bluuebunny/crossref_metadata_2025 huggingface dataset:
Soluble group- and type-specific antigens from type III group B Streptococcus
Authors: Carey R B , Eisenstein T K , Shockman G D , Greber T F , Swenson R M
Published: January 2020

Two soluble polysaccharide antigens of a type III group B Streptoccus were isolated from the culture medium after growth of strain M732 in a chemically defined broth supplemented with acid-hydrolyzed casein. The type- and group- specific antigens were isolated from the culture supernatant by anion-exchange chromatography with diethylaminoethyl-Sephacel. Two carbohydrate-containing peaks, which had serological reactivity with group B or type III antiserum, respectively, were eluted with a linear NaCl gradient and further purified by gel filtration. The type III polysaccharide was found to contain glucose, galactose, glucosamine, and sialic acid, whereas the group B polysaccharide contained galactose, glucosamine, and rhamnose. For the type III polysaccharide, sialic acid was shown to be the major immunodeterminant, and for the group B polysaccharide, rhamnose was the immunodominant sugar. Both the type III and group B polysaccharides were obtained in high yields without employing harsh physical or chemical treatment and both were immunologically distinct. By immunoelectrophoresis or counterimmunoelectrophoresis, type III antigen failed to react with group-specific antiserum and the group B antigen failed to react with type III antiserum.
Response in distant lymph nodes of mice to infection in the hind footpad with Mycobacterium marinum
Authors: Mor N , Lutsky I , Levy L
Published: January 2020

In an attempt to demonstrate the importance of the popliteal lymph node in limiting the progress of infection with Mycobacterium marinum in the hind footpads of C57BL mice, such infections were studied in mice subjected to popliteal or popliteal and inguinal adenectomies. In the absence of the popliteal node, the footpad infection was only slightly enhanced compared with infections of sham-operated control mice; the inguinal node was found to be greatly enlarged and appeared to have substituted for the absent popliteal node. In the absence of both popliteal and inguinal nodes, the disease process in the footpads was again only slightly enhanced, and the axillary node appeared to have enlarged greatly and to have functionally replaced the missing, more proximate nodes. In additional experiments, mice subjected to adenectomy only on one side and injected in that hind footpad with phytohemagglutinin or India ink demonstrated hypertrophy or deposition of carbon particles in the more distant node only on the side of the injection. Thus, there appear to be rather direct functional connections among popliteal, inguinal, and axillary nodes that do not depend on blood circulation.
Experimental Yersinia enterocolitica enteritis in rabbits
Authors: Pai C H , Mors V , Seemayer T A
Published: January 2020

Young rabbits weighing 500 to 800 g were inoculated orogastrically with clinical isolates of Yersinia enterocolitica (serotype O:3; enterotoxigenic; HeLa cell invasive) at a dose of 1.4 X 10(10) bacteria suspended in 10% sodium bicarbonate solution. Diarrhea developed in 41 (87%) of 47 rabbits, with a mean +/- standard deviation onset at 5.4 +/- 2.4 days. The attack rate and onset of diarrhea were correlated with inoculum size. The 50% infectious dose was 2.9 X 10(8) bacteria. Bacterial colonization occurred in almost all rabbits, regardless of inoculum size. Seroconversion was demonstrated in 30 (71%) of 42 rabbits with or without diarrhea. Histopathological alterations were present in the jejuna, ilea, and colons of rabbits with diarrhea; the most pronounced changes were generally noted in the ilea. Crypt abscesses localized at the depth of the intestinal glands were observed consistently and were composed of a bacterial nidus admixed with and enveloped by inflammatory cells comprised of eosinophils, neutrophils, and mononuclear cells. Rabbits inoculated with a raw fish isolate of Y. enterocolitica (serotype O:6,30; non-enterotoxigenic; HeLa cell noninvasive) did not exhibit infection clinically, bacteriologically, or pathologically.
Gamma-irradiated scrub typhus immunogens: analysis for residual, replicating rickettsiae
Authors: Eisenberg G H , Osterman J V , Stephenson E H
Published: January 2020

Scrub typhus immunogens that received inadequate gamma radiation contained residual, viable rickettsiae. The presence of these organisms in the host was masked by the rapid immune response elicited by the large number of inactivated rickettsiae. Transfer of homogenized spleen cells from immunized mice to normal syngeneic recipients provided a sensitive technique for the detection of these viable, replicating organisms.
Adenine Nucleotide Degradation by the Obligate Intracellular Bacterium
Rickettsia typhi
Authors: Williams Jim C.
Published: January 2020

Adenosine 5′-triphosphate (ATP) was catabolized by whole cells and cell-free extracts of
Rickettsia typhi
to adenosine 5′-diphosphate (ADP) and then to adenosine 5′-monophosphate (AMP), the end product of ATP catabolism under the experimental conditions used. The only intermediate of the pathway from ATP to AMP which was identified by thin-layer chromatography and quantitated by the
14
C content was ADP, whereas products such as adenine, adenosine, hypoxanthine, inosine, and inosine 5′-monophosphate were not detected. The enzymes which could be theoretically responsible for the catabolism or the anabolism of AMP were not detected by standard assay procedures. Most importantly, 5′-nucleotidase or nonspecific phosphatase and AMP nucleosidase activities were undetectable under a variety of experimental conditions. Although these two enzymes remove AMP from the adenylate pool in other cells, they are apparently nonfunctional in
R. typhi
. The biosynthesis of ATP was initiated by adenylate kinase because no adenine phosphoribosyltransferase or adenosine kinase could be detected. Furthermore, AMP was transported intact without prior dephosphorylation. These observations suggest that for
R. typhi
the in vivo activity of adenine nucleotide interconversion was limited to the nucleotides, with AMP being the end product of ATP catabolism, and that the salvage of purine bases and nucleosides was not an essential feature of purine metabolism. These results elucidate the findings of a previous study which showed that in the absence of glutamate as a source of energy, the adenylate energy charge of resting cells of
R. typhi
is drastically lowered by the high proportion of AMP.
Effects of molecular weight of dextran on the adherence of Streptococcus sanguis to damaged heart valves
Authors: Ramirez-Ronda C H
Published: January 2020

Dextran-producing streptococci such as Streptococcus sanguis are the organisms most frequently associated with infective endocarditis in humans. A series of experiments was designed to study how the molecular weight of dextrans affects the adherence of an endocarditis strain of S. sanguis to canine heart valves covered with platelets and fibrin. The data indicated that this adherence was dependent on dextrans of high molecular weight, such as dextran T-2000 or glucans isolated from S. sanguis or S. mutans. The adherence properties of the strain studied were not modified by prior exposure of the bacterial cells of valve leaflets to high-molecular-weight dextrans. Preexposure of bacterial cells or valve leaflets to low-molecular-weight dextrans decreased their adherence. Low-molecular-weight dextrans interfered with adherence of dextran-positive strains to damaged heart valves.
Membrane and cytoplasmic location of streptolysin S precursor
Authors: Calandra G B , Cole R M
Published: January 2020

Group A streptococci which produce streptolysin S (SLS) contain a cellular potential hemolysin (CPH) which is precursor to extracellular SLS. Since the cellular location of CPH is unknown, protoplasts prepared with group C phage-associated lysin or mutanolysin from 18 strains of group A streptococci were fractionated into subcellular components and assayed for CPH. In all strains, most of the CPH was membrane associated, and most could not be removed from membranes by washing with buffer or 2 M LiCl. CPH remaining in the cytoplasmic fraction was sedimentable, but not associated with membrane fragments. Ribonuclease digestion neither solubilized nor inactivated CPH from membranes. Streptococcal proteinase also did not affect CPH, although it did inactivate SLS. We conclude that group A streptococci contain a major pool of CPH in the membrane and a smaller pool in the cytoplasm.
Pathogenicity of Spiroplasma sp. strain SMCA in Syrian hamsters: clinical, microbiological, and histological aspects
Authors: Kirchhoff H , Kuwabara T , Barile M F
Published: January 2020

The intracerebral inoculation of newborn Syrian hamsters with pure cultures of Spiroplasma sp. strain SMCA caused severe, prolonged disease involving the central nervous system, culminating in death. The disease was characterized by spasms, muscular tremors, disturbances in motor control, inability to feed, dramatic loss of weight, and runting. The effect ws dose related, with the largest numbers of viable spiroplasmas producing the highest incidence of disease and death in the shortest period of time. Severe hemorrhaging developed throughout the brain, liver, and spleen, and spiroplasmas were readily recovered from these organs, indicating that the agent disseminated from the initial site of infection to distant host tissues. Newborn animals were susceptible, but adults were resistant; these findings are similar to those reported for newborn mice and rats. Unlike mice and rats, hamsters did not develop cataracts visible to the unaided eye. The histopathological features of eye disease in hamsters were different from those in rats and were characterized by microophthalmia (especially in runted hamsters) and abnormal proliferation, disorientation, and disorganization of corneal, lens, and retinal tissues. The significance of these findings is discussed.
Bartonella bacilliformis: colonial types and erythrocyte adherence
Authors: Walker T S , Winkler H H
Published: January 2020

Bartonella bacilliformis was cultivated on a solid medium, and two bartonella colonial morphologies were differentiated and designated colony types T1 and T2. Although both T1 and T2 bartonellae adhered to human erythrocytes in vitro, approximately twice as many T2 bartonellae adhered as did T1. Maximum adherence required bartonella energy, most likely proton motive force-dependent motility. Bartonellae did not penetrate or lyse erythrocytes in vitro. Bartonellae adhered poorly to alpha- or beta-glucosidase-treated erythrocytes, but pronase or subtilisin treatment of erythrocytes stimulated adherence. This indicates that bartonellae probably adhere to an erythrocyte glycolipid moiety.
Natural interferon-producing cells in mice
Authors: Ito Y , Aoki H , Kimura Y , Takano M , Shimokata K , Maeno K
Published: January 2020

When mouse lymphoid cells derived from untreated C57BL/6 mice were cocultivated in liquid cultures with L-cell monolayers for 3 h, overlaid with soft agar, and then further incubated for 12 h, protected foci of L cells against vesicular stomatitis virus infection were formed. Many strains of mice have been found to have the protected focus-forming cells on the L-cell monolayers. The formation of the protected foci was completely suppressed by addition of cycloheximide into soft agar. When anti-interferon (type I) antiserum was added to soft agar, there was a decrease in focus counts of about 80%. These experimental results indicated that the formation of protected foci by untreated mouse lymphoid cells was mediated for the most part by type I interferon that was produced without addition of special inducer. We have designated these focus-forming cells as natural interferon-producing cells (NIPC). NIPC belong to the glass-adherent fraction, and Thy-1 antigen, immunoglobulin, and Ia antigen could not be detected on the surface of the NIPC. NIPC were detected in congenitally athymic nude mice. These findings suggest that NIPC belong to the Ia-negative macrophages. Mouse lymphoid cells obtained from germfree mice could form the protected foci on L-cell monolayers and could produce interferon without the addition of a special inducer. NIPC are considered to be a cellular background for spontaneous interferon production.
Effect of oral administration of lysozyme or digested bacterial cell walls on immunostimulation in guinea pigs
Authors: Namba Y , Hidaka Y , Taki K , Morimoto T
Published: January 2020

The effect of oral administration of bacteriolytic enzymes and enzymatically digested bacterial cell walls on immunostimulation in guinea pigs was studied. Guinea pigs were given lysozyme or pronase or both orally for a period of 8 days, and on day 7 they were primed with hepatitis B surface antigen. Circulating antibody titers to the antigen in the enzyme-treated group were significantly higher (four to six times, P less than 0.05) than those in nontreated control groups on day 16 after immunization. Stimulation of cellular immunity in the group receiving both lysozyme and pronase simultaneously was significantly increased compared with the group receiving only one of them. The humoral immune response was enhanced by oral administration of enzymatically digested cell walls isolated from Bifidobacterium longum. The result suggested that intestinal bacteria might be solubilized by oral administration of bacteriolytic enzymes and that the absorbable fragment of peptidoglycan released from the bacterial cell walls might be responsible for the enhanced host immune responses.
Specific inhibition of Escherichia coli ferrienterochelin uptake by a normal human serum immunoglobulin
Authors: Moore D G , Earhart C F
Published: January 2020

Normal human serum contains an enterochelin-specific antibody which presumably acts with transferrin to hinder iron assimilation by enterochelin-producing pathogens. This antibody can be isolated from serum by sodium sulfate fractionation or affinity chromatography by employing an enterochelin-derived ligand (2,3-dihydroxy-N-benzoyl-L-serine) attached to aminohexyl Sepharose 4B. In assays of iron uptake by whole cells, the antibody inhibited enterochelin-directed uptake but not that mediated by citrate or ferrichrome. Also, the growth stimulatory effect of enterochelin on an Ent- strain of Escherichia coli was blocked by the immunoglobulin. This antibody has a high affinity for enterochelin; various elution procedures employing high salt concentrations and low pH failed to remove it from affinity columns. Elution with 3 M sodium thiocyanate or 13 mM 2,3-dihydroxybenzoic acid proved successful. Two pieces of evidence indicate the enterochelin-specific antibody is primarily of the immunoglobulin A (IgA) isotype. It could be removed from serum with goat antihuman IgA and was present only in sodium sulfate fractions of serum known to contain IgA.
Enzyme-linked immunosorbent assay for detection and identification of coxsackieviruses A
Authors: Yolken R H , Torsch V M
Published: January 2020

Coxsackieviruses A are known to cause a wide range of human disease processes. However, because many coxsackieviruses A present in clinical specimens do not produce a recognizable cytopathic effect in readily available tissue culture systems, infections with coxsackieviruses A are often difficult to diagnose. We have thus developed enzyme-linked immunosorbent assay (ELISA) systems for the detection and serotyping of coxsackievirus A antigens. The assays consist of a double-antibody ELISA which utilizes type-specific monkey and mouse coxsackievirus antisera. Although some cross-reactivity was noted, the ELISA systems correctly identified the serotypes of 22 to 23 coxsackievirus A complement fixation antigens available for testing. Testing of tissue culture fluids revealed that antigen could often be detected by ELISA before the appearance of a cytopathic effect. In addition, the infecting coxsackievirus A antigen could be unequivocally identified in 8 of 11 stool specimens obtained from patients with coxsackievirus A infections. The ELISA system might thus represent an important tool in the diagnosis and study of coxsackievirus A infections.
Persistence and spread of Candida albicans after intragastric inoculation of infant mice
Authors: Field L H , Pope L M , Cole G T , Guentzel M N , Berry L J
Published: January 2020

Infant mice have been shown previously to be a useful model for the study of gastrointestinal (GI) and systemic candidosis. In this study, the virulence of four strains of Candida albicans was compared in intragastrically inoculated infants and in adult mice inoculated intravenously. The four strains differed in their ability to kill both infant and adult mice. A smaller inoculum was required to kill adult mice inoculated intravenously. Neonates could not be inoculated intravenously. The ability of the strains to spread systemically from and to persist for long periods of time in the digestive tract was also examined in intragastrically inoculated infants. The yeast cells spread to liver, lungs, kidneys, and spleen within 30 min postinoculation. Yeast were not detectable in the lungs or in blood from the pleural cavity up to 15 min post-inoculation, thus making it unlikely that systemic spread resulted from faulty inoculation or from aspiration. The region where C. albicans crossed the GI tract of infant mice was visualized histologically in the upper third of the small intestine. The four strains varied in their ability to persist for long periods in the GI tract, in the rate at which they appeared systemically, and in ability to kill infant mice. Three of the four strains colonized the gut for up to 10 weeks postinoculation without use of any compromising agents.
Bacterial aggregating activity in human saliva: comparisons of bacterial species and strains
Authors: Malamud D , Appelbaum B , Kline R , Golub E E
Published: January 2020

Using a quantitative assay to measure saliva-mediated bacterial aggregating activity, we have surveyed 20 streptococcal strains with saliva samples obtained from a large population study. Individual saliva samples demonstrated characteristic levels of aggregating activity for Streptococcus sanguis M5. In general, high activity for this strain was associated with high activity for other strains of S. sanguis. Streptococcus mitis, and Streptococcus salivarius. The population distribution of aggregating activity for Streptococcus mutans, however, was different.
Role of antigen form in development of mucosal immunoglobin A response to Shigella flexneri Antigens
Authors: Keren D F , Collins H H , Gemski P , Holt P S , Formal S B
Published: January 2020

One major stumbling block in the development of an effective means to immunize against shigellosis and other enteric diseases has been the lack of a means to assess sequential mucosal immune responses to different potential immunogens. In the present study, we compared the abilities of live invasive organisms, noninvasive organisms, and nonviable antigen preparations of shigella to elicit mucosal immune responses. Whereas previous studies have found that effective immunity was produced best by vaccination with live invasive strains of shigella, in the present study, live noninvasive strains that did not produce any histopathological damage were consistently able to produce local (immunoglobulin A) immune responses as vigorous as those of the invasive strains. Further, acetone-killed shigella antigen was also an effective mucosal immunogen, whereas hot phenol-water-extracted shigella lipopolysaccharide was ineffective, possibly due to the method of preparation. A single oral or parenteral priming was ineffective in enhancing the mucosal immune response when restimulated 1 month later with the same antigen. However, a mucosal memory response was found to be present several months after a triple mucosal stimulation with a locally invasive vaccine strain.
Evidence for the presence of lipopolysaccharide in a ribonuclease-sensitive ribosomal vaccine of Pseudomonas aeruginosa
Authors: Gonggrijp R , Volleberg M P , Lemmens P J , van Boven C P
Published: January 2020

To obtain information about the nature of the immunogens in the ribosomal vaccine (fraction II) of Pseudomonas aeruginosa, we studied the specificity of rabbit antibodies to fraction II. Crossed immunoelectrophoresis demonstrated the presence of antibodies which precipitated with ribosomal antigens, but not with lipopolysaccharide (LPS). By means of an enzyme-linked immunosorbent assay, antibodies to LPS were detected in antibodies to fraction II. Antibodies to fraction II could protect mice against a lethal challenge with P. aeruginosa. Absorption experiments demonstrated that the protective ability of antibodies to fraction II was due to antibodies to cell envelope antigens, whereas antibodies to ribosomal antigens did not contribute to the protection. Antibodies to LPS could be detected in mice 1 week after a single vaccination with fraction II. It was concluded that the protective activity of fraction II was due, at least in part, to the presence of LPS in the ribosomal vaccine. Treatment of fraction II with ribonuclease decreased the protective activity of the ribosomal vaccine. Addition of synthetic polyadenylic acid-polyuridylic acid restored the protective activity of ribonuclease-treated fraction II, indicating that RNA in the ribosomal vaccine might act as an adjuvant or a carrier in the presentation of the of the contaminating cell envelope antigens. The protective activity and the toxicity of fraction II were compared with the protective activity and the toxicity of fraction I, which contained cell envelope components, including LPS, and of purified LPS. The results indicated that protection by the ribosomal vaccine was associated with a slightly higher toxicity than was protection by fraction I, whereas purified LPS was the most toxic vaccine.
Comparative virulence of opacity variants of Neisseria gonorrhoeae strain P9
Authors: Virji M , Everson J S
Published: January 2020

The invasive properties of nine variants of Neisseria gonorrhoeae strain P9 known to vary in their surface composition have been investigated. Relative virulence was evaluated by their cytotoxic effect on Chang epithelial cell monolayers. Piliated variants P9-2 (with alpha pili) and P9-20 (with beta pili plus protein II) showed increased ability to kill the target cells compared with the prototype P9-1 (lacking pili and additional outer membrane proteins). Two nonpiliated variants, P9-11 (with proteins IIa and IId) and P9-19 (with proteins II and IIc), were also relatively more virulent compared with P9-1. Enhanced attachment was exhibited by both piliated and some nonpiliated variants: beta-piliated P9-20 (with protein II; molecular weight, 29,000) and nonpiliated P9-16 (with protein IIb; molecular weight, 28,000) were the most effective in adherence to the target monolayers.
Rise in Inulin-Sensitive B Cells During Ontogeny Can Be Prematurely Stimulated by Thymus-Dependent and Thymus-Independent Antigens
Authors: Shahin Roberta D. , Cebra John J.
Published: January 2020

We have shown that the delayed acquisition of competence in expression of an anti-inulin (IN) response by neonatal BALB/c mice is preceded by a natural increase in the frequency of IN-sensitive B cells between 3 to 5 weeks of life. Up until 3 weeks of age, BALB/c mice resemble adult germfree mice in their low frequency of IN-sensitive B cells (1 to 2/10
6
B cells). Thereafter, the population of IN-reactive B cells rises about 10-fold to the young adult level, without deliberate immunization. This naturally expanded population of IN-reactive cells has an isotype profile resembling populations arising after intentional priming with other antigens in that it contained a large proportion of cells which generated clones expressing immunoglobulin G and immunoglobulin A isotypes, often without detectable immunoglobulin M. The late rise in frequency of IN-sensitive precursors could be induced prematurely by deliberate priming at 3 days of age with either the thymus-dependent antigen IN-hemocyanin or the thymus-independent bacterial levan. However, no circulating anti-IN could be detected following this early administration of antigen. Thus, the delayed expression of anti-IN does not reflect an absence of B cells of the appropriate specificity which can be stimulated to divide by antigen but rather other events occurring subsequent to perinatal generation of antigen-sensitive cells. Our observations support a role for the β2 → 1 fructosyl group as an environmental determinant which selectively expands out preexisting antigen-sensitive B cells at 3 to 5 weeks of age and these include clonotypes which express the predominant anti-IN idiotypes.
Colonization and cariogenicity of Streptococcus ferus in rats
Authors: Coykendall A L , Freedman M L
Published: January 2020

Streptococcus ferus, which is indigenous to wild rats, is a member of the mutans group of streptococci. We tested its ability to colonize and to cause caries in laboratory rats by comparing two strains of S. ferus with the very cariogenic Streptococcus sobrinus strain 6715. Groups of rats were fed either finely ground mouse chow or a 56% sucrose diet, or they were switched from chow to the sucrose diet. All three strains colonized the mouths of rats regardless of diet. However, the infectants reached higher proportions of the total flora more quickly in the rats consuming sucrose. Similarly, the percentage of the oral flora represented by an infecting organism increased numerically when rats originally fed chow were switched to the sucrose diet. S. ferus formed plaques on the teeth of the rats, but these plaques did not proliferate over smooth tooth surfaces as extensively as did those of S. sobrinus. Although S. ferus colonized and accumulated, it was non-cariogenic in rats fed sucrose compared both with rats fed similarly but infected with S. sobrinus 6715 and with uninfected controls. In vitro measurements suggested the S. ferus produced acid less rapidly than S. sobrinus. Thus, the lack of cariogenicity in S. ferus may result from an inability to form copious plaques on smooth tooth surfaces and from low acid production and, therefore, may represent a natural absence of the pathogenic potential usually inherent in the mutans streptococci.
Evaluation of the biological properties of different classes of human antibodies in relation to cholera
Authors: Majumdar A S , Ghose A C
Published: January 2020

Different classes of immunoglobulins (immunoglobulin M [IgM], IgG, and secretory IgA) were purified from pooled serum and milk samples of convalescent cholera patients by gel filtration and immunoadsorbent techniques. The purity of these preparations was established by immunodiffusion and the enzyme-linked immunosorbent assay, using class-specific antisera. The biological properties of antibodies present in these crude and purified immunoglobulin preparations were evaluated by tests related to cholera. Purified human IgM and IgG exhibited both agglutinating and vibriocidal properties. On the other hand, human secretory IgA was not vibriocidal (even in the presence of lysozyme), although it showed agglutinating properties. Both IgG and secretory IgA could effectively neutralize cholera toxin action in vivo, whereas such activity was virtually absent in IgM. The toxin-neutralizing capacity of IgG was, however, higher than that of secretory IgA. All three classes of human antibodies could significantly inhibit the adherence of Vibrio cholerae to intestinal slices in vitro. These results are discussed in relation to the protective immune mechanism during cholera infection.
Characterization of a bactericidal lipid developing within staphylococcal abscesses
Authors: Dye E S , Kapral F A
Published: January 2020

Extraction of staphylococcal abscesses by the Folch procedure revealed that all of the staphylocidal activity was present in the lipid fraction. Further separation of the lipids indicated that the bactericidal activity resided in the free fatty acid pool. Lipids similarly extracted from mesenteric or epididymal fat tissue, either before of after activation, did not possess comparable activity. Myristic, palmitic, palmitoleic, linoleic, and oleic acids, as well as lysolecithin, also failed to exhibit the properties of the fatty acid fraction obtained from abscess homogenates. These findings suggest the staphylocidal fatty acid is not a common host lipid.
Nonspecific immunodepression and protective immunity in mice infected with Leishmania mexicana
Authors: Pérez H , Pocino M , Malavé I
Published: January 2020

C57BL/6 mice infected with Leishmania mexicana showed depression of the in vitro immunoglobulin M-plaque-forming cell response to sheep erythrocytes. Immunodepression was present 3 weeks after inoculation and was maximal at 11 weeks. Thereafter, there was a gradual return to normal immunoresponsiveness correlated with the resolution of lesions. At the time of maximal immunodepression, spleen cells from infected mice diminished the plaque-forming cell response to sheep erythrocytes of normal spleen cells. On the other hand, specific responses, as exemplified by protective immunity to a challenge infection and delayed hypersensitivity responses to parasite antigens, were apparently unaffected. These responses were both present in mice bearing primary lesions and were maximal in recovered mice. The significance of these findings is discussed in relation to a current hypothesis on parasite-induced immunodepression.
Antigens of scrub typhus rickettsiae: separation by polyacrylamide gel electrophoresis and identification by enzyme-linked immunosorbent assay
Authors: Eisemann C S , Osterman J V
Published: January 2020

Antigens of plaque-purified Rickettsia tsutsugamushi strains Gilliam, Karp, and Kato were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were analyzed by an enzyme-linked immunosorbent assay. Six antigens were identified in each of the three prototype strains; in strain Gilliam, these antigens were located in the cell envelope fraction of the organisms. Reactivity of these isolated antigens with homologous or heterologous immune sera indicated that different macromolecules existed in all three strains, although they exhibited very similar mobilities during electrophoresis. Antigens of strain Gilliam reacted equally well with antibodies directed against Gilliam, Karp, or Kato rickettsiae. However, strains Karp and Kato each had two distinct antigens which did not react with heterologous antisera. R. tsutsugamushi antigens retained immunogenicity after electrophoresis, and antisera raised against them reacted with intact organisms and exhibited specificity in reactions with isolated antigens.
Genetics of Serum Resistance in
Neisseria gonorrhoeae
: The
sac-1
Genetic Locus
Authors: Cannon Janne G. , Lee Terrence J. , Guymon Lawrence F. , Sparling P. Frederick
Published: January 2020

A genetic locus affecting susceptibility to the bactericidal activity of normal human serum has been designated
sac-1
. This locus was shown to be closely linked to, but not identical with, a second locus (designated
nmp-2
) that affects protein 1 of the outer membrane. The
sac-1
locus could be linked to known antibiotic resistance markers on the gonococcal chromosome by genetic transformation.
Siderophore Production by Pathogenic
Neisseria
spp
Authors: Yancey Robert J. , Finkelstein Richard A.
Published: January 2020

Previous studies have established the importance of iron acquisition to the growth and virulence of
Neisseria meningitidis
and
Neisseria gonorrhoeae.
Although preliminary evidence that the
Neisseria
spp. produce siderophores has been presented, the exact mechanism of iron acquisition has remained obscure. Siderophore production by
N. gonorrhoeae
and
N. meningitidis
was induced in two different low-iron media. The iron-reactive siderophores, “gonobactin” and “meningobactin,” were partially purified by ion exchange chromatography followed by extraction with phenol-chloroform-ether or by gel filtration. The compounds were of low molecular weight, their synthesis was repressed by iron in the medium, and they appeared to be hydroxamic acids since they were stimulatory for
Arthrobacter flavescens
JG-9 (a hydroxamate auxotroph) and gave a positive Csáky reaction for bound hydroxylamine. In the iron form, the compounds had an absorption maximum of approximately 420 nm. Although meningobactin stimulated growth of the gonococcus in low-iron media and vice versa, the homologous activity was more marked, indicating that the compounds, though similar, were probably not identical. As determined by
A. flavescens
assay the meningococcus produced three to five times more siderophore than did the gonococcus; however, the amount of siderophore present in the culture fluids of even the meningococcus was 100- to 1,000-fold lower than the concentration of hydroxamate siderophores reported to be produced by
Bacillus megaterium
or
Aerobacter aerogenes.
Virulent, colony type 1
N. gonorrhoeae
produced significantly more gonobactin than did the avirulent colony type 3 gonococci.
One-dimensional peptide mapping of the major outer membrane protein of Neisseria gonorrhoeae
Authors: Wong T P , Johnston K H
Published: January 2020

The major outer membrane protein (MOMP), or protein 1, of Neisseria gonorrhoeae is one of the immunodominant proteins of the gonococcal cell surface. It is at least partially responsible for imparting serotyping specificity. This study attempted to compare the primary structure of MOMP molecules isolated from several gonococcal strains by preparative polyacrylamide gel electrophoresis. These isolated proteins were then subjected to enzymatic digestion with staphylococcal V8 protease and alpha-chymotrypsin. The generated peptides were separated by polyacrylamide gradient gel electrophoresis in the presence of sodium dodecyl sulfate. Of the eight strains analyzed, six exhibited distinct peptide maps after either staphylococcal V8 protease or alpha-chymotrypsin digestion. These six strains have also been shown to be immunologically distinct. The data suggest that the gene pool coding for the MOMP is diverse and reflect the complexity of the evolution of N. gonorrhoeae.
Construction of a potential bivalent vaccine strain: introduction of Shigella sonnei form I antigen genes into the galE Salmonella typhi Ty21a typhoid vaccine strain
Authors: Formal S B , Baron L S , Kopecko D J , Washington O , Powell C , Life C A
Published: January 2020

Shigella sonnei, an intestinal pathogen, produces a characteristic form I cell surface antigen now known to be plasmid encoded. We considered that the GalE Salmonella typhi Ty21a oral vaccine strain, highly effective against typhoid, might be modified so as to be protective also against shigellosis due to S. sonnei. The plasmid responsible for form I antigen synthesis was therefore conjugally transferred to the galE S. typhi strain. Serological studies revealed that the derivative strain produces the form I antigen in addition to the normal S. typhi somatic antigens. Testing in mice demonstrated that the derivative form I galE S. typhi strain is protective against both S. sonnei and S. typhi challenges. These data suggest that the galE S. Ty21a oral vaccine strain, which presumably stimulates the local immune system in the intestine, may also serve as a useful carrier for other antigenic determinants to protect against different intestinal infections.
Monoclonal antibody analysis of lipopolysaccharide from Neisseria gonorrhoeae and Neisseria meningitidis
Authors: Apicella M A , Bennett K M , Hermerath C A , Roberts D E
Published: January 2020

A hybridoma produced by the polyethylene glycol fusion of the NS-1 variant of the P3x63Ag8 BALB/c plasmacytoma to splenocytes harvested from a BALB/c mouse immunized with whole gonococci was found to be producing antibody to a common region on gonococcal lipopolysaccharide (LPS). Enzyme-linked immunosorbent assay inhibition systems were established by utilizing this antibody, designated 3F11, and 100% inhibition occurred with both LPS and the LPS-LPS and LPS-derived polysaccharides partially inhibited the enzyme-linked immunosorbent assay, whereas similar preparations isolated from Escherichia coli O:111, the J-5 mutant of this strain, and Salmonella minnesota Re595 failed to inhibit the assay. Studies utilizing whole gonococcal strains 4505 and the isogenic variant 4505r, which lacks both the LPS serotype and common determinants as inhibitors, demonstrated that the determinant recognized by the 3F11 antibody was present on the surface of 4505 and absent on 4505r. Inhibition studies were performed with beta-glucose, beta-galactose, D-glucosamine, D-galactosamine, heptose, 2-keto-3-deoxyoctanoate, N-acetylglucosamine, N-acetylgalactosamine, alpha-lactose, and beta-lactose. Complete inhibition of the enzyme-linked immunosorbent assay occurred with D-galactosamine, and partial inhibition was achieved with both alpha-lactose and beta-lactose. Based on these observations, the 3F11 antibody recognizes a site common to gonococcal LPS which is partially shared by meningococcal LPS. The chemical structure of the determinant appears to be a D-galactosamine-O-D-galactopyranosyl-(1-4)-D-glucopyranose. Additional specificity may be conferred by the steric relationship of the determinant on the intact LPS.
Characterization of herpes simplex virus persistence in a human T lymphoblastoid cell line
Authors: Cummings P J , Lakomy R J , Rinaldo C R
Published: January 2020

Persistent, dynamic-state infection with herpes simplex virus (HSV) type 1 has been maintained in human T lymphoblastoid (CEM) cells for many months after initial infection with the wild-type virus (HSV0) (input virus/cell multiplicity of 1.0). Persistently infected cells grew as well as uninfected cells, except during occasional periods of crisis (increased viral replication and cytopathic effect). Cells could survive the crisis when they were maintained for twice the usual time interval (8 to 10 rather than 4 to 5 days) before subculture. Interferon was not detectable in the cultures. HSV0 was compared with HSVp1, a small plaque-forming isolate from persistently infected CEM cells. Primary infection of CEM cells with HSV0 at a low input multiplicity (0.01) led to abortive replication, whereas infection with HSVp1 at the same multiplicity resulted in either rapidly lytic or persistent infection depending upon the time interval of subculture. Approximately 55% of plaque-purified clones of HSVp1, as compared with only 5% of HSV0 clones, displayed temperature-sensitive growth in Vero cells. Defective interfering virus was not detectable in uncloned HSVp1 by interference assay. Persistently infected cultures "cured" by treatment with HSV antiserum or incubation at 39 degrees C were resistant to reinfection with HSV but permissive for vesicular stomatitis virus replication, suggesting that these treatments modulated a shift from the dynamic-state of the static-state, latent infection. These studies provide a model for characterization of HSV persistence and latency in a highly differentiated human cell line.
Enolases from fluoride-sensitive and fluoride-resistant streptococci
Authors: Bunick F J , Kashket S
Published: January 2020

The enolase from a highly fluoride-sensitive strain of Streptococcus salivarius and its fluoride-resistant mutant, as well as those from strains of Streptococcus sanguis and Streptococcus mutans with intermediate and low sensitivities to fluoride have been shown to be inhibited by fluoride. Comparisons of the purified, strain-specific enzymes showed a high degree of similarity for all preparations. The Michaelis constants for the substrate 2-phosphoglycerate were 1.3 x 10(-4) to 2.4 x 10(-4) M, pH optima were 7.3 to 7.7, and Mg2+ optima were 2 mEq/liter for all. Inhibition by fluoride required the presence of inorganic phosphate and was competitive in nature, and the calculated modified inhibition indices were found to be in the range from 3.3 x 10(-14) to 5.8 x 10(-14) M4. Percent inhibitions were determined under standardized conditions (0.16 mM NaF, 2 mM MgSO4, 0.5 mM Pi, and 0.5 mM 2-phosphoglycerate) and were found to range from 53.3 to 65.9% for all of the purified enzymes. The differences do not appear to be meaningful metabolically. Inhibition was reduced to about 14% at pH 6.0. From the similarities in the behavior of the strain-specific enzymes it is concluded that the differences in the glycolytic sensitivities of the different strains of streptococci to fluoride are not the consequence of any kinetic differences between the respective enolases.
Protection against feline leukemia by vaccination with a subunit vaccine
Authors: Lewis M G , Mathes L E , Olsen R G
Published: January 2020

An effective vaccine against feline leukemia virus infection has been developed by the collection and concentration of tissue culture medium harvested from a tumor cell line. Lymphoid cells were grown to near saturation density in a normal growth medium and then transferred to a serum-free medium. The serum-free medium was collected, concentrated, and evaluated for its vaccine potential. Cats receiving the vaccine emulsified in complete Freund adjuvant developed high antiviral and antitumor titers and were protected (81%) against virus challenge. Cats receiving the vaccine without an adjuvant developed lower antibody levels and lower protection (53%) from viremia. Age-matched and litter-matched controls developed no antibody to test antigens before the challenge, and 100% became persistently viremic after the challenge. Vaccination with the soluble tumor cell antigen vaccine proved successful in preventing the induction of feline leukemia virus infection.
Response of CBA/N x DBA2/F1 mice to Nocardia asteroides
Authors: Beaman B L , Gershwin M E , Ahmed A , Scates S M , Deem R
Published: January 2020

Immunized and nonimmunized B-lymphocyte-deficient CBD2/F1 (CBA/N x DBA/2) mice were infected with Nocardia asteroides GUH-2 by different routes of inoculation. The 50% lethal dose, organ clearance, footpad response, and antibody titers were measured. It was observed that B-cell-deficient male mice were not significantly more susceptible to infection than normal female controls even though the female CBD2/F1 mice produced antinocardial antibodies while the deficient male animals did not. Preimmunized male and female mice were identical in their ability to clear N. asteroides from the adrenals, brain, kidneys, liver, lungs, and spleen. Both DBA/2 and CBD2/F1 female mice were more susceptible than their male littermates to intravenous challenge with N. asteroides GUH-2. This enhanced susceptibility of the female mice as compared to the male littermates appeared to be due to a decreased resistance to nocardial infections in the brains of the female animals. These data indicate that antibody and certain B-lymphocyte subpopulations are not essential components in host resistance to N. asteroides GUH-2 in these mice.
Preemption of Streptococcus mutans 10449S colonization by its mutant 805
Authors: Tanzer J M , Fisher J , Freedman M L
Published: January 2020

Oral infection of rats with Streptococcus mutans mutant 805 was used to prevent the establishment of its highly virulent wild-type progenitor NCTC 10449S. The dose of wild-type cells required to colonize 100% of the specific pathogen-free Osborne-Mendel rats (21 to 43 days old) consuming caries test diet 2000 was greater than 4 x 10(5) but less than 4 x 10(6) cells. Therefore, the latter dose was used to challenge rats which had already been colonized by an oral dose of about 6 x 10(8) cells of mutant 805. This prior infection by 805 either completely protected rats from subsequent colonization by wild-type cells or greatly delayed and diminished their emergence. Rats in which wild-type cells became established showed much lower percentages of wild-type cells in their total recoverable floras than did rats that were not first infected by the mutant. Large doses of mutant 805, however, did not displace wild-type cells from rats once it became established. There was no evidence of reversion of the mutant, which is defective in intracellular polysaccharide synthesis and hence is less virulent than wild-type cells. The data indicate that the S. mutans cell which first colonizes rats gains the strongest ecological position and is difficult to displace. Also, they suggest the possible prophylactic utility of infection by this mutant of S. mutans.
Comparison of specific and cross-reactive antigens of alphaviruses on virions and infected cells
Authors: Gates D , Brown A , Wust C J
Published: January 2020

Rabbit hyperimmune antisera against Sindbis (SIN) or Semliki Forest (SF) virus were absorbed with purified SIN virus or SIN virus-infected cells, or with SF virus or SF virus-infected cells. Residual antibody titers were determined by hemagglutination inhibition (HAI) and antibody-dependent, complement-mediated cytolysis (ADCMC) assays. It appeared that absorption with virus-infected cells removed ADCMC-detectable cross-reactive antibody much more efficiently than did absorption with either virus. HAI assays with the same absorbed antisera indicated that both virus and virus-infected cells removed HAI-detectable cross-reactive antibody. On the basis of these and other data, there appeared to be a cross-reactive antigen present on virus-infected cells which was detectable by ADCMC and was distinct from the cross-reactive antigen assayed by HAI.
Hemolysin plasmid coding for the virulence of a nephropathogenic Escherichia coli strain
Authors: Waalwijk C , van den Bosch J F , MacLaren D M , de Graaff J
Published: January 2020

The nephropathogenic Escherichia coli strain P673 was shown to harbor two plasmids with molecular sizes of 70 and 41 megadaltons, respectively. The 70-megadalton plasmid, pCW1, coded for tetracycline resistance, whereas hemolysin production was coded by the 41-megadalton plasmid, pCW2. Plasmid pCW1 proved to be self-transmissible, in contrast to pCW2. Transfer of the hemolysin character was associated with the appearance of a 110-megadalton plasmid, pCW3. The incompatibility of pCW3 with both native plasmids and restriction enzyme analysis led to the conclusion that pCW3 is a cointegrate of pCW1 and pCW2, pCW2, carrying the hemolytic determinant, is involved in the nephropathogenic character of strain P673, because (i) elimination of pCW2 from P673 was associated with a loss of virulence and (ii) the nephropathogenicity of the avirulent mutant could be restored by reintroduction of pCW2 DNA as part of a cointegrate structure.
Influence of Sublethal Antibiotic Concentrations on Bacterial Adherence to Saliva-Treated Hydroxyapatite
Authors: Peros W. J. , Gibbons R. J.
Published: January 2020

The influence of growth in the presence of sublethal concentrations of nine antibiotics on the ability of certain potentially odontopathic bacteria to attach to saliva-treated hydroxyapatite surfaces which mimic teeth was studied. Cells of
Actinomyces viscosus
LY7 and S2,
Bacteroides gingivalis
381,
Capnocytophaga ochraceus
6, and
Actinobacillus actinomycetemcomitans
N27 attached in lower numbers to saliva-treated hydroxyapatite when grown in the presence of 50% of the minimum inhibitory concentration of tetracycline. Electron microscopic observations of negatively stained preparations indicated that tetracycline-grown
A. viscosus
LY7 cells had fewer fimbriae than did untreated cells, which may account for the impaired ability of the treated cells to attach. However, cells of
Actinomyces naeslundii
L13 and S4 attached in higher numbers when grown in the presence of tetracycline, clindamycin, erythromycin, chloramphenicol, or neomycin.
Streptococcus mutans
strains H12 and JBP also exhibited increased adherence to saliva-treated hydroxyapatite when grown in the presence of 50 or 25% of the minimum inhibitory concentration of penicillin. Thus, growth in the presence of sublethal antibiotic concentrations could increase as well as decrease the adherence of bacteria to saliva-treated hydroxyapatite. Antibiotic-grown cells of the
Actinomyces
strains showed enhanced hemagglutination activity, but this did not correlate with their ability to attach to saliva-treated hydroxyapatite. Sublethal concentrations of antibiotics in the growth media also affected the coaggregation reactions of several organisms; the effects were specific for one member of the coaggregation pair.