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Biomedical subjects

Y Umino

Publications and source records attributed to Y Umino.

33 records · Page 2Linked to original sources
PubMed1990

Monoclonal antibodies to three structural proteins of Newcastle disease virus: biological characterization with particular reference to the conformational change of envelope glycoproteins associated with proteolytic cleavage.

Monoclonal antibodies (MAbs) to the haemagglutinin-neuraminidase (HN), fusion (F) and matrix (M) proteins of Newcastle disease virus were prepared and characterized. At least three non-overlapping or partially overlapping antigenic sites were delineated on the HN, three on the F and three on the M proteins by competitive binding assays. Antigenic sites on the HN and F proteins roughly represented functional domains defined by serological tests. Two antigenic sites on the F protein were involved in virus neutralizing and haemolysis-inhibiting activity. These antigenic determinants were readily affected by treatment with certain surfactants and acetone. Proteolytic cleavage of the HN and F proteins was associated with conformational change, revealed by altered reactivity with MAbs and by altered topological arrangements of some epitopes. None of the anti-M MAbs inhibited any biological activities of the virus.

Animals↗
PubMed1990

Protective effect of monoclonal antibodies to Newcastle disease virus in passive immunization.

A series of monoclonal antibodies (MAbs) against the haemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins and the matrix (M) protein of Newcastle disease virus (NDV) were tested for protective effects in passive immunization of newborn chickens against challenge with a virulent heterologous strain of NDV (Italien). MAbs with high virus-neutralizing activity directed to one antigenic site of the HN protein delayed virus growth and significantly prolonged survival time, but all chickens eventually succumbed to infection. MAbs directed to two antigenic sites of the F protein completely suppressed virus growth and prevented death of chickens, although the neutralizing activities of these anti-F MAbs were lower than those of the above anti-HN MAbs. Combined administration of the anti-HN and anti-F MAbs had a synergistic protective effect, but no protective effects were shown by MAbs against the M protein.

Animals↗
PubMed1989

A unique proteolytic action of HCE, a constituent protease of a fish hatching enzyme: tight binding to its natural substrate, egg envelope.

High choriolytic enzyme (HCE), a constituent protease of the hatching enzyme of the teleost, Oryzias latipes, swells its natural substrate, egg envelope (chorion) by hydrolyzing it partially. This enzyme was found to be bound tightly to the chorion when it exerted catalytic action. This was evidenced by the experimental results showing (i) that the turnover of this enzyme seemed to be hindered by the chorion, (ii) that the enzyme bound to the chorion could be recovered by washing with an alkaline medium, and (iii) that the bound enzyme could be quantified by radioimmunological estimation. The bound enzyme sustained its original activity and the binding between the enzyme and the chorion seems to be stoichiometric.

Animals↗
PubMed1987

Protective effect of antibodies to two viral envelope glycoproteins on lethal infection with Newcastle disease virus.

The protective effect of humoral immunity against lethal infection of chickens with Newcastle disease virus was studied. Chickens hatched from eggs laid by hens vaccinated with live attenuated Newcastle disease virus vaccine possessed antibody to various components of the virus, and were resistant to a challenge with a virulent strain of Newcastle disease virus which was 100 per cent fatal for the offspring of nonvaccinated hens. Passive administration of antiserum raised against whole virions provided susceptible chickens protection comparable to that seen in the birds with maternal antibody. When administered passively, both anti-HN serum with virus neutralizing activity, and anti-F serum with only marginal virus neutralizing activity significantly prolonged the survival of infected birds but failed to achieve the level of protection as afforded by the anti-whole NDV serum. The protection provided by the simultaneous presence of anti-HN and anti-F serum was significantly greater than that afforded by either alone and comparable to that of anti-whole NDV serum, indicating the complementary effect of anti-HN and anti-F antibodies not only in cell cultures as reported previously (19), but also in a natural host.

Animals↗
PubMed1987

Immunocytochemical focus assay for potency determination of measles-mumps-rubella trivalent vaccine.

The immunocytochemically stained focus assay for the determination of potency of individual components in measles-mumps-rubella trivalent vaccine is described. The method involves the reaction of infected cultures maintained under the agar overlay medium sequentially with rabbit antiserum specific to each component, biotinylated anti-rabbit IgG serum, avidin-biotinylated-peroxidase complex, and substrate mixture. The potency of one component determined by the method was not influenced by the presence of two other components and was comparable to that determined by either dilution end point titration or plaque assay. The method offers a number of advantages over the current method based on neutralization of components other than the one to be titrated.

Antibodies, Viral↗
PubMed1985

Inability of Japanese rubella vaccines to induce antibody response in rabbits is due to growth restriction at 39 degrees C.

We have compared the kinetic growth patterns of To-336, MEQ11, KRT, and SK2 rubella vaccine strains licensed in Japan at 37 degrees and 39 degrees C with those of progenitor wild strains of rubella virus. The growth of vaccine strains was depressed at 39 degrees C to a level about 3 log10 lower than that at 37 degrees C. The difference in virus titer attained by wild strains at 37 degrees and 39 degrees C was less than tenfold. The growth potential at 39 degrees C paralleled the immunogenic marker of rubella virus, i.e. the capability of virus to induce antibody response upon subcutaneous injection in rabbits for all wild and vaccine strains examined, including one strain at an intermediate level of attenuation. Several clones were isolated from the progeny produced by a vaccine strain during the growth at 39 degrees C. Among them were partial revertants in immunogenic marker as well as in the growth potential at 39 degrees C. It was concluded that the immunogenic marker of rubella virus in rabbits represented its capability to replicate at the body temperature of the animal.

Animals↗
PubMed1985

Monoclonal antibodies directed to E1 glycoprotein of rubella virus.

We have prepared four monoclonal antibodies to rubella virus E1 glycoprotein. Three nonoverlapping antigenic sites were delineated on E1 protein by competitive binding assays. Antibodies binding to one site were characterized by high hemagglutination inhibition (HI) titer but poor neutralizing activity. The addition of antiglobulin conferred neutralizing activity. Antibodies directed to two other antigenic sites had modest hemolysis inhibition but little or no HI and neutralizing activities. The addition of antiglobulin markedly augmented HI activity but had little effect on neutralizing activity. Epitopes defined by three antibodies were conserved among four rubella virus strains examined.

Antibodies, Monoclonal↗
PubMed1984

Biological functions of monospecific antibodies to envelope glycoproteins of Newcastle disease virus.

Monospecific antisera to HN and F glycoproteins of Newcastle disease virus were prepared, and their effects on the biological activities of the virus were investigated. Anti-HN serum inhibited hemagglutinating and neuraminidase activity, as well as hemolysis. Anti-F serum had no effect on hemagglutination or neuraminidase but inhibited hemolysis and virus-induced cell fusion. Anti-HN serum was highly neutralizing, while neutralization by anti-F serum was very inefficient in conventional plaque reduction tests, although both sera were estimated to contain comparable amounts of antibody reacting with the virus as indicated by complement fixation and immuno-diffusion tests. The neutralizing activity of anti-F serum was greatly enhanced by the addition of anti-IgG serum or fresh guinea pig serum, whereas that of anti-HN serum was little enhanced. Anti-HN serum incorporated in the agar overlay suppressed the development of plaques to some degree, while anti-F serum had little effect. The combination of anti-HN and anti-F sera resulted in a marked decrease in the number and size of plaques, demonstrating the synergistic effect of the two species of antibody in the containment of the spread of viral infection.

Animals↗
PubMed1978

Susceptibility of chick neural retina to viral multiplication in vitro during embryonic development.

Decrease in the susceptibility of embryonic chick neural retina cultures to the multiplication of various viruses was observed with increasing age of the embryo. In contrast the retinal cells supported the multiplication of Sindbis virus irrespective of the age when they were infected with the viral RNA. These results suggest that the restricted multiplication of the viruses observed is due to the modulated inability of the cell to process the adsorbed viruses for subsequent replication.

Aging↗
PubMed1975

Binding of polyriboinosinic-polyribocytidylic acid with cultured cells.

Homogenates prepared from polyriboinosinic-polyribocytidylic acid copolymer [poly(rI) - poly(rC)]-treated cells exhibited antiviral activity in chick embryo, L and rabbit kidney cells. The antiviral activity in the homogenate co-sedimented with cellular membrane material and was shown to be poly(rI) - poly(rC) by a hybridization competition test with immobilized polyribocytidylic acid. The results indicate that poly(rI) - poly(rC) binds firmly to cellular membrane. These studies, however, could not differentiate between specific binding leading to the interferon induction and non-specific binding possibly unrelated to the induction of interferon.

Animals↗
PubMedDate not supplied

Anesthesia can cause sustained hyperglycemia in C57/BL6J mice.

Effects of anesthesia on the blood glucose of C57/BL6J mice were evaluated under conditions commonly used for testing retinal sensitivity with electroretinographic (ERG) recordings. We evaluated the effects of four anesthetics: nembutal (50 mg/kg), pentothal (100 mg/kg), avertin (240 mg/kg), and ketamine/xylazine (100 mg/kg) using saline as control. We measured blood glucose (BG) levels from tail vein blood before and 15 and 60 min following intraperitoneal injections. Fifteen minutes postinjection, all four anesthetics and saline elevated BG with ketamine/xylazine and avertin having substantially greater effects than nembutal, pentothal, and saline. Only the effects of ketamine/xylazine and avertin persisted throughout the test period. Sixty minutes after injecting ketamine/xylazine BG remained elevated at 400 +/- 42 mg/dl, a 167% increase over preinjection levels. Sixty minutes after injecting avertin BG was 288 +/- 10 mg/dl, a 59% increase over preinjection levels. No sustained elevation in BG was detected 60 min following injection of nembutal, pentothal, or saline. Because BG can affect the amplitude of the ERG, caution should be exercised in the use of ketamine/xylazine or avertin. The choice of anesthesia may also be important in diabetes and metabolism research where changes in blood glucose could impact physiological processes.

Anesthesia↗