A monoclonal antibody specific for the cellular receptor for the group B coxsackieviruses.

A 50-kilodalton receptor protein (Rp-a) for the group B coxsackieviruses (CB) was isolated in a virus-receptor complex from detergent-solubilized HeLa cells (J. E. Mapoles, D.

Three high molecular weight protease inhibitors of rat plasma. Reactions with trypsin.

We have compared the reactions of trypsin with human alpha 2-macroglobulin (alpha 2M), and three rat plasma protease inhibitors, alpha 1-macroglobulin (alpha 1M), alpha 1-inhibitor III (alpha 1I3), and alpha 2M. All four of these proteins appear to contain reactive thiol esters. The electrophoretic mobility in agarose gels of human and rat alpha 2M is increased by 1 mol of trypsin, while the mobility of alpha 1M and alpha 1I3 is decreased.

Three high molecular weight protease inhibitors of rat plasma. Isolation, characterization, and acute phase changes.

Rat blood plasma contains three high molecular weight thiol ester-containing proteinase inhibitors, alpha 1-macroglobulin (alpha 1M), alpha 1-inhibitor III (alpha 1I3), and alpha 2-macroglobulin (alpha 2M). Rat serums have been analyzed using a two-dimensional gel electrophoretic technique which optimizes recovery of high molecular weight proteins. alpha 1M, and (alpha beta)4-tetramer in native solution, separated in the second sodium dodecyl sulfate-containing electrophoretic dimension as a disulfide-linked (alpha beta)2-dimer with an approximate Mr of 360 kDa.

Classification of malnutrition by statistical analysis of quantitative two-dimensional gel electrophoresis of plasma proteins.

An attempt to use the relative concentrations of major plasma proteins for clinical assessment of severe malnutrition is described. Quantitative two-dimensional gel electrophoresis was used to measure the concentrations of 24 major proteins in small aliquots of plasma obtained from children, aged 0 to 3 years, who were patients and outpatients in Liberian hospitals. Fifteen had a clinical diagnosis of kwashiorkor, 36 were diagnosed with marasmus, and 18 were controls.

Improved conversion of fumarate to succinate by Escherichia coli strains amplified for fumarate reductase.

Two recombinant plasmid Escherichia coli strains containing amplified fumarate reductase activity converted fumarate to succinate at significantly higher rates and yields than a wild-type E. coli strain. Glucose was required for the conversion of fumarate to succinate, and in the absence of glucose or in cultures with a low cell density, malate accumulated.

Two-dimensional gel electrophoresis method for investigation of human plasma proteins: detection of subtle changes during filtration leukapheresis.

Special problems are associated with analysis of human plasma proteins by standard "high-resolution" two-dimensional gel electrophoresis methods in which isoelectric focusing is followed by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels (SDS-PAGE). Individual plasma proteins are often separated into overlapping groups of multiple spots, and identification of individual spots is further confounded by genetic variation. Analytical recovery of components of high molecular mass is also low or variable.

Viral proteins and site-specific cleavage.

The protease coded by a picornavirus is central in the control of the viral replication. It is essential in the production of virus structural proteins, and regulates the viral RNA replicase in infected cells. The properties of the poliovirus protease are summarized and compared with other viruses.

Physical and metabolic requirements for early interaction of poliovirus and human rhinovirus with HeLa cells.

Attachment, ""tight binding'' and eclipse of radioactive poliovirus 2 (P2) and human rhinovirus 2 (HRV 2) were investigated. The activation energy for attachment of both HRV2 and P2 was about 13 kcal/mol. HRV2 differed from P2 in two respects: the Arrhenius plot for attachment of HRV2 showed a break at 15 to 19 degrees C when the cells were first treated several hours at 0 degrees C, and attachment of HRV2 was inhibited by treatment of cells with metabolic poisons able to reduce cellular ATP by more than 90%.

Interaction of liposomes with subviral particles of poliovirus type 2 and rhinovirus type 2.

Subviral particles ("A particles") were produced from rhinovirus type 2 by treatment with acid and from poliovirus type 2 by incubation at 37 degrees C in a low-ionic-strength buffer. A particles, but not virions, adsorbed to liposomes. It is proposed that these reactions may provide an in vitro model for two early steps of infection.

The effects of concanavalin A on the early events of infection by rhinovirus type 2 and poliovirus type 2.

The effect of concanavalin A (Con A) on the course of early infection of HeLa cells with purified radioactive human rhinovirus type 2 (HRV-2) or poliovirus type 2 (P-2) has been examined. Several early steps in infection were inhibited before the uncoating of parental virus. Con A, at 100 mug/ml, reduces attachment of virus when added to cells before infection.

Early alteration of poliovirus in infected cells and its specific inhibition.

HeLa cells infected with radioactive poliovirus type 2 were disrupted with ultrasonic treatment, followed by addition of a non-ionic detergent. Two types of virus particles were found to sediment at 80 to 90% the rate of native virus. The first of these appeared to be a complex of native virus particles and membrane components, since treatment with 0-2% SDS released infectious native particles.

Comparison of in vitro and cell-mediated alteration of a human Rhinovirus and its inhibition by sodium dodecyl sulfate.

After human rhinovirus type 2 (HRV-2) attaches to HeLa cells, two types of subviral particles are formed which closely resemble particles produced in vitro by acid or heat. One type of particle contains RNA whereas the second sediments as an empty capsid and is RNA-deficient. Sodium dodecyl sulfate (SDS) at 10(-4) M inhibits the cell-mediated formation of these particles from HRV-2 virions and the ability of HRV-2 to form plaques, but it does not inhibit the formation of plaques by human rhinovirus 14 (HRV-14).

Antigenic determinants of infective and inactivated human rhinovirus type 2.

Treatment of human rhinovirus type 2 (HRV 2) virions at pH 5, at 56 C or in 2 M urea, produces one or both of two types of subviral particles. These subviral particles sediment at 135S or at 80S and both share what have been designated as C-antigenic determinants; the determinants of native virions have been designated D. These sets of determinants have been contrasted by the techniques of immunodiffusion, complement fixation, and serum blocking, and the results indicate that many or most of the D-determinants are lost in the conversion to C antigenicity.

Lack of close relationship between three strains of human rhinoviruses as determined by their RNA sequences.

The possible genomic homologies between three serotypes of human rhinoviruses (HRV 1A, HRV 2, and HRV 14) were investigated. First we confirmed that these viruses were unrelated by the criterion of the absence of common antigenic determinants on the surfaces of the native virions, as detected by cross-neutralization of complementfixation. RNA-RNA hybridization was then examined with purified, highly radioactive, double-stranded, replicative-form RNA and excess single-stranded virion RNA.

Early interaction of rhinoviruses with host cells.

The rate of attachment of type 2 virions to suspensions of HeLa cells is much greater than that of type 14, but the number of receptor sites per cell is similar for each type. The receptor sites may be partly saturated with excess virions; attachment is greatly reduced after about 10(4) particles have been taken up per cell. A lack of saturation of type 14 receptors by excess type 2 indicates that their receptor sites are separate on the cell surface.