Neutralization Line Research Articles

Polymorphic Behavior in Protein−Surfactant Mixtures: The Water−Bovine Serum Albumin−Sodium Taurodeoxycholate System

Mixtures containing water, bovine serum albumin (BSA), and sodium taurodeoxycholate (NaTDC), a component of the bile in mammals, have been investigated in a wide range of composition and pH. Depending on the concentration of both solutes and the pH, solutions, precipitates, and gels are formed. Under spontaneous pH conditions, the transport properties in dilute solutions indicate the occurrence of significant interactions between BSA and the surfactant. Conversely, acidic media favor the formation of nonsoluble protein-surfactant complexes, with subsequent precipitation. The nucleation kinetics of the protein-surfactant complexes in solid form and the related precipitation processes can be slow or fast, depending on the overall solute content and the mole ratio. At high concentrations, a gel, extending on both sides of the charge neutralization line, and two-phase regions are observed. Gels shrink in open air and swell in the presence of excess water. Depending on concentration and temperature, the gels transform from an essentially liquidlike behavior to that peculiar to true gels (when G' > or = G''). The thermal gelation threshold, the temperature above which G' > or = G'', depends on BSA and NaTDC content and is concomitant to moderate heat effects, inferred by differential scanning calorimetry (DSC). The above data also indicate that the protein thermal denaturation in the gel is shifted to higher temperatures compared to water. Such a stabilizing effect is presumably related to the occurrence of both electrostatic and hydrophobic interactions with NaTDC. Water self-diffusion in the gels is slightly slower than that in the bulk and poorly sensitive to composition: it is about 65% the value of neat H2O in a wide concentration range, irrespective of the BSA, or NaTDC, concentration. A peculiar behavior is also observed in 23Na longitudinal and transverse relaxation rates. The T1 and T2 values, measured at 105.75 MHz on BSA-NaTDC gels, indicate that the motions determining the NMR relaxation of the sodium ions in the hydration layer of the protein-surfactant aggregates are not slow, having frequencies comparable with the Larmor one. The above properties, especially the rheological and the spectroscopic ones, are important for understanding the behavior of gels based on protein-surfactant mixtures.

Protein/surfactant interfacial interactions paet 2. Electrophoretic mobility of mixed protein + surfactant systems

Protein-protein and protein-surfactant interactions have been investigated in bulk aqueous solution and in oil-in-water emulsion systems by electrophoretic mobility measurements. The interaction between oppositely charged β-lactoglobulin and gelatin has been studied under neutral pH conditions. The addition of cationic gelatin to a β-lactoglobulin-stabilized emulsion induces flocculation and charge neutralization of the emulsion droplets. The procedure of mixing the gelatin solution with the β-lactoglobulin-stabilized emulsion has no significant effect on the observed mobility behaviour of the emulsion droplets. Binding of the anionic surfactant sodium lauryl ether sulphate (SLES 2EO) to β-lactoglobulin and gelatin was observed under neutral pH conditions. The charge neutralization line for gelatin + SLES 2EO complexes in distilled water appears consistent with its maximum precipitation line. However, the charge neutralization line of gelatin + SLES 2EO at pH 7.0 occurs at slightly lower surfactant concentrations compared to the maximum precipitation line. The addition of SLES 2EO to a gelatin-stabilized emulsion causes a change in calculated zeta potential of the emulsion droplets and a partial charge neutralization for the flocculated emulsion droplets. Electrophoretic mobility measured in solutions of β-lactoglobulin + gelatin + SLES 2EO shows that the three-component complexes (or precipitates) are negatively charged. Various possible interaction mechanisms are discussed taking account also of results obtained on the same systems by other complementary techniques.

Multiple track Doppler-shift spectroscopy system for TFTR neutral beam injectors

A Doppler-shift spectroscopy system has been installed on the TFTR neutral beam injection system to measure species composition during both conditioning and injection pulses using short and long pulse ion sources. Two intensified vidicon detectors and two spectrometers are utilized in a system capable of resolving data from up to 12 ion sources simultaneously. By imaging the light from six ion sources onto one detector, a cost-effective system has been achieved. Fiber optics are used to locate the diagnostic in an area remote from the hazards of the tokamak test cell allowing continuous access, and eliminating the need for radiation shielding of electronic components. Automatic hardware arming and interactive data analysis allow beam composition to be computed between tokamak shots for use in analyzing plasma heating experiments. Measurements have been made using lines of sight into both the neutralizer and the drift duct. Analysis of the data from the drift duct is both simpler and more accurate since only neutral particles are present in the beam at this location. Comparison of the data taken at these two locations reveals the presence of partially accelerated particles possessing an estimated 1/e half-angle divergence of 15° and accounting for up to 30% of the extracted power from the short pulse ion sources. Operation with long pulse ion sources indicates a higher atomic composition, fewer partially accelerated particles, and somewhat reduced neutralization line densities.

Neutralization of Visna Virus by Antisera from Sheep

Summary Neutralizing titers of visna antisera measured in tissue culture were found to increase with the time and the temperature at which serum-virus mixtures were incubated prior to inoculation into culture tubes. The omission of preincubation resulted in neutralizing titers about 50 to 100 times lower than those observed after preincubation at 37°C for 3 hr. The rate of neutralization of visna virus by antiserum was found to depend on the temperature and on the antiserum concentration, the rate being greatly reduced at increased serum dilution. An exponential linear relationship between the amount of virus neutralized and the antiserum titer was found for virus doses up to about 104.5. The neutralization line had a slope of about 4.0, a 10-fold increase in virus dose corresponding to a 1.8-fold decrease in serum titer. A virus fraction of about 10-5 to 10-4 could not be neutralized either by raising the antiserum concentration or by increasing the time of incubation at 22°C. The nonneutralizable fraction was found to be present in undiluted serum-virus mixture and it was not significantly increased by dilution, indicating practically no reactivation of neutralized visna virus.

エクトロメリア・ウイルスの免疫血清学的研究

Successively from the first report, the immunological and serological investigations on the ectromelia virus was carried out using rabbits.In the first place, the problem of development of neutralizing antibody (VN antibody) against ectromelia and vaccinia viruses in rabbits immunized with the ectromelia virus, was taken up. Its elucidation was attempted by the increase in number of experiments and by using the neutralization line of immune serum. Concerning the neutralization line of anti-ectromelial rabbit serum against ectromelia and vaccinia viruses, the singular property was recognized.And so the investigations was done about each neutralization line of the anti-vaccinial rabbit serum, the anti-ectromelial mouse serum and the anti-vaccinial mouse serum, like in the anti-ectromelial rabbit serum.The influence of method of immunization on the slope of neutralization line was investigated.In ordef to see the inhibition of vaccinia dermal infection in rabbits immunized with ectromelia virus, the courses of pox-pustulation and virus multiplication after the inoculation of vaccinia virus were observed in rabbits of normal and immunized with vaccinia and ectromelia virus.The results are summarized as follows.1. Even in rabbits immunized repeatedly with the ectromelia virus in large quantities, the serum which the neutralizing capacity against ectromelia virus can be recognized clearly, was not easily obtainable. However, considering the property of neutralization line, the VN antibody could be produced in rabbits.2. The slope of neutralization line of anti-ectromelial rabbit serum against vaccinia virus was steep, on the other hand, that against ectromelia virus was flat on the whole, thus two neutralization line were not parallel. This phenomenon is consistent with the fact that the neutralizing capacities of anti-ectromelial rabbit serum against ectromelia and vaccinia viruses were not parallel. The mechanism of the mode of neutralization reaction against both viruses might not be analogous.3. The phenomenon that the slope of neutralization line of anti-ectromelial rabbit serum against ectromelia virus was flat, might be caused by the property of the anti-serum itself, rather than by the system of neutralization test, or the particular relation of rabbit to ectromelia virus or the singularity of ectromelia virus as immunogen.4. The different slopes of neutralization line were obtained due to varying methods of immunization or varying periods of immunization, even though using the identical material.5. When the rabbit immunized with ectromelia virus was intracutaneously inoculated with the vaccinia virus, the course of pustulation and the growth curve of vaccinia virus was different from that in the normal rabbit. It was suggested by this fact that the mechanism of vaccinia dermal infection was different in these animals. The attention should be directed on this a point, when the inhibition test of vaccinia dermal infection in rabbits immunized with ectromelia virus was attempted.

エクトロメリア・ウイルスの免疫血清学的研究

Successively from the first report, the immunological and serological investigations on the ectromelia virus was carried out using rabbits.In the first place, the problem of development of neutralizing antibody (VN antibody) against ectromelia and vaccinia viruses in rabbits immunized with the ectromelia virus, was taken up. Its elucidation was attempted by the increase in number of experiments and by using the neutralization line of immune serum. Concerning the neutralization line of anti-ectromelial rabbit serum against ectromelia and vaccinia viruses, the singular property was recognized.And so the investigations was done about each neutralization line of the anti-vaccinial rabbit serum, the anti-ectromelial mouse serum and the anti-vaccinial mouse serum, like in the anti-ectromelial rabbit serum.The influence of method of immunization on the slope of neutralization line was investigated.In ordef to see the inhibition of vaccinia dermal infection in rabbits immunized with ectromelia virus, the courses of pox-pustulation and virus multiplication after the inoculation of vaccinia virus were observed in rabbits of normal and immunized with vaccinia and ectromelia virus.The results are summarized as follows.1. Even in rabbits immunized repeatedly with the ectromelia virus in large quantities, the serum which the neutralizing capacity against ectromelia virus can be recognized clearly, was not easily obtainable. However, considering the property of neutralization line, the VN antibody could be produced in rabbits.2. The slope of neutralization line of anti-ectromelial rabbit serum against vaccinia virus was steep, on the other hand, that against ectromelia virus was flat on the whole, thus two neutralization line were not parallel. This phenomenon is consistent with the fact that the neutralizing capacities of anti-ectromelial rabbit serum against ectromelia and vaccinia viruses were not parallel. The mechanism of the mode of neutralization reaction against both viruses might not be analogous.3. The phenomenon that the slope of neutralization line of anti-ectromelial rabbit serum against ectromelia virus was flat, might be caused by the property of the anti-serum itself, rather than by the system of neutralization test, or the particular relation of rabbit to ectromelia virus or the singularity of ectromelia virus as immunogen.4. The different slopes of neutralization line were obtained due to varying methods of immunization or varying periods of immunization, even though using the identical material.5. When the rabbit immunized with ectromelia virus was intracutaneously inoculated with the vaccinia virus, the course of pustulation and the growth curve of vaccinia virus was different from that in the normal rabbit. It was suggested by this fact that the mechanism of vaccinia dermal infection was different in these animals. The attention should be directed on this a point, when the inhibition test of vaccinia dermal infection in rabbits immunized with ectromelia virus was attempted.

狂犬病ウイルス免疫動物における脳乳剤の中和作用について

Horie, et al. reported that the animals intraperitoneally immunized with rabies virus had shown the protection to the intracerebral challenge of the virus, and was not always parallel to the neutralizing activity of the serum (Serum antibody), but was parallel to the neutralizing activity of the perfused brain-emulsion (Brain antibody).In this paper an investigation of the characteristics of Brain antibody formed in mice and guinea pigs which intraperitoneally inoculated with the rabies virus (strain CVS) was presented.The results are summarized as follows:1) The approximate slope rates of neutralization lines of Brain antibody and Serum antibody were 2.0 and 1.0, respectively.2) The slope of neutralization line of Brain antibody heated at 56°C for 30minutes was 2.0 and it was identical with the slope of the original non-heated Brain antibody.3) The slopes of neutralization line of mouse Serum antibody added with the normal mouse brain-emulsion, and of neutralization line of guinea pig Serum antibody added with the guinea pig brain-emulsion immunized with Japanese B Encephalitis virus, and of neutralization line of the mouse brain-emulsion injected intracerebrally with the anti-rabies mouse serum, were identical with the slope of the original Serum antibody.4) The slope of neutralization line of guinea pig Brain antibody added with the immune serum of guinea pigs immunized with Japanese B Encephalitis virus was identical with the slope of the original Brain antibody.5) The Brain antibody blocking test was carried out by using the anti-globulin serum. As a result, it was shown that Brain antibody was blocked by the anti-globulin serum and its neutralizing capacity diminished.6) The neutralizing capacity of Brain antibody was not influenced by the super centrifugation at 100, 000G for 1hour.As stated above, both Brain antibody and Serum antibody had the characteristics as the antibody, but there was the certain difference between two neutralization lines. It was thought that the mechanism of neutralization reaction of both antibodies might not be analogous.

The Tissue Culture Colour Test for Assaying the Virus and Neutralizing Antibody of Foot-and-Mouth Disease and its Application to the Measurement of Immunity in Cattle

SUMMARY A tissue culture colour test, which makes use of pig kidney cells, is described for the titration of the virus of foot-and-mouth disease (FMD) and its antibody. Polyvinyl chloride plates and automatic syringes have been employed to enable large numbers of sera to be assayed rapidly for neutralizing antibodies. Strains of the FMD virus titrated with 4 cups at each 10-fold dilution interval gave end-points with standard deviations of up to log ±0.22 and the sensitivity of the test compared favourably with that given by other methods. Uniform results were obtained when pools of cells from 4 different kidneys were used. The neutralization line was found to be rectilinear and to have a slope of — 3.2. The method adopted for performing neutralization tests has been to add 100 TCD50 of virus to each 2-fold serum dilution. Interaction was allowed to proceed in the cups of the sheets for 90 minutes at 22-240 C. Serum antibody levels in vaccinated cattle gave good correlation with the resistance shown by these animals when challenged.

The neutralization of influenza and other viruses by homologous immune serum. Studies in roller tube tissue cultures

Neutralization tests using influenza virus, poliovirus, and adenovirus in various tissue cultures showed a linear relationship between the log virus concentration and log serum concentration at the end point of neutralization, the slope of the neutralization line being steep. The effect on this slope of variables in the serum, virus seed, and tissue cultures used and in the method of performing the test was observed.

Characteristics of the New Respiratory Viruses (Adenoviruses)

Summary Neutralization titrations carried out with types 1–4 APC-RI viruses and type-specific rabbit sera, as well as human convalescent sera, indicated that preliminary incubation of virus-serum mixtures at 22° or 37°C was necessary to obtain maximum titers. Prolongation of the incubation period beyond 30 min did not increase the neutralization titer appreciably; with human convalescent sera, neutralization titers were similar whether a mixture of serum and either type 3 or 4 virus was incubated 30 min at 4°C or 120 min at 37°C. Investigation of the quantitative aspects of the neutralization reaction with the new respiratory viruses and type-specific immune sera indicates that the reaction between the two components, expressed as logarithms to the base 10, describes a linear relationship. The ratio between the two variables, the logarithm of the quantity of virus neutralized and the logarithm of the serum dilution end point, was 1.0 for types 3 and 4 viruses and 2.0 for types 1 and 2 viruses. The species of animal from which serum was obtained for the neutralization titrations did not influence the slope of the neutralization line.

Neutralization of viruses by homologous immune serum. I. Quantitative studies on factors which affect the neutralization reaction with Newcastle disease, influenza A, and bacterial virus T3.

Neutralization experiments with Newcastle disease, influenza A, or bacterial virus, T(3), reveal, under all conditions studied, a linear relationship between the logarithm of the serum dilution end point and that of the quantity of virus used. With Newcastle disease and influenza A, the slope of the neutralization line varies markedly with the host-cell system used and in the chick embryo is strikingly affected by the route of inoculation. The other variables examined have no definite effect upon the slope. Reactivation of neutralized influenza virus is demonstrable in the chick embryo on dilution of the mixture. There appears to be an inverse relationship between the degree of susceptibility of a host to infection with influenza A virus and the neutralizing titer of a serum as measured in that host. With the T(3)-serum system, comparable results are obtained when the number of unneutralized virus particles chosen as the end point is varied widely.

Lack of identity in neutralizing and hemagglutination-inhibiting antibodies against influenza viruses.

There is an exponential linear relationship between the quantity of influenza virus neutralized and the quantity of immune serum employed in in ovo neutralization. The slope of the neutralization line is extremely steep. The concentration of neutralizing antibody can be measured with considerable precision in ovo if the constant virus-varying serum technique is utilized. The amounts of hemagglutination-inhibiting and neutralizing antibodies which are absorbed by a given quantity of influenza virus (PR8) were found to be predictable and the degree of reactivity of these two antibodies was shown to be directly related to the extent of immunization. It was demonstrated that there are marked discrepancies in correlation between antibody titers obtained by in vitro hemagglutination-inhibition and in vivo neutralization techniques and that neutralizing antibody is preferentially absorbed by a given quantity of virus. Inasmuch as the results were found not to be attributable to peculiarities of the techniques employed, it appears that the antibodies measured by hemagglutination-inhibition in vitro and by neutralization in vivo are not identical.