bluuebunny/crossref_metadata_2025 huggingface dataset:
Phagocytosis of Cryptococcus neoformans by normal and thioglycolate-activated macrophages
Authors: Swenson F J , Kozel T R
Published: January 2020

Phagocytosis of Cryptococcus neoformans by normal and thioglycolate-activated mouse peritoneal macrophages was studied. Thioglycolate-activated macrophages exhibited a lower percent phagocytosis than did normal macrophages. Differences in phagocytosis could not be attributed to differences in macrophage viability, minor variations in the concentration of adherent macrophages, or a general depression in activated macrophage phagocytosis. Thioglycolate-activated macrophages required heat-labile opsonins for optimal phagocytosis of non-encapsulated cryptococci, whereas nonactivated macrophages did not require heat-labile opsonins for phagocytosis of the yeast. Both types of macrophages exhibited similar sensitivity to the phagocytosis-inhibiting properties of cryptococcal polysaccharide. The results show that depletion of heat-labile opsonins from serum or inactivation of yeast-bound, heat-labile opsonins by polysaccharide cannot account for the phagocytosis-inhibiting properties of cryptococcal polysaccharide.
Susceptibility of mice to acute and persistent measles infection
Authors: Neighbour P A , Rager-Zisman B , Bloom B R
Published: January 2020

Intracerebral inoculation of neonatal mice with the Edmonston strain of measles virus produced an acute, lethal encephalitis and thymic dysplasia in susceptible mice. There was an age-related development of resistance to infection. This resistance was strain-dependent and appeared to be associated with the extent of virus growth in the brain. Studies on the genetic basis for susceptibility, using hybrid and backcross mice, revealed that the principal determinant of host resistance to acute infection was a dominant gene or genes which segregated independently of the H-2 complex. A small number of survivors of the acute infection showed persistence of measles virus antigens in the cerebellum and spleen for up to 2 months after inoculation. However, the low frequency of this persistence indicated that, at this time, intracerebral inoculation of neonatal mice with the Edmonston strain of measles virus constitutes a difficult model for the study of persistant measles infection.
Bacteriology of Human Experimental Gingivitis: Effect of Plaque Age
Authors: Syed S. A. , Loesche W. J.
Published: January 2020

Twenty-five subjects with previously excellent hygiene and healthy gingiva developed heavy plaque accumulations and bleeding or nonbleeding gingivitis about certain papilla after 21 days of no oral hygiene. Gingival marginal plaque about a single papilla was collected at 0, 1, 2, and 3 weeks of no oral hygiene in each subject. The plaque was dispersed, serially diluted, and plated on MM10 sucrose agar in an oxygen-free atmosphere. From 50 to 100 colonies from a single high-dilution plate were characterized for each sample. Over 8,500 isolates were partially characterized and placed into one of 29 taxonomic species or groups. The flora was predominantly gram-positive at all time periods. Streptococcal species dominated in the 0- and 1-week-old plaques, i.e. 62 and 43% of the colonyforming units (CFU), but dropped to 26 to 32% of the CFU in the 2- and 3-week-old plaques.
Actinomyces
species dominated in the older plaques, i.e., 40 to 50% of the CFU.
Actinomyces israelii
was the most prominent species in the older plaques.
Veillonella
accounted for 15 to 20% of the CFU at all time periods. Although the other gram-negative species increased with time, collectively they averaged less than 5% of the CFU at week 3. The shift from a
Streptococcus
-dominated plaque to an
Actinomyces
-dominated plaque was the most striking microbial change observed as the plaque aged.
Bacteriology of Human Experimental Gingivitis: Effect of Plaque and Gingivitis Score
Authors: Loesche W. J. , Syed S. A.
Published: January 2020

The plaque flora isolated from discrete dentogingival sites during a human gingivitis experiment was analyzed as a function of the plaque score and of the gingivitis score. When the gingivitis score was plotted as a function of the plaque score, a nonbleeding gingivitis was associated with a proportional increase in the
Actinomyces
sp. at the expense of the
Streptococcus
sp. In particular, the percentage of
Actinomyces israelii
increased significantly, while the percent
Streptococcus sanguis
decreased significantly.
A. israelii
also increased significantly when a bleeding gingivitis developed. When the plaque score was plotted as a function of the gingivitis score,
A. israelii
increased significantly as the nonbleeding gingivitis developed, but
A. viscosus
and
Bacteroides melaninogenicus
increased significantly when the bleeding gingivitis developed. The availability of a sufficient number of plaques with a plaque score of 2.0 permitted the examination of the interrelationship of gingivitis and flora minus the effect of plaque biomass. The bacteriological profile showed that when bleeding occurred, the levels and proportions of
A. viscosus
and
B. melaninogenicus
increased significantly. These findings raise the possibility that proportional changes in the gingival plaque flora may uniquely contribute to the development of gingival inflammation in this experimental model.
Immune interferon induced by phytohemagglutinin in nude mouse spleen cells
Authors: Wietzerbin J , Stefanos S , Falcoff R , Lucero M , Catinot L , Falcoff E
Published: January 2020

Phytohemagglutinin is able to trigger interferon synthesis in spleen cell cultures from nude (nu/nu) mice as effectively as in splenic cell cultures from haired, control (nu/+), thymus-bearing mice. A minor theta-bearing cell population present in the spleen of nude mice appears essential to phytohemagglutinin interferon production, although cooperating cells are also required. The properties of nude mouse phytohemagglutinin interferon are indistinguishable from those displayed by the interferon induced in thymus-bearing mouse spleen cell cultures. Both interferons are unstable at pH 2 and cannot be neutralized by an antiviral interferon serum; hence, their characteristics correspond to those described for type T interferon. As in the case of viral interferon, pretreatment of L cells with nude phytohemagglutinin interferon induced specific enhanced phosphorylation of a 67,000-molecular-weight protein in vitro when cell extracts were incubated with double-stranded RNA and gamma-[32P]ATP.
Evidence that L-rhamnose is the antigenic determinant of hyporesponsiveness of BALB/c mice to Klebsiella pneumoniae type 47
Authors: White-Scharf M E , Rosenberg L T
Published: January 2020

The genetic polymorphism in early, immunoglobulin M, responsiveness to the Klebsiella pneumoniae type 47 polysaccharide (K47-PS) is determinant specific, and L-rhamnose is probably the determinant against which differential responsiveness is expressed. This is inferred from tests of the response to the cross-reacting Streptococcus pneumoniae type 23 and non-cross-reacting pneumococcal polysaccharides of known chemical construction. B10.2/Sn new-line mice are high responders and BALB/c mice are low responders to K47-PS. Upon immunization with killed S. pneumoniae type 23, these strains produce cross-reacting antibody to K47-PS. The cross-reacting antibody responses of these strains are congruent with their responses to K47-PS.
Immunogenicity of gonococcal Gc2 polysaccharide: comparative studies with pneumococcal type III polysaccharide and Salmonella typhosa Vi antigen
Authors: Breen J F , Apicella M A
Published: January 2020

A plaque assay technique was used to assess the immunogenicity of a gonococcal cell wall polysaccharide (Gc2 antigen) in BALB/c mice. The Gc2 antigen was shown to be immunogenic, and the kinetics of the response differed from that of a pneumococcal polysaccharide (SSS-III) and a polysaccharide antigen of Salmonella typhosa (Vi antigen). In addition, using antithymocyte sera, the T-lymphocyte dependency of these antigens was investigated. The immune response to the Gc2 antigen was demonstrated to be dependent on a population of helper T cells, whereas the response to SSS-III appears to be regulated by suppressor T cells. There appears to be marked differences in the immune response of mice to different bacterial polysaccharides.
Effect of L-form Streptococcus pyogenes and of lipoteichoic acid on human cells in tissue culture
Authors: DeVuono J , Panos C
Published: January 2020

These studies showed the destruction of growing primary and established human cell lines with a predilection for the group A streptococci by an L-form of Streptococcus pyogenes adapted to grow in isotonic media. Also, this L-form was detected by fluorescent antibody for longer periods of time than by viable count in infected but recovered tissue culture monolayers. Additional studies with human heart cells showed changes in their protein profile and fatty acid content (but not composition) after L-form infection. This report is the first to show that the morphological changes and death of human kidney cells by this viable L-form were mimicked by the structurally different lipoteichoic acids from this organism and its parental streptococcus. These lipoteichoic acids were also equally effective in preventing attachment of S. pyogenes to human cell monolayers, but their deacylation obviated these two activities. Finally, the attachment of the isotonic L-form, as well as the parental streptococcus, to growing human kidney cells suggested that a rigid cell wall is not a prerequisite for host attachment in vitro.
Heat stability of Mycobacterium leprae immunogenicity
Authors: Shepard C C , Walker L L , van Landingham R
Published: January 2020

The protection provided to mice by vaccines administered intradermally was measured after footpad challenge with Mycobacterium leprae. The protection offered by M. leprae suspensions was not decreased when the vaccines were killed by 60 degrees C heat or at the higher temperatures tested, which included 215 degrees C (autoclave). Even highly purified suspensions retained their immunogenicity. In contrast, the vaccine protection provided by intradermal M. bovis (strain BCG) was markedly reduced when heated to 60 degrees C. The enlargement of the lymph nodes regional to the intradermal vaccines was measured and found generally to parallel the vaccine protection provided by M. leprae and by BCG.
Adherence of an enteropathogenic strain of Escherichia coli to human intestinal mucosa is mediated by a colicinogenic conjugative plasmid
Authors: Williams P H , Sedgwick M I , Evans N , Turner P J , George R H , McNeish A S
Published: January 2020

The capacity of a human enteropathogenic Escherichia coli (EPEC) strain serotype O26:K60:H11, to adhere to the mucosa of the human fetal small intestine was shown to be plasmid mediated. Adherence was transferred at a high frequency in a long-term conjugal mating experiment to E. coli K-12 and was lost by treatment of the EPEC strain with the curing agent ethidium bromide. Analysis of radioactively labeled DNA from lysates of the EPEC, transconjugant, and cured strains indicated that adherence was correlated with the presence of plasmid DNA species with an approximate average molecular weight of 56 X 10(6). Resistance to the antibiotics spectinomycin, streptomycin, sulfonamides, and tetracycline and production of colicin Ib were all transferred in long-term mating and lost upon curing coordinately with the property of adherence. In conjugal mating experiments of limited duration between E. coli K-12 strains, however, segregation of colicin production and mucosal adherence from multiple drug resistance was observed. Analysis of plasmid DNA of segregant transconjugant strains confirmed the presence in the 56 X 10(6)-dalton plasmid species of two previously unresolved components, pLG101 designating the ColIb plasmid which also carries the determinant for mucosal adherence and pLG102 representing the slightly smaller multiple drug resistance plasmid.
Chemotactic deactivation of human neutrophils: evidence for nonspecific and specific components
Authors: Nelson R D , McCormack R T , Fiegel V D , Simmons R L
Published: January 2020

Human polymorphonuclear neutrophils have been preexposed to activated complement as zymosan-activated serum (ZAS) or to the chemotactic oligopeptide N-formyl methionylphenylalanine (F-Met-Phe). Spontaneous migration and chemotactic responses toward the deactivating and other cytotaxins were monitored after washing and resuspension of cells in cytotaxin-free medium. Two patterns of deactivation were observed. Preexposure of the leukocytes to high doses of ZAS or F-Met-Phe decreased all subsequent migratory responses. Preexposure of the leukocytes to lower doses of ZAS or F-Met-Phe decreased only a subsequent chemotactic response to the deactivating cytotaxin. These results suggest two mechanisms, or components, of chemotactic deactivation.
Synthesis of DNA and protein by Anaplasma marginale in bovine erythrocytes during short-term culture
Authors: Davis W C , Talmadge J E , Parish S M , Johnson M I , Vibber S D
Published: January 2020

Bovine erythrocytes infected with Anaplasma marginale were cultured for 1 to 5 days in a CO2 incubation chamber, pulse-labeled with [3H]thymidine and [14C]methionine, lysed, and fractionated by differential centrifugation and continuous density gradient centrifugation in Renografin. Anaplasma and associated fragments of stroma formed two distinct bands in the dense region of the gradient. Electron microscopic examination of pelleted material from the bands from cells cultured for 1 day revealed the presence of organisms that were morphologically intact or in various states of degeneration. Examination of fractions from the gradient for incorporation of label revealed that analplasma present in erythrocytes can incorporate both [3H]thymidine and [14C]methionine. Subsequent experiments demonstrated that organisms cultured for 3 and 5 days incorporated the radiolabeled compounds also, but to a lesser extent. The experiments demonstrate that it is possible to culture analplasma in vitro for short periods of time and monitor their growth characteristics.
Enzyme-linked immunosorbent assay for detection and quantitation of capsular antigen of Haemophilus influenzae type b
Authors: Crosson F J , Winkelstein J A , Moxon E R
Published: January 2020

An enzyme-linked immunosorbent assay was developed to detect the presence of the ribose-ribitol phosphate capsular antigen of Haemophilus influenzae type b in laboratory and clinical specimens. The assay is simple, sensitive, specific, and quantitative and should prove to be of value in the diagnosis and management of H. influenzae infections.
Strain difference of delayed-type hypersensitivity to BCG and its genetic control in mice
Authors: Nakamura R M , Tokunaga T
Published: January 2020

Delayed-type hypersensitivity to BCG was remarkably different in two inbred strains of mice, SWM/Ms and C3H/He, when measured by the spleen index, the disappearance of peritoneal macrophage, or the footpad reaction. High responsiveness in the SWM/Ms strain appeared to be dominant over low responsiveness in the C3H/He strain. Results of the footpad reaction test if F1, F2, and backcross hybrids of these two strains of mice suggested that the delayed-type hypersensitivity was mainly controlled by a gene which was transmitted under Mendel's laws and was possibly non-H-2 linked. The spleen cells and their nylon wool nonadherent fraction from BCG-infected C3H/He mice were not reactive to purified protein derivative in vitro, whereas both the spleen cells and the nylon wool nonadherent fraction from BCG-infected SWM/Ms mice reacted well to purified protein derivative. Possible mechanisms of the different responses in the delayed-type hypersensitivity to BCG were discussed.
Biological activities of pyochelins: iron-chelating agents of Pseudomonas aeruginosa
Authors: Liu P V , Shokrani F
Published: January 2020

Strains of Pseudomonas aeruginosa able to grow readily in serum (serum resistant) produce siderophores in large quantity, enabling them to extract iron from transferrins. The term pyochelin has been proposed for this group of compounds. Pyochelin extractable with ethyl acetate and designated pyochelin A appears to be a mixture of catechols and other phenolates. The structures of water-soluble siderophores, designated pyochelin B, have not been determined. Pyochelins enabled growth in serum of strains of serum-sensitive P. aeruginosa and other gram-negative bacilli. Serum-resistant strains of P. aeruginosa tended to be more virulent than equally toxigenic strains of the serum-sensitive group. However, incorporation of pyochelins into the inocula of serum-sensitive strains could reduce, rather than enhance, their virulence. Utilization of pyochelins by serum-sensitive strains of P. aeruginosa rendered some of these organisms resistant to pyocins which were otherwise lethal to them.
Correlation between in vivo and in vitro functional tests for activated macrophages
Authors: Rhodes J M , Bennedsen J , Larsen S O , Riisgaard S , Spärck J V
Published: January 2020

Mice undergoing graft-versus-host reaction, skin grafting, and inoculation with tumor cells were tested for nonspecific resistance by intravenous challenge with Listeria monocytogenes. Peritoneal exudate macrophages from mice treated in a similar manner were tested in vitro for increased degradation of [1-14C]glucose, ability to degrade antigen/antibody complexes, ability to inhibit intracellular growth of listeria, and staining for beta-galactosidase. There was good correlation between in vivo resistance towards L. monocytogenes and in vitro inhibition of intracellular growth. There was also good correlation between increase in beta-galactosidase and in vivo resistance in mice undergoing a graft-versus-host-reaction.
Regulation of lactose catabolism in Streptococcus mutans: purification and regulatory properties of phospho-beta-galactosidase
Authors: Calmes R , Brown A T
Published: January 2020

Phospho-beta-galactosidase (P-beta-gal), the enzyme which catalyzes the first step in the metabolism of intracellular lactose phosphate, occurred at high specific activity in the cytoplasm in 12 of 13 strains of streptococcus mutans grown on lactose but not other carbon sources. The P-beta-gal from S. mutans SL1 was purified 13-fold using diethylaminoethyl-cellulose ion exchange and agarose A--0.5 M molecular exclusion column chromatography. The molecualr weight of the enzyme was estimated to be 40,000, and its pH optimum was 6.5 in three different buffer systems. P-beta-gal activity was inhibited by Co2+, Zn2+, and Cu2+, but other cations, ethylenediaminetetraacetic acid, orthophosphate, and fluoride had no effect upon enzyme activity. The kinetic response of P-beta-gal to a model substrate, o-nitrophenyl-beta-D-galactopyranoside-6-phosphate, obeyed Michaelis-Menten kinetics, and the Km for this substrate was 0.19 mM. In addition to being under genetic control, P-beta-gal activity was regulated by a number of biologically active metabolites. Enzyme activity was inhibited in a sigmoidal fashion by phosphoenolpyruvate. The M 0.5 V value for phosphoenolpyruvate was 2.8 mM, and the Hill coefficient (n) was 3. In addition, P-beta-gal exhibited strong inhibition by ATP, galactose-6-phosphate, and glucose-6-phosphate. In contrast to inhibition of P-beta-gal activity by phosphoenolpyruvate, the inhibition exerted by ATP, galactose-6-phosphate, and glucose-6-phosphate obeyed classical Michaelis-Menten kinetics; the Ki values for these inhibitors were 0.55, 1.6, and 4.0 mM, respectively.
Nutritional Requirements for Synthesis of Heat-Labile Enterotoxin by Enterotoxigenic Strains of
Escherichia coli
Authors: Gilligan Peter H. , Robertson Donald C.
Published: January 2020

Optimal growth conditions have been established for production of heat-labile enterotoxin (LT) by both porcine and human strains of enterotoxigenic (ENT
+
)
Escherichia coli.
There were no unusual growth factor requirements, and some strains produced fairly high levels of LT in a basal salts medium containing 0.5% glucose if the pH was carefully controlled. Several amino acids markedly stimulated LT synthesis when added to the basal salts-glucose medium. Methionine and lysine were the most stimulatory for both human and porcine strains. Either aspartic acid or glutamic acid further enhanced LT synthesis in the presence of methionine and lysine, with aspartic acid being more stimulatory for porcine strains and glutamic acid more stimulatory for human strains. There were no apparent vitamin requirements and no unusual cations needed for toxin synthesis except that Fe
3+
was slightly stimulatory for porcine strains. The stimulation by Fe
3+
was observed only in the presence of the three amino acids, suggesting that the effect was indirect rather than on toxin synthesis. The carbon source also influenced the yield of LT. Glucose supported maximal synthesis, but other carbon sources which exhibit a high degree of catabolite repression also supported high levels of synthesis. Little or no LT was released below pH 7.0; therefore, because the pH drops during growth from 7.5 to 6.8, even in highly buffered media, it was necessary to adjust the pH to 8.0 to effect complete release of cell-associated toxin. The defined medium containing three amino acids reduced the amount of UV-absorbing material in culture supernatants about fivefold and increased LT activity for various strains from two- to fivefold over a complex Casamino Acids-yeast extract medium. Conditions found to be optimal for synthesis of LT were inhibitory for the heat-stable enterotoxin.
Macrophage activation during experimental murine brucellosis: a basis for chronic infection
Authors: Cheers C , Pagram F
Published: January 2020

Evidence is presented that the chronicity of infection in CBA mice after injection of Brucella abortus 19 is related to a number of factors: (i) the relative resistance of B. abortus to macrophage killing, which allowed some bacteria to survive the peak of macrophage activity occurring at 14 days; (ii) the decline in macrophage activity thereafter (this decline was related in part to the presence of fewer bacteria to stimulate the bactericidal activity and also to specific, active suppressor mechanisms not identified in this study); and (iii) the insensitivity of the persistent Brucella organisms to activated macrophages. This was not due to a selection of genetically resistant bacteria, but possibly to their inaccessibility, either within "incompetent" macrophages or outside macrophages altogether.
Cellular immunity against Semliki Forest virus in mice
Authors: Kraaijeveld C A , Harmsen M , Khader Boutahar-Trouw B
Published: January 2020

Intracutaneous immunization of BALB/c mice with purified inactivated Semliki Forest virus resulted in cellular immunity without detectable antibodies. The animals were protected against subcutaneous challenge, from which the challenge virus spreads slowly. After intraperitoneal challenge, which permits a rapid virus spread, the protection was marginal. Stimulation of the intraperitoneal cell population with thioglycolate before challenge resulted in complete protection. The protection could be transferred to normal mice with peripheral lymph node cells, but not with spleen cells. The course of the infection in immunized and normal mice was also studied. Semliki Forest virus does not multiply in peritoneal cells in vivo. In immunized mice part of the challenge virus in the peritoneal cavity was rapidly eliminated and viremia was reduced. After challenge, immunized mice produced less antibody than normal mice.
Lymphocyte Proliferative Response to Viral Antigen in Pigs Infected with Transmissible Gastroenteritis Virus
Authors: Shimizu Mitsugu , Shimizu Yukio
Published: January 2020

Development and sequence of lymphocytes reactive to viral antigen in Peyer's patches, mesenteric lymph nodes, spleen, and peripheral blood of pigs orally inoculated with transmissible gastroenteritis virus were investigated by a lymphocyte proliferative assay. Lymphocytes reactive to the viral antigen were first detected in all the tissues of pigs tested on postinoculation day 7. Thereafter, they increased in proliferative reactivity and reached a maximal amount on postinoculation days 10 to 14. Antigen-reactive cells were persistently demonstrated in Peyer's patches and mesenteric lymph nodes for at least 110 days after inoculation, although lymphocytes decreased a little in reactivity to the viral antigen with the lapse of time. On the other hand, splenic and peripheral blood cells were found to have only transient proliferative reactivity. No antigen-reactive cells were detected in spleen or peripheral blood after postinoculation days 20 to 30. Lymphocytes decreased remarkably in reactivity to the viral antigen and phytohemagglutinin when treated with anti-porcine thymocyte serum and complement. Their reactivity to lipopolysaccharides was hardly affected by the treatment. Cells harvested on postinoculation days 45 to 60, however, responded a little to the viral antigen even after they were treated with anti-porcine thymocyte serum and complement. Lymphocytes reactive to the viral antigen and phytohemagglutinin belonged mainly to the erythrocyte rosette-forming cell fraction, whereas those reactive to lipopolysaccharides were mostly found in the rosette-nonforming cell fraction.
Antigenic properties of human lymphoblastoid interferons
Authors: Dalton B J , Paucker K
Published: January 2020

Most virus-induced human lymphoblastoid interferons examined contained variable proportions of the Le and F antigenic species described for human leukocyte interferon. The F species was not detectable in interferons liberated spontaneously from human lymphoblastoid cells in culture. Lymphoblastoid interferons differed considerably in their interaction with the same anti-interferon serum. Spontaneous interferons required approximately ten times less antibody for neutralization than interferon induced by virus in the same cultures or in Namalva cells. The findings suggest that either spontaneous interferons contain fewer inactive antibody-binding molecules than virus-induced lymphoblastoid interferons or the number and distribution of antibody-combining sites, and possibly other surface properties of the interferon molecule, may be influenced by the manner in which spontaneous and induced interferons egress from the cells.
Route of infection, systemic host resistance, and integrity of ganglionic axons influence acute and latent herpes simplex virus infection of the superior cervical ganglion
Authors: Price R W , Schmitz J
Published: January 2020

The character of acute and latent herpes simplex virus (HSV) infection of the superior cervical ganglion (SCG) in mice depended on the route by which the virus reached the ganglion, the level of systemic host resistance, and the integrity of postganglionic nerves. Prevention of ganglionic infection by postganglionic neurectomy carried out before intraocular (i.o.) virus challenge established the importance of the neural route in the development of SCG infection. However, hematogenous virus dissemination also led to SCG infection although with reduced frequency compared to that with i.o. inoculation. Enhanced host systemic antiviral resistance had two divergent effects on ganglionic infection depending on the dose and timing of virus inoculation. Thus, both acute and latent ganglionic infections were concomitantly reduced when resistant C57B1/6 mice were challenged with low doses of virus or when less resistant BALB/c mice were actively immunized 1 week before virus challenge. On the other hand, when resistant mice were challenged with high doses of virus or when either active or passive (antibody) immunization was delayed long enough to assure viral access to the ganglion, intraganglionic viral replication during the acute phase of infection was reduced, but the prevalence of subsequent latent infection was either unaffected or actually enhanced. Postganglionic neurectomy, performed after virus had reached the ganglion, altered the course of SCG infection in a direction opposite that of immunization, augmenting the acute phase of viral replication while reducing latency. In athymic nude mice and mice immunosuppressed with cyclophosphamide, intraganglionic viral replication was prolonged. These results emphasize that host factors both extrinsic and intrinsic to the SCG modify the course of ganglionic infection.
Specificity of response to viral proteins in horses infected with equine infectious anemia virus
Authors: Charman H , Long C , Coggins L
Published: January 2020

Three structural proteins of equine infectious anemia virus were purified, labeled with 125I, and utilized in radioimmunoassays with horse sera and antisera to heterologous retroviruses. Whereas radioimmunoassay titers for the major protein, p25, were 500- to 1,000-fold higher than titers in immunodiffusion, for clinical purposes these two procedures were equivalent. Antibodies to two low-molecular-weight proteins, p12 and p10, were also found in infected horses, but with a lower frequency and lower titers. As a rule, only sera positive for p25 also contained antibody to p12 and p10. Antisera to the major structural protein of other retroviruses did not precipitate equine infectious anemia virus p25. These sera include antibody to mammalian type C viruses, bovine leukemia virus, visna virus, mouse mammary tumor virus, squirrel monkey retrovirus, and Mason-Pfizer monkey virus.
Murine neurotropic retrovirus spongiform polioencephalomyelopathy: acceleration of disease by virus inoculum concentration
Authors: Brooks B R , Swarz J R , Narayan O , Johnson R T
Published: January 2020

A 10-fold reduction in the incubation period of murine neurotropic retrovirus spongiform polioencephalomyelopathy was effected by a 1,000-fold concentration of the cloned virus inoculum.
Production of a mutagen from ponceau 3R by a human intestinal anaerobe
Authors: Hartman C P , Andrews A W , Chung K T
Published: January 2020

Ponceau 3R was reduced in vitro by Fusobacterium sp. 2, a human intestinal anaerobe, to a product which is mutagenic when metabolically activated by liver S9 preparations in the Salmonella/mammalian-microsome mutagenicity test. This mutagenic metabolite has been identified as 2,4,5-trimethylaniline.
Activation of the alternative complement pathway by L-phase variants of gram-positive bacteria
Authors: Saulsbury F T , Winkelstein J A
Published: January 2020

The present studies were performed to investigate the potential role of the alternative complement pathway in the host's defense against bacterial L-phase variants and to gain insight into the subcellular component of gram-positive bacteria responsible for activation of the alternative pathway. L-phase variants of Staphylococcus aureus and Streptococcus faecalis were able to activate the alternative pathway and consume C3 in C4-deficient guinea pig serum in amounts comparable to their respective bacterial-phase parent organisms. Activation of the complement system via the alternative pathway resulted in death of the L-phase variants. Membranes prepared from S. faecalis L-phase variants, by either osmotic lysis or mechanical disruption, retained their ability to activate the alternative pathway. Treatment of the membranes by three different methods (water washes, hot trichloroacetic acid, and cold trichloroacetic acid) resulted in a greatly diminished ability of the membranes to activate the alternative pathway. In addition, the extracts derived from the membranes by water washes and by cold-trichloroacetic acid treatment were able to activate the alternative pathway. These studies indicate that these L-phase variants can activate the alternative pathway and suggest that membrane-associated factors play a role in the alternative pathway activation by S. faecalis L-phase variants.
Local cholera immunity in mice: intestinal antitoxin-containing cells and their correlation with protective immunity
Authors: Lange S , Hansson H A , Molin S O , Nygren H
Published: January 2020

Methods for light and electron microscopic identification and characterization of intestinal cholera antitoxin-containing cells (ACC) using peroxidase-labeled immunoreagent are described and used to study the ACC response in mice after immunizations with cholera toxin. Specific ACC appeared in significant numbers after two oral immunizations and increased six- to eightfold with two additional oral boosters, whereas further oral immunizations caused no additional stimulation. Intravenous immunizations had to be repeated seven times before ACC could be detected. After two oral immunizations, most of the ACC were found in the proximal part of the small intestine and no ACC were seen in the colon. This uneven distribution of ACC within the small intestine was eliminated after four oral immunizations, when ACC could also be detected in the colon. The ACC response after four oral immunizations demonstrated a peak at 4 days with far fewer cells present at 2 and 7 days. Electron microscopic studies showed that the ACC were mature plasma cells with the staining localized to the endoplasmic reticulum. Regression analysis of the relationship between the number of ACC and the magnitude of protective immunity against intestinal challenge with cholera toxin indicates a highly significant correlation (r = 0.91, P less than 0.001).
Induction of cell-mediated immunity to Mycobacterium leprae in guinea pigs
Authors: Mehra V , Bloom B R
Published: January 2020

Guinea pigs immunized with intact or disrupted armadillo-grown human Mycobacterium leprae administered in aqueous or oil vehicles were tested with various dilutions of M. leprae suspended in saline, water-soluble M. leprae extract, purified protein derivative, and a water-soluble extract of normal armadillo tissue. The results demonstrated the following. (i) Under no conditions was any skin test reactivity found to normal armadillo tissue extract. (ii) Positive sensitization to both M. leprae and its water-soluble extract was achieved by sensitizing guinea pigs with M. leprae suspended in Hanks solution or saline. Autoclaved M. leprae in Hanks solution or saline inoculated intradermally was an effective immunogen. Oil suspensions or emulsions were effective at sensitization, but appeared to be no better and, in general, slightly weaker, than simple inoculation in aqueous suspension. (iii) Living BCG failed to reveal a significant adjuvant effect on sensitization to M. leprae. However, cord factor appeared to potentiate slightly the sensitization to M. leprae in aqueous suspension. (iv) The minimum dose required for sensitization with M. leprae in aqueous suspension was 55 micrograms of purified bacilli. (v) Animals inoculated with M. leprae in saline or with M. leprae together with BCG showed positive skin test reactivity to the first skin test application made fully 1 year after the initial sensitization. The efficacy of autoclaved, irradiated M. leprae in aqueous, oil-free medium suggests a relatively safe approach to human vaccination studies.
Studies on gonococcus infection. XVIII. 125I-labeled peptide mapping of the major protein of the gonococcal cell wall outer membrane
Authors: Swanson J
Published: January 2020

The major outer membrane proteins from 10 gonococcal strains were examined after 125I-labeling of the proteins as single bands resolved by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. These 125I-proteins were then treated with either trypsin or alpha-chymotrypsin, and the resultant 125I-peptides were visualized by autoradiography after two-dimensional electrophoretic and chromatographic separation on thin-layer cellulose sheets. Several 125I-peptides were present in all the major outer membrane proteins examined. The presence and absence of additional 125I-peptides segregated the major proteins into two pattern groups. One group consisted of major outer membranes with molecular weights of 34,000 or 33,000; major proteins with molecular weights of 32,000 constituted the other group. Two beta-lactamase-producing gonococcal isolates were examined. Their major outer membrane proteins were identical in apparent molecular weights and alpha-chymotryptic 125I-peptide fingerprints; these proteins contained 125I-peptides not found in other gonococcal major proteins. No 125I-peptide differences were found among the major outer membrane proteins of strain F62 gonococci that exhibited differences in piliation and/or colony opacity characteristics.
Immunoregulatory responses in experimental disseminated histoplasmosis: depression of T-cell-dependent and T-effectory responses by activation of splenic suppressor cells
Authors: Artz R P , Bullock W E
Published: January 2020

The cellular immune responses of mice with disseminated histoplasmosis are markedly diminished in association with the generation of potent immunosuppressor activity by spleen cells. The zenith of suppressor activity was observed during most active infection, from 1 to 3 weeks after inoculation. During this time there was: (i) depression of the delayed-type hypersensitivity response to sheep erythrocytes and histoplasmin, (ii) impairment of concanavalin A- and histoplasmin-induced blastogenic transformations by splenocytes in vitro, (iii) depressed cytotoxic activity of spleen cells from infected mice, and (iv) marked suppression by splenocytes from infected mice of the primary antibody response to sheep erythrocytes by normal spleen cell cultures. With resolution of the infection by week 8, there was a shift of immunoregulatory function from dominant suppressor activity to expression of helper activity. At this time, delayed-type hypersensitivity responses to the above antigens were vigorous; furthermore, the cytotoxic activity and plaque-forming cell response of splenocytes from 8-week-infected mice were equal to or greater than normal control values. The shift in the immunoregulatory response from a suppressor to a helper mode indicated that the net amount of help or suppression measured at any given time during infection represented the algebraic sum of both helper and suppressor activities mediated by different populations or subpopulations of cells within the splenic microenvironment of infected mice.
Clearance of bacteria from cerebrospinal fluid to blood in experimental meningitis
Authors: Scheld W M , Park T S , Dacey R G , Winn H R , Jane J A , Sande M A
Published: January 2020

The occurrence and importance of secondary bacteremia in the pathogenesis of and response to therapy in meningitis is uncertain. Streptococcus pneumoniae type III was injected into the cerebrospinal fluid of the cisterna magna in anesthetized, curarized dogs, and sequential simultaneous samples were obtained from the superior sagittal sinus, cisterna magna, and peripheral blood. The results show that: (i) bacteria are rapidly transported from the cerebrospinal fluid to blood but only after active multiplication within the cerebrospinal fluid, and (ii) entrance into the blood from the cerebrospinal fluid occurs before the height of the febrile response or cerebrospinal fluid pleocytosis.
Thymus-dependent control of host defense mechanisms against Trypanosoma cruzi infection
Authors: Kierszenbaum F , Pienkowski M M
Published: January 2020

Congenitally athymic homozygous (nu/nu) mice were shown to be significantly more susceptible to Trypanosoma cruzi infection than their thymus-bearing heterozygous (nu/+) littermates, as measured by increased parasitemia, mortality rate, and shortened survival time. In addition, transplantation of neonatal thymus into athymic mice reestablished normal levels of resistance to T. cruzi, i.e., comparable to those of normal littermates. These results constitute conclusive evidence that host defense mechanisms active in experimental Chagas' disease are under thymic control.
Endotoxin lethality and tolerance in mice: analysis with the B-lymphocyte-defective CBA/N strain
Authors: Zaldivar N M , Scher I
Published: January 2020

Immune-defective and immunologically normal F1 mice derived from the CBA/N strain were used to study the influence of anti-endotoxin antibody on the lethal effects of endotoxin. Immune-defective F1 male mice were unable to make specific responses to purified preparations of E. coli O111:B4 endotoxin, whereas their immunologically normal F1 female littermates made excellent responses. The ability to form antibody to lipopolysaccharide (LPS) in these F1 mice did not influence either their natural resistance to endotoxin challenge or the effects of pretreatment with sublethal amounts of endotoxin on subsequent challenge with higher normally lethal doses. Furthermore, transfer of sera with high titers of anti-LPS antibody to mice prior to challenge with LPS failed to protect. Thus, anti-LPS antibody does not appear to play a critical role in protection of immune-defective (CBA/N X DBA/2) F1 male mice to the lethal effects of endotoxin or to the protective effects of a single sublethal dose of endotoxin on subsequent endotoxin challenge.
Comparison of Intratracheal and Intravenous Inoculation of Sheep Erythrocytes in the Induction of Local and Systemic Immune Responses
Authors: Stein-Streilein Joan , Gross Gary N. , Hart David A.
Published: January 2020

The interdependence of the local and systemic immune systems in the development of the immune responses relating to the lung was evaluated. Hamsters were inoculated with 10
9
sheep erythrocytes (SRBC) via local (intratracheal) or systemic (intravenous) routes of immunization. The local immune response was quantitated by the specific antibody-forming cell (sAFC) response in the pulmonary draining lymph nodes (pdLNC). sAFC in the spleens and serum hemagglutination titers evaluated the systemic immune response. The local inoculation of antigen was superior for induction of the maximal numbers of immunoglobulin M (IgM) and non-IgM sAFC in the pdLNC at 4 days post-immunization. However, the local response coould be enhanced by a concomitant splenic response. The local route of inoculation did not consistently induce an sAFC response in the spleen, but when the spleen was involved, two unique observations were recorded regarding the IgM response: (i) an approximate twofold increase in the numbers of sAFC was seen in the pdLNC on day 7 post-inoculation in animals that had a splenic sAFC response; and (ii) the appearance of an early (day 4) serum IgM hemagglutination titer was observed in the animals with a splenic sAFC response. However, the appearance of IgG serum hemagglutination titers was independent of the indirect sAFC response in the spleen but correlated with the appearance of indirect sAFC response in the pdLNC. As expected, intravenous inoculation of antigen was superior for inducing a systemic IgM response. We concluded that the local and systemic immune responses are related and interdependent in providing immune reactivity related to the lung. Whereas the systemic response enhanced both the serum IgM titer and the specific IgM antibody-forming cell response in the draining nodes, we observed that the local response was sufficient for the IgG serum hemagglutination titer even in the absence of a splenic sAFC response.
Assessment of protease (elastase) as a Pseudomonas aeruginosa virulence factor in experimental mouse burn infection
Authors: Pavlovskis O R , Wretlind B
Published: January 2020

The data presented indicate that in experimental Pseudomonas aeruginosa infection of mice, protease enhances the virulence of the organism. Anesthetized CBA/Lü mice were subjected to a 15-s flame burn and infected with a wild-type protease-producing strain and two of its protease-deficient mutants. The average bacterial cell mean lethal dose (LD50) of 3.8 +/- 0.3 standard deviation (log10) for mice infected with the protease-producing P. aeruginosa was at least 1 log lower than the LD50 of the protease-deficient mutants (0.02 greater than P greater than 0.01). The addition of purified protease to the infecting inoculum of protease-deficient strains reduced the LD50. Although the generation time in vitro was the same for all three bacterial strains used, there were consistently fewer viable bacteria in the blood of mice infected with protease-deficient strains than in those infected with the protease-producing strain. When a protease-deficient strain was mixed with the protease-producing wild-type strain, the number of protease-producing pseudomonas found in the blood remained constant, whereas the number of protease-deficient organisms increased, suggesting that protease contributed to the invasiveness of the organisms. The survival of mice infected with protease-producing pseudomonas was enhanced by antiprotease serum. Antiprotease serum had no effect in mice infected with protease-deficient mutants.
Delayed-type hypersensitivity responses in mice infected with St. Louis encephalitis virus: kinetics of the response and effects of immunoregulatory agents
Authors: Hudson B W , Wolff K , DeMartini J C
Published: January 2020

Labeled monocyte infiltration techniques have been used to study delayed-type hypersensitivity responses in mice immunized with St. Louis encephalitis virus. A delayed 24- to 48-h inflammatory response occurred 6 to 7 days after immunization. This response can be potentiated by cyclophosphamide treatment, by BCG administration, or by splenectomy. Treatments known to selectivity inhibit T-cell function suppressed the response.
Immune and mitogenic responses by BALB/c, C3H/HeJ, and nude mice to Brucella abortus bacterin and lipopolysaccharide
Authors: Spellman J M , Reed N D
Published: January 2020

The immunogenic and mitogenic properties of Brucella abortus 1119-3 bacterin (BA) and biologically active B. abortus lipopolysaccharide (BA-LPS) were studied using normal and athymic (nude) BALB/c and C3H/HeJ mice. Although BA stimulated 2-mercaptoethanol-sensitive (2-ME-S) primary and secondary antibody responses in all mice, nude mice, in contrast to normal BALB/c and C3H/HeJ mice, did not make substantial 2-mercaptoethanol-resistant (2-ME-R) antibody responses. Similarly, all mice injected with BA-LPS made 2-ME-S primary responses, and the secondary response of thymus-bearing mice contained a substantial 2-ME-R component. Collectively, these observations suggest that although both BA and BA-LPS can stimulate thymus-independent 2-ME-S antibody synthesis, thymus-derived cells are required for optimal immune responses containing a 2-ME-R component. The antibody responses of normal BALB/c and C3H/HeJ mice to BA and BA-LPS were qualitatively and quantitatively similar. Both BA and BA-LPS were mitogenic for spleen cells from normal and nude BALB/c and C3H/HeJ mice but not for thymus cells from normal BALB/c or C3H/HeJ mice, suggesting that both preparations are B-cell mitogens.
Mitsuda-type lepromin reactions as a measure of host resistance in Mycobacterium lepraemurium infection
Authors: Curtis J , Turk J L
Published: January 2020

The footpad reaction to autoclaved whole Mycobacterium lepraemurium organisms (MLM lepromin) in high-resistance (C57BL) and low-resistance (BALB/c) mice was studied. Infected C57BL mice gave a prolonged footpad response persisting for 4 weeks after skin testing with high and low doses of lepromin. This was accompanied by mononuclear cell infiltration. Uninfected C57BL mice gave no response. The majority of infected BALB/c mice gave no increase in footpad thickness. However, a high proportion of infected and control BALB/c mice tested with the high dose showed mononuclear cell infiltration which resembled that in C57BL mice. The low dose caused little infiltration in infected or control BALB/c mice. The course of infection in the two strains was different. Dissemination of organisms from the infected footpad was minimal in C57BL mice 5 months after infection. In BALB/c mice, dissemination to the draining lymph node and to some extent to the liver had occurred by 5 months. The draining lymph node of BALB/c mice showed histological evidence of local antibody formation, which uas not found in C57BL mice. On the basis of these findings, it was possible to fit murine leprosy in these two strains into a classification similar to that used for human leprosy.