bluuebunny/crossref_metadata_2025 huggingface dataset:
Lack of greater seroconversion of rhesus monkeys after subcutaneous inoculation of dengue type 2 live-virus vaccine combined with infection-enhancing antibodies
Authors: Kraiselburd E N , Lavergne J A , Woodall J P , Kessler M J , Meier G , Chiriboga J , Moore C G , Sather G E , Pomales A , Maldonado E , Rivera R
Published: January 2020

Four groups of six nonimmune male rhesus monkeys were inoculated subcutaneously with formulations of dengue type 2 vaccine virus DEN-2/S-1. Group A received 1.9 x 10(4) plaque-forming units of vaccine in normal human serum albumin diluent. Group B received the same dose combined with a dengue type 2-immune human serum diluted 1:1,600, beyond its neutralization endpoint of 1:300, but having an immune enhancement titer of 250,000. Groups C and D received 10-fold dilutions of these respective formulations. No migration-inhibitory factor was found when peripheral blood mononuclear leukocytes obtained on day 68 post-immunization from monkeys of all experimental groups were tested. No viremia was detected in any of the monkeys when sera taken on postvaccination days 1 through 12 were inoculated into adult Toxorhynchites amboinensis mosquitoes and LLC-MK2 cells. By day 89, four of the six monkeys had seroconverted by the neutralization test in each of groups A, B, and C, and three of five monkeys in group D (one monkey died from cardiac collapse after anesthesia) had seroconverted. Immune enhancement of dengue virus infection is known to occur in humans and monkeys circulating heterologous flavivirus antibodies. In this study, there was no enhancing effect when antibody was mixed with dengue type 2 vaccine virus and injected subcutaneously.
Diarrhea in lambs: experimental infections with enterotoxigenic Escherichia coli, rotavirus, and Cryptosporidium sp
Authors: Tzipori S , Sherwood D , Angus K W , Campbell I , Gordon M
Published: January 2020

Thirteen gnotobiotic lambs, aged from a few hours to 8 days, were inoculated orally with single infections of enterotoxigenic Escherichia coli (ETEC) (four animals), lamb rotavirus (five animals), and Cryptosporidium (four animals). Six gnotobiotic and two specific-pathogen-free lambs were co-inoculated with either rotavirus and ETEC (four animals), rotavirus and Cryptosporidium (two animals), or ETEC and Cryptosporidium (two animals). Lambs 4 days of age and older became only subclinically infected with either rotavirus, ETEC (08:K87:K99 ST+), or both enteropathogens given simultaneously. Six-day-old lambs inoculated with Cryptosporidium became extremely depressed, anorectic, and had intermittent diarrhea. There was no difference in the clinical manifestations, level of disaccharidase activity in the small intestine, or extent of histological damage between lambs inoculated with Cryptosporidium alone or together with either of the other two agents. The results indicate that under the conditions of these experiments, lambs become clinically resistant to infection with ETEC, rotavirus, or both agents together, by 4 days after birth, whereas lambs 2 days old or younger were clinically susceptible to infection by these agents. In contrast, they remained clinically susceptible to infection with Cryptosporidium up to at least 6 days of age. Cryptosporidium infections were not aggravated by coinfection with either ETEC or rotavirus.
Effects of human neutrophil granule extracts on macromolecular synthesis in Neisseria gonorrhoeae
Authors: Buck P , Rest R F
Published: January 2020

Neisseria gonorrhoeae were exponentially killed for 120 min (i.e., they were prevented from forming colonies on agar) by extracts of human neutrophil granules; however, macromolecular synthesis, indicated by incorporation of radiolabeled precursors in trichloroacetic acid-precipitable material, continued at or above zero time control values for 45 min. Protein, deoxyribonucleic acid, and ribonucleic acid synthesis appeared to decrease simultaneously after 45 min. Little or no lysis gonococci occurred during the first 60 min of incubation. The ions K+, Na+, Ca2+, Cl1-, SO4(2-) and PO4(3-) at concentrations of less than or equal to 100 mM did not affect granule extract bactericidal activity. On the other hand, 20 mM Mg2+ completely inhibited killing when initially present along with granule extract or when added within 2 to 5 min after granule extract was added to a suspension of gonococci. Gonococci treated with granule extract, washed, and then incubated in gonococci. Gonococci treated with granule extract, washed, and then incubated in the absence of extract died as if extract were still present. The ability of subinhibitory concentrations of actinomycin D or erythromycin to inhibit growth and protein and nucleic acid synthesis was synergistically increased in the presence of granule extract. The above information suggests that a bactericidal component(s) of human neutrophil granules sticks to gonococci, altering their outer membrane permeability and their ability to divide.
Effect of fractions of Ethiopian And Norwegian colostrum on rotavirus and Escherichia coli heat-labile enterotoxin
Authors: Otnaess A B , Orstavik I
Published: January 2020

Samples of colostrum from both Ethiopian and Norwegian women contained antirotavirus activities of immunoglobulin and non-immunoglobulin nature. No significant differences in rotavirus immunoglobulin A or in rotavirus-inhibiting activity were found between samples from the two countries. The non-immunoglobulin inhibitory activity was trypsin sensitive and heat stable (100 degrees C for 10 min). Escherichia coli heat-labile enterotoxin antibodies were measured in the colostrum samples by enzyme-linked immunosorbent assay. No E. coli enterotoxin-specific immunoglobulin A was detected, possibly due to the high background caused by the nonspecific adsorption of immunoglobulin A to the enzyme-linked immunosorbent assay plates in the absence of toxin. A total of 5 of 15 Ethiopian colostrum samples and 0 of 11 Norwegian colostrum samples neutralized the effect of E. coli heat-labile enterotoxin on YI adrenal cells. Both the Ethiopian and the Norwegian colostrum samples contained a non-immunoglobulin enterotoxin-inhibitory activity when the toxin was measured by enzyme-linked immunosorbent assay. This inhibitory activity was not trypsin sensitive, and extraction by chloroform-methanol indicated that the inhibitor was of a lipid nature.
Mechanism for nonspecific immunity of Listeria monocytogenes in rats mediated by platelets and the clotting system
Authors: Davies W A , Ackerman V P , Nelson D S
Published: January 2020

A proposed mechanism for nonspecific immunity to Listeria monocytogenes in rats based on the existence of an activatable lysin is described. Using a deoxyribonucleic acid release assay, we found lysin activity in serum made from whole blood but not in serum made from platelet-free plasma. Washed platelets and platelet lysates exhibited only partial activity as compared with that in serum. This activity was amplified by the addition of platelet-free plasma serum. The activity of the lysin was unaffected by heparin, dialysis, a serine esterase inhibitor, or heating to 56 degrees C for 30 min. Effective inhibitors were ethylenediaminetetraacetic acid and stronger heating (to 65 degrees C). Listeria organisms were found to reduce the recalcified clotting time to platelet-rich plasma in a dose-dependent fashion, indicating that the organisms can exhibit procoagulant activity. The susceptibility of rats to Listeria infection was enhanced by anticoagulant treatment. Rats were infected with Listeria organisms with and without administration of heparin. Heparin-treated rats developed bacteremia, and some died. None of the control rats developed bacteremia or died. These results suggest that natural immunity to Listeria infection is partly due to a platelet-dependent lysin which is activated during clotting and is, in turn, promoted by the Listeria organisms themselves.
Inactivation of varicella zoster virus in vitro: effect of leukocytes and specific antibody
Authors: Gershon A A , Steinberg S P
Published: January 2020

Inactivation of varicella zoster virus in vitro by nonadherent, mononuclear peripheral blood leukocytes and antibody is described. When leukocytes and specific antibody were incubated with this virus, marked inactivation of the virus occurred. In contrast, leukocytes alone or with serum devoid of varicella zoster antibody caused only a small degree of inactivation of varicella zoster virus. The leukocytes involved appeared not to be monocyte-macrophages or T or B lymphocytes, and only minute amounts of specific antibody were required. We had found previously that leukocytes from unsensitized (varicella susceptible) as well as sensitized (varicella immune) donors could cause this reaction. We therefore propose that the reaction may be a form of antibody-dependent cellular cytotoxicity, as has been described for 51Cr release by lymphoid (K) cells for other herpesviruses.
Regulation of the immune response to bacterial lipopolysaccharide by adherent cells
Authors: Citron M O , Michael J G
Published: January 2020

Immune response to bacterial lipopolysaccharide is usually short lived, but it often reappears without additional stimulus in a cyclic fashion. Activated adherent cells, presumably macrophages, were found to have a role in the reduction of the immune response to Escherichia coli O127 lipopolysaccharide. The suppressive activity of the adherent cells was abrogated before renewal of the responsiveness.
Susceptibility of mice to rotavirus infection: effects of age and administration of corticosteroids
Authors: Wolf J L , Cukor G , Blacklow N R , Dambrauskas R , Trier J S
Published: January 2020

We examined susceptibility to the murine rotavirus, epizootic diarrhea of infant mice virus (EDIM), in normal suckling and weaned mice and in suckling mice treated with glucocorticoids. Normal mice 1 to 40 days old were inoculated by gastrin intubation with high doses of EDIM and subsequently evaluated for rotavirus infection by solid-phase radioimmunoassay, by electron microscopy of intestinal tissue sections or by both. Radioimmunoassay and electron microscopy showed a concordance of 89.5% in the detection of rotavirus infection. After a period of low susceptibility to EDIM infection during the first 3 days after birth (23%), susceptibility was high for the next 11 days (95%), but decreased abruptly as mice approached weaning (41% on days 15 through 17). Mice 34 days or older did not develop EDIM infection after inoculation, but rotavirus antigen was detected in 12% of uninoculated mothers nursing inoculated litters. Administration of cortisone acetate to 8-day-old mice induced partial intestinal maturation prematurely. At 3 to 6 days after cortisone acetate treatment, susceptibility to EDIM infection decreased to 60% compared with 94% in age-matched controls. Our data suggest (i) that susceptibility of mice to EDIM infection is age dependent, decreasing in concert with intestinal maturation, and (ii) that glucocorticoids, which induce premature partial intestinal maturation, modulate susceptibility of mice to EDIM.
Detection of extracellular toxin(s) produced by Vibrio vulnificus
Authors: Kreger A , Lockwood D
Published: January 2020

Conditions are described for the production, in high titers, a heat-labile, antigenic, extracellular toxin(s) by Vibrio vulnificus, a recently recognized human pathogen. Bacteriologically sterile culture filtrate preparations obtained from mid-logarithmic-phase cultures of the bacterium possessed cytolytic activity against mammalian erythrocytes, cytotoxic activity for Chinese hamster ovary cells, vascular permeability factor activity in guinea pig skin, and lethal activity for mice. The specific activity of toxin preparations from cultures of a virulent strain of the bacterium was ca. 25-fold more than that of toxin preparations obtained from cultures of a weakly virulent strain. The four toxic activities were inseparable by gel filtration with Sephadex G-100; however, two components, which had markedly different elution behavior but which possessed the four activities mentioned above, were obtained. The major (ca. 88% of the recovered activity) and minor components had apparent molecular weights of ca. 38,500 and greater than 150,000, respectively.
Chemotactic Activity of Bone Marrow-Derived Macrophages Changes with Time in Culture
Authors: Falk Werner , Tomisawa Shogo , Klimetzek Volker , Meltzer Monte S.
Published: January 2020

The number of bone marrow-derived macrophages able to respond to chemotactic stimuli varies with time in culture. Chemotactic response was optimal at 2 weeks and may depend on cell maturation or differentiation or both.
Extracellular enzymes of Legionella pneumophila
Authors: Thorpe T C , Miller R D
Published: January 2020

All strains of Legionella pneumophila tested produced detectable levels of extracellular protease, phosphatase, lipase, deoxyribonuclease, ribonuclease, and beta-lactamase activity. Weak starch hydrolysis was also demonstrated for all strains. Elastase, collagenase, phospholipase C, hyaluronidase, chondroitinase, neuraminidase, or coagulase were not detected in any of these laboratory-maintained strains.
Inhibition of the Mitotic Response in Regenerating Mouse Liver During Viral Hepatitis
Authors: Carthew P.
Published: January 2020

Viral hepatitis caused by infection with murine hepatitis virus strain A59 has been shown to affect the mitotic response after partial hepatectomy in mice. Normal mice showed a delayed response, whereas nude mice did not show any response, even 5 days after partial hepatectomy.
Salivary immunoglobulin A antibodies reacting with antigens from oral streptococci: longitudinal study in humans
Authors: Gahnberg L , Krasse B
Published: January 2020

The salivary immunoglobulin A (IgA) activity to antigens from four common oral streptococci was analyzed in samples from five humans. From each individual, parotid and whole saliva were collected 12 times over a period of 4 months. In samples collected at different occasions, the salivary IgA activity varied considerably. The variations showed a covariation with the concentration of total IgA in the saliva samples. A covariation was also found between salivary IgA antibodies of different specificity. It is concluded that reference antigens, in combination with measurement of total IgA concentration, ought to be used when evaluating the salivary IgA response in humans.
Medium for the accumulation of extracellular hemolysin and protease by Aeromonas hydrophila
Authors: Riddle L M , Graham T E , Amborski R L
Published: January 2020

A medium for the accumulation of extracellular hemolysin (300 to 1,600 hemolytic units per ml) and protease (2 to 3 proteolytic units per ml) was developed for an anaerogenic strain of Aeromonas hydrophila. In this medium, growth yields were less but levels of accumulated toxin were greater or equivalent when compared with the same responses in brain heart infusion and nutrient broths. The medium was considered to be partially defined since the conditions for maximum observed hemolysin accumulation (1,600 hemolysin units per ml) were not identified. The results showed that iron and zinc contributed to the control of the extracellular accumulation of both toxins. Whereas iron exerted an inhibitory effect, zinc stimulated the accumulation of both toxins.
Reduction in antiviral activity of human beta interferon by gallic acid
Authors: Osborne L C , Peeler J T , Archer D L
Published: January 2020

Gallic acid (GA) is a common part of the human diet, both in the free form and as a metabolite of tannic acid and propyl gallate. Cell cultures were incubated with mixtures of either GA and beta interferon (IFN-beta) (formerly fibroblast IFN) or medium and IFN-beta. The cells were subsequently challenged with virus. The virus plaque yields were greater in cells incubated with IFN-beta and GA than in cells incubated with IFN-beta and medium, indicating that in the former mixture, IFN-beta had lost antiviral activity. The magnitude of the loss was dependent upon the GA concentration. IFN-alpha and IFN-gamma (formerly leukocyte IFN and immune IFN, respectively) were not similarly affected. The effect of GA on IFN-beta could be reversed with 2-mercaptoethanol, suggesting a possible sulfhydryl involvement. Extensive dialysis of IFN-beta-GA mixtures to remove the GA failed to reverse the reduction in antiviral activity. This suggests that a direct and irreversible interaction between IFN-beta and GA took place, reducing the activity of IFN-beta. The significance of this finding with regard to virus infections of the intestine is discussed.
Specific receptor binding of staphylococcal enterotoxins by murine splenic lymphocytes
Authors: Buxser S , Bonventre P F , Archer D L
Published: January 2020

We describe a reliable assay to measure the specific binding of 125I-labeled staphylococcal enterotoxin A (SEA) by murine spleen cells. Toxin binding by lymphocytes was specific in that it was inhibited by unlabeled SEA but not by unrelated proteins. The biological activity of SEA (T-lymphocyte mitogenesis) correlated with toxin binding to splenic lymphocytes. In the presence of high concentrations of [125I]SEA, specific binding increased rapidly and approached saturation after 2 h. Toxin binding was sensitive to temperature and pH and was directly proportional to the concentration of spleen cells in the incubation mixture. We estimated that there was a single class of toxin-binding sites, which had an apparent equilibrium dissociation constant (Kd) of 8 x 10(-7) M and numbered 3,600 sites per cell. SEA and the antigenically distinct compounds staphylococcal enterotoxins B and E in excess competitively inhibited binding of [125I]SEA to mouse spleen cells. Our data suggest a common class of binding sites for the three staphylococcal enterotoxins.
Adjuvant activity of carbohydrate analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine on the induction of delayed-type hypersensitivity to azobenzenearsonate-N-acetyl-L-tyrosine in guinea pigs
Authors: Azuma I , Okumura H , Saiki I , Kiso M , Hasegawa A , Tanio Y , Yamamura Y
Published: January 2020

The adjuvant activity of 29 kinds of carbohydrate analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine on the induction of delayed-type hypersensitivity to azobenzenearsonate-N-acetyl-L-tyrosine was examined in guinea pigs. It was found that the D-manno- and D-galacto-type muramyldipeptides were as active as the D-gluco-type muramyldipeptide (MDP). The structural requirement of the carbohydrate moiety of analogs of N-acetylmuramyl-L-alanyl-D-isoglutamine is discussed.
Enzyme-linked immunosorbent assay for detection of type A streptococcal exotoxin: kinetics and regulation during growth of Streptococcus pyogenes
Authors: Houston C W , Ferretti J J
Published: January 2020

We describe the detection and quantitation of type A streptococcal exotoxin (erythrogenic toxin, streptococcal pyrogenic exotoxin) by an enzyme-linked immunosorbent assay. This sensitive and specific technique detected microgram amounts of type A exotoxin and was useful for studying the kinetics and regulation of type A exotoxin production during the growth of Streptococcus pyogenes NY5. Maximum production of type A exotoxin was observed during the mid-log phase of growth, similar to the production of other streptococcal extracellular products. When S. pyogenes NY5 was grown at 42 degrees C, decreases in both growth and type A exotoxin production were observed. The results obtained when we studied the influence of nutrient additives and metal ions on the production of type A exotoxin led to the conclusion that none of these factors significantly affected type A exotoxin synthesis and that regulation was constitutive.
Plasmids in Yersinia enterocolitica serotypes O:3 and O:9: correlation with epithelial cell adherence in vitro
Authors: Vesikari T , Nurmi T , Mäki M , Skurnik M , Sundqvist C , Granfors K , Grönroos P
Published: January 2020

Human isolates of Yersinia enterocolitica serotypes O:3 (biotype 4) and O:9 (biotype 3) harbored plasmids sized approximately 47 and 44 megadaltons, respectively. No such plasmids were found in "apathogenic" strains of Y. enterocolitica belonging to biotype 1. There was a positive correlation among the presence of plasmid, autoagglutination, and adherence to and toxicity for HEp-2 cell cultures; all of these properties were lost by culturing at 37 degrees C in the absence of calcium. Strains of Y. enterocolitica O:3 and O:9 cured of the plasmids showed increased invasiveness in the HEp-2 cell culture model, but no invasiveness in guinea pig eye. It is suggested that the plasmids of Y. enterocolitica primarily determine epithelial cell adherence, but may also be associated with other pathogenic properties.
Role of L-forms of Nocardia caviae in the development of chronic mycetomas in normal and immunodeficient murine models
Authors: Beaman B L , Scates S M
Published: January 2020

Single-cell suspensions of Nocardia caviae 112 were injected into normal, athymic, and asplenic mice by several different routes. The 50% lethal dose values, kill curve characteristics, histological and electron microscopic properties, organ clearance patterns, and induction of L-forms during the acute and chronic phase of disease were determined in groups of mice for up to 2 years after infection. From these data we concluded the following. (i) Athymic and asplenic animals were significantly more susceptible to N. caviae than their littermate controls regardless of inoculation route. (ii) All mice were most susceptible to lethal infection after intranasal administration and least affected when the organisms were injected into the peritoneal cavity. (iii) Chronic, progressive disease leading to the formation of mycetomas occurred only in mice injected intravenously. (iv) T-cell-deficient animals were impaired in the development of typical mycetomas. (v) L-forms of N. caviae were induced within immunocompetent hosts, whereas the cell wall-less state of the bacteria was not observed in the immunodeficient animals. (vi) Two colony types of the cell wall-deficient state were isolated from infected animals. (vii) These cell wall-deficient organisms were intimately involved in the pathogenesis of disease and bacterial persistence within the host. Finally (viii), with this strain of Nocardia, cell wall-deficient organisms played a major role in the development of the characteristic bacterial granule formed within the mycetomatous lesions 6 months to 1 year after intravenous inoculation.
Role of Surface Fimbriae (Fibrils) in the Adsorption of
Actinomyces
Species to Saliva-Treated Hydroxyapatite Surfaces
Authors: Clark William B. , Webb Eldon L. , Wheeler Timothy T. , Fischlschweiger Werner , Birdsell Dale C. , Mansheim Bernard J.
Published: January 2020

We studied the adsorption, morphological, and serological characteristics of selected
Actinomyces
and related species. Evaluation of uranyl acetate-stained cells by electron microscopy revealed wide variations among strains in the frequency of surface fimbriae. These variations did not always correlate with the percent adsorption to saliva-treated hydroxyapatite of the various
Actinomyces
strains. However, two strains of
Rothia dentocariosa
possessing no surface fimbriae and five strains of
A. israelii
possessing very few surface fimbriae exhibited feeble adsorption to saliva-treated hydroxyapatite. Although the calculated number of adsorption sites on saliva-treated hydroxypatite did not vary widely among the strains tested, significant differences were observed in the affinities calculated for some species or serotypes. The mean affinities for strains of
A. viscosus
serotype 2 and
A. naeslundii
serotype 3 were similar, and these strains adsorbed well to saliva-treated hydroxyapatite. The mean adsorption and affinity for the
A. naeslundii
strain serotype 1 and all strains of
A. israelii
tested were significantly less than those determined for the
A. viscosus
serotype 2 or
A. naeslundii
serotype 3 strains. Adsorption inhibition activity of antiserum to strain T14V, previously shown to be solely related to antibodies in immune serum directed against the VA1 fimbria (fibril) antigen, was removed by preadsorption of the antiserum with most
A. viscosus
and
A. naelundii
strains, but not with
A. israelii
strains. This suggests some cross-reactivity among strains of
A. viscosus
and
A. naeslundii
but not
A. israelii.
Adsorption to saliva-treated hydroxyapatite of all
A. viscosus
and
A. naeslundii
strains tested was strongly inhibited by fimbriae isolated from
A. viscosus
strain T14V. Collectively, these data suggest that the adsorption of certain
A. viscosus
and
A. naeslundii
strains is mediated by surface fimbriae, many of which appear serologically cross-reactive with strain T14V fimbriae.
Staining technique for peptides of Escherichia coli heat-stable enterotoxin
Authors: Pesti L , Lukács K
Published: January 2020

Crude and purified Escherichia coli heat-stable enterotoxin was stained directly in polyacrylamide gel rods after electrophoresis with Coomassie brilliant blue G-250 dissolved in 1 N H2SO4--one-month volume of 10 N KOH-12% trichloroacetic acid. The stained heat-stable toxin bands were partially characterized.
Distinctive ribonucleic acid patterns of human rotavirus subgroups 1 and 2
Authors: Kalica A R , Greenberg H B , Espejo R T , Flores J , Wyatt R G , Kapikian A Z , Chanock R M
Published: January 2020

The ribonucleic acid migration patterns of 7 subgroup 1 and 16 subgroup 2 human rotaviruses recovered from four geographic areas were compared. The subgroup 1 ribonucleic acid patterns had strikingly slower-moving segments 10 and 11, suggesting a correlation between the ribonucleic acid pattern and the subgroup specificity.
Genetic studies of the murine corneal response to Pseudomonas aeruginosa
Authors: Berk R S , Beisel K , Hazlett L D
Published: January 2020

The murine genetic control of resistance to Pseudomonas aeruginosa eye infection previously has been demonstrated to be regulated by two complementing dominant genes, PsCR1 and PsCR2. The PsCR1 locus apparently is not associated with the H-2 complex, whereas the PsCR2 locus could not definitively be associated with H-2. In this study we attempted to demonstrate a possible H-2 linkage of the PsCR2 locus. A panel of inbred congenic strains varying with either the H-2 haplotype or genetic background from inbred partners of C57BL/10, C3H, A, and BALB/c strains were characterized for their P. aeruginosa infectivity phenotypes. These studies indicated that the PsCR2 locus is not associated with the H-2 locus. Furthermore, variations of the H-2 haplotype did not change the resistance patterns observed in these strains. However, BALB.B and BALB.K congenic lines were resistant to P. aeruginosa eye infection, whereas BALB/cJ mice were susceptible. Examination of hybrids (BALB.K X BALB/cJ)F1 and (BALB.B X BALB/cJ)F1 demonstrated that an autosomal dominant gene(s), PsCR, confers resistance. Segregation analysis for the H-2 haplotype and the PsCR gene in offspring of backcross matings with the BALB/cJ parental strain suggested that this PsCR gene is not linked to the H-2 complex and has an inheritance pattern of a single locus or several tightly linked loci.
Sequential determination of circulating immune complexes in experimental filariasis
Authors: Karavodin L M , Ash L R
Published: January 2020

Levels of circulating immune complexes were measured in jirds (Meriones unguiculatus) infected with the filarial nematode Brugia pahangi during an 11-month infection. Using 16 infected and 8 control animals, we found three general trends, which correspond to events in the life cycle of the filarial worm in the host, in all individually infected jirds. These were (i) an initial peak of immune complexes at 2 weeks postinfection, (ii) a drop to a minimum postinfection value near the beginning of patency, and (iii) a gradual increase in immune complex levels beginning at the time of peak adult worm size and continuing to a maximum value at approximately 10 months postinfection. Microfilarial levels and hemagglutination assay titers to adult worm antigens did not correlate with immune complex levels.
Enhancement of Neisseria meningitidis infection in mice by addition of iron bound to transferrin
Authors: Holbein B E
Published: January 2020

Small quantities of iron bound specifically to human transferrin were found to stimulate infection with Neisseria meningitidis strain M1011 in mice. An intraperitoneal injection of 17.5 mg of transferrin carrying 22.7 micrograms of Fe resulted in 100% mortality from infection, as compared with no mortality for the controls which had received saline. Five milligrams of ferri-transferrin (FeTf), carrying 6.5 micrograms of Fe, stimulated and prolonged bacteremia in the mice. Thus, FeTf maintained infection, whereas infection was controlled due to iron limitation in control mice. Comparative studies with apotransferrin (iron-free) revealed that the enhancement of infection was due to the supply of iron. FeTf was also found to relieve an iron limitation of growth achieved by ethylenediaminedihydroxyphenylacetic acid (EDDA) in vitro. FeTf abolished the lag phase for growth of N. meningitidis in a defined medium. The results of this study suggest that human FeTf is an immediate source of iron to N. meningitidis both in vitro and in vivo. These findings support the hypothesis that the levels of iron in the circulating transferrin pool of mice determine the course of experimental N. meningitidis infection.
Stimulation of human gamma interferon production by diterpene esters
Authors: Yip Y K , Pang R H , Oppenheim J D , Nachbar M S , Henriksen D , Zerebeckyj-Eckhardt I , Vilcek J
Published: January 2020

The diterpene ester 12-O-tetradecanoylphorbol-13-acetate (TPA) and several structurally related compounds were tested for their ability to stimulate interferon (IFN) production in primary cultures of human leukocytes. In cultures of Ficoll-Hypaque-purified mononuclear cells, TPA treatment alone induced only low levels of IFN, but TPA pretreatment of cells caused significant enhancement of IFN yields produced with phytohemagglutinin or several other T cell mitogens. In cultures of unprocessed cells derived from plateletpheresis residues or buffy coats, TPA treatment alone induced high levels of IFN and costimulation with TPA and phytohemagglutinin produced some further enhancement of IFN production. Phorbol 12,13-dibutyrate was comparable to TPA in its ability to enhance phytohemagglutinin-induced IFN production. Several other phorbol ester analogs were also active, but maximal stimulation occurred only at higher drug concentrations. Mezerein, a structurally related diterpene ester, was at least as active as TPA in stimulating IFN production in either Ficoll-Hypaque-purified or unprocessed cells. IFN produced after stimulation with TPA or mezerein, singly or in combination with phytohemagglutinin, had several properties characteristic of IFN-gamma, e.g., it was largely inactivated by dialysis at pH 2, or after exposure to sodium dodecyl sulfate, whereas it was not neutralized by antibody to IFN-alpha and IFN-beta. The stimulatory effect of diterpene esters has proved helpful in producing IFN-gamma for physicochemical analysis and other studies.
Modulation of bacterial association to HeLa cell cultures by cell density and by chlamydial infection
Authors: Bose S K , Mudd R L
Published: January 2020

The effect of cell density on the rate of association of Escherichia coli and Staphylococcus aureus by monolayer cultures of HeLa 229 cells was investigated. Radioactively labeled bacteria were incubated with sparsely and densely plated cells. The rate of bacterial uptake was 10- to 20-fold higher in sparse cultures. Kinetic analysis of data with different multiplicities of input bacteria showed that the Km of the reaction was unaltered, whereas the Vmax was inversely related to cell density. Pretreatment of HeLa cultures with dibutyryl adenosine 3',5'-phosphate had little effect on the rate of bacterial association. The simultaneous presence of an obligately parasitic bacterium, Chlamydia trachomatis LGV434, enhanced the Vmax of association of E. coli and S. aureus. This effect was more pronounced in dense HeLa cell cultures. Heat-inactivated chlamydiae were unable to modify the association. Enhanced association persisted for at least 3 h after infection with chlamydiae.
Mechanisms in the in vivo release of lymphokines: relationship of high and low responsiveness to other parameters of the immune response
Authors: Neta R , Salvin S B
Published: January 2020

Variations exist between different strains of inbred mice in the release of lymphokines into the circulation. A number of manifestations of cell-mediated immunity in mice sensitized intravenously with Mycobacterium bovis BCG were analyzed to determine their association with the in vivo release of gamma interferon (IFN-gamma) and migration inhibitory factor. Differences occurred among the strains in the proliferative responses of splenic cells to specific antigen and in the release of IFN after the challenge of BCG-sensitized mice with lipopolysaccharide. However, the capacity of an individual strain to release migration inhibitory factor and IFN-gamma into the circulation did not parallel the extent either of the proliferative responses or of the release of IFN induced by lipopolysaccharide. Not all of the strains developed marked delayed footpad reactions to challenge with PPD regardless of the extent of their responses by other parameters. Delayed footpad reactions did develop in mice sensitized via the subcutaneous route, although this sensitization did not result in the capacity to release migration inhibitory factor and IFN-gamma into the circulation of individual inbred strains.
Effects of pneumolysin on human polymorphonuclear leukocytes and platelets
Authors: Johnson M K , Boese-Marrazzo D , Pierce W A
Published: January 2020

Pneumolysin was bound by human polymorphonuclear leukocytes in a reaction which occurred very rapidly at 0 degrees C. Low concentrations of pneumolysin were found to stimulate leukocyte migration and lysosomal enzyme secretion. At increasing lysin levels, inhibition of spontaneous migration and chemotaxis, cell death, and lysis were observed. Pneumolysin was also found to lyse platelets and to activate serum to become chemotactic.
Serum antibody and opsonic responses after immunization with pneumococcal vaccine in kidney transplant recipients and controls
Authors: Bortolussi R , Marrie T J , Cunningham J , Schiffman G
Published: January 2020

We immunized 31 renal transplant patients and 6 control subjects with a pneumococcal vaccine containing 14 capsular polysaccharides. Antibody levels to Streptococcus pneumoniae types 3 and 6A were measured by a radioimmunoassay, and opsonic activity to S. pneumoniae types 3 and 6B was determined by using a luminol-enhanced chemiluminescence phagocytic assay on serum samples obtained before and 1 month after immunization. There was a 10.2-fold and a 2.9-fold increase in antibody to S. pneumoniae type 3 (P less than 0.005) and type 6A (P less than 0.01), respectively, but only a 1.3-fold (P greater than 0.05) and 1.1-fold (P greater than 0.05) increase in opsonic activity. For S. pneumoniae type 3, changes in opsonic activity correlated well with antibody concentration (P less than 0.05). However, for S. pneumoniae type 6, these two tests correlated poorly (P greater than 0.05). This poor correlation suggests that concentrations of antibody to type 6A polysaccharide which are achieved after immunization may not be opsonically active in vitro against S. pneumoniae type 6B.
Inhibition of dental plaque acid production by the salivary lactoperoxidase antimicrobial system
Authors: Tenovuo J , Mansson-Rahemtulla B , Pruitt K M , Arnold R
Published: January 2020

Resting human whole saliva inhibited acid production by glucose-stimulated, homologous plaque. The degree of inhibition of plaque acid production correlated positively with the concentration of hypothiocyanite (OSCN-) ions in saliva. Supplementation of saliva with an appropriate combination of thiocyanate and hydrogen peroxide resulted in a significant increase in the concentration of OSCN- ions and in more effective inhibition of plaque acid production. In most cases, the inhibition was complete when the supplements were added directly to saliva-plaque mixtures. Acid production resumed when the inhibitory effect of OSCN- was reversed by addition of thiols. Among the oral defense factors, the salivary lactoperoxidase system seems to play an important role by producing highly reactive antibacterial products (including OSCN-) which can regulate bacterial metabolism in the human mouth. The concentration of OSCN- in normal human whole saliva seems to be just below the threshold level required for plaque inhibition. Therefore, enhancement of this system in vivo may be effective in the regulation of plaque acid production.
Role of chemotaxis in the association of motile bacteria with intestinal mucosa: fitness and virulence of nonchemotactic Vibrio cholerae mutants in infant mice
Authors: Freter R , O'Brien P C
Published: January 2020

Contrary to earlier findings with all other in vivo and in vitro models of cholera studied, nonchemotactic vibrio mutants showed a relatively greater fitness in 5-day-old infant mice as compared with chemotactic parent or chemotactic revertant strains. This trend was manifest in the relatively greater number of nonchemotactic mutants recovered from the upper small intestine at 4 and 18 h after intragastric infection. The same trend was also revealed in the significantly greater virulence (in terms of time to death) of nonchemotactic mutants as compared with the chemotactic parent or revertant strains. Histological studies in infant mice of the penetration of chemotactic and nonchemotactic vibrios into the mucus gel of the small intestine yielded the same findings as in all other models studied, i.e., significantly greater penetration by chemotactic vibrios. There was no correlation between the relative fitness of nonchemotactic vibrios in the small intestine of infant mice and the rate of recovery of viable nonchemotactic vibrios from that site. In contrast, excellent correlation was found between the relative fitness of nonchemotactic vibrios and a decrease in the recovery of viable cells of the chemotactic strain from the small intestine. This indicates that the relatively greater fitness of the nonchemotactic vibrios in infant mice was only apparent and that the observed phenomenon was actually due to an antibacterial mechanism which prevented the accumulation of the chemotactic strains in the small intestine rather than to any stimulating effect on the nonchemotactic mutant itself. To study the in vivo fate of the inoculum in infant mice, vibrios were labeled with either 32P, 35S, or [3H]thymidine. Specific activity determinations of the 32P label were compatible with the assumption of an accelerated rate of death of the chemotactic parent strain in the small intestine. Results with the other isotopes, however, were significantly different. Indeed, the amount of radioactivity retained in the small intestine after feeding labeled bacteria correlated more closely with the isotope used than with the strain of vibrio under study. Consequently, considerable doubt must be cast on the general validity of this not uncommon technique for determining the in vivo location and the death or survival of radioactively labeled bacteria.
Role of chemotaxis in the association of motile bacteria with intestinal mucosa: in vivo studies
Authors: Freter R , O'Brien P C , Macsai M S
Published: January 2020

In vivo loops were prepared in the small intestine of rabbits and injected with mixtures of Vibrio cholerae and polystyrene spheres (1.1-micrometers diameter). The loops were removed and frozen after 15 min and then sectioned in a cryostat. The locations of particles and vibrios were determined microscopically. The vibrio/particle ratio was unity in the lumen of the loops, but increased 10-fold in the deep intervillous spaces, indicating active invasion of the mucus gel by the chemotactic parent strain. Motile nonchemotactic mutants and nonmotile mutants of this strain invaded the mucus at the same rate as inert particles. Similar results were obtained with intestinal loops prepared in germfree mice. When germfree mice were disassociated with mixtures of chemotactic (parent or revertant) and nonchemotactic mutant vibrios in equal proportions, the chemotactic strain rapidly outgrew its nonchemotactic counterpart in the intestine. Nonchemotactic mutants introduced as monoassociates into germfree mice were rapidly overgrown by nonmotile mutants which apparently arose spontaneously in the gut. Motility was therefore beneficial to survival only when it was directed by chemotactic stimuli, whereas it was a liability in the absence of such stimuli. Growth of chemotactic vibrios in small intestinal loops of rabbits paralleled that of nonchemotactic mutants for the first 4 to 6 h. Thereafter, the growth rate of the chemotactic vibrios was significantly faster. This was correlated with a significantly higher degree of association with the mucosa on the part of the chemotactic vibrios.
Dissociation of bactericidal activity from other functions of activated macrophages in exudates induced by thioglycolate medium
Authors: Spitalny G L
Published: January 2020

Macrophages displayed increased spreading, increased Fc-receptor-mediated phagocytosis, and increased secretion of plasminogen activator when collected from the peritoneal cavities of either Listeria-immune mice challenged intraperitoneally 3 days earlier with Listeria or nonimmune mice injected intraperitoneally 3 days earlier with fluid thioglycolate medium. In contrast, macrophages from the thioglycolate-induced peritoneal exudates were severely impaired in vitro in their ability to destroy Listeria. Injection of thioglycolate markedly interfered with the destruction of sublethal intraperitoneal challenge of Listeria, which resulted in nonimmune animals dying of an overwhelming systemic infection. In animals immune to Listeria, injection of thioglycolate delayed the onset of the expression of immunity to an intraperitoneal challenge of bacteria. The thioglycolate-induced suppression of bactericidal activity was determined to be confined to the site of injection. Results of experiments indicated that the colloidal agar in thioglycolate medium was the cause of the impairment of macrophage bactericidal activity. In addition to the impairment of bactericidal activity induced by agar, additional studies showed that an intraperitoneal injection of colloidal agar (0.075% wt/vol) by itself was a sufficient inflammatory stimulus for the accumulation of a large number of host phagocytic cells.
Studies of immune responses during recovery from Sindbis virus encephalitis in selectively reconstituted, thymectomized, lethally irradiated mice
Authors: Park M M , Griffin D E , Johnson R T
Published: January 2020

Recovery from acute Sindbis virus encephalitis was studied in selectively reconstituted, thymectomized, irradiated mice. Intact mice cleared virus from the brain by day 10 and developed inflammation along with immunoglobulin M (IgM) and IgG antibodies 4 to 6 days after infection. Unreconstituted mice died by day 11, with virus still present but decreasing, no detectable antibody, and no evidence of inflammation. Mice reconstituted with bone marrow cells alone produced only IgM antibody and no inflammation, but cleared virus by day 14. Mice reconstituted with sensitized T cells alone cleared virus by day 10, produced very small amounts of antibody, and developed a prompt inflammatory response.
Intracellular replication of Leishmania tropica in mouse peritoneal macrophages: comparison of amastigote replication in adherent and nonadherent macrophages
Authors: Nacy C A , Diggs C L
Published: January 2020

Intracellular replication of Leishmania tropica was assessed in mouse peritoneal macrophage cultures. L. tropica replicated poorly in macrophage monolayers: both the percentage of cells infected and the number of intracellular amastigotes decreased with time in culture. In contrast, nonadherent macrophages supported continuous replication of the parasite, and intracellular amastigotes increased more than 10-fold in these cultures over 8 days.
Polyclonal B-cell activation induced by extracts of Gram-negative bacteria isolated from periodontally diseased sites
Authors: Bick P H , Carpenter A B , Holdeman L V , Miller G A , Ranney R R , Palcanis K G , Tew J G
Published: January 2020

The objective of this research was to determine whether gram-negative bacteria frequently isolated from periodontally diseased sites contained polyclonal B-cell activators. Polyclonal B-cell activation, which results in nonspecific activation of multiple B-cell clones was analyzed by a hemolysis-in-gel assay designed to detect a broad range of antibody specificities. Extracts from numerous bacterial strains, including Bacteroides gingivalis, Bacteroides melaninogenicus subsp. melaninogenicus, B. melaninogenicus subsp. intermedius, Fusobacterium nucleatum, Selenomonas sputigena, Capnocytophaga ochracea, and Actinobacillus actinomycetemcomitans, were tested. Extracts of the above organisms were found to stimulate polyclonal antibody responses in cultures of normal human peripheral blood lymphocytes, although the magnitude of stimulation varied among the extracts. Optimal antibody-forming cell responses were found at stimulator doses between 5 and 1,000 micrograms/ml. We conclude that the resident gram-negative subgingival flora associated with periodontal lesions possesses potent polyclonal B-cell activators. These activators may contribute to disease pathogenesis by inducing B lymphocytes to produce antibody, osteolytic factors, or both and possibly other mediators of inflammation.
Degradation of gonococcal outer membrane proteins by human neutrophil lysosomal proteases
Authors: Rest R F , Pretzer E
Published: January 2020

Interest in the molecular mechanisms of leukocyte bactericidal activity led us to study the effects of human neutrophil lysosomal proteases on the outer membrane (OM) proteins of Neisseria gonorrhoeae. A protease fraction containing cathepsin G and elastase activity was partially purified by gel filtration chromatography of acetate extracts of purified neutrophil granules. OM was obtained from gonococci by French press-Sarkosyl or by LiCl2 extraction. The principal (protein I) and opacity-associated (proteins II) OM proteins of N. gonorrhoeae were hydrolyzed by lysosomal proteases; proteins II were more susceptible to hydrolysis than protein I. Treatment of whole gonococci, with subsequent purification of OM, or direct treatment of purified OM led to identical hydrolysis of OM proteins by lysosomal proteases as indicated by sodium dodecyl sulfate-polyacrylamide gel patterns. Similarly, hydrolysis of purified OM proteins was identical whether OM was treated with unfractionated granule extract or with the partially purified lysosomal proteases, indicating that the observed hydrolysis by unfractionated lysosomal contents was due solely to the lysosomal protease fraction. Hydrolysis of OM proteins was dependent upon the concentration of proteases, time, and temperature. Hydrolysis of proteins II was observed with as little as 1 microgram of proteases per ml for 1 h at 37 degrees C. OM incubated alone or with heat-inactivated proteases showed no hydrolytic activity. The addition of 25 mM Na+, K+, Mg2+, or Ca2+ to incubation mixtures containing proteases and OM did not alter hydrolytic activity as indicated by sodium dodecyl sulfate-polyacrylamide gel patterns.