The Journal of Experimental Medicine

Wannamaker, Lewis W.

doi: 10.1084/jem.107.6.783pmid: 13539304

Concentrates of the extracellular products of group A streptococci were prepared which were essentially free of constituents of the medium. The extracellular products appeared to consist primarily of protein material. The yield of total extracellular products was of the order of magnitude of 10 mg. per liter of supernatant broth. When studied by zone electrophoresis, the concentrates showed protein over a wide distribution with distinct peaks in certain areas. The locations of streptolysin O, streptokinase, desoxyribonuclease, and ribonuclease activities were identified, and partial separation of these enzymes was achieved. Considerable variation in the electrophoretic patterns of the extracellular products from different strains was noted. Footnotes Submitted: 27 January 1958

Wannamaker, Lewis W.

doi: 10.1084/jem.107.6.797pmid: 13539305

Group A streptococci were found to produce three different desoxyribonucleases, designated here as A, B, and C. These enzymes migrated separately on analysis with starch zone electrophoresis, were immunologically distinct, and showed certain differences in inhibition by citrate and in optimal pH of activity. The relative amount of each enzyme produced was a function of strain variation. Footnotes Submitted: 27 January 1958

Linazasoro, José M.; Hill, R.; Chevallier, François; Chaikoff, I. L.

doi: 10.1084/jem.107.6.813pmid: 13539306

Rats were fed, for 3 days, four synthetic diets, all of which contained the same proportion of carbohydrate (50 per cent) and were of equal caloric value per gram. These diets contained either 0 or 15 per cent fat. The fats used were lard, corn oil, Wesson oil, and a hydrogenated vegetable oil. The feeding of the fat-containing diet for 3 days increased the liver's capacity for incorporating acetate carbon to cholesterol. The fats tested were of about equal value in stimulating hepatic cholesterogenesis. The various diets fed had no effect on the lipide or glycogen content of the liver nor on the lipide content of plasma. Footnotes Submitted: 30 January 1958

Bélanger, Leonard F.; Migicovsky, B. B.

doi: 10.1084/jem.107.6.821pmid: 13539307

One day old chicks were fed a vitamin D-deficient diet for 3 weeks. Some were then given an oral dose of vitamin D and sacrificed at various times thereafter. The tibiae were x-rayed; demineralized sections were stained for neutral polysaccharides and sulfated mucopolysaccharides; other specimens were ashed; and others still were autoradiographed to determine their uptake of Ca 45 in vitro . Mineralization reappeared in the treated animals after 2 days, along with new P.A.S.-positive spicules. Earlier, the immature cartilage rapidly matured morphologically. At the same time, the rachitic matrix, highly concentrated in cation binder, presumably chondroitin sulfate, lost this material progressively. Footnotes Submitted: 22 December 1957

Hamre, Dorothy; Loosli, Clayton G.; Gerber, Paul

doi: 10.1084/jem.107.6.829pmid: 13539308

Seven variant strains of influenza A PR8-S virus, each derived from the previous one by serial passage in the lungs of mice immunized with the homologous agent have been produced. With the H.I. and neutralization procedures these variants showed a progressive serological deviation from the parent PR8-S virus. The seven variants provoked antibodies in varying titers to the preceding variants and the parent virus but not in relation to their position in the series. Thus, the seventh variant provoked significantly more antibody to the PR8-S virus than did the fifth variant. A possible explanation for this is presented. The first four variant viruses showed progressively less ability to react with antisera of the preceding variants and the PR8-S virus, and the three most recently derived variants showed essentially no ability to react with PR8-S and first variant antisera. The variant viruses remained antigenically stable through numerous lung passages in normal mice. Cross absorption tests revealed common antigenic components among the variant viruses and also individual characteristics which classify them as being different from one another. The implications of these findings in relation to studies by others have been discussed. Footnotes Submitted: 5 February 1958

Hamre, Dorothy; Loosli, Clayton G.; Gerber, Paul

doi: 10.1084/jem.107.6.845pmid: 13539309

A second series of four variants of PR8-S virus has been produced by passage of the variants in the lungs of mice immunized with the PR8-S virus as well as the homologous strain. The PR8-S virus was added as a constant component of the vaccine so that a high antibody titer to it would suppress selectively the development of variants with PR8-S characteristics. Comparative H.I. and in ovo neutralization tests with the first and second series of variants revealed that the three variants, Fd/s, Gf/s, and Hg/s, of the second series, failed to react with PR8-S antisera and produced significantly smaller amounts of antibody which reacted with PR8-S, the variants of the first series, and the first variant (D/s) of the second series. Although these three variants reacted quite similarly in the H.I. and neutralization tests cross-absorption of these sera with the PR8-S virus and themselves revealed individual antigenic characteristics. While these studies emphasize the importance of the immune state of the host the precise mechanism in the selection of a new antigenic component in the emerging variant must yet be determined. Footnotes Submitted: 5 February 1958

Loosli, Clayton G.; Hamre, Dorothy; Gerber, Paul

doi: 10.1084/jem.107.6.857pmid: 13539310

Two series of variants of influenza PR8-S virus have been described. While all retain the same degree of pathogenicity for mice and fertile eggs, there was a progressive loss in the ability of the variants to provoke antibody following vaccination or infection of mice and ferrets. The immunogenicity of the variants was, therefore, less than that of the original strain. Although little or no serological relationship could be demonstrated between some of the variants and the PR8-S virus a considerable degree of cross-immunity could be demonstrated in the cross-protection tests with these viruses if observations were based solely on death or survival of the mice. By employing the occurrence of lesions in the lung and the titer of virus in the lung 48 hours after challenge, the amount of cross-protection in mice could be related to the amount of serological cross-reaction. In general mice vaccinated with PR8-S virus were less resistant to infection with the variant viruses than mice vaccinated with variants and challenged with the PR8-S parent virus. The role of the immune environment of the host in the production of the variant influenza viruses with their serological differences, decreasing antigenicity, and persisting pathogenicity as well as the epidemiological implications of these findings with respect to epidemic influenza in man are discussed. Footnotes Submitted: 5 February 1958