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Y Kawade

Publications and source records attributed to Y Kawade.

At least 73 records · Page 4Linked to original sources
PubMed1980

An analysis of neutralization reaction of interferon by antibody: a proposal on the expression of neutralization titer.

Methods of determining and expressing the neutralization titer of anti-interferon antibody were discussed based on considerations of the mass-action law and on experimental data of neutralization of L cell interferon by various antisera. The antibodies in all the sera so far examined were inferred to have low affinities (low association constants compared to the reciprocal of molar concentrations of free interferon), regardless of whether the serum had a low (a few hundred) or high (over 10(5) titer. Then the equilibrium equation can be approximated by a simple formula which relates the antibody concentration to the ratio of total to free interferon concentrations; the absolute amount of interferon neutralized (the difference between total and free interferons) is not involved in computing the titer, and therefore the problem of variations in interferon sensitivity in different assays is eliminated. It is proposed that the neutralization titer be defined, not as the antibody dilution that neutralizes a certain quantity of interferon (such as 10 international units, as often found in the literature), but as the dilution that reduces the interferon titer by a certain factor (taken to be 10 in this paper). A simple formula for calculating the titer from experimental data is given.

Animals↗
PubMed1980

Antigenic relationships among various interferon species.

Mouse L-cell interferon consists of two antigenically distinct species, F (22 to 24K) and S(32 to 40K). Various type I mouse interferons, regardless of lymphoid or nonlymphoid origin, likewise consist of two species, whose antigenicities are indistinguishable from the two L-cell interferons. Interferon F was found to be completely neutralizable by an antiserum against human leukocyte interferon, suggesting a structural similarity between the important species of human and mouse interferons.

Animals↗
PubMed1978

Nonglycosylated mouse L cell interferon produced by the action of tunicamycin.

The effect of tunicamycin, a specific inhibitor of protein glycosylation, on interferon production by L cells induced by Newcastle disease virus was studied. The interferon yields in the presence of tunicamycin ranged from 20 to 100% of control in various experiments. The two molecular species of normal L cell interferon with 40,000 and 24,000 daltons were completely eliminated, and a new species of a smaller size (18,000 daltons) was produced. Radiolabeling of interferon with [35S]methionine and [3H]glucosamine added to the induced cultures, as studied by immunoprecipitation and polyacrylamide gel electrophoresis, indicated that the two species of control interferon were both glycoproteins but tunicamycin interferon contained little or no sugar. In support of this was the loss of binding to lectin from Wistaria floribunda. A change in physical property of the molecule due to the absence of sugar was found in decreased heat stability in the presence of sodium dodecyl sulfate, although in its absence no significant difference from control interferon was observed. These results indicate that tunicamycin is an effective agent in producing nonglycosylated but fully active interferon molecules; the sugar moiety appears to be unnecessary for the antiviral activity and for secretion from cells.

Glucosamine↗
PubMed1978

Purification of mouse L cell interferon. Essentially pure preparations with associated cell growth inhibitory activity.

Mouse L cell interferon induced by Newcastle disease virus was purified by a combination of salt precipitation, ion exchange chromatography, gel filtration, and affinity chromatography using anti-interferon anti-body. The preparation was labeled with 125I at a later step of purification, which served as an index of protein concentration. Two main species of interferon molecules differing in molecular weight were separated from each other, and the final preparations obtained were shown to be essentially pure by polyacrylamide gel electrophoresis in the absence as well as in the presence of sodium dodecyl sulfate. The highest specific activities obtained were 2.6 X 10(9) and 7.3 X 10(8) international units/mg of protein (determined by 125I radioactivity) for the 40,000- and 24,000-dalton species, respectively. The preparations at different steps of purification, including those of the highest purity, were tested for the anti-cell growth activity. Their activities were found to be indistinguishable from each other when compared at the same antiviral doses, indicating that the anti-cell growth activity is carried by the interferon molecules themselves.

Cell Division↗
PubMed1976

Purification of two components of mouse L cell interferon: electrophoretic demonstration of interferon proteins.

Mouse L cell interferon induced by Newcastle disease virus was purified by the procedure described previously (Yamamoto et al. 1974) followed by gel filtration. The two fractions obtained containing interferon species S (36000 daltons) and F (24000 daltons), respectively, were analysed electrophoretically at pH 4-3, or in the presence of sodium dodecyl sulphate (SDS) at pH 7-2. In both fractions, interferon activity was invariably associated with distinct protein bands. In the F-containing fraction there were essentially no other proteins, and in the S-containing fraction, impurity proteins were well separated from the interferon activity. The apparent mol. wt. determined by SDS-gel electrophoresis showed little or no dependence on gel concentration, suggesting that the interferons had low carbohydrate contents, and did not change after reduction with thiol reagents in SDS and urea.

Animals↗