bluuebunny/crossref_metadata_2025 huggingface dataset:
Inactivation or elimination of potentially trypanolytic, complement-activating immune complexes by pathogenic trypanosomes
Authors: Balber A E , Bangs J D , Jones S M , Proia R L
Published: January 2020

Trypanosoma brucei subsp. brucei and T. congolense incubated in homologous antibody at 0 degrees C for 30 min were lysed by subsequent addition of guinea pig complement. Trypanosomes incubated in antibody at 37 degrees C before complement treatment remained intact. Parasites bearing adsorbed antibody also remained intact when incubated at 37 degrees C before complement treatment. The proportion of cells which survived complement treatment decreased with increasing antibody concentration. Parasites which survived complement treatment continued to express antigens which could bind complement-activating antibody, but did not bear complement-activating immune complexes. Virtually all cells in T. brucei populations exposed to antibody at 37 degrees C, but only 10(-3) to 10(-5) of the cells in populations exposed to antibody at 0 degrees C before complement treatment, remained infective for X-irradiated mice. Only 10(-6) to 10(-7) of T. brucei populations exposed to antibody at 0 or 37 degrees C before complement treatment infected mice immunized with homologous antigens. Serotype analysis of substrains and of T. brucei populations isolated from mice infected with antibody and complement-treated parasites suggested that variant-specific antigens participated in trypanolysis and that T. brucei which survived complement treatment could undergo antigenic variation. Mechanisms by which trypanosomes may inactivate or eliminate surface immune complexes and the possible significance of this phenomenon in trypanosomiasis are discussed.
Interaction of Chlamydia psittaci reticulate bodies with mouse peritoneal macrophages
Authors: Brownridge E , Wyrick P B
Published: January 2020

Noninfectious reticulate bodies of Chlamydia psittaci are readily phagocytized by thioglycolate-elicited mouse peritoneal macrophages in monolayer culture. The internalized reticulate bodies are rapidly destroyed as indicated by a 60 to 70% decrease in trichloroacetic acid-precipitable radioisotopic counts in the macrophage pellet by 10 h and a concomitant increase of the trichloroacetic acid-soluble radiolabeled chlamydial nucleic acid in the cytoplasm. This intracellular destruction of reticulate bodies in macrophages is independent of the multiplicity of infection. Reticulate bodies at a high multiplicity of infection, up to 1,000:1, are also incapable of inducing immediate cytotoxicity in macrophages as evidenced by the lack of early release of the host cell-soluble cytoplasmic enzyme lactic dehydrogenase. Thus, it appears that the virulence factors for (i) initiation or maintenance of intracellular survival via circumvention of phagolysosome formation and (ii) host cell damage are either missing or not expressed by the RB form of this bacterium.
Effect of protein deficiency on suppressor cells
Authors: Khorshidi M , Mohagheghpour N
Published: January 2020

The effects of moderate protein deficiency on the in vitro response of spleen cells to phytohemagglutinin in A/Jax mice were studied. The response of spleen cells from protein-deficient mice to phytohemagglutinin was found to be enhanced as compared with that of cells from control animals. Since inadequate development or function of suppressor cells in the protein-deficient mice offered a possible explanation for the enhanced lymphoproliferative activity, cocultures of spleen cells from protein-deficient and control animals were tested for their responses to phytohemagglutinin. Suppression of [3H]thymidine incorporation was detected in coculture of 25% mitomycin-treated spleen cells from control animals and 75% spleen cells from protein-deficient mice. The suppressor (regulator) elements in control spleens were found to reside in the adherent cell population.
Antigenic Specificity of Neutralizing Antibody to Cholera Toxin
Authors: Peterson Johnny W. , Hejtmancik Kelly E. , Markel Daiel E. , Craig John P. , Kurosky Alexander
Published: January 2020

Selected rabbit antisera to cholera toxin antigens and convalescent cholera patient sera were analyzed using the permeability factor neutralization test and two sensitive in vitro serological assays specific for cholera toxin, cholera toxin A subunit, and cholera toxin B subunit. The results indicated that antisera to cholera toxin contained toxin-neutralizing activity as well as antibodies specific for both the A subunit and B subunit. It was clearly established that antisera to B subunit, devoid of significant anti-A subunit activity, neutralized the vascular permeability activity of cholera toxin. Antisera to A subunit contained neutralizing antibodies and antibodies to both A and B subunits. Absorption with B subunit removed both the toxin-neutralizing and anti-B subunit activities, while the anti-A activity was unaffected. Neutralizing antibody titers of rabbits immunized with B subunit were also observed to be significantly higher than neutralizing antibody titers of sera from A subunit-immunized rabbits, despite the overall similarity in anti-B subunit titers as determined by passive hemagglutination and radioimmunoassay of sera from the two groups of rabbits. Anti-α chain sera neither neutralized cholera toxin nor possessed significant antitoxin or anti-B subunit titers as determined by passive hemagglutination and radioimmunoassay. The anti-α chain sera contained high levels of antibody specific for A subunit, which is consistent with the hypothesis that the α chain is part of the A subunit structure. In contrast, the γ chain was not shown to be antigenic. Sera from convalescent cholera patients possessed toxin-neutralizing antibody as well as passive hemagglutination and radioimmunoassay antibody against both A and B subunits.
Characterization of a phosphoenolpyruvate-dependent sucrose phosphotransferase system in Streptococcus mutans
Authors: St Martin E J , Wittenberger C L
Published: January 2020

A phosphoenolpyruvate-dependent sucrose phosphotransferase system has been identified in Streptococcus mutans. Sucrose phosphotransferase activity was inducible by sucrose and had an apparent Km for sucrose of 70 microM. The product of the sucrose phosphotransferase reaction was isolated and identified as sucrose phosphate. Additional analysis revealed that the phosphate group was on the glucose moiety. Mutants unable to grow in media containing low concentrations of sucrose were isolated and found to be missing either sucrose phosphotransferase activity or the ability to hydrolyze sucrose phosphate.
Experimental bacterial keratitis in neutropenic guinea pigs: polymorphonuclear leukocytes in corneal host defense
Authors: Chusid M J , Davis S D
Published: January 2020

Quantitative techniques were used to determine the relative concentrations of viable bacteria and polymorphonuclear leukocytes (PMNs) in the corneas of neutropenic and non-neutropenic guinea pigs with experimental bacterial keratitis induced with three strains of Pseudomonas aeruginosa. Neutropenia was produced by whole-body X-irradiation 1 week before infection. Significantly greater numbers of bacteria were present in the cornea of neutropenic animals 48 h after infection than were present in the corneas of non-neutropenic animals. The same was true 24 and 48 h after infecting animals with Staphylococcus aureus. Examination of histological sections showed that fewer PMNs were present in the corneas of infected neutropenic animals than in the corneas of infected non-neutropenic animals. Radiolabeling of PMNs confirmed a significant reduction in PMN concentration in the corneas of infected neutropenic animals. Tears and the corneal epithelium appear to be the most important elements protecting the cornea against local invasion by bacteria. However, once bacterial keratitis is established, PMNs play a role in limiting bacterial multiplication.
Protection of mice against Giardia muris infection
Authors: Roberts-Thomson I C , Mitchell G F
Published: January 2020

Strains of mice showing relatively rapid (BALB/c) and defective (C3H/He) spontaneous elimination of Giardia muris displayed marked differences in the degree of resistance to infection induced by prior injection of trophozoites in Freund complete adjuvant.
Isolation of plasmids from mycobacteria
Authors: Crawford J T , Bates J H
Published: January 2020

A procedure for preparing sodium dodecyl sulfate-salt-cleared lysates of mycobacteria was developed. Standard techniques were employed to demonstrate covalently closed circular deoxyribonucleic acid in lysates of nine strains of Mycobacterium avium-intracellulare.
Induction of Listeria monocytogenes infection by the consumption of ponderosa pine needles
Authors: Adams C J , Neff T E , Jackson L L
Published: January 2020

An infectious microorganism, identified as Listeria monocytogenes, has been isolated from the bloodstream of pregnant mice fed a diet containing Pinus ponderosa needles. When the isolate was injected into pregnant mice, reproductive dysfunction and other changes, including speckled livers, spleen atrophy, and hemorrhagic intestines, appeared to mimic the signs of the disease in pregnant mice fed pine needles. Moreover, these pathological changes are similar to those observed in cattle and other mammals experiencing abortions or toxemia, or both, attributed to the ingestion of P. ponderosa needles, suggesting that L. monocytogenes may be a part of the etiology of "pine needle abortion."
Cell-mediated immunity to varicella-zoster virus measured by virus inactivation: mechanism and blocking of the reaction by specific antibody
Authors: Gershon A A , Steinberg S P
Published: January 2020

The process whereby varicella-zoster (V-Z) virus is inactivated in vitro by immune human peripheral blood leukocytes stimulated with V-Z antigen was examined. It was found that stimulation of leukocytes by V-Z antigen, but not by other viral antigens, was required for inactivation of V-Z virus to occur. Viral inactivation could be blocked by addition of V-Z antiserum to either the stimulation phase of the reaction or the inactivation phase, further demonstrating the specificity of the reaction. In addition these blocking experiments suggested that modulation of V-Z membrane antigen by antiserum occurred with an accompanying loss of immunological recognition of virus-infected cells. Inactivation of V-Z virus in vitro in this study appeared not to be dependent upon the secretion of interferon or upon antibody-dependent cellular cytotoxicity. The specific cells required for V-Z inactivation were T lymphocytes and monocytes (macrophage precursors).
Metabolic and Functional Characteristics of Alveolar Macrophages Recovered from Rats Exposed to Marijuana Smoke
Authors: Drath David B. , Shorey Jeannette M. , Price Louise , Huber Gary L.
Published: January 2020

Pulmonary alveolar macrophages were obtained by bronchopulmonary lavage from male rats after 30 consecutive days of in vivo exposure to marijuana and tobacco smoke. No significant differences were found between either group of experimental animals and controls in the number of cells recovered, the protein content per 10
6
cells, or the percentage of cells that adhered to plastic surfaces. The ability of macrophages to phagocytize viable bacteria was not affected by exposure to either marijuana or tobacco smoke in that both treatment groups ingested
Staphylococcus aureus
over a 60-min period as well as did control cells. Differences were found between the groups, however, with respect to cellular metabolism. Marijuana smoke inhalation caused a small decrease in the amount of oxygen consumed by macrophages during phagocytosis, as compared with control cells. This may have been reflected in the even greater decrease in superoxide formation observed during particle engulfment by these treated cells. Tobacco smoke, on the other hand, increased oxygen consumption and was without effect on superoxide release. Neither tobacco nor marijuana smoke treatment had an effect on the direct oxidation of glucose via the hexose monophosphate shunt. Our results indicate that, despite several metabolic alterations in response to marijuana and tobacco smoke, alveolar macrophages were not compromised with respect to their ability to ingest a particulate challenge.
Adoptive transfer of cross-protection among alphaviruses in mice requires allogeneic stimulation
Authors: Peck R , Wust C J , Brown A
Published: January 2020

Cell-mediated (T-effector cell) immunity is proposed as playing the major role in cross-protection between Sindbis and Semliki Forest viruses, which are alphaviruses that do not elicit cross-neutralizing antibodies. In adoptive transfer experiments, T-cells from spleens of Sindbis virus-immunized mice were found to confer specific cross-protection to Semliki Forest virus upon recipient mice. This cross-protection was observed in the outbred ICR strain of mice and when transfers were made between several combinations of inbred and hybrid strains. Cross-protection was substantially reduced if syngeneic rather than allogeneic cell transfers of one spleen equivalent per mouse were made. The results suggest that allogeneic stimulation (mixed lymphocyte reaction in vivo) is necessary to increase the number of effector cells (donor) in the recipient. This was supported by the observation that blastogenic stimulation of donor cells in vitro by concanavalin A induces cross-protection in syngeneic animals. Conversion of recipient cells to specific effector cells also appears to play a role in protecting mice against Semliki Forest virus. This was concluded from the experiments described above, a time course study, and the results of experiments that involved serial passages of transferred cells across histocompatibility barriers. Thus, we propose that both donor and recipient cells are active in protecting recipient mice against challenge with Semliki Forest virus after adoptive transfer.
Antibody-dependent cellular cytotoxicity of Trypanosoma cruzi: characterization of the effector cell from normal human blood
Authors: Madeira E D , de Andrade A F , Bunn-Moreno M M , Barcinski M
Published: January 2020

The antibody-dependent cellular cytotoxicity activity of normal human blood cells against epimastigotes of Trypanosoma cruzi was measured by the release of incorporated [3H]uridine. Sera from patients with chronic Chagas' disease were used to sensitize the parasites to the lytic activity of the effector cells. Different steps of peripheral blood cell purification were employed, and different cell subpopulations were tested as effectors in the system. The main cytotoxic activity was detected in the granulocyte-rich fraction.
Growth of Pseudomonas aeruginosa in normal and burned skin extract: role of extracellular proteases
Authors: Cicmanec J F , Holder I A
Published: January 2020

Growth curves and mean generation times (MGT) were determined for Pseudomonas aeruginosa strain M-2 (protease +) and strain PA-103 (protease +/-) in burned skin extract (BSE) and in normal skin extract (NSE). Strain M-2 grew on NSE or BSE with an MGT of 30 min. Strain PA-103 grew in NSE at a similar MGT; however, PA-103 in BSE had a MGT of 65 min. When protease was added to BSE, PA-103 grew as rapidly as M-2. When ammonium sulfate was added to inhibit protease production, the MGT of M-2 slowed to that of M2 in both BSE in NSE. The MGT of PA-103 in amino acid-supplemented BSE was similar to that of PA-103 in BSE. The MGT of PA-103 in amino acid-supplemented BSE was similar to that of M-2 in both BSE andNSE. These data suggest that protease may serve as a virulence factor by modifying the available nutrients in burned skin. As a result, nutrients are formed that permit an enhanced growth rate and amore rapid establishment of the infection in the host.
Type C virus and immunoglobulin A production by murine myeloma MOPC-315: two independent activities
Authors: Gazit A , Yaniv A , Halperin D , Ben-Efraim S
Published: January 2020

The suspected correlation between cessation of type C virus production and halt in immunoglobulin secretion by murine myeloma cells was studied. Employing two variants of the murine myeloma MOPC-315, immunoglobulin A-producing and nonproducing cells, we demonstrated that the two myelomas release similar levels of type C viruses which share common nucleotide sequences and that the viral genomes are equally expressed within the cells. Thus, the suggested relation between these two activities does not apply for MOPC-315 cells and probably for other murine myelomas also.
Purification and Chemical Characterization of the Heat-Labile Enterotoxin Produced by Enterotoxigenic
Escherichia coli
Authors: Kunkel Steven L. , Robertson Donald C.
Published: January 2020

Heat-labile enterotoxin (LT) produced by a human strain of enterotoxigenic
Escherichia coli
(286C
2
) was purified to homogeneity from pH extracts of fermentor-grown cells by ultrafiltration, (NH
4
)
2
SO
4
fractionation, hydrophobic chromatography on norleucine-Sepharose 4B, hydroxylapatite chromatography, and Bio-Gel P-150 filtration. Purified LT preparations exhibited biological activity comparable to that of cholera toxin in four bioassays specific for the two enterotoxins (Y-1 adrenal tumor cells, Chinese hamster ovary cells, pigeon erythrocyte lysates, and skin permeability test). The overall yield of LT protein was 20%, which represented a 500-fold purification over pH extracts. A native molecular weight of 73,000 was determined by gel electrophoresis. The toxin dissociated upon treatment with sodium dodecyl sulfate, pH 7.0, into two components with molecular weights of 44,000 and 30,000. Purified LT preparations were remarkably stable over a wide range of storage conditions, temperatures, and pH's. The biological activity was increased by incubation with trypsin and completely destroyed by pronase and proteinase K, whereas deoxyribonuclease I, ribonuclease, and phospholipase D had no effect. The amino acid composition of purified LT was quite different from that of cholera toxin. Neither carbohydrate nor lipopolysaccharide was present in purified preparations. The purification scheme appeared applicable to LT produced by other human and porcine enterotoxigenic strains, but reflected the amount of LT produced by each strain. These data show that LT and cholera toxin share many common chemical and physical properties, but must be purified by different techniques.
Action of bacterial endotoxin and lipid A on mitochondrial enzyme activities of cells in culture and subcellular fractions
Authors: McGivney A , Bradley S G
Published: January 2020

Escherichia coli O127:B8 lipopolysaccharide (LPS), prepared by the Westphal procedure, caused a marked decrease in the activities of mitochondrial malate dehydrogenase, succinate dehydrogenase, and adenylate kinase in African green monkey kidney (Vero) cells and primary cultures of mouse liver cells within 2 h after exposure to 10 micrograms of LPS/ml of culture medium. These three enzyme activities leaked into the supernatant fraction, and cytochrome oxidase activity was lost from the mouse liver mitochondrial particulate fraction within 45 min after exposure to 10 micrograms of LPS/mg of protein. Loss malate dehydrogenase activity from isolated mitochondria was also accelerated by LPS from E. coli O26:B6 (Boivin preparation) or Salmonella typhosa O901 (Westphal preparation), and by lipid A from Salmonella minnesota or Shigella sonnei. In addition, LPS and lipid A inhibited state 3 respiration by isolated mitochondria with attendant loss of respiratory control, but adenosine 5'-diphosphate/O ratios were relatively unchanged. Impaired mitochondrial function is an early event after exposure to biologically relevant amounts of LPS or lipid A.
Listeria
Pneumonitis: Influence of Route of Immunization on Resistance to Airborne Infection
Authors: Lefford Maurice J. , Warner Sandra , Amell Laura
Published: January 2020

Mice that are immunized with an airborne inoculum of BCG are more highly resistant to airborne challenge with
Mycobacterium tuberculosis
than are mice that are immunized by the subcutaneous or intravenous route. To discover whether this phenomenon is peculiar to tuberculosis, we studied the influence of the route of immunization upon pulmonary resistance in
Listeria monocytogenes
infection. Mice were immunized by the airborne, intravenous, or footpad route and were subsequently challenged by the same route at 1 to 4 weeks after immunization. Mice were highly and uniformly resistant to intravenous challenge, regardless of the route of immunization. The route of immunization bore no influence upon resistance to footpad infection, but resistance was appreciably better in mice challenged within 2 weeks of immunization than it was at later time points. In mice immunized by the footpad and intravenous routes, the pattern of resistance to airborne and footpad challenges was similar, in that there was substantially less immunity at 4 weeks than at 2 weeks after immunization. However, mice immunized by the airborne route were highly resistant to airborne challenge, regardless of the interval between immunization and reinfection. In this last respect, resistance of the lungs to reinfection was similar after
Listeria
and tuberculosis pneumonitis. It is suggested that a similar pattern of resistance may prevail in pneumonitis caused by other facultative intracellular parasites.
Cytomegalovirus Isolation from a Chimpanzee with Acute Demyelinating Disease After Inoculation of Multiple Sclerosis Brain Cells
Authors: Wroblewska Zofia , Gilden Donald , Devlin Mary , Huang Eng-Shang , Rorke Lucy B. , Hamada Takeshi , Furukawa Toru , Cummins Larry , Kalter Seymour , Koprowski Hilary
Published: January 2020

A strain of cytomegalovirus (CMV) was isolated during the third subcultivation of explants from the left frontal lobe of a chimpanzee that developed paralysis more than 3 years after intracerebral inoculation at birth with brain cell cultures derived from a patient with multiple sclerosis. Another strain of CMV was also isolated from a lymph node culture taken from the same chimp. The isolates, designated MZM-13 and MZM-14, produced a cytopathic effect characteristic for CMV when inoculated into brain, ganglion, or fibroblast cultures of human or simian origin. Infected cells contained characteristic Cowdry A intranuclear as well as intracytoplasmic inclusion bodies, and 100-nm spherical herpes-like virus particles were detected by electron microscopy in the nucleus and cytoplasm of infected cells. Virus was further identified as CMV with convalescent human anti-CMV serum. Complement-fixing antibody to CMV was present at a titer of 1:32 when the acutely ill chimpanzee was sacrificed. No antibody was detected at birth or at 1 or 2 years of age. A newborn chimpanzee inoculated intracerebrally with MZM-13 developed clinically asymptomatic lesions in the central nervous system characterized by acute and chronic inflammation and degeneration of myelin in cranial and spinal nerve roots. Restriction endonuclease analysis of viral deoxyribonucleic acid isolated from these two viruses indicated that MZM-13 and MZM-14 are identical and are closely related to chimpanzee CMV. No similarity in restriction endonuclease fragment patterns was found between MZM virus and the Towne and Clegg strains of human CMV.
Vaccinia virus infection of the central nervous system in X-irradiated mice
Authors: Simon J , Werner G T
Published: January 2020

The effect of X-irradiation on experimental vaccinia infection of BALB/c mice was studied. As compared with nonirradiated controls, the X-irradiated animals exhibited (i) a time lag in virus replication (delayed, but protracted replication); (ii) a delayed and repressed immune response: (iii) more severe acute cytocidal infection of leptomeninges, choroid plexus, ependyma, and vessels, with extensive damage to the brain-barrier system; and (iv) noncytocidal, latent infection of glial cells and neurons. Several animals developed acute or subacute demyelination disease, resembling experimental allergic encephalomyelitis or postinfectious encephalomyelitis.
Purification and Immunobiological Properties of R Antigen and Its Relation to M Protein of Type 3 Group A
Streptococcus
Authors: Johnson Rudolph H. , Beachey Edwin H.
Published: January 2020

R protein was extracted from type 3 group A streptococci with hot (95°C) HCl and was purified by ammonium sulfate precipitation followed by molecular-sieve and ion exchange chromatography. Although the R3 antigen was present in a heterogeneous population of proteins ranging from 78,000 to 100,000 daltons in size, we were able to separate an R-rich fraction that contained minimal amounts of heterogeneous proteins as indicated by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The final yield of the purified R protein was approximately 15 μg (dry weight) per g (wet weight) of washed and sedimented streptococci. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a molecular size of approximately 78,000 daltons. Amino acid analysis showed lysine, glutamic acid, alanine, and aspartic acid as the predominant amino acids. A detailed comparison of the purified R3 protein with type 3 M protein indicated a similarity in composition and order of frequency of amino acids. However, the R3 antigen was found to be distinctive from the M3 antigen in agar gel diffusion tests. In addition, R3 and M3 proteins behaved differently in opsonophagocytosis tests and opsonization inhibition tests. Thus, R3 and M3 proteins produced precipitin lines of nonidentity with an unabsorbed antiserum against whole type 3 streptococci: M3-specific antiserum, but not R3-specific antiserum, enhanced the phagocytosis of type 3 streptococci. Purified M3 but not R3 protein was capable of inhibiting the type-specific opsonization of type 3 streptococci. The physicochemical resemblance between M and R proteins in general suggests a common genetic origin. Perhaps R proteins are variant forms of M proteins from which the antiopsonic determinant has been deleted.
Influence of preformed antibody on experimental Streptococcus sanguis endocarditis
Authors: Scheld W M , Thomas J H , Sande M A
Published: January 2020

The influence of preformed, anti-whole organism antibody on the development of Streptococcus sanguis endocarditis was examined in both in vivo and in vitro systems. Antibody prevented, rather than potentiated, endocarditis in rabbits. The infectious dose in 30 control animals was 10(6.5) +/- 0.33 (mean +/- standard deviation); this increased to 10(7.71 +/- 0.05 in 36 immunized animals (P less than 0.01). No differences in bacterial clearance mechanisms were apparent between groups. Antibody also prevented the adherence of S. sanguis to the constituents of nonbacterial thrombotic endocarditis (fibrin and platelets) in vitro. When preincubated in high-titer antisera, adherence of S. sanguis was reduced compared with controls (adherence ratio mean +/- standard error of the mean, X 10(4): 174 +/- 5 versus 427 +/- 10, P less than 0.001). Preadsorption of immune sera with intact S. sanguis restored adherence to normal values, whereas preadsorption with dextran was partially effective. These studies demonstrate that preformed antibody had a protective role in vivo and suggest that a possible mechanism is blockade of adherence, a crucial early step in the pathogenesis of endocarditis.
Diphtheria toxin-binding glycoproteins on hamster cells: candidates for diphtheria toxin receptors
Authors: Proia R L , Eidels L , Hart D A
Published: January 2020

Diphtheria toxin-binding glycoproteins of high molecular weight (greater than 100,000) were identified on the surface of lymph node and thymus cells from hamsters, a diphtheria toxin-sensitive species. These diphtheria toxin-binding glycoproteins also interacted with CRM197 protein, which possesses toxin-blocking activity, but not with diphtheria toxoid, fragment A of diphtheria toxin, or cholera toxin, all of which lack toxin-blocking activity. These observations are consistent with the hypothesis that the detected diphtheria toxin-binding glycoproteins are involved in intoxication of cells by this toxin and possibly serve as the plasma membrane receptors for diphtheria toxin.
A hamster-attenuated, temperature-sensitive mutant of Venezuelan encephalitis virus
Authors: Krieger J N , Scherer W F , Wiebe M E , Pancake B A , Harsanyi Z P
Published: January 2020

Pathogenicities of 10 temperature-sensitive mutants of Venezuelan encephalitis virus were studied using the hamster model of human virulence. The parental strain and nine of the temperature-sensitive mutants produced lethal infections in hamsters. Strain ts 126 showed reduced hamster virulence. Deaths with the lethal mutants usually occurred 1 to 3 days later than with parental virus. Nine mutants produced lower levels of viremia than parental virus. Attenuation of ts 126 was related to restriction of viral growth in spleen and probably bone marrow and to absence of the usual pathological lesions in hemopoietic tissues and brain, but was functionally unrelated to temperature sensitivity since temperatures of both normal and infected hamsters remained within the permissive range of the mutant. Deaths did not correlate with titers of the 10 mutants in blood at permissive temperatures or with reversions of four temperature-sensitive mutants to non-temperature-sensitive virus in hamsters.
Role of environment in the development of "natural" hemagglutinins in Minnesota miniature swine
Authors: Scheffel J W , Kim Y B
Published: January 2020

"Natural" hemagglutinin titers against a panel of fixed erythrocyte antigens were determined for groups of Minnesota miniature swine reared conventionally, in a specific pathogen-free facility, and in germfree isolators. Sera were assayed for hemagglutination (HA) titers by the microtiter method against 12 species of erythrocytes stabilized by treatment with pyruvic aldehyde and formaldehyde. These erythrocytes were stable for up to 2 years and gave slightly enhanced HA titers as compared to fresh, unfixed erythrocytes. Of the sera from conventional swine tested, the highest "natural" HA titers were directed towards rabbit, cat, swine dog, and burro erythrocytes (greater than 1:1,000), intermediate titers were detected against human A, B, and O, and sheep, pig, and chicken erythrocytes (1:64 to 1:1,000), whereas the lowest titers were found against ox and goat erythrocytes (less than 1:8). Titers obtained with sera from specific pathogen-free swine were 2- to 16-fold lower than those of conventional swine, but were of a similar distribution with regard to the species of erythrocyte tested. Germfree swine sera uniformly exhibited HA titers less than 1:4 against all species of erythrocytes. The majority of these hemagglutinins were immunoglobulin M class but there were some agglutinins of immunoglobulin A class and a slight amount of immunoglobulin G class. Specificity of these agglutinins was examined by absorption tests. The results are consistent with the hypothesis that natural hemagglutinins develop due to dietary or microbial antigenic stimulation, or both.
Baculovirus replication in a mosquito (dipteran) cell line
Authors: Sherman K E , McIntosh A H
Published: January 2020

The baculovirus from the lepidopteran host Autographa californica (alfalfa looper) was shown to replicate in a dipteran cell line without the production of characteristic polyhedral inclusion bodies. The low level of replication could not be detected by 50% tissue culture infective dose titrations, but was apparent by [3H]thymidine labeling of the viral genome. Immunoprecipitation of the radioactive product confirmed baculovirus production.
Effect of cholera toxin on the antiviral and anticellular activities of human leukocyte interferon
Authors: Fuse A , Kuwata T
Published: January 2020

Cholera toxin added into cell cultures together with human leukocyte interferon inhibited the establishment of the antiviral state by interferon but not the anticellular activity of interferon in human cells. Sensitivities of various human cell lines to anticellular activities of interferon and cholera toxin were compared, but no direct correlation between both activities were demonstrated. These results suggest that antiviral and anticellular activities of interferon are due to different mechanism of actions, and cholera toxin does not act directly on the receptor site for interferon.
Enzyme-linked immunosorbent assay for bovine immunoglobulin subclass-specific response to Brucella abortus lipopolysaccharides
Authors: Lamb V L , Jones L M , Schurig G G , Berman D T
Published: January 2020

An enzyme-linked immunosorbent assay was developed to follow the bovine response, by immunoglobulin class and subclass, to defined smooth and rough lipopolysaccharides (LPS) of Brucella abortus. Binding to smooth LPS of immunoglobulin G1 (IgG1) and IgG2 in sera from Brucella-infected animals was significantly greater than binding in sera from normal uninfected animals. Competition or steric blocking among IgM, IgG1, and IgG2 for binding sites on smooth LPS was shown to occur. Binding of IgM to Brucella smooth LPS with sera from uninfected animals was elevated above the assay control levels, and attempts to eliminate this nonspecific IgM binding were not successful. The same levels of nonspecific IgM binding were also seen with Brucella rough LPS, Escherichia coli LPS, and Pseudomonas solanacearum LPS. Sera from some, but not all, Brucella-infected animals showed elevated binding of IgG1 and IgM to both E. coli LPS and Brucella rough LPS as well as to Brucella smooth LPS. This was interpreted as specific antibody. Cross-reactions between B. abortus smooth or rough LPS and E. coli LPS could not be shown by immunodiffusion.
Immunoglobulin A1 protease production by Haemophilus influenzae and Streptococcus pneumoniae
Authors: Male C J
Published: January 2020

Bacterial strains of Haemophilus species and Streptococcus pneumoniae were examined for synthesis of the enzyme immunoglobulin A1 (IgA1) protease. Of 36 H. influenzae strains examined, 35 produced IgA1 protease; strains included all six capsular types, unencapsulated variants of types b and d, and untypable H. influenzae. Eight Haemophilus strains (non-H. influenzae) were studied, and two produced IgA1 protease. All 10 strains of S. pneumoniae produced IgA1 protease; these strains included 9 different capsular polysaccharide types and 1 untypable strain. Both IgA1 proteases cleaved myeloma IgA1 and secretory IgA but not myeloma IgA2, IgM, or IgG as determined by immunoelectrophoresis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that both enzymes cleaved IgA1 myeloma sera, but not IgA2, into two fragments. The apparent molecular weight of the cleaved fragments was dependent both on the apparent molecular weight of the cleaved fragments was dependent both on the specific IgA1 protease assayed and the specific IgA1 substrate utilized. It is postulated that both carbohydrate variation between the IgA1 substrates studied and the ability of S. pneumoniae glycosidases to cleave carbohydrates from glycoprotein offer an explanation for the different fragment sizes observed.
Prevalence of antibody to the Norwalk virus in various countries
Authors: Greenberg H B , Valdesuso J , Kapikian A Z , Chanock R M , Wyatt R G , Szmuness W , Larrick J , Kaplan J , Gilman R H , Sack D A
Published: January 2020

Serum samples from children and adults from several countries were tested by radioimmunoassay for antibody to the Norwalk virus. Antibody was commonly found in adults from all the countries tested. Antibody appears to be acquired more rapidly in children from underdeveloped countries than in children from the United States.
Binding of lipoteichoic acid of group A streptococci to isolated human erythrocyte membranes
Authors: Chiang T M , Alkan M L , Beachey E H
Published: January 2020

The spontaneous binding of group A streptococcal lipoteichoic acid (LTA) to mammalian cell membranes was studied in isolated membranes of human erythrocytes. The binding of radiolabeled LTA to erythrocyte membranes was dependent on membrane concentration and time. Binding approached a maximum within 30 min of incubation. The bound LTA could be displaced by adding a 50-fold excess of unlabeled LTA. The displaced LTA was eluted from a column of Sepharose 6B in a position identical to that of authentic LTA, suggesting that binding did not alter the size of the molecule. A dissociation constant of 42 micrometers was calculated, and only one population of approximately 5.5 X 10(6) binding sites per erhtyrocyte membrane was detected. Since these results suggested that erythrocyte membranes possess specific binding sites for LTA, an attempt was made to localize the putative receptors to the outside or the inside surface of the erhtyrocyte membrane. Assays of the binding of LTA to resealed right-side-out and inside-out membrane ghosts demonstrated that the outside surface was able to bind over 10 times more LTA than the inside surface. These results support the concept that the membranes possess specific binding sites for LTA and inciate that these binding sites are located almost entirely on the outside surface of erythrocyte membranes.
Radioimmunoassay for Gram-negative bacterial lipopolysaccharide O antigens: influence of antigen solubility
Authors: Munford R S , Hall C L
Published: January 2020

We have developed a solid-phase radioimmunoassay technique for specific gram-negative bacterial lipopolysaccharide (LPS) O antigens. The method exploits the high-titer, specific immunoglobulin M response of the rabbit to LPS immunization to measure as little as 5 ng of homologous LPS per ml with less than 0.5% cross-reactivity toward heterologous LPS or culture supernatants. We found that O antigen in complete LPS was less available for antibody binding than O antigen in the soluble polysaccharide derived by mild acid hydrolysis of LPS and that triethylamine-induced disaggregation of complete LPS increased its activity in the assay. Quantitation of O antigen with the assay was thus influenced by the physical state of LPS or "free" O antigen.
Alterations in Lung Macrophage Antimicrobial Activity Associated with Viral Pneumonia
Authors: Warr Glenn A. , Jakab George J.
Published: January 2020

Secondary bacterial infections are a common sequelae of viral pneumonias. To study 2 functions of the phagocytic defenses of the lung, macrophages were obtained by lung lavage from parainfluenza 1 virus-infected and noninfected mice. The phagocytic capacities (binding, ingestion, and killing) of these cells were assessed in vitro against viable
Candida krusei
. Viral pneumonia resulted in a progressive suppression (through day 7 of the infection) of the ability of macrophages to bind candida to their surfaces by nonimmunological or complement receptors; ingestion and intracellular killing of candida were also decreased. After day 7, all these functions returned and, in fact, cells with enhanced activities were present on day 17. After introduction of virus into the lungs, the lung macrophage population increased significantly between days 3 and 7 of infection. This resulted in an increase in the phagocytic potential of the lung, despite the virus-associated suppression of the phagocytic activity in a portion of the macrophages. However, the ability of the macrophages to kill ingested microorganisms was also reduced, resulting in an overall deficiency in the lung macrophage defenses. It was concluded that viral pneumonia was associated with at least two suppressive effects on the lung macrophage—decreased receptor activity and microbicidal activity—resulting in a deficiency in the lung phagocytic defenses represented by these cells. These effects were maximal 1 week after infection and could account for the increased susceptibility of these lungs to secondary bacterial pneumonias. In contrast, during the period of convalescence, the lung macrophage antimicrobial activities were increased and reflected in enhanced resistance of the lungs to infections.
Relationships between adjuvant, immunosuppressive, and mitogenic activities of staphylococcal peptidoglycan
Authors: Dziarski R
Published: January 2020

Staphylococcal peptidoglycan (PG) possesses in vivo immunodulating activity and is a B-cell mitogen in mice. The effect of PG on in vitro immune response of mouse splenocytes to sheep erythrocytes (SRBC) was studied, as well as the relationships between in vivo and in vitro adjuvant, immunosuppressive, and mitogenic activities of PG in terms of dose response, time kinetics, and physical state. Particulate PG suppressed in vivo anti-SRBC response when injected in a large dose before or simultaneously with SRBC. A small dose of particulate PG given before or along with the antigen was immunostimulatory. Soluble PG was adjuvant active in both high and low doses when injected before or along with the antigen. Both PG preparations were adjuvant active for mouse splenocytes in vitro immunized with SRBC, but particulate PG was more active. Even high doses of particulate PG were not directly suppressive for the in vitro immune response. Particulate PG was also mitogenic for mouse splenocytes, and the maximum increase in [3H]thymidine incorporation was observed after 2 days of culture. Soluble PG was not mitogenic during the 5-day incubation period. These results indicate that the physical state of PG, its dose, and its time of application are important factors determining its immunomodulating and mitogenic activities, and that by changing them it is possible to dissociate the adjuvant, immunosuppressive, and mitogenic properties of PG.
Effect of Passage History on Dengue-2 Virus Replication in Subpopulations of Human Leukocytes
Authors: Brandt Walter E. , McCown Jack M. , Top Franklin H. , Bancroft William H. , Russell Philip K.
Published: January 2020

Three passage levels of dengue-2 virus strain PR-159, obtained during the course of deriving the attenuated S-1 vaccine, were tested for their ability to replicate in subpopulations of human peripheral blood leukocytes: (i) 6th primary African green monkey kidney (PGMK) cell passage (parent virus); (ii) 19th PGMK cell passage of a small-plaque-forming clone derived from the parent virus (S-1 PGMK virus); and (iii) virus derived by four additional passages of the S-1 PGMK virus in diploid fetal rhesus lung cells (S-1 vaccine virus). Replication of these PR-159 viruses and another strain of dengue-2 virus adapted to Raji cells (16681-Raji virus) was measured in adherent and nonadherent mononuclear cells. All viruses except the S-1 PGMK virus replicated in monocytes. Occasional replication of the S-1 PGMK virus was associated with reversion to parent virus. The addition to the monocyte cultures of low concentrations of homologous dengue-2 antibody or non-neutralizing heterologous antibody increased the yield of the parent virus as much as 400-fold. This phenomenon of immune enhancement usually enabled the S-1 PGMK virus to replicate slowly in monocytes, but the progeny virus produced large plaques similar to the parent virus. Replication of the S-1 vaccine virus in cultured monocytes did not result in the appearance of large plaques. We could not recover S-1 vaccine virus from monocytes harvested from infected volunteers in the same manner that monocytes from natural human infections yield wild virus. The three passage levels of PR-159 virus were tested for replication in lymphocytes in comparison with the 16681-Raji virus. Only the 16681-Raji virus replicated in human lymphocytes cultured with or without enhancing antibody.
Protection against experimental cholera by oral or parenteral immunization
Authors: Peterson J W
Published: January 2020

Comparisons were made between the antigenic potency and protective capacity of several cholera toxin derivatives. Rabbits were immunized parenterally with 50 microgram of cholera toxin, A subunit, B subunit, procholeragenoid, or Wyeth glutaraldehyde toxoid 20101. Examination of the antibody response curves revealed that cholera toxin elicited serum antitoxin responses that rose more quickly than in the subunit-immunized animals; however, antitoxin levels were of the same magnitude after 10 weeks. Parenteral immunization with procholeragenoid evoked antibody titers that were similar to the toxin, whereas Wyeth toxoid yielded only one-tenth the level of antitoxin. Oral immunization with procholeragenoid as well as Wyeth toxoid resulted in lower serum antitoxin titers than that achieved with parenteral immunization, despite the oral administration of 10 times the parenteral dose. Analysis of protection against live-cell challenge revealed that parenteral administration of procholeragenoid provided the best protection against fluid accumulation. Oral immunization with procholeragenoid also was very effective, whereas oral immunization with B subunit or Wyeth toxoid resulted in minimal protection. Also, the A subunit provided surprisingly more protection than did cholera toxin.
Cell-mediated immune response of human lymphocytes to influenza A/USSR (H1N1) virus infection
Authors: Lazar A , Wright P F
Published: January 2020

Cell-mediated immunity to influenza A/USSR (H1N1) virus was assessed by measuring transformation response and interferon production by Ficoll-Hypaque-purified peripheral blood lymphocytes from children and adults. Lymphocyte transformation was found to be related to the individual's previous experience with H1N1 influenza virus. Lymphocyte cultures, obtained from adults who had their last contact with the H1N1 virus over 20 years ago, were able to transform when incubated with H1N1 influenza antigens. This response suggests that influenza virus can induced long-term cell-mediated immunity for periods of at least 20 years. Interferon produced by stimulated lymphocytes was found to be unrelated to previous contact with influenza H1N1 virus; seronegative as well as seropositive individuals were capable of producing interferon in response to viral antigens. The interferon produced was type I.
Curing of a plasmid is correlated with an attenuation of virulence in the marine fish pathogen Vibrio anguillarum
Authors: Crosa J H , Hodges L L , Schiewe M H
Published: January 2020

The transposon A sequence Tn1 containing the ampicillin resistance determinants was transposed from RP4 to a plasmid of the marine fish pathogen Vibrio anguillarum. Curing experiments in which plasmid loss was determined by analysis of the segregation of the ampicillin resistance phenotype showed the association of virulence with the specific V. anguillarum plasmid class.
Association of protein with the cell wall of Streptococcus mutans
Authors: Nesbitt W E , Staat R H , Rosan B , Taylor K G , Doyle R J
Published: January 2020

Cell walls from Streptococcus mutans were prepared by conventional technique and subjected to a series of extraction procedures involving classical protein solvents. The extracted walls contained several non-peptidoglycan amino acids and were also amenable to radiolabeling with [125I]sodium iodide and chloramine T. The cell walls could be chemically modified with tetranitromethane and diazo-1H-tetrazole, suggesting the presence of tyrosine or histidine or both. Flourescence spectra of the walls revealed the presence of either tyrosine or tryptophan. Several proteases, including pronase, trypsin, subtilisin, and proteinase K, removed some of the label from the walls. In contrast, treatment of the walls with salts or denaturants did not result in the solubilization of label. When the walls were solubilized with mutanolysin and subjected to chromatography, three peaks of radioactivity with apparent molecular weights of 73,000, 39,000, and 9,600 were observed. Wall digests subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a single band of radioactivity corresponding to an apparent molecular weight of 79,000. Isoelectric focusing of labeled wall digest gave rise to two major bands of radioactivity with isoelectric points of approximately 2.4 and 5.6. The results suggest that the cell wall of S. mutans contains tightly and possibley covalently bound polypeptide molecules. We propose that the cell wall polypeptides of S. mutans serve as factors in the attachment of the bacteria to smooth surfaces.