bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification and characterization of a staphylococcal epidermolytic toxin
Authors: Dimond R L , Wuepper K D
Published: January 2020

A staphylococcal exotoxin that causes epidermolysis when injected into the skin of the newborn mouse and man was highly purified by coventional biochemical techniques. With Staphylococcus aureus EV, the epidermolytic toxin was a major protein component of supernatant culture fluids. The initial step in purification was zone electrophoresis in Pevikon carried out at pH 9.0, the isoelectric point of alpha-hemolytic toxin, which remained near the origin. Fractions containing the epidermolytic toxin, but free of alpha-toxin, were then subjected to cation exchange chromatography on carboxymethyl-Sephadex C-50 to remove trace contaminants. A major highly purified epidermolytic toxin migrated as a single band in polyacrylamide gel electrophoresis, sedimented as a single component in the analytical ultracentrifuge, and elicited a single precipitating antibody after injection into rabbits. A smaller amount of a second epidermolytic toxin, identical in molecular weight and antigenicity but differing in electrophoretic behavior from the major molecular species, was also identified. The epidermolytic factor had a molecular weight of 28,600 +/- 400 by sodium dodecyl sulfate-acrylamide electrophoresis and 32,500 +/- 120 by approach to sedimentation equilibrium.
Purification of complement-fixing antigens of Rickettsia sennetsu by ether treatment
Authors: Tachibana N , Kusaba T , Matsumoto I , Kobayashi Y
Published: January 2020

Soluble and particulate complement-fixing antigens of Rickettsia sennetsu were prepared from spleen suspensions of mice infected with the rickettsia and treated with cyclophosphamide. The medium used during purification of antigens, a solution consisting of equal volumes of phosphate-glutamate-sucrose buffer and veronal-buffered saline, was suitable for obtaining antigens with high titers and no anti-complementary activity. By heat treatment, it was demonstrated that the soluble antigen was heat labile and the particulate antigen was heat stable. The soluble antigen was precipitated by 80% saturation with ammonium sulfate. Cross-complement fixation tests using both soluble and particulate antigens revealed that there was no antigenic difference among strains of R. Sennetsu. On the other hand, no cross-activity was observed between R. sennetsu and R. orientalis.
Evaluation of type-specific and non-type-specific pseudomonas vaccine for treatment of pseudomonas sepsis during granulocytopenia
Authors: Harvath L , Andersen B R
Published: January 2020

The protective role of serotype-specific and non-type-specific active immunity against Pseudomonas aeruginosa infection was assessed in granulocytopenic dogs. Dogs were preimmunized with either specific serotype 6 vaccine (SI) or nonspecific serotype 3 vaccine (NSI) and challenged intravenously with 10(7) viable serotype 6 P. aeruginosa during granulocytopenia. Control dogs (C) having insignificant anti-pseudomonas antibody levels were also tested. Results showed: (i) significant increase in survival of SI dogs (P less than 0.05) compared to C and NSI dogs, with no significant difference between C and NSI animals; (ii) lower febrile responses in SI dogs; and (iii) markedly reduced bacteremia in SI dogs compared to C and NSI animals. SI dog sera from survivor animals did not kill the infecting pseudomonas strain in vitro. The study demonstrated that type-specific immunity to P. aeruginosa induced by active immunization is effective in protection against pseudomonas during granulocytopenia and that non-type-specific immunity offers no cross-reactive protection. The findings suggest that the reticuloendothelial system in conjunction with specific immunity constitute an important defense against pseudomonas infections.
Experimental mycoplasma mastitis in mice
Authors: Anderson J C , Howard C J , Gourlay R N
Published: January 2020

Thirteen strains of mycoplasma representing six different species, Acholeplasma laidlawii, Mycoplasma dispar, M. bovirhinis, M. bovigenitalium, M. agalactiae subsp. bovis, and M. mycoides subsp. mycoides, were inoculated into the mammary glands of mice, and the number of mycoplasmas present in the glands three days after inoculation was determined. The predominant response included involution of inoculated glands and a neutrophil infiltration. With the exception of M. dispar, the pathogenicity of the six species for mice was found to be similar to their pathogenicity for cattle.
Characterization of the virulence and antigenic structure of Salmonella typhimurium strains with lipopolysaccharide core defects
Authors: Lyman M B , Steward J P , Roantree R J
Published: January 2020

The virulence and antigenic characters of Salmonella typhimurium strains, identical except for known lipopolysaccharide core defects, were compared. Smooth strains multiplied extensively and killed most mice. Deep rough strains containing only heptose I or heptose I and II in the rough core were completely eliminated after 6 h, whereas more superficial rough strains containing additional core sugars could be detected in low numbers (10(4) colony-forming units/g of tissue) for at least 7 days postinjection. Normal human serum exhaustively absorbed with certain rough strains was tested for ability to kill other rough strains. Two strains with the most superficial defects (rfaJ, rfaL) each had a unique serological character; strains with deeper defects showed much cross-reactivity. Similarities between the susceptibility of strains to the bactericidal effect of specifically absorbed serum correlated, in some cases, with similarities in in vivo behavior.
Bacillus pumilus polysaccharide cross-reactive with meningococcal group A polysaccharide
Authors: Vann W F , Liu T Y , Robbins J B
Published: January 2020

A polysaccharide, antigenically and structurally related to meningococcal group A polysaccharide, was isolated from Bacillus pumilus Sh-17. This enteric bacterium has been implicated as a source of natural meningococcal group A immunity (Myerowitz et al., 1973). The B. pumilus polysaccharide was composed of a homopolymer of (1-6)-N-acetyl-manosamine-1-phosphate, glycerol phosphate teichoic acid-containing N-acetylglucosamine and alkali-labile alanine esters, and a mucopeptide. The cross-reaction was due to the poly-(1-6)-N-acetyl-mannosamine-1-phosphate in the B. pumilus and the meningococcal group A polysaccharides, based on the following evidence. Both polysaccharides contained N-acetyl-mannosamine phosphate. Periodate oxidized the mannosamine phosphate residues of the polysaccharide and destroyed their precipitating activity with meningococcal group A antiserum. Mild acid treatment released phosphomonoesters and destroyed the meningococcal group A precipitating activity of both polysaccharides. N-acetyl-mannosamine-6-phosphate inhibited the precipitation reaction between strain Sh-17 and meningococcal group A antisera. Only mannosamine phosphate was detected in trichloroacetic acid extracts of Sh-17 polysaccharide and meningococcal group A antigen-antibody precipitates.
Preparation of a purified antigenic cholera toxoid
Authors: Germanier R , Fürer E , Varallyay S , Inderbitzin T M
Published: January 2020

Purified cholera enterotoxin was prepared by methods described by Finkelstein and Lo Spalluto (1970). This toxin was detoxified by treatment with heat and formaldehyde. Heating cholera toxin at 60 C for 25 min resulted in the formation of a polymer named procholeragenoid by Finkelstein et al. (1971). The weak toxic activity of this product was removed by treatment with formalin. No residual toxicity could be demonstrated in formalinized procholeragenoid by the rabbit ileal loop assay and the highly sensitive rabbit skin tests. This toxoid was nevertheless at least as antigenic in the rabbit as was the toxin. No reversion to toxicity was observed in vivo and in vitro at 4 C. The toxicity of formalinized procholeragenoid never exceeded 1/5,000 to 1/10,000 that of the toxin.
Immunological and biochemical studies of meningococcal C polysaccharides isolated by diethylaminoethyl chromatography
Authors: Apicella M A
Published: January 2020

Meningococcal C polysaccharides isolated from the broth supernatant of C1+ and C1- strains by a combination of Sepharose 4B and diethylaminoethyl-52 chromatography are antigenically identical to the group C antigen isolated by the Cetavlon procedure. Immunizations result in the induction of precipitating, hemagglutinating, and bactericidal antibodies in rabbits and sheep and hemagglutinating and bactericidal antibodies in rabbits and sheep and hemagglutinating and bactericidal antibodies in gerbils. Selective destruction of C1- polysaccharides with neuraminidase has demonstrated that these antibodies are directed against the C polysaccharide. Neuraminidase digestions of the C1- polysaccharides resulted in release of up to 84% of the antigen as N-acetylneuraminic acid. C1+ polysaccharides proved to be more resistant to neuraminidase, requiring greater concentrations of enzyme and longer intervals of exposure for digestion. Chemical analysis of the C1+ and C1- polysaccharides indicated that they contain less than 0.5% protein and less than 0.5% nucleic acid.
Thermal inactivation of rabies and other rhabdoviruses: stabilization by the chelating agent ethylenediaminetetraacetic acid at physiological temperatures
Authors: Michalski F , Parks N F , Sokol F , Clark H F
Published: January 2020

Thermal inactivation of rabies and several other rhabdoviruses was studied using virus suspended in several different diluents. Rabies serogroup viruses were more stable than Kern Canyon or vesicular stomatitis viruses. Limited studies of two fish rhabdoviruses requiring low temperatures (less than 33 C) for replication indicated that they were not markedly more thermolabile than rabies virus. Bovine serum protein components in complex cell culture media stabilized virus at 56 C, but at temperatures of less than or equal to 37 C, sodium tris (hydroxymethyl)-aminomethane (NT) buffer containing ethylenediaminetetraacetic acid (EDTA) (NTE) was a much more efficient stabilizer of virus infectivity. Chelating agents EDTA and ethyleneglycol-bis-(beta-aminoethyl ether)tetraacetic acid were equally efficient in protection of rabies virus infectivity; the effect of each was lost when excess Ca2+ was added. Bovine serum in NT or NTE buffers produced a thermostabilizing effect at 37 C not provided by the same serum concentration in complex cell culture media. Bovine serum was more efficient than EDTA in stabilizing virus infectivity during repeated cycles of freezing and thawing.
Rescue of vesicular stomatitis virus from homologous and heterologous interferon-induced resistance in human cell cultures by poxviruses
Authors: Thacore H R
Published: January 2020

In human cell cultures the ability of poxviruses to rescue vesicular stomatitis virus from human interferon-induced resistance was significantly more efficient than the ability to rescue it from simian interferon-induced resistance. The sensitivity of the poxvirus to interferon was not related to its ability to rescue vesicular stomatitis virus.
Reverse plaque formation by hog cholera virus of the GPE-strain inducing heterologous interference
Authors: Fukusho A , Ogawa N , Yamamoto H , Sawada M , Sazawa H
Published: January 2020

A simple and rapid plaque procedure was developed for the assay of hog cholera virus (HCV) of a particular strain, GPE-, based on its intrinsic interference with vesicular stomatitis virus (VSV) on the primary swine testicle cells and on an established swine kidney cell line; the procedure is called the reverse plaque formation (RPF) method. The plaques were produced as colonies of HCV-infected cells which were VSV-sensitive, disintegrated cell sheet. These plaques became visible after 15 to 20 h of superinfection with VSV done 2 days after an initial inoculation of the GPE- strain. The plaque formation was inhibited by a specific antiserum against HCV. All cells within the plaque had HCV antigen detectable by fluorescent-antibody staining. The variations of reverse plaque count were low enough to permit virus titration. The relationship between virus concentration and the number of plaques was essentially linear. The titer measured by the RPF method was a little higher than that of the tube culture interference method.
Partial characterization of a factor extracted from sensitized lymphocytes that inhibits the growth of Mycobacterium tuberculosis within macrophages in vitro
Authors: Turcotte R , Des Ormeaux Y , Borduas A G
Published: January 2020

Spleen lymphocytes of BCG-immunized mice contain a soluble factor that inhibits in vitro the growth of the H37Rv strain of Mycobacterium tuberculosis within normal peritoneal macrophages. The water-soluble extracts of sensitized lymphocytes, disrupted by freezing and thawing, although less active than the corresponding viable cells retained a significant growth-inhibiting activity. Dialysis against distilled water, lyophilization, exposure to ribonuclease and deoxyribonuclease, and storage at -20 degrees C of the water-soluble extracts did not affect their antimycobacterial activity, whereas extracts heated at 100 degrees C were completely devoid of such an activity. All the inhibiting activity was recovered in the void volume of the column after chromatography on Sephadex G-200. Water-soluble constitutents of sensitized lymphocytes did not affect BCG grown in vitro, and on repeated treatments of tuberculous mice they led to a negligible protection against pulmonary tuberculosis. Preliminary observations seem to indicate that other soluble factors in lymphocytes of BCG-sensitized mice have the capacity to potentiate in vitro the phagocytic activity of normal macrophages.
Cell-mediated immunity to Vibrio cholerae with ribonucleic acid-protein fractions of V. cholerae L-form lysates
Authors: Agarwal S C , Sundararaj T
Published: January 2020

Different L-form lysate vaccines of Vibrio cholerae serotypes Ogawa and Inaba and their combination along with ethyl alcohol-precipitated ribonucleic acid (E-RNA) and phenol-extracted RNA (P-RNA) fractions of V. cholerae Ogawa lysates were tested for production of cell-mediated immunity. Both E-RNA and P-RNA fractions induced an increase in leukocyte migration inhibition, macrophage migration inhibition, and macrophage aggregation. They also induced delayed hypersensitivity in rabbits. More consistent results were obtained with the P-RNA fraction.
Peptido polysaccharide antigens from Trichophyton mentagrophytes var. granulosum
Authors: Arnold M T , Grappel S F , Lerro A V , Blank F
Published: January 2020

Two highly purified peptido polysaccharide antigens have been isolated from surface-grown cultures of Trichophyton mentagrophytes var. granulosum. Trichloroacetic acid extraction and ethanol precipitation yielded a mixture containing high-molecular-weight components which were first separated on Sephadex G-200. Subsequent fractionation by ion-exchange chromatography on DE-52-cellulose (borate form) yielded the two peptido polysaccharides. Both of the peptido polysaccharides reacted with rabbit antiserum to T. mentagrophytes var. granulosum. The two peptido polysaccharides contain 73.2% hexoses (mannose-galactose-glucose, 7.5:0.7:1), 8.6% amino acids and 1.8% amino sugars and 77.4% hexoses (mannose-galactose-glucose, 9:0.3:1), 6.2% amino acids, and 0.4% amino sugars, respectively. Each contains 16 different amino acids, threonine, proline, and serine predominating.
Extracellular and bacterial factors influencing staphylococcal phagocytosis and killing by human polymorphonuclear leukocytes
Authors: Peterson P K , Verhoef J , Sabath L D , Quie P G
Published: January 2020

Extracellular and bacterial factors that influence the phagocytosis and killing of staphylococci by human polymorphonuclear leukocytes have been studied. Staphylococcus epidermidis strains were, in general, more rapidly phagocytized than were S. aureus strains. However, two strains of S. epidermidis had a very slow rate of ingestion. Although the rate of phagocytosis of S. aureus Wood 46 was greater than that of S. aureus 502A, the Wood 46 strain was more difficult to kill. Serum was essential for phagocytosis of both S. aureus and S. epidermidis. The opsonic titer of pooled serum was similar for S. aureus and S. epidermidis. In normal pooled serum, heat-labile factors were more important for effective phagocytosis than they were in immune serum. Although a saturation point for ingestion was reached, the percentage of ingested bacteria that remained alive within the leukocyte remained relatively fixed. Heat-killed and live staphylococci were igested in a similar fashion. The rate of phagocytosis was greatly reduced at 41 degrees C.
Pathogenesis of herpes simplex virus types 1 and 2 in mice after various routes of inoculation
Authors: Renis H E , Eidson E E , Mathews J , Gray J E
Published: January 2020

The pathogenesis of herpes simplex virus (HSV) types 1 and 2 was compared after inoculation of mice by different routes. Intravaginal inoculation of HSV-1 and HSV-2 produced a local infection, with virus recovery from the vagina through 5 days. Virus was recovered from the spinal cords 4 to 5 days after inoculation but not from liver, kidney, lung, spleen, or blood. Intravenous or intraperitoneal inoculation of HSV-2 produced a focal necrotic hepatitis similar to that described previously (S. C. Mogenson, B. Teisner, and H.K. Andersen, 1974). The viral etiology of the liver lesions was confirmed by virus isolation (through 4 days) and electron microscopy. No evidence of infection of the kidney, lung, blood, or spleen was observed, although virus was isolated from spinal cord homogenates 7 days after inoculation. HSV-1 inoculation by the intraperitoneal or intravenous route resulted in virus isolation from the kidney during the 7-day harvest period, without producing overt pathological changes. Virus was isolated from spinal cord homogenates 2 to 3 days after HSV-1 inoculation but not from homogenates prepared from spleen, lung, or blood. Increases in serum transaminase activity were observed after systemic (intravenous) inoculation of HSV-2 but not after HSV-1 inoculation.
Ability of temperature-sensitive mutants of the recombinant influenza S/N (H2N1) virus to induce immunity to parental (H0N1 and H2N2) viruses
Authors: Dolezalová B , Tuĉková E , Stárek M , Vonka V , Zavadova H
Published: January 2020

The behavior in mice of two thermosensitive (ts) mutants (denoted ts217 and ts700) of the recombinant influenza virus S/N (H2N1) was studied. The parental thermoresistant (tr) virus and both of the mutants were capable of inducing protection against pneumotropic A/Singapore (H2N2) and A/WS (H0N1) challenge viruses. Immunity against the Singapore virus, with which the S/N virus shared the hemagglutinin, developed earlier than against the WS virus, with which the S/N virus shared the neuraminidase. The tr and ts217 viruses were immunologically more active than the ts700 virus. The first two viruses grew markedly better in mouse lungs than did the latter. In the course of ts217 virus replication in vivo, revertants capable of growing at 39 degrees C appeared readily. On the other hand, the ts700 virus proved to be genetically stable. These data seem to provide evidence of a linkage between the stability of the ts phenotype, reproductive capacity in mouse lungs, and immunogenicity in the viruses examined.
Relationship of bacteriophages to alpha toxin production in Clostridium novyi types A and B
Authors: Eklund M W , Poysky F T , Peterson M E , Meyers J A
Published: January 2020

The relationship of specific bacteriophages to the production of the lethal alpha toxin in Clostridium novyi types A and B was investigated. When type A strain 5771 reverted to the phage-sensitive state, it ceased to produce alpha toxin but continued to produce the gamma and epsilon antigens. This "nontoxigenic" culture, therefore, more closely resembled C. botulinum types C and D than the other C. novyi types. Phage-sensitive type B strains also ceased to produce the alpha toxin but continued to produce the beta toxin, and therefore very colesly resembled C. novyi type D (C. haemolyticum). Alpha toxin was again produced when the phage-sensitive cultures were reinfected with the respective tox+ phages. Alpha toxin production could also be induced in the "nontoxigenic" phage-sensitive derivatives from type B strain 8024 by tox+ phages isolated from other strains of type B. tox- phages were also isolated, but they did not affect alpha toxin production. The tox+ phages also caused a marked change in the colonial morphology of type B strains. In this report we present evidence that alpha toxin production by C. novyi type A strain 5771 and type B strain 8024 depends upon the continued presence and participation of specific bacteriophages designated as NA1tox+ and NB1tox+, respectively.
Plasmid-mediated resistance to the bactericidal effects of normal rabbit serum
Authors: Reynard A M , Beck M E
Published: January 2020

An Escherichia coli K-12 strain bearing the plasmids R1 or R100 was more resistant to the bactericidal activity of normal rabbit serum than was the same strain without a plasmid. When the plasmid R100 was transferred to several K-12 strains, the strains acquired resistance to serum bactericidal activity.
Isolation of a factor causing morphological changes of chinese hamster ovary cells from the culture filtrate of Vibrio parahaemolyticus
Authors: Honda T , Shimizu M , Takeda Y , Miwatani T
Published: January 2020

A factor changing Chinese hamster ovary cells from an oval to a spindle shape was isolated from the culture filtrate of Vibrio parahaemolyticus. It was partially purified by successive column chromatographies on diethylaminoethylcellulose, diethylaminoethyl-Sephadex A-25, hydroxylapatite, and Sephadex G-200. This factor was separated from thermostabl direct hemolysin and was heat labile.
Mycobacterial ribonucleic acid: comparison with mycobacterial cell wall fractions for regression of murine tumor growth
Authors: Millman I , Scott A W , Halbherr T , Youmans A S , Youmans G P
Published: January 2020

Mycobacterial ribonucleic acid (RNA) and cell wall skeleton fraction isolated from H37Ra caused P-815 mastocytoma regression in DBA/2 mice provided the animals were presensitized with freshly harvested living H37Ra cells. In the absence of presensitization, only the RNA fraction inhibited. Cell wall skeleton fraction, under these conditions, stimulated tumor growth. Cell wall lipids (from H37Ra) added to H37Ra cell wall skeleton fraction did not increase the inhibitory activity of cell wall skeleton fraction alone. Mycobacterial RNA appeared to be an effective inhibitor of P-815 mastocytoma metastases as shown by (i) the inhibition of a second footpad lesion distant from the one treated and (ii) increase in survival time.
Adoptive transfer of variant-specific resistance to Trypanosoma rhodesiense with B lymphocytes and serum
Authors: Campbell G H , Phillips S M
Published: January 2020

Mice survive an otherwise lethal infection with Trypanosoma rhodesiense if previously inoculated with irradiated organisms. This resistance demonstrates immunological specificity, since even animals inoculated with irradiated trypanosomes were killed when challenged with trypanosomes of a nonhomologous or variant antigenic type. This resistance could be transferred to syngeneic recipients with serum or B lymphocytes. T lymphocytes had no capacity to transfer resistance. Although mice were protected from active infection on challenge at least 25 days after inoculation of irradiated organisms, this resistance could be transferred with spleen cells for only 10 days after immunization. Resistance could be transferred with serum for a minimum of 25 days after immunization. These studies implicate an antibody-mediated mechanism as having a major role in resistance to T. rhodesiense infections.
Synthesis and release of sulfolipid by Mycobacterium avium during growth andcell division
Authors: McCarthy C
Published: January 2020

Mycobacterium avium exhibits a life cycle wherein small cells elongate to form filaments. The life cycle is unique in that elongated cells will undergo rapid division by fragmentation only if fatty acid is present. The utilization of [14C]palmitic acid and [3H]oleic acid by M. avium during the life cycle was assessed. Four glycolipids, identifiable by elution patterns from hydroxylapatite columns, were associated with postfission cells and contained isotope from the precursor fatty acid. The incorporation of 3H from oleic acid into the cellular glycolipids was maximal during cell division, but as much as 73% of the radioactivity was lost to the lipids from cells in the postfission status. Three of the glycolipids were sulfatides into which 36S was incorporated by M. avium. The [35]sulfatides were synthesized by cells undergoing fragmentation and were recovered from the medium at the termination of cell fission. These results demonstrated that the isotope was not lost to the cells because of turnover, but rather that the labeled compounds were released, intact, from the cells after fission. Because of the facile release of the sulfolipids, it was suggested that they were part of the cell envelope of M. avium cells during the division process.
Phage-dependent changes in Shigella flexneri type antigen synthesis
Authors: Financsek I , Ketyi I , Sasak W , Jankowski W , Janczura E , Chojnacki T
Published: January 2020

Lysogenic conversion of Shigella flexneri type antigens was studied with the aid of wild-type and thermosensitive mutant phages. With all wild-type phages, the appearance of glycosylated antigen was accompanied by the appearance of polyprenyl phosphate glucose synthetase activity. With some of the mutant phages, the appearance of glycosylated antigen was not followed by the formation of lipid-linked glucose in the enzyme assay. The reverse has also been observed, i.e., the high rate of formation of lipid-linked glucose and the lack of V-type antigen.
Influence of serum-derived chemotactic factors and bacterial products on human neutrophil chemotaxis
Authors: Issekutz A C , Biggar W D
Published: January 2020

The chemotaxis of neutrophils has been shown to be modulated by serum factors, tissue factors, bacterial products, and a host of other substances. In vivo, these factors may act in concert with each other to modify neutrophil movement. We examined the effect of aggregated gamma globulin-activated serum (AS), bacterial factors, and endotoxin either alone or in combination with each other, on human neutrophil chemotaxis. Exposure of neutrophils to AS resulted in deactivation to AS but not to Escherichial coli or Staphylococcus epidermis culture filtrate. Exposure of neutrophils to S. epidermis or E. coli CF or E. coli endotoxin resulted in deactivation to AS or C5a but not to E. coli or S. epidermis culture filtrate. Addition of endotoxin to AS or C5a resulted in inhibition of chemotaxis by untreated neutrophils toward this combination as compared with AS alone. These results suggest that separate mechanisms may be involved when serum or bacterial chemotactic factors initiate human neutrophil chemotaxis. Furthermore, the potent but specific inhibitory effect of endotoxin on chemotaxis toward AS may be of clinical significance.
Some factors affecting selective adherence of microorganisms in the bovine mammary gland
Authors: Frost A J , Wanasinghe D D , Woolcock J B
Published: January 2020

Some parameters affecting the adherence of microbes to the ductular epithelium of the bovine mammary gland were studied. Adherence increased from teat sinus to lactiferous sinus to the large ducts, and cells from the lactiferous sinus to the large ducts, and cells from the lactiferous sinus were used for all other experiments. There was no difference in adherence to cells from different quarters of the same cow, but there were significant differences between cows. Scanning electron microscopy suggested that the cells of the ductular epithelium undergo dynamic changes that probably result in secretion and/or desquamation. Adherence to cells could be demonstrated only at a late stage of these changes. The adherence of organisms associated with mastitis was studied using an in vitro test. Adherence generally paralleled prevalence as cause of disease, with Staphylococcus aureus and Streptococcus agalactiae adhering best. Strain variation suggested that virulence was related to adherence with S. agalactiae and S. dysgalactiae but not with S. aureus. It is proposed that specific adherence is an important aspect of pathogenesis of mastitis due to S. aureus and S. agalactiae.
Protection against endotoxin-induced mortality in mice treated with transition metal salts
Authors: Snyder S L , Walker R I , Moniot J V
Published: January 2020

Administration of manganese or chromium chloride 1 h before challenge with a single bolus of Salmonella typhosa endotoxin completely obviated death in endotoxin-challenged mice.
Selection of influenza B virus recombinants and their testing in humans for attenuation and immunogenicity
Authors: Beare A S , Sherwood J E , Callow K A , Craig J W
Published: January 2020

The selection of influenza B virus recombinants from plaques in bovine kidney cell monolayers is described. Two sets of recombinants were each derived from parents of high and low virulence for humans, respectively. Recombination frequency was apparently high, and reassortment of genes made it possible to obtain attenuated recombinants containing the surface antigens of the virulent parents. Attenuation and immunogenicity were demonstrated in a series of volunteer trials. However, technique proved less satisfactory than for influenza A viruses which periodically undergo antigenic shift and for which there is a wide choice of parent viruses with distinctive surface antigens. In our two influenza B recombinant series there was appreciable antigenic overlap in the neuraminidases of the parents, even though in both cases these were chronologically widely separated. Another marker used was comparative titer at 35 and 38 degrees C. In practice, technical problems might sometimes make it difficult to ensure rapid production of live influenza B vaccines by recombination.
Interactions between calf alveolar macrophages and parainfluenza-3 virus
Authors: Probert M , Stott E J , Thomas L H
Published: January 2020

Cells washed from the lungs of freshly killed calves (lung wash cells; LWC) were cytotoxic for calf kidney (CK) target cells infected with parainfluenzavirus type 3 (Pi-3) when assayed by chromium release. LWC collected from 25 calves, including two gnotobiotic animals that had not previously been infected with Pi-3, were all cytotoxic, giving a specific chromium release between 11 and 50%. Cytotoxicity was detected at ratios of LWC to target cell as low as 5:1. The cytotoxic reaction required viable LWC, was inhibited by Pi-3 antiserum, and was not the result of virus-induced damage to the target cells. The cytotoxic cells in the LWC population were identified as alveolar macrophages from observations on glass adherence, phagocytic activity, killing by silica and fine-structural appearance. When LWC were added to CK cells or organ cultures of bovine trachea infected with Pi-3, the yield of virus was reduced for the first 2 to 3 days. However, subsequently, Pi-3 virus replicated in the LWC. Infection of LWC with Pi-3 virus reduced their cytotoxic activity. The significance of these interactions between alveolar macrophages and Pi-3 virus is discussed.
Occurrence of K99 antigen on Escherichia coli isolated from pigs and colonization of pig ileum by K99+ enterotoxigenic E. coli from calves and pigs
Authors: Moon H W , Nagy B , Isaacson R E , Orskov I
Published: January 2020

Several strains of enterotoxigenic Escherichia coli (ETEC) isolated from pigs were found to have an antigen (K99) previously reported only on strains of calf and lamb origin and which facilitates intestinal colonization in the latter two species. Several human ETEC were also tested for K99; however, none were positive. Each of four K99-positive ETEC strains of calf origin and one of pig origin produced K99 in pig ileum in vivo, adhered to villous epithelium in pig ileum, colonized pig ileum, and caused profuse diarrhea in newborn pigs. In contrast to the K99-positive strains above, four K99-negative ETEC from humans and chickens and one K99-positive ETEC from a calf either did not colonize pig ileum or did so inconsistently. When the K99-negative strains did colonize, they had little or no tendency to adhere to intestinal villi. These results are consistent with the hypothesis that K99 facilitates adhesion to and colonization of pig ileum by some ETEC.
Pyocin sensitivity of Neisseria gonorrhoeae and its feasibility as an epidemiological tool
Authors: Sidberry H D , Sadoff J C
Published: January 2020

Pyocin inhibition of Neisseria gonorrhoeae and its feasibility as a gonococcal typing scheme were examined. Mitomycin C-induced pyocin lysates of Pseudomonas aeruginosa were able to selectively inhibit the growth of gonococcal strains. The particles associated with the inhibitory activity were non-dialyzable, heat labile, Pronase sensitive, trypsin resistant, and of large molecular weight by membrane and gel filtration techniques. The inhibitory activity was shown to be specific by absorption with sensitive and insensitive strains of N. gonorrhoeae and P. aeruginosa. Partial purification of pyocin lysates by ammonium sulfate precipitation followed by ultracentrifugation revealed phagelike particles consistent with high-molecular-weight R-type pyocines. These particles were associated with increased inhibitory activity and could be seen associated with the gonococcal cell surface. One hundred and six gonococcal strains could be differentiated on the basis of their sensitivity of 23 pyocin extracts. Thirty different patterns of pyocin inhibition were seen. Isolates from different body sites from the same patient could generally be identified as being similar strains. Strains isolated from known consorts had the same patterns. In general, agreement between pyocin typing and available epidemiological information was good.
Enteropathogenicity of various isolates of Treponema hyodysenteriae
Authors: Kinyon J M , Harris D L , Glock R D
Published: January 2020

Isolates of Treponema hyodysenteriae from 25 geographically separated outbreaks of swine dysentery were tested for their ability to produce the disease. Clinical signs and lesions typical of acute swine dysentery were produced in 52 of 68 (75%) susceptible specific pathogen-free pigs that had been orally inoculated with pure cultures of 23 of 25 beta-hemolytic isolates. In addition, 13 weakly beta-hemolytic isolates of nondysentery origin with morphology similar to T. hyodysenteriae did not produce disease when orally inoculated into susceptible specific pathogen-free pigs. Two of these latter isolates, Puppy and B296, and one pathogenic, beta-hemolytic isolate failed to produce disease when orally inoculated into puppies.
Effect of squamous metaplasia on infection of hamster trachea organ cultures with Mycoplasma pneumoniae
Authors: Engelhardt J A , Gabridge M G
Published: January 2020

An organ culture system for hamster trachea was developed for maintenance of the ciliated respiratory epithelium during periods of extended cultivation (i.e., greater than 20 days). Evaluation of five serum types showed that horse serum and fetal calf serum were best for the maintenance of epithelial ciliary activity and morphology. Rings that were opened on one side ("split rings") had the best maintenance of the ciliated epithelium as judged by the retention of ciliary activity and normal histological appearance after 3 to 4 weeks in culture. The in vitro induction of squamous metaplasia was achieved by cultivating explants in Waymouth MAB 87/3 (vitamin A-free) medium, without serum. This system allowed a direct comparison of the effects of Mycoplasma pneumoniae infection in two epithelial types, ciliated pseudostratified columnar and keratinizing squamous. Attachment of 14C-labeled mycoplasmas was more than twofold greater in the normal epithelium. Pretreatment of explants with neuraminidase decreased attachment for both squamous and pseudostratified epithelial surfaces to a similar basal level. Recovery of viable organisms from infected tissue of both epithelial types indicated that the organism titer remained essentially constant during the infection period, but was significantly higher for the pseudostratified ciliated epithelium. These results suggest that specific receptor sites for M. pneumoniae are markedly reduced by the induction of squamous metaplasia and, hence, appear to be specific for the normal respiratory surface containing goblet cells and pseudostratified, ciliated epithelial cells.
Human rotavirus in lambs: infection and passive protection
Authors: Snodgrass D R , Madeley C R , Wells P W , Angus K W
Published: January 2020

A human stool filtrate containing rotavirus which was administered orally to gnotobiotic lambs caused diarrhea, virus excretion, development of antibodies to rotavirus, and pathological changes in the villi of the small intestine. Thus, lambs may serve as experimental animals for the study of human rotavirus infections. This model system was used to study passive protection. Human immunoglobulin G (IgG) containing antibody to rotavirus was fed to lambs 24 to 78 h after birth, and the lambs were infected with lamb-passaged human rotavirus when 30 h old. The lambs treated with IgG did not develop diarrhea, and virus excretion was delayed in onset and shortened in duration. It may be possible to make similar use of IgG to protect children at risk in a rotavirus outbreak. The treatment did not prevent the lambs developing antibody to rotavirus.
Possible Dual Function of M Protein: Resistance to Bacteriophage A25 and Resistance to Phagocytosis by Human Leukocytes
Authors: Cleary Paul P. , Johnson Zaiga
Published: January 2020

Spontaneous phage A25-resistant (A25
R
) mutants of group A streptococci, strain K56, were isolated. The mutant cultures were unable to adsorb phage particles and hyperproduced M protein. Trypsin-digested A25
R
cells regained the ability to adsorb phage particles, but failed to become infectious centers. This failure indicated that the mutation created a double barrier to phage growth: (i) receptors were masked by M protein; (ii) irreversibly adsorbed phage were unable to multiply. Spontaneous variants of one A25
R
mutant, shown to be M negative (M
−
) by electron microscopy, serological tests, and sensitivity to phagocytosis, rapidly adsorbed phage and were able to become infectious centers. Therefore, it was concluded that the mutant phenotype, A25
R
, arose by a single mutation and genes coding for this trait and M protein synthesis were either genetically linked, controlled by a common gene or were biochemically interdependent. The A25
R
phenotype was unstable and, as expected for plasmid-coded properties, acridine orange induced segregation of this phenotype. The parental M
+
, A25-sensitive (A25
S
) cultures proved to be a mixed population. Infection at various multiplicities indicated that this culture was composed of phage A25
S
cells and cells more resistant to infection. Morphological comparison of thin sections of A25
R
and A25
S
cells by electron microscopy demonstrated striking differences. The A25
R
culture was composed entirely of cells uniformly covered with M protein, whereas the A25
S
M
+
wild-type culture was a mixed population, the majority of cells devoid of M protein. Phagocytosis by human blood enriched the culture for the latter cell type, suggesting that differences in phage sensitivity in the wild-type culture were also determined by the presence or absence of M protein. Thus M protein can serve a dual function for the streptococcal cell by allowing it to avoid infection by bacteriophage and ingestion by human leukocytes.
Passive immunity to feline leukemia: evaluation of immunity from dams naturally infected and experimentally vaccinated
Authors: Hoover E A , Schaller J P , Mathes L E , Olsen R G
Published: January 2020

Antibodies against feline leukemia virus (FeLV) and the feline oncornavirus-associated cell membrane antigen (FOCMA) were transferred from pregnant cats to their suckling kittens. All of these kittens were protected against infection and oncogenesis by virulent FeLV when challenged at 2 weeks of age. Suckling kittens acquired 25 to 100% of maternal virus-neutralizing and FOCMA titers by 3 days of age, and titers underwent linear decay to undetectable levels by 2 to 3 months of age. FOCMA antibody in dams and kittens was identified as immunoglobulin G (IgG) by use of goat anti-human IgG serum, which cross-reacts with feline IgG in the indirect membrane immunofluorescence test for FOCMA antibody. In an attempt to induce protective maternal antibody by vaccination, 10 pregnant cats were immunized by three to five weekly intramuscular injections with purified FeLV inactivated by ultraviolet irradiation. After the course of immunization, neither virus-neutralizing nor FOCMA antibody was detectable in the dams or in 19 kittens born to these cats. When these kittens were challenged with FeLV at 2 weeks of age, 18 of 19 developed persistent viremia and FeLV-related disease.
Responsiveness of rabbit spleen and appendix cells to bacterial mitogens
Authors: Scheffel J W , Kreutzer D L , Robertson D C , Draper L R
Published: January 2020

Rabbit spleen and appendix cells were used to test the mitogenic activity of a commercial lipopolysaccharide (LPS) preparation from Salmonella typhimurium (Difco), a preparation extracted from it, and cell wall preparations from smooth (45/0) and rough (45/20) strains of Brucella abortus. On the basis of [3H]thymidine incorporation ratios (E/C), that is, the incorporation rate among cells treated with the mitogen relative to that of untreated cells, the extracted LPS and both Brucella cell wall preparations, but not the commercial LPS were potent mitogens for rabbit spleen cells. By the same criterion, only the Brucella cell wall preparation produced a significant, but minimally so, response among appendix cells. The weak responsiveness of appendix cells may be more apparent than real, however, and may not imply a difference in intrinsic susceptibility to mitogens by these two populations, because unstimulated appendix cells incorporated thymidine at 10 times the rate of unstimulated spleen cells. Appendix cells, then, may not be susceptible to further stimulation, even by active mitogens. Therefore, the significance of E/C ratios may be equivocal when materials are assayed for mitogenic activity on lymphoid populations whose basal activity is relatively high.
Indirect fluorescent-antibody test for human cytomegalovirus infection in the absence of interfering immunoglobulin G receptors
Authors: Swack N S , Michalski F J , Baumgarten A , Hsiung G D
Published: January 2020

The presence of immunoglobulin G receptors in human fibroblasts infected with human cytomegalovirus (CMV) resulted in a nonspecific cytoplasmic reaction in the indirect fluorescent-antibody test. Both CMV antibody-positive and antibody-negative sera from human or other animal species produced the cytoplasmic reaction. The substitution of a simian CMV strain for the human virus successfully eliminated this cytoplasmic reaction and, thus, allowed for the observation of virus-induced fluorescent intranuclear inclusions. With the latter system, CMV antibody titers in human sera were equivalent to those obtained by using the human virus and, in addition, allowed for the detection of relatively low-titered serum samples in which antibody measurement was difficult when human CMV-infected cells were used in the indirect fluorescent-antibody test.
Adenovirus of ring-necked pheasants: purification and partial characterization of marble spleen disease virus
Authors: Iltis J P , Daniels S B
Published: January 2020

A method for purification of marble spleen disease virus (MSDV) from the spleens of infected turkeys and pheasants is described. It combines chloroform or fluorocarbon extraction with subsequent purification by centrifugation on a cushion of cesium chloride (CsCl). Further purification of MSDV was accomplished with a CsCl equilibrium density gradient. A viral buoyant density of approximately 1.32 to 1.33 g/cm3 was determined. Negative-stain electron microscopy revealed that virus isopycnically banded by CsCl gradient had non-enveloped icosahedral capsids composed of 252 capsomeres. The direct colorimetric diphenylamine assay indicated that MSDV has deoxyribonucleic acid as its nucleic acid. The above evidence demonstrates that MSDV is an avian adenovirus, the first recognized in the ring-necked pheasant (Phasianus colchicus L.).
Activation of complement by opportunist pathogens and chemotypes of Salmonella minnesota
Authors: Bjornson A B , Bjornson H S
Published: January 2020

Washed cells of Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and Salmonella minnesota chemotypes (S, Rb, and Re) were tested for their ability to activate the alternative complement pathway (ACP). Parameters of ACP activation were (i) conversion of C3 in 10 mM ethyleneglycol-bis-(beta-aminoethyl ether)-N,N1-tetraacetic acid-treated human serum supplemented with 2.5 mM MgCl2, (ii) lysis of glutathione-treated human erythrocytes in the presence of human serum, and (iii) C3 to C9 consumption in C4-deficient guinea pig serum. With the exception of S. minnesota Re and S. aureus, all of the strains were highly active in the test systems when compared with inulin. S. minnesota Re and S. aureus initiated C3 conversion in untreated human serum, suggesting that these microorganisms were capable of activating complement by a mechanism other than the ACP. These results provide direct evidence for ACP activation by opportunist gram-negative bacilli and refute the hypothesis that the lipid A moiety of the lipopolysaccharide cell wall is responsible for ACP activation.
Immunization of mice against Naegleria fowleri infection
Authors: John D T , Weik R R , Adams A C
Published: January 2020

Naegleria fowleri produces fatal meningoencephalitis in humans and in experimentally infected laboratory animals. The course of the disease in mice is dependent upon the infecting dose of amoebae, route of inoculation, and prior exposure to Naegleria antigens. DUB/ICR mice were immunized by various routes and antigen preparations, held for 21 days, and, together with noninfected control mice, challenged intravenously (i.v.) or intranasally (i.n.) with 10(7) or 10(6) N. fowleri per mouse, respectively. Mice immunized with liver or formalinized N. fowleri or live N. gruberi subcutaneously, intraperitoneally, i.v., or i.n. were significantly protected against a subsequent lethal challenge with N. fowleri i.v. or i.n. In general, i.v. inoculation afforded greated protection than other routes of immunization, intact cells immunized mice better than did cell fragments, and N. gruberi appeared to be a better immunogen than N. fowleri.
Terminal electron transport in Treponema pallidum
Authors: Lysko P G , Cox C D
Published: January 2020

Reduced-minus-oxidized difference spectra of sonically treated virulent Treponema pallidum disclosed cytochromes of the b anc c types as well as large amounts of flavoprotein. Difference spectra of the carbon monoxide-binding pigment identified cytochrome o as the terminal oxidase. Physiological reduction of the cytochromes indicated that the cytochrome system was functional and established the capability of T. pallidum for aerobic respiration. The potential significance of these findings is discussed.