Antibodies↗
PubMed1986

Immunogenic and antigenic epitopes of immunoglobulins. XIV. Antigenic variants of IgG4 proteins revealed with monoclonal antibodies.

Two IgG4 paraproteins having heavy chains of normal molecular weight are shown to be antigenically distinct in their reactivity profiles with 18 monoclonal antibodies having specificity for the IgG2 or IgG4 subclasses. One protein expresses IgG2 and IgG4 epitopes within the C gamma 2 domain. A second protein is deficient in the expression of IgG4 Fc-specific epitopes. These proteins will be of value in defining the structural basis of Fc effector functions and individual epitope expression.

Antibodies, Monoclonal↗
PubMed1985

Magnetic monosized polymer particles for fast and specific fractionation of human mononuclear cells.

Magnetic monodisperse polymer particles were developed and the necessary conditions established to use them for both quantification and fractionation of human peripheral blood mononuclear cell populations. The particles consist of a styrene divinylbenzene core into which magnetite has been deposited by an in situ oxidation process. Thereafter the core has been coated with a hydrophilic polymer containing epoxy and hydroxyl groups. The particles have strong nonspecific binding capacity for protein and can be coated with the appropriate antibodies by physical adsorption only. However, the hydroxyl groups on the outer polymer also make covalent coupling possible. After appropriate blocking they can be used in a rosette assay for quantification of mononuclear leukocytes previously sensitized with monoclonal antibodies. Furthermore, a suitable magnet makes it possible to deplete the cell suspension efficiently of the rosette-forming cells. We have thoroughly investigated the functional properties of human mononuclear cells depleted of T lymphocytes by this technique. Our results show that T cells are virtually completely eliminated, as demonstrated by flow cytometry and various functional assay systems.

Antibodies, Monoclonal↗
PubMed1984

Subclasses of IgG produced in the rheumatoid synovium.

The subclass distribution of IgG plasma cells was studied in sections of rheumatoid synovial tissue from 15 cases with seropositive rheumatoid arthritis and 8 cases with various types of seronegative arthritis, using the immunofluorescence technique and monoclonal IgG-subclass-specific antibodies. In most tissues, plasma cells of all the four subclasses were present, and IgG1 was usually the dominating subclass. The frequency of IgG3 plasma cells was usually higher than that of IgG2. The results are partly in contrast with previous observations and do not give evidence for a subclass-specific polyclonal B-cell activator, growth factor or differentiation factor.

Antibodies, Monoclonal↗
PubMed1983

Imprint immunofixation of electrofocused immunoglobulins.

An imprint immunofixation (IIF) technique for the characterization of electrofocused immunoglobulins (Ig) is described. Electrofocused proteins are blotted (imprinted) from the separating polyacrylamide gel to agarose gels by gel-to-gel overlays. The protein imprints are chemically fixed in the agarose gels with a solution of 46% methanol, 8% acetic acid and 46% water. The imprinted Ig are then identified radioimmunologically, using an indirect system with monoclonal mouse anti-human Ig antibodies in the first layer and 125I-labelled rabbit anti-mouse Ig in the second, followed by autoradiography. The method is sensitive and permits characterization of Ig in unconcentrated cerebrospinal fluid. By sequential imprinting, each separated specimen can be characterized for up to 10 separate antigenic determinants without loss of sensitivity.

Autoradiography↗
PubMed1983

Imprint immunofixation of IgG subclasses, using monoclonal subclass-specific antibodies.

Monoclonal mouse hybridoma antibodies to human IgG subclasses 1-4 were used in an imprint immunofixation (IIF) technique to characterize the IgG subclass of a panel of IgG myeloma and normal sera separated by thin-layer electrofocusing. The results show that the antisera were IgG subclass-specific by this technique and that IIF can be a useful method in identifying IgG subclasses of IgG myeloma proteins in whole sera.

Antibodies, Monoclonal↗
PubMed1983

Multiple sclerosis: subclasses of intrathecally synthesized IgG and measles and varicella zoster virus IgG antibodies.

Paired samples of serum and concentrated cerebrospinal fluid (CSF) from 20 multiple sclerosis (MS) patients and 10 controls with no central nervous system disease were electrofocused and analysed for IgG and measles and varicella zoster virus IgG antibodies by imprint immunofixation using IgG subclass specific monoclonal antibodies. All but one of the MS patients had intrathecally synthesized bands of oligoclonal IgG in the CSF. In fifteen of the MS patients the oligoclonal IgG bands were restricted to the IgG1 subclass. Intrathecal synthesis of both IgG1 and IgG3 bands was observed in three, and of IgG1, IgG2 and IgG3 bands in one patient. Fourteen and 15 of the MS patients displayed intrathecal synthesis of oligoclonal varicella zoster and measles virus specific IgG1 antibodies, respectively, and no serum or CSF sample contained antibodies of other IgG subclasses to these viruses. Low levels of polyclonal IgG1 antibodies to measles or varicella zoster viruses were detected in serum and CSF from the controls; none displayed evidence of intrathecal antibody synthesis. These findings are discussed in relation to theories of specific and non-specific intrathecal immune responses in MS.

Antibodies, Viral↗
PubMed1983

Characterization of classes of intrathecally synthesized antibodies by imprint immunofixation of electrophoretically separated sera and cerebrospinal fluids.

The use of imprint immunofixation (IIF) method to identify IgG, IgA and IgM classes of microbial antibodies in electrophoretically separated sera and cerebrospinal fluids (CSF) is described. The method was applied to the analysis of intrathecal antibody responses in mumps meningitis, subacute sclerosing panencephalitis (SSPE), neurosyphilis and multiple sclerosis (MS). Intrathecally synthesized mumps virus-specific IgG, IgA and IgM antibodies were demonstrated in the CSF of patients with mumps meningitis. The intrathecally synthesized IgG and IgM antibodies displayed oligoclonal characteristics, while the IgA antibodies appeared to be mainly polyclonal. The intrathecal measles antibody responses in SSPE appeared to be confined to IgG antibodies. In neurosyphilis, the intrathecal treponemal antibody response was predominantly of the IgG class, but IgA antibodies were demonstrated in two of nine patients. Intrathecally synthesized IgG antibodies to measles and/or varicella-zoster viruses were demonstrated in 17 of 18 patients with MS; IgA or IgM antibodies to these viruses were not detected.

Antibodies, Bacterial↗
PubMed1982

Neurosyphilis: intrathecal synthesis of oligoclonal antibodies to Treponema pallidum.

Oligoclonal IgG was present in the cerebrospinal fluid (CSF) of each of three patients with neurosyphilis studied. Conventional serological tests disclosed reduced serum/CSF ratios of antibodies to Treponema pallidum (TP) in each patient, consistent with intrathecal production of treponemal antibodies. Antibody analyses of electrofocused specimens by an immunofixation technique disclosed intrathecal production of oligoclonal TP antibodies in all patients. Treponemal antibody light chains showed a close correlation with the light chains of the oligoclonal CSF IgG. Absorption of the CSF with TP caused removal of the oligoclonal IgG. The results provide strong evidence that the oligoclonal CSF IgG in neurosyphilis represents TP antibodies, reflecting a specific immune response in the central nervous system to the infectious agent.

Aged↗
PubMed1982

Herpes simplex virus encephalitis: intrathecal synthesis of oligoclonal virus-specific IgG, IgA and IgM antibodies.

Paired specimens of serum and CSF from seven patients with acute herpes simplex virus encephalitis were examined during the acute illness or the convalescent stage or during both stages. Imprint immunofixation analyses of viral antibodies separated by agarose electrophoresis and by electrofocusing disclosed intrathecal production of herpes simplex virus IgG antibodies in all seven patients, and of IgA and IgM antibodies in six and three of six patients, respectively. Intrathecal production of herpes simplex virus-specific IgG and IgA was observed in two patients from whom samples were collected after 1 year, while intrathecal production of virus-specific IgM was not demonstrated later than 5 weeks after onset. The intrathecally synthesized IgG and IgM, and to a lesser extent IgA antibodies displayed oligoclonal characteristics. Oligoclonal bands of IgG were observed in the CSF of all patients. Evidence is presented to show that the bulk of the oligoclonal CSF IgG represents herpes simplex virus-specific antibodies. Intrathecally synthesized populations of herpes simplex virus antibodies cross-reacting with varicella-zoster virus were identified in three of the patients.

Adolescent↗
PubMed1982

Multiple sclerosis. Electrofocused "bands" of oligoclonal CSF IgG do not carry antibody activity against measles, varicella-zoster or rotaviruses.

Electrofocused serum and cerebrospinal fluid (CSF) specimens from patients with multiple sclerosis (MS) were analysed for immunoglobulins (Ig) and for antibodies to measles, varicella-zoster and rotaviruses by an imprint immunofixation method. Patterns of intrathecally synthesized antibodies to the 3 viruses differed from patterns of oligoclonal IgG in the CSF. A variable proportion of virus antibody bands (average 19% for measles antibodies, 8% for varicella-zoster antibodies, 31% for rotavirus antibodies) displayed isoelectric points identical to bands of IgG, but absorption with measles, varicella-zoster and rotavirus antigens produced no change in the bands of IgG and no quantifiable decrease of the CSF IgG. The results confirm previous evidence that the intrathecally synthesized viral antibodies so far demonstrated in MS are not carried by the oligoclonal bands of CSF IgG and account for only a minor fraction of the CSF IgG.

Antibodies, Viral↗
PubMed1982

Mumps meningitis: specific and non-specific antibody responses in the central nervous system.

Intrathecal production of oligoclonal mumps-specific IgG was demonstrated in nine out of 10 children with mumps meningitis by imprint immunofixation (IIF) of sera and cerebrospinal fluids (CSF) separated by agarose electropheresis and by thin-layer electrofocusing. Four of the patients had intrathecal mumps antibody synthesis demonstrable also by conventional serological tests. Oligoclonal CSF IgG was demonstrable by agarose electrophoresis in four of the patients. A dominance of lambda over k type oligoclonal Ig and mumps antibodies was observed in the CSF of three of these patients. The bulk of the oligoclonal CSF IgG was concluded to represent mumps-specific antibodies on the basis of the IIF as well as virus absorption analysis. Intrathecal production of oligoclonal IgG antibodies to one, two, or three other (measles, rubella, herpes simplex) viruses was demonstrated by IIF in four patients. These antibodies were not associated with the oligoclonal CSF IgG present in three of the patients. It is concluded that a specific intrathecal IgG antibody response is a common feature in children with mumps meningitis. This response sometimes reaches a magnitude that permits detection of oligoclonal IgG in the CSF. In some patients, the specific response appears to be associated with a non-specific activation of cells producing antibodies of other (unrelated) specificity.

Antibodies, Viral↗