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N M Tauraso

Publications and source records attributed to N M Tauraso.

54 records · Page 3Linked to original sources
PubMed1969

Yellow fever vaccine. II. Antigenicity and neurovirulence of a vaccine seed free from avian leukosis virus.

Avian leukosis virus (ALV)-free candidate primary and secondary seed lots were indistinguishable from corresponding ALV-contaminated lots with respect to (i) potency as measured by titration in newborn and weanling mice and in the MA-104 plaque system, (ii) degree of viscerotropism as measured by viremia in monkeys, (iii) neurotropism as determined by the monkey neurovirulence test, and (iv) potency as determined by antibody response in monkeys inoculated by the intracerebral route.

Animals↗
PubMed1969

Yellow fever virus. II. Factors affecting the plaque neutralization test.

In studies on the factors and conditions influencing the yellow fever (YF) virus plaque neutralization test, 60 min was found to be the minimal time necessary for equilibration of the virus-antibody complex at 23 and 37 C. Maximal virus titers in the diluent controls and the pre- and postinoculation serum-containing mixtures occurred by the 60-min adsorption time. Serum neutralization indices also seemed to level by this time. Heating (56 C for 30 min) decreased the neutralizing capacity of serum. However, the slope of the neutralization curve was not affected. The addition of native (unheated) "serum factor" in the form of fresh guinea pig or monkey sera partially restored the neutralizing activity lost by heating in some, but not all, sera. Many sera contained nonspecific inhibitors of YF virus infectivity and neutralization. Preliminary studies with ether extraction suggest that these inhibitors are lipid in nature.

Adsorption↗
PubMed1969

Problems of influenza virus vaccine standardization.

The lack of reliable laboratory methods of determining the antigenicity of inactivated influenza virus vaccines prompted a reinvestigation of the reproducibility of the tests used for measuring the antigenic content of influenza vaccines, namely, the CCA and mouse potency tests.The data obtained in the second part of the mouse potency test, i.e., the neutralization test performed either in mice or in embryonated eggs, statistically demonstrated protective differences between 2 vaccines differing in antigenic mass by as little as 2-fold. However, the dependence upon a single egg or mouse neutralization test to provide the correct vaccine/reference ratio assumed more than "biological" variation would allow. Further, the test was long and tedious and it would be impracticable to perform the number of tests needed to obtain statistically significant results. Thus, the extreme variability observed between individual mouse potency tests and the impracticability of performing this test in statistically sufficient numbers precluded its use for measuring antigenic content of inactivated influenza vaccines.The simpler CCA test, on the other hand, did provide the reproducibility required for the correct determination of the vaccine/reference ratio once a stable CCA reference vaccine was prepared. This test was easily reproducible and results obtained were sufficient to allow a meaningful and reliable conclusion to be drawn with respect to vaccine potency.The problems of measuring the relative content of several components in multivalent vaccine preparations and of finding a test which positively correlates with vaccine potency in man, however, remain unsolved.

Agglutination Tests↗
PubMed1969

Effect of dosage and route of inoculation upon antigenicity of inactivated influenza virus vaccine (Hong Kong strain) in man.

Earlier studies on the antibody response to inactivated influenza vaccines injected by different routes have given contradictory results, some suggesting that 0.1 ml intradermally is superior to 1.0 ml subcutaneously, others suggesting the opposite. With the advent of the 1968-69 Hong Kong influenza epidemic it seemed worth while to re-evaluate whether a smaller intradermal dose would elicit antibody responses comparable to those following a larger subcutaneous dose.A study was performed evaluating 3 doses: 0.1 ml (65 CCA), 0.25 ml (160 CCA), and 0.5 ml (320 CCA) of zonal-purified vaccine. The 0.1-ml dose was administered by both routes, and the other doses subcutaneously only. The effect of "booster" inoculation by the same route 2 and 4 weeks later was also studied. Sera were examined for haemagglutination-inhibiting antibody, and antibody response was determined by the percentage showing 4-fold or greater titre rises and by increase in geometric mean titre.The antibody response to the first inoculation was highest in the 0.1-ml intradermal groups and the lowest in the 0.1-ml subcutaneous groups. All groups receiving a second inoculation 2 weeks after the first experienced an increase in antibody response; responses to the second inoculation given 4 weeks after the first were variable. Considering the over-all effect of all combinations of doses and routes, the intradermal groups appeared to achieve the best antibody response and the 0.1-ml subcutaneous groups the least.There appeared to be an inverse relationship between antibody response and pre-immunization antibody titre.The data show that, with vaccine of similar CCA content, 0.1 ml intradermally would be a reasonable alternative to, and perhaps better than, the usual 0.5-ml subcutaneous dose. The limitations of this approach are discussed.

Adult↗
PubMed1968

Yellow fever virus. I. Development and evaluation of a plaque neutralization test.

Heretofore, the most reliable way of measuring yellow fever virus antibody was to use the mouse neutralization (MN) test employing either suckling or weanling mice. Certain disadvantages (e.g., expense both of animals and of maintaining a mouse colony, allergic reactions of many laboratory workers, and the relatively long time, 21 days, before end points are reached) are inherent in any program with mice or other laboratory animal species and have discouraged the use of the MN test by many laboratories. A previously reported plaque neutralization (PN) test with primary chick embryo cell cultures could not be consistently reproduced by later investigators. We have developed a convenient and reproducible PN test employing the MA-104 embryonic rhesus monkey kidney cell culture and a single agar-overlay procedure. When compared with MN tests with newborn (1 to 3 days old) and weanling (16 to 20 g, 24 to 28 days old) mice inoculated by the intracranial route, the PN test was the most sensitive for measuring neutralizing antibody; it was also less variable, less costly, and it achieved results in the shortest period of time. End points could be determined in 5 to 6 days for the PN test as compared to 21 days for the MN test.

Agar↗
PubMed1968

A method for the formulation of influenza virus vaccine using numerical taxonomy.

The relationship of new "field" isolates of influenza virus to previously isolated strains might not be evident by inspection of haemagglutination-inhibition data. Numerical taxonomic methods have been applied to experimental results in order to clarify these relationships so that antigenic trends may be more easily seen. The diagrammatic representations so derived suggest that numerical taxonomic methods may be useful in the future in selecting the most representative influenza virus strains for inclusion in a vaccine.

Antigen-Antibody Reactions↗
PubMed1967

Effect of diethylaminoethyl dextran on the growth of Mycoplasma in agar.

The growth of certain strains of Mycoplasma is inhibited by substances present in commercial agar preparations. The addition of diethylaminoethyl (DEAE) dextran (10 mg per 100 ml) to agar media appears to enhance the growth of some strains. Of eight strains initially tested, the presence of DEAE dextran grossly enhanced the growth of three strains. One strain appeared not to be affected, and a clearly enhancing effect was not evident with four strains. Quantitative studies revealed that growth enhancement varied from 10 colony-forming units (CFU) for M. hominis type II (strain Campo) to 10(3.3) CFU for M. pulmonis (strain 880). The growth-enhancing effect is probably due to the ability of DEAE dextran to bind the sulfated polysaccharide moieties in agar and not to the DEAE dextran, per se.

Agar↗