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Biomedical subjects

R Netter

Publications and source records attributed to R Netter.

10 recordsLinked to original sources

Comparison studies on potency tests for rabies vaccines.

Eleven laboratories from eight countries and four continents took part in a collaborative study to evaluate experimental procedures to be used in selecting the new standard reference rabies vaccine prepared in human diploid cell cultures. The following procedures were used : (a) the NIH potency test in mice, (b) the antibody binding technique (by either mouse inoculation or the tissue culture method), (c) virus-neutralizing antibody levels in mice used for the NIH test, and (d) antibody induction in human volunteers treated with vaccine alone and in combination with human rabies gamma globulin. The four methods used for determination of rabies antibodies were mouse inoculation, rapid fluorescent focus inhibition, plaque reduction and complement fixation techniques. All results were expressed in International Units as compared to the standard WHO serum and vaccine preparations. In general, a close correlation was noted in results from different laboratories, and it was recommended that the future rabies standard vaccine should be evaluated by three testing procedures, the NIH test, the antibody-binding technique, and antibody levels in mice used for the NIH test.

Animals

Studies on candidate reference preparations of rabies vaccine.

Two candidate reference rabies vaccines were tested in a collaborative study involving seven laboratories. Using four different testing procedures it was determined that both vaccine preparations were highly potent and demonstrated satisfactory stability in the thermal degradation test.

Animals

[Titration of serum and antirabies immunoglobulins by the radial immunodiffusion method].

Titration on mice of sera and immunoglobulin rabies anibodies is expensive, tedious and long. We are proposing a cheap, easy and rapid method which could be useful during the preparation of immunoglobulin or for the final titration. The antigen is a purified inactivated vaccine cultured on human diploid cells and purified by dextran sulfate and ultracentrifugation; it is included in agar on a glass slide. The reference serum was given us by Dr Atanasiu from Pasteur Institute; its titre was compared with international reference on mice test and was given a titre of 65 IU per ml. Five specific rabies immunoglobulin and 3 sera were received from two producers for titration. For IDR test, immunoglobulin and reference serum dilutions are diposed in wells of the same agar slide and then incubated at ambiant room temperature during 48 hours. Migration of each Ig and serum dilution is measured after coloration reported on a graph and compared. Each of the samples was checked 4 times by radial immunodiffusion test and twice by seroneutralization test on mice. Statistical analysis of the results by Student's test demonstrates that both methods are comparable.

Animals

Identification of Orthopox virus by isoelectrofocusing in a granulated gel.

Twenty strains of Orthopox viruses (vaccina (3), cowpox (2), monkeypox (2), variola major and minor (7) and whitepox (6)) have been tested by electrofocusing in a granulated gel. From our preliminary results, it appears that there is a clearcut distinction between smallpox and whitepox. If our results are confirmed, it will be the first real genetic marker identified because other in vitro or in vivo test have heretofore failed to differentiate between smallpox and whitepox. Further work is now in progress, to evaluate of the test and it is hoped to find and explanation for the observations now reported.

Isoelectric Focusing

Study on the stability of a measles vaccine.

With live measles freeze-dried vaccine, accelerated storage test provides more information than does a titration of residual moisture. From our results, it appears that there is a good correlation between storage at 37 degrees and the tests usually required by the manufacturer, i. e. storage for 1 year at refrigerator temperature. The accelerated test in neither tedious nor expensive and is recommended for routine use.

Drug Stability