bluuebunny/crossref_metadata_2025 huggingface dataset:
Exocytosis of polymorphonuclear leukocyte lysosomal contents induced by dental plaque
Authors: White R R , Montgomery E H
Published: January 2020

Rabbit polymorphonuclear leukocytes were incubated with a sonically treated suspension of pooled dental plaque to determine if the plaque would induce release of lysosomal enzymes from the polymorphonuclear leukocytes. Cells incubated with plaque at 37 degrees C released significantly greater amounts of the lysosomal enzymes, beta-glucuronidase and lysozyme, than did cells incubated with plaque at 0 degrees C or without plaque at 37 degrees C. This response was both dose and time dependent. Release of the cytoplasmic enzyme lactate dehydrogenase was minimal, and there were no significant differences in lactate dehydrogenase release between cells at 0 and 37 degrees C, or without plaque. These results indicate that dental plaque can induce the selective release of lysosomal enzymes, which could be involved in the periodontal injury produced by dental plaque.
Immunoglobulin Classes of Antibodies in Milk of Swine After Intranasal Exposure to Pseudorabies Virus or Transmissible Gastroenteritis Virus
Authors: Saif Linda J. , Bohl Edward H.
Published: January 2020

Experiments were conducted to evaluate whether infection of the respiratory tract of pregnant swine with pseudorabies (Pr) virus would induce the secretion of immunoglobulin A (IgA) antibodies in their milk as was observed after enteric infection with transmissible gastroenteritis (TGE) virus. The immune response of sows to Pr virus inoculated intranasally and to TGE virus inoculated orally/intranasally or via a natural infection was studied. Emphasis was placed upon titers and Ig classes of Pr and TGE virus-neutralizing antibodies in colostrum and milk. All animals exposed to Pr virus (alone or in combination with TGE virus) developed Pr-neutralizing antibody titers in both serum and milk. Pr antibody titers were generally higher in colostrum than in serum, but the opposite was true in milk compared with serum, with milk titers declining markedly during lactation. In contrast, TGE antibody titers in milk from experimentally or naturally infected sows usually remained higher than the corresponding serum titers and persisted at relatively constant levels throughout lactation. Gel filtration studies of milk indicated that the antibody activity against Pr virus was associated almost entirely with IgG fractions, with small amounts of antibody detectable in IgM fractions in colostrum from two of nine sows. By comparison, TGE antibodies were primarily of the IgA class, with varying but lesser amounts of antibody associated with the IgG class. Such results suggest that viral infection of the intestinal tract of the sow, but not the upper respiratory tract, stimulates the secretion of IgA antibodies in the milk.
Enzyme activity of salivary lactoperoxidase adsorbed to human enamel
Authors: Pruitt K M , Adamson M
Published: January 2020

Human saliva was incubated with human enamel powder, and the lactoperoxidase activity of the saliva was measured before and after incubation. Liquidphase lactoperoxidase activity was reduced in direct proportion to the weight of enamel powder added. Lactoperoxidase molecules were adsorbed to the enamel surface in an enzymatically active conformation, and this enamel-bound lactoperoxidase activity was also measured. The adsorption of lactoperoxidase was irreversible and produced at least a 40% increase in the concentration of lactoperoxidase in the enamel surface phase as compared with its concentration in the liquid phase. Enamel-bound lactoperoxidase, as well as the free enzyme, was capable of inactivating the key glycolytic enzyme hexokinase. The implications of the adsorption phenomenon for bacterial colonization are discussed.
Antigenicity of lateral flagella of Vibrio parahaemolyticus: existence of two distinct antigenic determinants in a flagellum
Authors: Shinoda S , Nakahara N
Published: January 2020

Cells of Vibrio parahaemolyticus treated with Formalin agglutinated with anti-lateral flagella antiserum. On the basis of agglutination tests, antigens of lateral flagella were divided into three groups. HL1, HL2, and HL3. However, in gel diffusion tests, flagellins prepared from strains belonging to different groups showed a common antigenicity. It is assumed that these results are due to the existence of two distinct antigenic determinants in the lateral flagella. One of them exists on the surfaces of the flagella and is responsible for H-agglutination, and the other exists inside the flagella and is exposed when the flagella are solubilized to flagellin monomers.
Sucrose Metabolism in Resting-Cell Suspensions of Caries-Associated and Non-Caries-Associated Dental Plaque
Authors: Minah G. E. , Loesche W. J.
Published: January 2020

Small specimens of cariogenic plaque (CP) and non-cariogenic plaque (NCP) from the same tooth were individually dispersed in buffer, divided equally, and incubated for 45 min with [
14
C]sucrose uniformly labeled either in the glucosyl moiety or the fructosyl moiety. Sucrose metabolism was analyzed periodically during an anaerobic incubation at 37°C. Radiochemical techniques were devised to analyze formation of lactic acid, soluble extracellular polysaccharide, total cell-bound and insoluble products, intracellular polysaccharide, lactic acid from intracellular polysaccharide catabolism, insoluble extracellular glucan, CO
2
, total volatile acids, individual volatile acids, and rates of sucrose consumption. The contribution of the glucosyl and fructosyl moieties of sucrose to each metabolic by-product was determined. All of the metabolic data were adjusted to the size of the plaque specimens as determined by colony-forming units, Coulter counter particle counts, and fluorometric protein analyses. Both types of dental plaque transformed from 70 to 80% of the consumed sucrose into lactic acid and cell-bound and insoluble products, primarily intracellular polysaccharide and extracellular glucan. Volatile acids accounted for most of the remaining by-products. CP metabolized significantly more sucrose than NCP and consequently produced significantly higher levels of each metabolic by-product. High levels of
Streptococcus mutans
were found in CP (averaging 40% of colony-forming units), whereas it was virtually absent in NCP.
Actinomyces
and
S. sanguis
levels were distinctly higher in NCP. NCP harbored more anaerobes and dextranase-forming microorganisms than CP.
Sucrose metabolism by prominent members of the flora isolated from cariogenic and non-cariogenic dental plaques
Authors: Minah G E , Loesche W J
Published: January 2020

Sucrose metabolism by resting-cell suspensions of pure cultures of representative members of the predominant cultivable flora isolated from cariogenic and non-cariogenic dental plaque was investigated by means of radiochemical techniques. Streptocococcus mutans utilized sucrose at a considerably faster rate than S. sanguis, S. mitis, Actinomyces viscosus, A. naeslundii, or Lactobacillus casei, forming lactic acid, intracellular polysaccharide, insoluble extracellular glucan, and lactic acid from intracellular polysaccharide catabolism at faster rates than the other bacteria. The Actinomyces formed more volatile acids than the streptococci, mostly acetic, and S. sanguis formed more soluble extracellular polysaccharide than the other bacteria. The metabolic activity of S. mutans resembled the pattern of sucrose metabolism of cariogenic plaque, whereas the metabolic activity of the Actinomyces species, the predominant members of non-cariogenic plaque flora, resembled the sucrose metabolism of non-cariogenic plaques.
Host immunological mechanisms in the resistance of mice to leptospiral infections
Authors: Adler B , Faine S
Published: January 2020

Several serovars of Leptospira virulent for hamsters and guinea pigs caused acute lethal leptospirosis in mice immunosuppressed with cyclophosphamide. Neither BCG vaccine nor Corynebacterium parvum suspension influenced the course of leptospiral infection in either immunosuppressed or normal BALB/c mice. Nude athymic mice produced anti-leptospiral antibody and were therefore resistant to infection with leptospires. Nude mice were made susceptible with cyclophosphamide but were immune if they had acquired antibody from previous infection or immunization. The evidence suggests that mechanisms of resistance to primary infection and immunity to reinfection are exclusively humorally mediated in mice. The roles of host and microbial factors in the outcome of infection are discussed.
Diarrhea caused by Escherichia coli that produce only heat-stable enterotoxin
Authors: Levine M M , Caplan E S , Waterman D , Cash R A , Hornick R B , Snyder M J
Published: January 2020

To determine the role of Escherichia coli heat-stable enterotoxin (ST) as a virulence factor in human diarrhea, a strain that elaborates only ST (E. coli 214-4) was fed to free-living volunteers in doses of 10(6), 10(8), and 10(10) organisms. Short-lived (1 day) mild illness consisting of abdominal cramps with vomiting or diarrhea occurred in three of five individuals fed 10(8). Typical travelers' diarrhea (loose stools, abdominal cramps, and low-grade fever for 2 to 3 days) was seen in four of five volunteers given 10(10); two had brief cholera-like purging of rice-water stools. Despite fever, there was no evidence of mucosal invasion. E. coli 214-4 became the predominant coliform in stools; coproculture isolates were uniformly negative for heat-labile enterotoxin (LT), whereas most produced ST. Ten of 13 individuals developed rises in antibody to somatic E. coli antigen, and none had rises in LT antitoxin. E. coli that elaborate only ST can cause diarrheal disease in adults.
Effect immunization with highly purified alpha- and beta-toxins on staphylococcal mastitis in rabbits
Authors: Adlam C , Ward P D , McCartney A C , Arbuthnott J P , Thorley C M
Published: January 2020

Experiments were carried out to determine whether immunization of female rabbits with highly purified staphylococcal alpha- or beta-toxins would protect them against intramammary challenge with staphylococci. High circulating anti-alpha-toxin titers reduced the lethal hemorrhagic edematous form of the disease ("blue-breast") produced by strains BB and Compton 201 to a localized chronic abscess form. No such protection was afforded by high anti-beta-toxin titers. Immunization with alpha- or beta-toxins produced no change in the clinical picture of the disease produced by CN.6708, a strain of Staphylococcus responsible for a natural outbreak of abscess-type rabbit mastitis. From these experiments it would appear that alpha-toxin is a key antigen in the blue-breast form of rabbit mastitis. Since the abscess form of the disease was not prevented by immunization with either alpha- or beta-toxin, other virulence factors must be acting to produce this more localized disease.
Prevalence of hepatitis B surface antibodies in ethnic groups of a Canadian hospital staff population
Authors: Leers W D
Published: January 2020

Hospital staff members were analyzed with respect to ethnic origin and prevalence of anti-hepatitis B surface antibodies (Anti-HBs). The staff members were categorized into four "risk groups" according to frequency of exposure to blood, patients' speciments, and patient care. Of the total 526 staff members studied, one-half (51.5%) were of North American origin, one-quarter came from Europe (25.9%), and the rest came from Asia, the West Indies, Africa, and Australia. The prevalence of Anti-HBs was lowest among North American staff members (8.1%) and highest among Asians (42.3%) (P less than or equal to 0.05). Low-risk administrative staff had the significantly lowest number of Anti-HBs-positive members (6.1%), whereas low-risk dietary staff (29.6%) and hospital assistants (30.6%) had the significantly highest prevalence of Anti-HBs staff members. In contrast, the high-risk group of laboratory workers and special nurses had only 16.1% of staff members with Anti-HBs. Our results show that ethnic background and socioeconomic conditions have to be considered when various risk groups are compared for the presence of Anti-HBs. The frequency of exposure to blood and patients' specimens or patient care is not the only determining factor in the prevalence of Anti-HBs in health workers.
Mechanisms of resistance to Corynebacterium kutscheri in mice
Authors: Hirst R G , Campbell R
Published: January 2020

Involvement of the mononuclear phagocyte system in the mechanism of resistance to Corynebacterium kutscheri was studied in C57B1/6 and Swiss Lynch mice. A major difference between the two mouse strains was that the phagocytic cells of the livers of C57B1/6 mice destroyed the bacteria with much greater efficiency. There was no evidence of serum factors which might have led to this greater bacterial killing observed in the C57B1/6 mice, and in vivo phagocytosis of C. kutscheri was identical in both mouse strains. Resistance to C. kutscheri could be transferred with spleen and/or bone marrow cells from resistant (Swiss Lynch X C57B1/6) F1 mice to 650-rad irradiated susceptible Swiss Lynch mice. Nonspecific and acquired mechanisms of resistance to C. kutscheri are discussed.
Blastogenic transformation by lipopolysaccharide of blood leukocytes from immunized but not normal cattle
Authors: Schurig G G , Duncan J R , Case J , Winter A J
Published: January 2020

Escherichia coli lipopolysaccharide produced blastogenic transformation in whole-blood leukocytes from heifers that had been infected and immunized with Campylobacter fetus, but not in cells from control animals. This suggests that lipopolysaccharide dose not function as a B-cell mitogen in cattle and that its stimulation of cells from immunized animals occurred through another mechanism.
Heterogeneity of nonimmune immunoglobulin Fc reactivity among gram-positive cocci: description of three major types of receptors for human immunoglobulin G
Authors: Myhre E B , Kronvall G
Published: January 2020

Two hundred and thirty strains of various gram-positive cocci were tested for quantitative, nonimmune binding of radiolabeled human polyclonal immunoglobulin G (IgG). The majority of coagulase-positive staphylococci and streptococci belonging to serogroups C and G showed a high uptake of IgG. The binding of immunoglobulin to group A streptococci was considerably less, with a number of strains completely negative. None of the pneumococcal or the group B or D streptococcal strains displayed any binding capacity. Heterogeneity of the IgG reactivity of various reactive strains was studied in an inhibition assay using 10 different animal serum pools. Three different inhibition patterns were seen, each of them revealing a striking degree of homogeneity within single bacterial species. Staphylococcus aureus and group A streptococci, respectively, constituted two homogeneous groups which differed markedly from each other and from C and G streptococci. No differences were observed between group C and G streptococci. Based on the profound differences between these homogeneous groups, three major types of Fc receptors could be defined. Type I and II Fc receptors were found on S. aureus and on group A streptococci, respectively. Fc receptor type III represented the immunoglobulin-binding structure of both group C and G streptococci.
Production of colicin V in vitro and in vivo and observations on its effects in experimental animals
Authors: Ozanne G , Mathieu L G , Baril J P
Published: January 2020

In recent years, a possible relationship between pathogenicity and colicinogeny in some Escherichia coli strains responsible for gastrointestinal infection and bacteremia in man and animals has been inferred. Using enterotoxigen-negative, colicin V-producing E. coli strains, we have (i) elaborated a simple in vitro method for producing greater yields of colicin V free of bacterial cells and large, non-dialyzable molecules; (ii) detected the presence of the bacteriocin in peritoneal fluids of moribund mice injected intraperitoneally 18 h previously with colicin V-producing strains (in these mice, Col V+ exconjugants survived and multiplied more extensively than the Col V- recipient strains from which they were derived; and (iii) observed an increased vascular permeability and inflammatory response in rabbits and guinea pigs when a culture supernatant demonstrating colicin activity was injected intradermally. The vascular response obtained after the injection of either a colicin V-containing dialysate alone or that of a trypsinized colicin-containing supernatant was always smaller than when the colicin V-active supernatant was injected. An enterotoxin-free dialysate containing colicin V also increased markedly in rabbits and guinea pigs the mild inflammatory reaction that occurred in the skin when purified endotoxin was injected subcutaneously in microgram doses. Our results are consistent with the hypothesis that colicin V may act as a virulence factor in some E. coli strains.
Bacterial adherence to nasal mucosal cells
Authors: Aly R , Shinefield H I , Strauss W G , Maibach H I
Published: January 2020

The ability of several bacterial species to adhere to human nasal mucosal cells and their distribution on nasal mucosal surfaces was studied. Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, and Pseudomonas aeruginosa adhered to scraped nasal mucosal cells. In contrast, viridans streptococci and Klebsiella pneumoniae exhibited feeble or no adherence to nasal mucosal cells. S. aureus affinity for the nasal mucosal cells of carriers of S. aureus was greater than for those of the noncarriers (P less than 0.005). Heat treatment of S. aureus did not block, but slightly reduced, its binding to mucosal cells. The data suggest a high degree of specificity involved in the adherence of bacteria to nasal mucosal cells. The greater affinity of S. aureus for the nasal mucosal cells of carriers (than noncarriers) seems to be a property of mucosal cells rather than bacteria.
Repression of heat-stable enterotoxin synthesis in enterotoxigenic Escherichia coli
Authors: Alderete J F , Robertson D C
Published: January 2020

Five different carbon sources were examined for their ability to control synthesis of heat-stable enterotoxin (ST) by enterotoxigenic (ENT+) Escherichia coli grown in either a defined medium containing four amino acids or a minimal salts medium. No ST activity was observed when D-glucose, D-gluconate, and L-arabinose were added separately to the defined medium, whereas glycerol and pyruvate decreased toxin levels. Similar results were obtained using a minimal salts medium, except with pyruvate, which did not support growth. Inhibition of ST synthesis by D-glucose was overcome by the addition of 3 X 10(-3) M cyclic adenosine 3',5'-monophosphate. Glucose repression of beta-galactosidase synthesis under conditions optimal for inhibition of ST synthesis was also reversed by exogenous cyclic adenosine 3',5'-monophosphate in the presence of the inducer isopropyl-beta-D-thiogalactopyranoside. The data suggest that control mechanisms for the synthesis of plasmid gene products of bacterial pathogens are similar to those exerted on the host chromosome.
Role of sialic acid in saliva-induced aggregation of Streptococcus sanguis
Authors: McBride B C , Gisslow M T
Published: January 2020

The ability of saliva to induce aggregation of Streptococcus sanguis was destroyed by treating the saliva with protease or neuraminidase. Loss of aggregating activity could be correlated with the appearance of free sialic acid. Clarified saliva contains an endogenous neuraminidase that modifies aggregating activity. Aggregation was inhibited by mixed ganglioside preparations but less effectively by acid-hydrolyzed gangliosides. The aggregating activity of S. sanguis was not related to the rhamnose or phosphorous content of the cell wall or to antigen a, b, c, d, or e.
Interactions Between Salmonellae and Macrophages of Guinea Pigs IV. Relationship Between Migration Inhibition and Antibacterial Action of Macrophages
Authors: Mayo Donald R. , Hsu H. S. , Lim Franklin
Published: January 2020

The in vitro macrophage migration inhibition test was used to detect the development of delayed-type hypersensitivity in guinea pigs infected with
Salmonella typhimurium.
Four different preparations from supernatants of
S. typhimurium
cultures were used as the antigens in this test. They included the concentrated bacterial antigens, the high-molecular-weight (>50,000) antigens, the ammonium sulfate-precipitated antigens, and the ribonuclease-treated antigens. All four antigen preparations were shown to inhibit the migration of peritoneal macrophages of salmonella-infected (immune) guinea pigs from capillary tubes, in comparison with cells of normal control animals. By use of the high-molecular-weight antigens and the ammonium sulfate-precipitated antigens, the production of the migration inhibition factor(s) was elicited from cultures of lymphocytes obtained from the peripheral blood of immune guinea pigs. The activity of the migration inhibition factor(s) was demonstrated by its ability to inhibit the migration of peritoneal macrophages of normal guinea pigs from capillary tubes. In contrast, normal peritoneal macrophages exposed to products of antigen-stimulated immune lymphocytes did not exhibit an enhanced phagocytic or bactericidal action against virulent
S. typhimurium
as compared with those of the normal control. The present study indicated that the bacterial antigens responsible for the elicitation of the production of the migration inhibition factor from lymphocytes of immune guinea pigs are inactivated by proteolytic enzymes, but not by ribonuclease, and have molecular weights of >50,000.
Evaluation of live attenuated plague vaccines in Praomys (Mastomys) natalensis
Authors: Hallett A F
Published: January 2020

A live attenuated Yersinia pestis vaccine designated EV76-51f, which had previously been shown to be pathogenic in vervet monkeys but not in guinea pigs, was tested in the multimammate mouse Praomys (Mastomys) natalensis. Doses of 10(6) viable organisms inoculated subcutaneously as either a lyophilized suspension or an agar-grown culture resulted in vaccination fatalities in Praomys but not in white mice. Hemagglutinating antibodies to the fraction 1 antigen were not stimulated by doses lower than 10(4) viable organisms. Agar-grown cultures of the vaccine gave better protection against a virulent Y. pestis challenge than did a lyophilized suspension. All Praomys vaccinated with a dose of 10(6) agar-grown EV76-51f protected against a virulent challenge, whereas even doses up to 10(8) lyophilized bacilli failed to give complete protection. The pathogenicity of a live attenuated plague vaccine derived from the Y. pestis EV76 vaccine strain can be detected in Praomys (Mastomys) natalensis, a rodent species highly susceptible to plague. This animal species may therefore be valuable for the testing of live attenuated plague vaccines before they are tested in costly nonhuman primates.
Mitogenic stimulation of murine spleen cells by brief exposure to Staphylococcus aureus enteroxin B
Authors: Warren J R
Published: January 2020

Staphylococcal enterotoxin B rapidly and firmly attached to external membrane surfaces of C57BL/6 spleen cells and, unless neutralized by specific antitoxin, committed the spleen cells to strong blastogenic responses.
Serotype B staphylococcal bacteriophage singly converting staphylokinase
Authors: Kondo I , Fujise K
Published: January 2020

A new staphylococcal phage, Pphi-2, which could convert the capability of producing staphylokinase, was isolated. The phage is different from the phage reported by Winkler and co-workers [Nature(London) 195:407-408, 1962; J. Gen. Microbiol. 39:321-333, 1965]. The former is a single-converting phage belonging to serotype B, but the latter is a serotype F phage capable of converting not only staphylokinase but also beta-hemolysin. Staphylokinase, i.e., the fibrinolysin produced by Staphylococcus aureus, therefore, can now be classified into three types. One is controlled by the genes on the bacterial chromosome, and the other two are mediated by lysogenic conversion by prophage Pphi-2 and the classical phage reported by Winkler and co-workers.
Effect of interferon, elevated temperature, and cell type on replication of acute hemorrhagic conjunctivitis viruses
Authors: Stanton G J , Langford M P , Baron S
Published: January 2020

Five strains of enterovirus type 70 (E 70) and four of coxsackievirus type A 24 (CA 24) were studied for their sensitivity to interferon (IF), ability to induce IF, replication at various temperatures, and adaptability to human and mouse cell cultures. We found that isolates ranged from 0.01 to 16 times as sensitive to fibroblast IF as vesicular stomatitis virus, depending upon the cell type used and the multiplicity of infection. Most of the isolates induced no detectable IF; however, when induction occurred the titers were relatively low (5 to 300 U). Only E 70 virus isolates were adaptable to growth in L-cells. Replication of all viruses was inhibited approximately 90% at 37 to 39 degrees C depending upon the cell type. These results and the accessibility of the eye to application of IF and/or heat suggests the possibility of their use for treatment. The adaptation of certain E 70 viruses to mouse L-cells opens the possibility of development of a mouse model infection.
Isolation and properties of complement-resistant strains of Escherichia coli K-12
Authors: Akiyama Y , Inoue K
Published: January 2020

Several strains that were resistant to the bactericidal action of antibody and complement were isolated from Escherichia coli K-12 W3110/SM by selecting them through the medium containing antiserum and complement. They can be agglutinated by antiserum against the parent strain and showed similar immune adherence reactivity to the parent when sensitized with this antiserum. Few differences were found in the compositions of phospholipids and proteins between both inner and outer membranes of these strains and those of the parent. However, there were fewer short-chain and more long-chain fatty acids in these strains than in the parent. It was also found that unsaturated fatty acide decreased and saturated and cyclopropanoic acids increased in phosphatidylethanolamine and phosphatidylglycerol in both inner and outer membranes of one of these strains when compared with those from the parent. Therefore, the resistance of these strains to the complement-mediated bactericidal action was considered to be due to the rigidity of their membrane structures which might repel the insertion of membrane-attack complement complex C5b-9, although they could fix the earlier complement components up to the step of the formation of C4b,2a,3b complex enzyme.
Adherence pharyngeal and skin strains of group A streptococci to human skin and oral epithelial cells
Authors: Alkan M , Ofek I , Beachey E H
Published: January 2020

Group A streptococci isolated from skin adhere in greater numbers to human skin epithelial cells than to cells obtained from buccal mucosa whereas streptococci isolated from a throat tend to adhere in greater numbers to buccal epithelial cells than to skin epithelial cells in vitro. M protein-producing strains of group A streptococci did not adhere in significantly greater numbers than M-negative strains. Lipoteichoic acid inhibited binding of streptococci to skin epithelial cells as well as was previously shown for oral epithelial cells. Our results suggest that lipoteichoic acid is more centrally involved than M protein in binding streptococci to skin and mucosal surfaces.
Immune response to Cryptococcus neoformans soluble polysaccharide: immunological unresponsiveness
Authors: Kozel T R , Gulley W F , Cazin J
Published: January 2020

Mice injected with 100 to 800 microgram of Cryptococcus neoformans soluble polysaccharide showed a reduced ability to produce antibody after a challenge immunization with polysaccharide emulsified in Freund incomplete adjuvant. These animals were considered immunologically unresponsive. Animals given an initial injection of 25 or 50 microgram of polysaccharide responded to a challenge immunization in the same manner as control animals. Reversion of unresponsive mice to antibody production without further antigenic stimulation did not occur during a 12-week experimental period. These animals exhibited a partial response to challenge immunization 8 weeks after induction of unresponsiveness, and they were fully responsive to challenge immunization at 12 weeks. Animals given a single dose of 0.1, 0.4, or 1.6 microgram of polysaccharide produced a marked anamnestic response after challenge immunization. Repeated injections of subimmunogenic doses of polysaccharide did not produce a marked anamnestic response and would induce unresponsiveness only when the cumulative dose reached 100 to 400 microgram of polysaccharide, suggesting that injected cryptococcal polysaccharide might be sequestered in some manner until an amount of antigen sufficient for induction of unresponsiveness is accumulated. This possibility was confirmed by immunofluorescence studies that revealed a long-term deposition of polysaccharide in the tubular epithelial cells of the kidney.
Vero response to a cytotoxin of Escherichia coli
Authors: Konowalchuk J , Speirs J I , Stavric S
Published: January 2020

A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E. coli. It was cytotoxic for Vero but not for Y-1 or CHO cells, and its effect on Vero was distinctly different from that of heat-labile enterotoxin. It was labile to heat and antigenically different from heat-labile enterotoxin, and membrane filtration indicated a molecular weight of 10,000 to 30,000.
Epidemic caprine keratoconjunctivitis: experimentally induced disease with a pure culture of Mycoplasma conjunctivae
Authors: Trotter S L , Franklin R M , Baas E J , Barile M F
Published: January 2020

The induction of caprine keratoconjunctivitis by the subconjunctival inoculation of a cloned culture of Mycoplasma conjunctivae is described. The clinical course of the experimental disease was similar to that noted in naturally occurring outbreaks of "pink-eye" among goats, and biopsies of inflamed conjunctivae showed similar histological response. M. conjunctivae was consistently recovered from the inflamed conjunctival tissues of inoculated animals that developed ocular disease, thus fulfilling Koch's postulates and establishing this organism as an etiological agent of caprine keratoconjunctivitis. Immunological studies suggested that cellular immune mechanisms may play a role in protecting animals from disease produced by this mycoplasma.
Susceptibility of inbred and outbred mouse strains to Sendai virus and prevalence of infection in laboratory rodents
Authors: Parker J C , Whiteman M D , Richter C B
Published: January 2020

Sendai virus is one of the more prevalent and serious virus infections of rodents. Infection was found in 66% of the mouse, 63% of the rat, 83% of the hamster, and 44% of the guinea pig colonies examined. Twenty-four inbred and outbred strains of mice were tested for their sensitivity to lethal Sendai virus infection. The 129/J mice tested were approximately 25,000-fold more sensitive than SJL/J mice; however, both mouse strains were similarly permissive in support of viral replication in their lung tissues. Histopathological studies revealed that whereas lesions in both sensitive and resistant mice were qualitatively similar, the lesions in the more sensitive 129/J mice appeared earlier, were much more extensive, and persisted longer than in the resistant SJL/J mice. These results suggest that the observed variance in sensitivity is not the result of a genetic restriction on virus infection and replication but rather is the result of a physiological factor(s) possibly related to some aberration of strain difference in the humoral or cell-mediated immune response.
Secretion of Antimycobacterial Fatty Acids by Normal and Activated Macrophages
Authors: Hemsworth George R. , Kochan Ivan
Published: January 2020

Cellular resistance to facultative intracellular parasites has been studied by determining the antimycobacterial activity and the amount of fatty acids in sera and in heptane extracts of freshly collected and 24-h-cultured normal and activated guinea pig alveolar macrophages and liver cells. The quantity and the antimycobacterial activity of extractable fatty acids were determined by gas chromatography and the agar plate diffusion test, respectively. These determinations showed that heptane extracts of activated cells inhibited the growth of BCG much more effectively than fractions prepared from normal cells; chromatographic analyses showed that extracts of activated cells contained six times more C
16
and C
18
long-chain fatty acids than did fractions of normal cells. Heptane extracts of 24-h-cultured cells and of their media showed that during incubation normal and activated cells release fatty acids into the culture media without apparent cell injury; in all experiments liver cells produced larger amounts of fatty acids than alveolar macrophages. Sera collected from activated guinea pigs inhibited the growth of BCG and contained two to five times more total fatty acids than did the growth-supporting normal serum. That bactericidal fatty acids are excreted into the tissue culture medium of incubated cells or into the blood of immunologically stimulated animals suggests that macrophages can exert antibacterial effects without phagocytosis.
Varicella-zoster virus: isolation and propagation in human melanoma cells at 36 and 32 degrees C
Authors: Grose C , Brunel P A
Published: January 2020

Cell lines derived from human malignant melanoma tumors are susceptible to infection with varicella-zoster virus (VZV). Within 5 days after inoculation of vesicular fluid, cytopathic changes appeared in melanoma cell monolayer cultures that were incubated at either 36 or 32 degrees C. The VZV isolates at the two temperatures were serially propagated by passage of trypsin-dispersed infected cells. A plaque assay was developed utilizing melanoma cell monolayers overlaid with nutrient medium containing carboxymethylcellulose. By this assay method, the growth cycle of a VZV isolate propagated at 36 degrees C was studied and compared with that of another VZV isolate grown at 32 degrees C. With equivalent infected-cell inocula at a ratio on one inoculum cell to eight uninfected cells, the yield of cell-free virus at an incubation temperature of 32 degrees C was slightly higher than at 36 degrees C, although the peak occurred 60 h, rather than 36 h, postinfection. It was also found that the titer of low-passage VZV propagated at 36 degrees C was 0.5 to 1 log higher when assayed at 32 degrees C rather than at 36 degrees C.
Macrophages and age-dependent resistance to hepatitis induced by herpes simplex virus type 2 im mice
Authors: Mogensen S C
Published: January 2020

An age-dependent increase in the resistance of BALB/c mice to induction of focal necrotic hepatitis by herpes simplex virus type 2 was demonstrated. In 3-week-old mice inoculated intraperitoneally with virus, numerous necrotic foci developed in the liver. As the mice matured, the number of lesions declined until the age of 8 weeks, when no further increase in resistance appeared. Corresponding to this, the virus titers of livers and spleens of 3-week-old mice were higher than in 8-week-old animals throughout the infection, and the infection was apparently terminated in these organs of the adult mice by day 5. In vitro infection of peritoneal macrophages from 3-week-old and 8-week-old mice showed that this age-related resistance was concomitant with an increased restriction of virus replication in peritoneal macrophages from adult mice. Since, furthermore, the resistance of adult mice could be abolished by intravenous inoculation of the macrophage-toxic agent silica before infection, and since adoptive transfer of 2 X 10(6) syngeneic macrophages from adult mice to young ones conferred to the latter a resistance comparable to that of the adult mice, it is concluded that macrophage maturation is responsible for the age-dependent resistance seen in this infection.
Alteration of clearance function by group A streptococcal pyrogenic exotoxin and its relation to suppression of the antibody response
Authors: Cunningham C M , Watson D W
Published: January 2020

The effect of purified group A streptococcal pyrogenic exotoxin (SPE) type A on the processing of and antibody response to sheep erythrocytes (SRBC) was studied in BALB/cWat mice. The rate of clearance of 51Cr-labeled SRBC from the bloodstream was decreased 3 or 24 h following a single intravenous injection of 1 or 10 microgram of SPE. Delayed uptake of label was observed in both the livers and spleens of SPE-treated mice, suggesting an inhibitory effect of the toxin on phagocytic cells of the reticuloendothelial system. Three daily intravenous injections of 0.1 or 1 microgram of purified SPE type A suppressed the early immunoglobulin response to SRBC. The role of altered macrophage function in producing the immunosuppression was tested in macrophage transfer experiments. SPE treatment suppressed the antibody response to SRBC transferred by normal macrophages, indicating that the immunosuppressive effect of the toxin was not due solely to altered antigen processing by macrophages.
Antigenic relationship between the common antigen (OEP) of Pseudomonas aeruginosa and Vibrio cholerae
Authors: Hirao Y , Homma J Y
Published: January 2020

Antibodies were found by the OEP-passive hemagglutination test to cross-react with the common antigen (OEP) of Pseudomonas aeruginosa in sera of rabbits immunized with two serotype (Inaba and Ogawa) strains of Vibrio cholerae. The titer in the OEP-passive hemagglutination reaction rose later than did the agglutinin titer and reached a peak of 640 to 1,280. The titers of OEP antibody formation in rabbits immunized with V. cholerae were almost the same as that of P. aeruginosa. The common antigen of P. aeruginosa was confirmed to exist serologically in both strains of V. cholerae as determined by the indirect fluorescent antibody test and the agar gel precipitin test. Passive immunization with the V. cholerae immune rabbit serum significantly protected mice against P. aeruginosa infection. Purified antibodies cross-reacting with the OEP of P. aeruginosa derived from the V. cholerae immune rabbit sera by OEP-coupled affinity chromatography protected mice against P. aeruginosa infection as compared with the control group, which was injected with 100 microgram of immunoglobin G not containing OEP antibody. The purified antibodies (2.5 microgram per mouse) protected animals challenged with approximately 10,000 50% lethal doses in the control group. Consequently, the common antigen (OEP) of P. aeruginosa proved to be a common antigen of V. cholerae both serologically and in possessing infection protective properties.
Chicken embryo model for type III group B beta-hemolytic streptococcal septicemia
Authors: Tieffenberg J , Vogel L , Kretschmer R R , Padnos D , Gotoff S P
Published: January 2020

A lethal septicemia was induced in 11- and 12-day-old chicken embryos with intravenous inoculation of relatively small numbers of a clinical isolate (GBBHS-III-Bell) or a reference strain (GBBHS-III-D136-C) of group B beta-hemolytic streptococci (GBBHS). GBBHS-III-Bell was more virulent than GBBHS-III-D136-C, and 11-day-old chicken embryos were more susceptible than 12-day-old chicken embryos. Type-specific rabbit antisera protected the embryos from bacterial challenge, and this protective effect was absorbed with homologous but not heterologous GBBHS strains. A heterologous antiserum and normal rabbit sera provided some protection, which could be absorbed with either homologous or heterologous GBBHS strains. The chicken embryo is a suitable animal model for the study of infection and immunity with GBBHS type III.
Staphylococcal enterotoxin and thermonuclease production during induced bovine mastitis and the clinical reaction of enterotoxin in udders
Authors: Niskanen A , Koranen L , Roine K
Published: January 2020

Enterotoxin A- and C-producing strains of Staphylococcus aureus and partially and extensively purified enterotoxin A were inoculated into the udder quarters of cows. In the course of experimentally induced mastitis caused by the inoculated S. aureus strain, enterotoxin C but not A was detected in the infected udder. Enterotoxin C was observed in mastitic milk samples at very low S. aureus population levels (10(2) to 10(3) colony-forming units per ml). The results suggest that either the synthesis of enterotoxin C is stimulated in vitro or that growth of S. aureus cells in udders was, in fact, higher than the colony-forming unit values indicated. Thermonuclease was shown to be excreted into mastitic milk at a slower rate than was enterotoxin. An inoculation of 1 microgram of enterotoxin A in autogenic milk returned to the udder caused clinical reactions (swelling, palpation sensitivity, and increase in the level of somatic cells) within 6 h.
Protein-free and low-protein media for the cultivation of Leptospira
Authors: Bey R F , Johnson R C
Published: January 2020

A protein-free medium composed of charcoal-detoxified Tweens (polysorbates), vitamins B12 and B1, inorganic salts, and organic buffer is described that supports the growth and subculture of pathogenic and saprophytic Leptospira. Growth was initiated from small inocula, and cell densities of 10(9) organisms per ml were attained. Antigenicity and immunogenicity of Leptospira cultivated in this medium were similar to those of cells cultivated in serum-containing media. The protein-free medium was converted to a low-protein medium by the addition of 0.1% bovine serum albumin.
Immunity to experimental renal candidiasis in rats
Authors: Rogers T J , Balish E
Published: January 2020

Germfree rats were found to be more susceptible to intravenous challenge with Candida albicans than were conventional rats. The resistance of conventional rats could be overcome by increasing the challenge dose. The resistance of the germfree rat was enhanced by vaccination with Formalin-killed C. albicans in complete Freund adjuvant, complete Freund adjuvant, or incomplete Freund adjuvant. These results, and histological evidence obtained from infected gnotobiotic rats, provided further information on the mechanism of resistance to the disseminated form of candidiasis.
Purification and Chemical Characterization of the Heat-Stable Enterotoxin Produced by Porcine Strains of Enterotoxigenic
Escherichia coli
Authors: Alderete John F. , Robertson Donald C.
Published: January 2020

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+)
Escherichia coli
has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100°C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
Resistance and susceptibility of mice to bacterial infection: genetics of listeriosis
Authors: Cheers C , McKenzie I F
Published: January 2020

A survey of various strains of mice showed distinct differences in resistance or susceptibility to Listeria monocytogenes. C57B1, related sublines, NZB, and SJL were resistant to Listeria, whereas BALB/c, CBA, A, DBA/1, C3H, LP.RIII, 129, and WB were susceptible. The gene(s) responsible for resistance and susceptibility to Listeria were studied in detail. C57BL6/6, B10.D2, and B10.A mice were 100 times more resistant than were BALB/c, CBA, and A. Resistance of the (C57B1/6 X BALB/C)F1 was intermediate between the two parents, suggesting partial penetration of a dominant gene. Backcross studies in which the (C57B1/6 X BALB/c)F1 were crossed with the susceptible BALB/c parent suggested that a single gene or group of linked genes were the major determinant of resistance, although the possibility that other genes exerted a modifying influence was not excluded. By using the backcross and various congenic and recombinant mice, linkage of the genes involved to the H-1, H-2, H-3, H-4, H-7, or H-8 loci, to the immunoglobulin allotype, to the Thy-1 gene, to the Hc gene specifying C5, or to coat color genes (B, c) was excluded. There was no difference in the response of males and females. In all studies, the powerful overriding influence of the C57B1 genome was evident.
Phagocytosis by sheep alveolar macrophages: relationship between opsonin concentration and light emission in the presence of luminol
Authors: Ziprin R L
Published: January 2020

The observations reported may be applied to determining the effects of various compounds, e.g., environmental pollutants and agricultural chemicals, upon the phagocytic activity of alveolar macrophages, and the method described will aid in detecting compounds which alter Fc receptor activity. A direct linear relationship existed between the concentration of antibody used to opsonize bacterial particles and the quantity of luminol-dependent light emitted by a population of sheep alveolar macrophages exposed to the opsonized particles. The relationship can be illustrated with a Lineweaver-Burk-style double-reciprocal plot. An analogy is suggested between the kinetics of enzyme substrate reactions and the interaction of antibody-coated particles with Fc receptors on cell membranes.
Production of interferon and serum hyporeactivity factor in mice infected with murine cytomegalovirus
Authors: Tarr G C , Armstrong J A , Ho M
Published: January 2020

Mice injected intraperitoneally with murine cytomegalovirus produced as many as 1,000 U of serum interferon. The response appeared biphasic, with maximum titers in the first phase detectable from 2 through 4 days after infection. A second phase peaked 10 days after infection. By carboxyhexyl-Sepharose affinity chromatography, the serum interferon behaved like lymphocyte interferon. The infected mice also produced substantial quantities of serum hyporeactivity factor (D.A. Stringfellow, E.R. Kern, D.K. Kelsey, and L.A. Glasgow, J. Infect. Dis. 135:540-551, 1977), although always in the presence of interferon. This factor was separated from the serum interferon by concanavalin A-Sepharose affinity chromatography.