Galactose oxidase labeling of membrane proteins from human brain white matter

The use of galactose oxidase (EC 1.1.3.9) and tritiated sodium borohydride for labeling of membrane glycoproteins, described by Gahmberg and Hakomori, has previously been applied to the study of myelin glycoproteins of experimental animals. Rat brain myelin glycoproteins have been studied by sequential lectin affinity of chromatography and recently the lectin-binding capacity of rat central nervous system myelin glycoproteins has been characterized. Complex heterogeneity of the glycoprotein pattern of rat central nervous system myelin has been reported, and so a variety of glycoproteins can be expected to exist in human white matter membranes. Application of the galactose oxidase procedure to the study of human brain membranes could be useful in research concerning certain neurological diseases if the properties of autopsy brain material are taken into account. In this study, membrane proteins of human autopsy brain white matter were subjected to the galactose oxidase/NaB3H4 labeling procedure and the membrane labeled by this method or by the [3H]acetic anhydride techniques were studied by lectin affinity chromatography using Lens culinaris phytohemagglutinin (lentil lectin) attached to Sepharose 4B beads.

Lymphocyte blast transformation responses and viral antibodies in relation to HLA antigens in multiple sclerosis

Fifty four clinically stable multiple sclerosis (MS) patients and 54 age- and sex-matched control subjects were HLA-typed, and their responses to herpes simplex, measles, mumps and rubella antigens were examined by the lymphocyte blast transformation test and by serum antibody titrations. Blast transformation response to purified tuberculin (PPD), mitogen phytohaemagglutinin (PHA), pokeweed mitogen (PWN) and concanavalin A (Con A) and spontaneous proliferation of lymphocytes were also studied. MS patients differed from controls by higher antibody levels to measles and rubella viruses and by lower specific blast transformation responses to rubella and measles antigens. When the relative strength of transformation responses was measured, mumps and herpes simplex responses were also lower in MS patients than in controls. In addition, spontaneous lymphocyte proliferation of MS patients in 6-day cultures was lower than that of control lymphocytes. In mitogen stimulations there were no differences between whole groups, but the oldest patients had lower responses to PHA and Con A than their matched controls. The frequency of HLA-Dw2 was 56.6% in MS patients and 32.1% in controls. The patients with and without Dw2 differed from each other only by a lower specific response to PPD in the Dw2-positive group. The immunological response of Dw2-positive controls resembled that of MS patients: low transformation response to viral antigens, low spontaneous proliferation and elevated measles antibodies. This finding supports the function of a genetically determined type of immune responsiveness with low cell-mediated immunity and high levels of certain viral antibodies as one susceptibility factor in multiple sclerosis.

Circulating immune complexes, immunoconglutinins, and rheumatoid factors in nephropathia epidemica

Circulating immune complexes (CICs), immunoconglutinins, and antiglobulins were studied in nephropathia epidemica, an acute infectious hemorrhagic fever occurring in Finland and Scandinavia. Sixty-one serum specimens from 18 serologically confirmed patients were collected between day -5 and day 230 from the onset of fever. Five CIC tests, three immunoconglutinin tests, and various other tests were used to characterize the disease immunologically. CICs were found in all patients. The percentage detection of positive cases varied in the tests from 100% to 22%. A marked stimulation of levels of the IgM class of immunoglobulins were observed. Antiglobulin tests were positive for all of the patients. No correlation between the test results and the clinical severity of the disease could be found. Of special interest was the delay in the rise of CIC levels compared with the chromologic pattern of the clinical course. In some patients a prolonged appearance of CICs for eight months was observed.

Proliferation of multiple sclerosis cerebrospinal fluid lymphocytes after stimulation with measles virus antigens

A method for measuring the proliferative response of cerebrospinal fluid (CSF) lymphocytes upon stimulation and mitogens and viral antigens has been developed. The number of lymphoid cells in DNA synthesis after in vitro stimulation is counted and the results expressed as a percentage of the total number of surviving lymphocytes. Preliminary results on four MS patients indicated that their CSF lymphocytes responded considerably more strongly to purified measles virus antigen than did corresponding peripheral blood lymphocytes (PBL). The responses to crude herpes virus antigen were at least as strong in PBL as in CSF lymphocyte cultures from the same patients. The CSF lymphocytes responded slightly stronger to phytohemagglutinin than PBL did.

Lymphocyte blast transformation responses in measles infection

Lymphocyte blast transformation responses were studied in eight patients with natural measles infection. A specific response to purified measles virus antigen and a weaker response to crude measles virus antigen were found after infection. The response to purified measles antigen appeared 1-3 weeks after the beginning of the rash, when the great number of proliferating mononuclear cells found in the peripheral blood during the rash was declining. In the first weeks after onset of the rash also leucocyte and lymphocyte numbers were decreased, and specific responses to purified tuberculin (PPD) and to rubella and mumps virus antigens were suppressed. In mitogen stimulation tests there was no significant suppression of phytohaemagglutinin and concanavalin responses in this small series, but the response to pokeweed mitogen was decreased. The responses to antigens other than measles virus antigens recovered in parallel with the increase of the measles-specific response.

Involvement of the central nervous system in acute, uncomplicated measles virus infection

A prospective study on acute, uncomplicated measles infection was carried out in 59 patients hospitalized for an ordinary measles infection. A clinical and serological diagnosis of an acute measles infection was made in all cases. Serial serum and cerebrospinal fluid (CSF) specimens were taken two to five times from each patient and tested for pleocytosis, albumin, and measles-specific antibodies. Pleocytosis was found in 18 patients (30%), usually shortly after the onset of rash. Nine patients had antibodies against measles virus in their CSF. Six of them seemed to have damage to the blood-brain barrier, but in two cases there was a very high serum antibody titer with a normal serum/CSF ratio. One patient had a local antibody production against measles virus in the central nervous system. Conventional electroencephalography (EEG) was recorded on 22 children, and a separate, quantitative EEG study with two to six consecutive recordings was also performed on a group of nine patients. Moderate or strong slowing of background EEG activity was found in 50% of the patients. In the consecutive recordings, the changes culminated a few days after the onset of rash. No correlation seemed to exist between the changes in the CSF and the age of the patient, on the one hand, and slowing of the EEG, on the other.

The glycoprotein of measles virus. External radioactive labelling of its carbohydrate and partial characterization of the glycopeptide

Measles virus was propagated in VERO cells and purified from the culture supernatants by two successive tartrate-density-gradient centrifugations. Surface carbohydrates were labelled both in vitro and in vivo with 3H after treatment with galactose oxidase/NaB3H4 or with [3H]glucosamine. The major labelled glycoprotein in measles virions had a mol.wt. of 79 000. After labelling with periodate/NaB3H4, which would result in specific labelling of sialic acid residues, the 79 000-mol.wt. glycoprotein was very weakly labelled. This suggests that there is no or a very low amount of sialic acid in the virions. Further analysis of the glycoprotein showed that galactose is the terminal carbohydrate unit in the oligosaccharide, and the molecular weight of the glycopeptide obtained after Pronase digestion is about 3000. The oligosaccharide is attached to the polypeptide through an alkali-stable bond, indicating a N-glycosidic asparagine linkage.

Tumorigenicity and karyotype of rat embryo cell lines transformed by BK virus

A rat embryo cell line transformed by BK virus was used to induce tumors in rats. Cell lines were established from these tumors. Other sublines were obtained by in vitro cloning of the parental line. Growth characteristics and karyotypes were compared to the tumorigenicity of these cell lines. The in vitro cloned sublines had a low tumorigenicity. Tumorigenicity of the tumor cell lines varied from high to undetectable. The tumor cell line with the highest tumorigenicity also had the highest saturation density in vitro, but otherwise there was little correlation between tumorigenicity and the in vitro characteristics of the cells. Karyotype analysis was done for two cell lines with high or low tumorigenicity which both had a near-diploid complement of chromosomes. The findings were in agreement with the expression-supression model of Rabinowitz and Sachs (1970). The suppression chromosomes seemed to be confined in group A, the expression chromosomes in group B.

Measles and rubella virus antibodies in patients with multiple sclerosis. A longitudinal study of serum and CSF specimens by radioimmunoassay

A longitudinal study on rubella, measles, and respiratory syncytial virus antibodies in serial serum and CSF specimens from 20 multiple sclerosis (MS) patients was performed, using solid-phase radioimmunoassay. Albumin and immunoglobulin G (IgG) levels were also measured to check the integrity of the blood-brain barrier and the intrathecal IgG production. All the patients had local IgG production in their CNA. A local antibody production against one or more of the viruses studied was evident in 15 patients. Fluctuations in the intrathecal viral antibody synthesis were evident in eight patients. No correlation was found between these changes and the clinical course of the disease. The results suggest that the intrathecal antibody synthesis in MS is only partially against any given virus, and in most patients the bulk of the oligoclonal CSF antibodies is against antigens other than those studied here.

Adherence of multiple sclerosis lymphocytes to measles infected cells

Adherence of lymphocytes from multiple sclerosis (MS) patients and control subjects to cells persistently infected by measles and control cells was studied. No statistically significant difference between MS patients and controls could be found in this test. Lymphocytes adhered more readily to cells infected by measles than to control cells. The cell to cell contacts are made by the tips of the microvillii of the Lu cells.

Isolation and characterization of BK virus-transformed rat and mouse cells

The isolation and characterization of four groups of BK virus (BKV)-transformed rat embryo fibroblast (RE) and mouse kidney (MK) cells are described. They consist of (1) seven RE lines transformed with a BKV pool containing a high proportion of defective virions, and (2) 16 RE, (3) 14 Balb/c-MK and (4) 2 Swiss ICR-MK lines, all transformed, at different input multiplicities, with a pool of BKV free of defective virions. None of the lines produces BKV, all contain BKV T antigen and all grow to higher saturation densities and have higher plating efficiencies than do the corresponding control cells. Cells of the RE lines, transformed with the BKV pool containing defective virions, form colonies in soft agar and produce tumours in irradiated weanling rats, while those of the RE lines transformed with the defective virion-free pool do neither. Cells of the Balb/c-MK, but not of the ICR-MK lines are tumorigenic, although cells of both groups form colonies in soft agar. In general, those lines transformed at higher multiplicities express the biological properties associated with transformation more strongly than do those transformed at lower multiplicities.

OC43 strain-related coronavirus antibodies in different age groups

Serum antibodies against human coronavirus OC43 in different age groups were measured by complement fixation (CF), haemagglutination inhibition (HI), radial diffusion haemolysis-in-gel (HIG), and solid-phase radioimmunoassay (RIA) methods. Antigen grown in suckling mouse brain was used in all tests. Results obtained by the CF and HIG tests, and the RIA, were in good agreement with regard to the presence or absence of antibodies. Similar results were also obtained with the HI test if nonspecific haemagglutination inhibitors were first removed by treatment with phospholipase C and only titers of 1:20 or greater were considered positive. Children 6--23 months of age (n = 45) were without measurable coronavirus antibodies in all four assays. A rapid increase in the prevalence of antibodies then occurred in subsequent age groups, and practically all persons 6 years of age or older were found to have OC43 antibodies as measured by the HIG test or the RIA. The mean antibody levels determined by these two methods continued to increase, however, up to the age group of 10--14 years. This increase in antibody levels after the initial antibody incidence plateau may be due to boosting effects caused by related coronavirus strains, since OC43 antigens are known to cross-react with antibodies induced by other human coronaviruses. Taken together, these data suggest that OC43 virus, or an antigenically related coronavirus strain, is very common in Finland.

Measles virus polypeptides in purified virions and in infected cells

A wild-type measles virus was radiolabeled during growth in VERO cells and purified by two successive potassium tartrate gradient centrifugations. The virion polypeptide composition was determined by SDS-polyacrylamide gel electrophoresis employing two different buffer systems. Six virus-specific polypeptides were consistently detected. The largest (L) had a molecular weight (MW) of greater than 150,000. The second largest polypeptide, G (MW 79,000), was the only glycoprotein found. The proteins designated polypeptide 2 (MW 66 to 70,000) and nucleocapsid protein or NP (MW 61,000) were phosphorylated. The remaining virus-coded proteins were polypeptide 5 (MW 40,000) and the matrix or M protein (MW 37,000). Measles virions also contained a polypeptide (MW 42,000) thought to be actin due to co-migration with this component of uninfected cells. Analysis of in vitro 3H-acetic anhydride radiolabeled virions confirmed the presence of these seven polypeptides. Acetic anhydride also labeled a protein designated polypeptide 4 (MW 53,000) which was not consistently radiolabeled in vivo, as well as several other minor proteins believed to be cellular in origin. Synthesis of the six virus-specific structural polypeptides was detected in lysates of infected cells by SDS-polyacrylamide slab gel electrophoresis. Virus specificity of polypeptide 4 could not be confirmed due to the similar MW of several cellular polypeptides. Two non-virion, but virus-specified polypeptides, of MW 38,000 and 18,000 were also detected. Synthesis of the virus structural proteins was in the same proportions as the polypeptides found in virions except for under production of polypeptide G and over production of polypeptide 2.

Determination of human immunoglobulin M rheumatoid factor by a solid-phase radioimmunoassay which uses human immunoglobulin G in antigen-antibody complexes

A solid-phase radioimmunoassay for the rapid determination of human immunoglobulin M (IgM) rheumatoid factor (RF) has been developed. Preparation of the solid phase for the assay involved the formation of complexes between respiratory syncytial virus-specific human IgG antibodies and virus antigen on the surface of polystyrene balls. Binding of serum RF to IgG in the immune complex was subsequently detected by 125I-labeled mu-chain-specific antibodies to human IgM. The amount of radioactive indicator antibody bound was converted to units of RF by comparison to the standard curve for an RF reference-serum pool. This assay should prove useful in studies of the physiological role of RF, since it can effectively measure low levels of circulating RF.

Polystyrene balls as the solid-phase of a double-antibody radioimmunoassay for human serum albumin

Polystyrene balls have been incorporated as the solid-phase of a model double-antibody radioimmunoassay for human serum albumin. Purified IgG from the secondary antiserum is adsorbed on the 6.4 mm diameter balls. The solid-phase secondary antibody is then used to separate primary antibody bound iodinated antigen from unbound antigen. The secondary antibody coated polystyrene balls are easily prepared and manipulated; several hundred sample dilutions can readily be processed in a single assay. Assay background values of 1.5% or less are consistently obtained without extensive or special washing procedures.