bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell surface origin of antigens shed by Leishmania donovani during growth in axenic culture
Authors: Kaneshiro E S , Gottlieb M , Dwyer D M
Published: January 2020

Antisera against isolated cell surface preparations (PCSP-As) of Leishmania donovani promastigotes were used to detect extracellular antigens produced during the growth of these organisms in four different growth media. The PCSP-As precipitated two major antigenically identical but electrophoretically distinct components, in addition to several minor antigens. Immunoelectrophoretic studies employing PCSP-As, PCSP-As absorbed with intact, live promastigotes, and PCSP-As absorbed with a major extracellular antigen demonstrated the antigenic identity between the major extracellular antigens and two major components externally disposed at the surface of promastigotes. Growth curve kinetic investigations suggested that the major extracellular antigens did not appear in the growth media primarily as a result of cell lysis or damage. The carbohydrate nature of the major extracellular antigens was indicated by physicochemical characterization.
Serum Regulation of In Vitro Lymphocyte Responses in Early Experimental Syphilis
Authors: Baker-Zander Sharon A. , Sell Stewart , Lukehart Sheila A.
Published: January 2020

Sera from rabbits with early experimental syphilis were tested for their effect on in vitro lymphocyte transformation responses to related specific antigens (sonicated
T. pallidum
), unrelated specific antigens (sheep erythrocytes), and the T cell mitogen, concanavalin A. Results were compared with responses in preinfection sera and in sera from sham-infected rabbits. Titration experiments in which normal serum was used indicated that optimal lymphocyte responsiveness is obtained with a final serum concentration of 1%. Under these conditions, no differences in concanavalin A stimulation were observed in cultures with syphilitic sera. Responses to sonicated
T. pallidum
were inhibited, but only by 17 to 25% when compared with the response in preinfection sera. In cultures containing 10% serum, inhibition of lymphocyte proliferation to sonicated
T. pallidum
antigens was evident with sera from all syphilitic animals from day 10 (55% inhibition) through day 31 (80% inhibition) of infection. Responses to concanavalin A and sheep erythrocytes were significantly inhibited by day 10 sera; only 20% of the sera tested demonstrated substantial nonspecific inhibitory capacity. No differences were evident among sera from any of the sham-infected animals or among the preinfection sera from either group. Pooled serum with high inhibitory activity was fractionated by ammonium sulfate precipitation, DEAE ion exchange chromatography, and Sephadex G-200 gel filtration. Two separate inhibitors were identified: (i) a low-molecular-weight, ammonium sulfate-soluble, nonspecific inhibitory fraction containing albumin and alpha-globulins with the capacity to inhibit both antigen and mitogen responses and (ii) a high-molecular-weight, ammonium sulfate-precipitable, inhibitory fraction containing alpha-globulin and FTA-ABS-reactive immunoglobulin M which affected only the antigen-specific response to sonicated
T. pallidum.
Immunodiffusion failed to detect immunoglobulin or
T. pallidum
antigens in either fraction. DEAE-purified immunoglobulin G from immune serum was not inhibitory.
Immunoglobulin M and G antibody responses and persistence of these antibodies in adults after vaccination with a combined meningococcal group A and group C polysaccharide vaccine
Authors: Beuvery E C , Leussink A B , Van Delft R W , Tiesjema R H , Nagel J
Published: January 2020

Adult volunteers were injected with a combined meningococcal group A and group C polysaccharide vaccine. Immunoglobulin M (IgM) and IgG antibody levels against both polysaccharides were measured in serum samples taken 14 days as well as 3 years after vaccination. For both group A and group C polysaccharides, the IgM and IgG antibody levels at 14 days postvaccination were positively related. The IgM-to-IgG antibody ratio at 14 days postvaccination was an indicator for the persistence of both IgM and IgG antibodies during the next 3 years; a high ratio meant a short persistence, whereas a low ratio was associated with a long persistence.
Acquired resistance of hamsters to challenge with homologous and heterologous virulent treponemes
Authors: Schell R F , Azadegan A A , Nitskansky S G , LeFrock J L
Published: January 2020

Hamsters infected with Treponema pallidum Nichols (venereal syphilis), T. pallidum Bosnia A (endemic syphilis), or T. pertenue (frambesia, or yaws) developed substantial resistance to homologous reinfection. Hamsters infected for 10 weeks developed no lesions, and their lymph nodes contained fewer treponemes after reinfection with the same strain. The degree of cross-resistance among the treponemes correlated well with pathological changes occurring in infected hamsters and with the persistence of treponemal antigen during primary infection. Only hamsters infected with T. pallidum Bosnia A developed substantial resistance to heterologous reinfection. These animals also had extensive chronic skin lesions and lymph nodes containing measurable numbers of treponemes. Frambesial hamsters had less extensive lesions and were resistant to T. pallidum Nichols and, to a lesser extent, to T. pallidum Bosnia A. Hamsters infected with T. pallidum Nichols developed no cutaneous lesions and were resistant only to reinfection with T. pertenue. Confirmation of these results was obtained in normal hamsters infused with syphilitic (Nichols or Bosnia A) or frambesial immune cells and challenged with homologous or heterologous treponemes.
Surface peptide mapping of protein I and protein III of four strains of Neisseria gonorrhoeae
Authors: Judd R C
Published: January 2020

Whole cells and isolated outer membranes (OMs) of four strains of gonococci were surface radioiodinated with either lactoperoxidase or Iodogen (Pierce Chemical Co., Rockford, Ill.). These preparations were solubilized in sodium dodecyl sulfate and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Surface-radioiodinated protein I (PI) and PIII bands were excised from the sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels and digested with alpha-chymotrypsin, and the resultant 125I-peptide fragments were resolved by high-voltage electrophoresis and thin-layer chromatography (i.e., surface peptide mapping). Radioemitting peptidic fragments were visualized by autoradiography. Results demonstrated that the PI molecule of each gonococcal strain studied had unique iodinatable peptides exposed on the surface of whole cells and OMs, whereas PIIIs appeared to have the same portion of the molecule exposed on the surface of bacteria or OMs, regardless of the gonococcal strain from which they were isolated. Many more radiolabeled peptides were seen in surface peptide maps of PIs from radiolabeled OMs than in those from radioiodinated whole cells, whereas different peptidic fragments were seen in the surface peptide maps of PIIIs from radiolabeled OMs than were seen in those from radiolabeled whole cells. These data suggest that PI may contribute strain-specific antigenic determinants and PIII may contribute cross-reactive determinants and that the surface exposure of PI and PIII is different in isolated OMs than in the OM of intact gonococci.
Genetic Relatedness Among Human Rotaviruses as Determined by RNA Hybridization
Authors: Flores Jorge , Perez Irene , White Laura , Perez Mireya , Kalica Anthony R. , Marquina Ruben , Wyatt Richard G. , Kapikian Albert Z. , Chanock Robert M.
Published: January 2020

Viral RNAs from human rotaviruses were compared by gel electrophoresis and by hybridization to probes prepared by in vitro transcription of two well-characterized laboratory strains (Wa and DS-1). Also, the viral RNAs were compared by hybridization to probes prepared from three of the test viruses. Thirteen specimens (diarrheal stools) were obtained from infants and children 5 to 21 months old on a single day at the emergency ward of the Caracas Children's Hospital, and an additional specimen was obtained from the same hospital 6 months before. When the electrophoresed viral RNAs were stained with ethidium bromide and examined by UV light, five different migration patterns (electropherotypes) were distinguished on the basis of differences in mobility of the RNA segments. The hybridization technique that was employed permitted only qualitative comparisons of corresponding genes of different human rotaviruses. Ten of the specimens contained enough virus to yield sufficient RNA for hybridization studies. Eight of the viruses studied by hybridization contained 4 to 11 genes that reacted specifically with the Wa probe to yield double-stranded RNA segments with a mobility similar to that of Wa viral RNA or test virus RNA. The other two viruses contained 11 genes that reacted specifically with the DS-1 hybridization probe to yield double-stranded RNA segments with a mobility similar to DS-1 viral RNA or test virus RNA. A more complex picture emerged when hybridization probes were prepared from three of the test viruses and used to compare the different electropherotypes. Corresponding genes that exhibited similar migration did not necessarily exhibit homology when studied by hybridization. Also, some corresponding genes that exhibited homology did not have the same mobility by gel electrophoresis.
Effects of local immunization with glucosyltransferase on colonization of hamsters by Streptococcus mutans
Authors: Smith D J , Taubman M A , Ebersole J L
Published: January 2020

Experiments were performed to study the effect of antibody to Streptococcus mutans glucosyltransferase (GTF) on the implantation of these organisms in hamsters. Salivary (immunoglobulin A) and serum (immunoglobulin G) antibodies to GTF and GTF-inhibiting activity were elicited by injection of GTF in Freund complete adjuvant in the salivary gland region. Sham-immunized and GTF-immunized groups were then orally challenged with approximately 10(7), 10(8), or 10(9) colony-forming units of cariogenic S. mutans 6715. The results were evaluated by systematically swabbing molars 4 days and approximately 4 weeks after challenge. In general, fewer GTF-immunized hamsters became infected with S. mutans after challenge with 10(7) or 10(8) organisms than did identically challenged sham-immunized hamsters. Of the animals that did become infected, fewer S. mutans colony-forming units were recovered from GTF-immunized hamsters. These results indicate that the presence of antibody to GTF can diminish the ability of S. mutans to implant in the oral cavity of immunized hamsters.
Protection against pulmonary blastomycosis: correlation with cellular and humoral immunity in mice after subcutaneous nonlethal infection
Authors: Morozumi P A , Brummer E , Stevens D A
Published: January 2020

A model of pulmonary blastomycosis in the mouse, in which the portal of entry is the same as natural human infection, was used to study resistance to challenge after subcutaneous infection. One week after subcutaneous infection, mice were partially resistant to pulmonary challenge, and mice challenged two weeks after infection were resistant. Measurement of cellular and humoral immune responses to Blastomyces dermatitidis antigens after subcutaneous infection showed the following. (i) Delayed-type hypersensitivity appeared 1 week after infection, and responses increased for 3 weeks thereafter. (ii) Proliferative responses in vitro appeared in spleen cells at 1 week and in contralateral lymph node cells at 3 weeks, (iii) Serum antibody, detected by an enzyme-linked immunosorbent assay, appeared 1 week after infection and then increased in titer. (iv) Peritoneal macrophages were activated to inhibit replication of B. dermatitidis in vitro by the first week after infection. Prior subcutaneous infection also resulted in rapid clearing of a second subcutaneous challenge, as well as resistance to a lethal intraperitoneal challenge. This resistance was associated with the development of cell-mediated and humoral immune responses. These data provide a chronological framework for selective transfer experiments.
Oral Immunization of Dogs with Purified Cholera Toxin, Crude Cholera Toxin, or B Subunit: Evidence for Synergistic Protection by Antitoxic and Antibacterial Mechanisms
Authors: Pierce Nathaniel F. , Cray William C. , Sacci John B.
Published: January 2020

The immunogenicity and safety of purified cholera toxin (CT), its B subunit, and a crude culture filtrate of toxigenic
Vibrio cholerae
(CrT) were compared in dogs immunized orally and challenged with virulent
V. cholerae.
CT and CrT caused marked protection in two- or three-dose regimens. Protection due to CT occurred only with doses that caused transient, sometimes severe, diarrhea in most dogs; this protection was proportional to the peak antitoxin response in jejunal mucosa and lasted at least 15 weeks. In contrast, minimum protective doses of CrT contained much less cholera toxin, caused very mild diarrhea in only 21% of the dogs, and evoked protection that was greater than predicted from the modest jejunal antitoxin response. B subunit caused smaller jejunal antitoxin responses than did similar doses of CT and was poorly protective, the 50% protective dose being >40-fold greater than that of CT. Two observations indicated that protection due to CrT involved synergy between antibacterial and antitoxic immune responses. First, the 50% protective dose of CrT was 24-fold and >36-fold smaller than the 50% protective doses of its CT and non-CT antigenic components, respectively, when tested separately. Second, protection was greater in CrT-immunized dogs than in CT-immunized dogs for a given mucosal antitoxin response. Low doses of CrT evoked serotype-specific protection, indicating that the serotype-specific O somatic antigen contributed significatly to antibacterial protection. These results suggest that a simple, effective, nonliving oral vaccine for cholera based on combined antibacterial and antitoxic immunity can probably be achieved. However, further studies are needed to determine how a protective antitoxic response can be evoked without causing diarrhea during immunization.
Lymphokine-induced mycobacteriostatic activity in mouse pleural macrophages
Authors: Zlotnik A , Crowle A J
Published: January 2020

We have developed an in vitro assay to study the intramacrophage replication of Mycobacterium tuberculosis or Mycobacterium bovis BCG. In this assay, extracellular mycobacterial replication was avoided by using a small infecting inoculum and a new method for efficiently removing nonphagocytocytized bacilli. The ability of different mycobacterial strains to replicate in mouse pleural macrophages correlated with their virulence. The effect of lymphokines prepared by incubating spleen cells from BCG-immunized mice with mycobacterial antigens was tested with this assay. In the presence of lymphokines, mouse pleural macrophages were able to inhibit the intramacrophage replication of both BCG and M. tuberculosis. This assay is a useful in vitro model for studying antibacterial cellular immunity expressed by macrophages.
Influenza A virus-induced polymorphonuclear leukocyte dysfunction
Authors: Abramson J S , Lyles D S , Heller K A , Bass D A
Published: January 2020

Previous studies have shown that influenza A virus can activate the polymorphonuclear leukocyte (PMN) respiratory burst and that upon subsequent stimulation of the cell there is depressed metabolic function. We examined the mechanism by which influenza virus causes PMN dysfunction by measuring the effect upon the chemiluminescent activity of cells of varying the type of influenza virus used, the period of time that cells were exposed to virus, and the secondary stimulus that was used. The various types of intact influenza virus elicited different amounts of chemiluminescent activity, but when cells were subsequently stimulated with phorbol myristate acetate, each virus caused equivalent depression of the PMN response. Purified glycoproteins incorporated into a liposome structure similarly stimulated the PMN chemiluminescence, yet did not induce PMN dysfunction. Depressed PMN function was noted after as little as 5 min of incubation of cells with virus and occurred to both receptor-dependent (zymosan, N-formylmethionyl-leucyl-phenylalanine, and phorbol myristate acetate) and -independent (calcium ionophore A23187) stimuli.
Fibronectin-mediated binding of group A streptococci to human polymorphonuclear leukocytes
Authors: Simpson W A , Hasty D L , Mason J M , Beachey E H
Published: January 2020

Human plasma was shown to promote the attachment of an avirulent strain of Streptococcus pyogenes to human polymorphonuclear leukocytes. Removal of the fibronectin by absorption of the plasma with agarose-immobilized gelatin abolished the attachment-promoting activity. The activity of the absorbed plasma was restored with purified human serum fibronectin. The fibronectin was found to promote the attachment of three M protein-negative, but not of three M protein-positive, strains of streptococci. Radiolabeled fibronectin was shown to bind in various degrees to all strains of S. pyogenes tested. Thus, in the absence of streptococci surface M protein, fibronectin promotes the association of group A streptococci with human polymorphonuclear leukocytes.
Comparison of simian and human cytomegalovirus reactivities in an enzyme-linked immunospecific assay: effect of antigen preparation on cross-reactive antigens
Authors: Tinghitella T J , Swack N , Baumgarten A , Hsiung G D
Published: January 2020

Simian cytomegalovirus was substituted for human cytomegalovirus in an enzyme-linked immunoassay. Unlike the indirect immunofluorescence assay which demonstrates a two-way cross-reactivity, only one-way cross-reactivity was observed. Altering the method of simian antigen preparation gave some insight other this different reactivity.
Differences in virulence of clinical isolates of Candida tropicalis and Candida albicans in mice
Authors: Wingard J R , Dick J D , Merz W G , Sandford G R , Saral R , Burns W H
Published: January 2020

Prior reports from this institution indicated that Candida tropicalis was more pathogenic than C. albicans in oncology patients. Pairs of clinical isolates of C. tropicalis and C. albicans recovered from similar patients at other institutions were examined to determine their relative virulence. After intravenous inoculation in normal mice, three pairs of isolates had no significant differences in the 50% lethal dose, and one C. tropicalis isolate was less virulent than its companion C. albicans isolate. In contrast, in mice treated with antibiotics and cytarabine, an antineoplastic drug which damages the gastrointestinal mucosa and produces granulocytopenia, oral inoculation of yeast cells produced striking differences in the 50% infective dose: each C. tropicalis isolate was more virulent than the companion C. albicans isolate from the same institution. The increased virulence of the C. tropicalis isolates compared with the C. albicans isolates when given orally to compromised mice parallels clinical observations in compromised patients.
Motility as a Selective Force in the Reversion of Cystic Fibrosis-Associated Mucoid
Pseudomonas aeruginosa
to the Nonmucoid Phenotype in Culture
Authors: Boyce John R. , Miller Robert V.
Published: January 2020

Motility acted as a strong positive selection for nonmucoid
Pseudomonas aeruginosa
in unshaken cultures. Consistent with this finding, electron microscopic examination of mucoid and nonmucoid revertant strains indicated that the mucoid cells were nonflagellated whereas the nonmucoid revertants were flagellated.
Effect of polymers of L-lysine on the cytotoxic action of diphtheria toxin
Authors: Eidels L , Hart D A
Published: January 2020

L-Lysine and poly(L-lysine) polymers of defined sizes were tested for their effect on diphtheria toxin-mediated cytotoxicity of Chinese hamster ovary cells. Poly(L-lysine)8-12 and poly(L-lysine)15 were protective, whereas lysine and lysine polymers of three and four residues were not. The protection by poly(L-lysine)8-12 occurred by affecting the initial toxin receptor interaction. Furthermore, poly(L-lysine)8-12 acted as a competitive inhibitor with an apparent dissociation constant of 6 X 10(-7) M. These observations are consistent with a previously proposed model (Proia et al., J. Biol. Chem. 256:4991-4997, 1981) in which (i) the cationic polyphosphate-binding site (P site) on the B fragment of diphtheria toxin interacts with a putative polyanionic binding site on the toxin receptor, and (ii) the protection of cells from diphtheria toxin by poly(L-lysine) and other polycationic molecules would be the result of the competition between these polycationic molecules and the cationic domain of the diphtheria toxin molecule for the polyanionic toxin-binding site on the cell surface receptor.
Role of macrophages in innate and acquired host resistance to experimental scrub typhus infection of inbred mice
Authors: Jerrells T R , Osterman J V
Published: January 2020

Mechanisms of innate resistance to infection with the Gilliam strain of Rickettsia tsutsugamushi were examined using congenic strains of mice resistant (C3H/RV) or susceptible (C3H/He) to intraperitoneal infection. Both strains of mice were resistant to infection with 1,000 50% mouse lethal doses of rickettsiae if given intravenously. In both systems rickettsial replication occurred after intravenous infection, as evidenced by an increase in rickettsial numbers in the spleens of infected animals, followed by a decrease in rickettsiae to low levels by day 14 postinfection. Administration of the antimacrophage agents silica and carrageenan to C3H/He mice intravenously rendered these animals susceptible to lethal infection. Neither irradiation nor silica given individually rendered C3H/RV mice susceptible to intravenous infection. However, if silica and irradiation were given together, a lethal infection occurred after intravenous infection. C3H/RV mice became susceptible to lethal infection after sublethal doses of irradiation only if they were infected intraperitoneally. Administration of silica or carrageenan had no effect on the outcome of intraperitoneal infection of these mice with Gilliam rickettsiae. These data suggest that both strains of mice share innate resistance mechanisms to intravenous infection that consist of fixed macrophages. Resistance of C3H/RV mice to intraperitoneal infection, in contrast, apparently was dependent only on an irradiation-sensitive process.
Pyridine analogs inhibit the glucosyltransferase of Streptococcus mutans
Authors: Thaniyavarn S , Taylor K G , Singh S , Doyle R J
Published: January 2020

Soluble glucan synthesis catalyzed by dextransucrase preparations from Streptococcus mutans 6715 were inhibited by pyridoxal-5-phosphate and several other pyridine analogs, including pyridoxine, pyridoxamine, pyridoxamine-5-phosphate, pyridoxal, and 4-pyridoxic acid. Pyridine and pyridine-4-carboxaldehyde were not effective inhibitors of the enzyme. Kinetic analyses suggested that pyridoxal-5-phosphate is a noncompetitive inhibitor of dextransucrase. The inactivation was dependent on time, pyridoxal-5-phosphate concentration, and hydrogen ion concentration. Apparent Ki values were 4.9 mM at pH 7.0 and 4.2 mM at pH 5.5. Dextransucrase activity could be restored by dialysis to remove the inhibitors. Maximum inhibition was observed after a 120-min incubation of the enzyme with pyridoxal-5-phosphate. The pH optima for inhibition by pyridoxal-5-phosphate were 4 and 7. The sucrose-dependent adherence of S. mutans cells to saliva-coated hydroxylapatite beads was also inhibited by pyridoxal-5-phosphate but only marginally by the other pyridine anatogs. In addition, pyridoxal-5-phosphate markedly reduced the rate of acid production by intact S. mutans cells from sucrose or glucose substrates. Another pyridoxal-5-phosphate analog, 2-methyl-5-hydroxypyridine, was also effective in preventing the production of acid by S. mutans from sucrose or glucose. When S. mutans cells were preincubated with pyridoxal-5-phosphate or pyridine analogs, significant reductions in the rate of D-glucose uptake were observed. It is suggested that the inhibition of dextransucrase occurs because of a change iun enzyme conformation which results from the binding of the pyridine derivatives. The results suggest that pyridoxal-5-phosphate or structural analogs may ultimately be useful in reducing the incidence of dental caries.
Antigenic Relationship Between Serotype-Specific Agglutinogen and Fimbriae of
Bordetella pertussis
Authors: Ashworth L. A. E. , Irons L. I. , Dowsett A. B.
Published: January 2020

The widely held view that the filamentous hemagglutinin (FHA) of
Bordetella pertussis
is derived from fimbriae (pili) is not supported by studies of fimbriation and FHA content of the organism. Fimbriae do not label specifically with antibody to FHA in immuno-electron microscopy but do label with antibody to serotype-specific agglutinogen.
Stimulation of Resistance of Immunocompromised Mice by a Muramyl Dipeptide Analog
Authors: Osada Yasuaki , Mitsuyama Masao , Matsumoto Kensuke , Une Tsutomu , Otani Tsuyoshi , Ogawa Hidemasa , Nomoto Kikuo
Published: January 2020

L18-MDP(Ala), a synthetic derivative of muramyl dipeptide, enhanced resistance against
Escherichia coli
and
Candida albicans
infections in aged mice and younger adult mice whose defense mechanism(s) had been depressed by X-ray irradiation or by treatment with cyclophosphamide.
High-Molecular-Weight Plasmid Correlates with
Escherichia coli
Enteroinvasiveness
Authors: Harris Jeffrey R. , Wachsmuth I. Kaye , Davis Betty R. , Cohen Mitchell L.
Published: January 2020

We tested by the Sereny method and examined for plasmids 14 previously Sereny-test-positive and 17 previously untested
Escherichia coli
strains. The presence of a 140-megadalton plasmid was significantly associated with enteroin-vasiveness as measured by the Sereny test in the 31
E. coli
strains examined.
Genetic and molecular studies of plasmids coding for colonization factor antigen I and heat-stable enterotoxin in several escherichia coli serotypes
Authors: Willshaw G A , Smith H R , McConnell M M , Barclay E A , Krnjulac J , Rowe B
Published: January 2020

Plasmids coding for colonization factor antigen I (CFA/I) and heat-stable enterotoxin (ST) were identified in 10 strains of human enterotoxigenic Escherichia coli. The strains, which belonged to serogroups O63, O114, O128, and O153, were isolated in Bangladesh, Latin America, Spain, and South Africa. Two strains produced heat-labile enterotoxin in addition to ST. CFA/I-ST plasmids were mobilized from two O128 strains into E. coli K-12 with the R factor R1-19K-. Like the prototype CFA/I-ST plasmid NTP113, mobilized previously from an E. coli O78 strain into K-12, these two plasmids were non-autotransferring. All 10 CFA/I-ST plasmids were incompatible with NTP113 and had molecular weights ranging from 59 X 10(6) to 72 X 10(6). The molecular properties of seven of these plasmids were compared with those of six CFA/I-ST plasmids previously mobilized from O78 strains from Ethiopia, South Africa, and Bangladesh and with those of one plasmid coding for CFA/I, ST and heat-labile enterotoxin from a South African strain of serogroup O63. Digestion with the restriction endonuclease HindIII showed that several plasmids had very similar fragment patterns and two were identical. Generally, a larger proportion of HindIII fragments were of common size in digests of plasmids identified in strains from related geographical areas, regardless of serogroup. However, all except one plasmid shared five or six HindIII fragments of the same size, one of which had been shown previously to be involved in CFA/I production. There was at least 90% DNA homology between CFA/I-ST plasmids with a molecular weight of about 58 X 10(6) from O78 strains from different sources. Most of the DNA sequences of these plasmids were present in a larger CFA/I-ST plasmid (72 X 10(6) from an O128 strain. The results of genetic and molecular studies suggest that CFA/I and ST production is determined by very similar plasmids in different serogroups of human enterotoxigenic E. coli from several sources.
Seroepidemiology of heat-labile enterotoxigenic Escherichia coli and Norwalk virus infections in Panamanians, Canal Zone residents, Apache Indians, and United States Peace Corps volunteers
Authors: Ryder R W , Greenberg H , Singh N , Oro G , de Guardia A , Sack R B , Kapikian A Z
Published: January 2020

Serum antibody titrations against the heat-labile enterotoxin (LT) of Escherichia coli were carried out on Panamanians, U.S. citizens resident in the Panama Canal Zone, Apache Indians living on the reservation in Whiteriver, Arizona, and Peace Corps volunteers before they traveled overseas. Antibody titers to Norwalk virus were also carried out on serum from Panamanian and Canal Zone residents. A high prevalence of low-titer LT antibodies was found in infants and adults from Panama, the Canal Zone, and Whiteriver. Panamanian children aged 1 to 5 years had the highest LT antibody titers. Peace Corps volunteers had a low prevalence and titer of LT antibodies. Prevalence and titer of antibodies to Norwalk virus were generally higher in Panamanians compared with Canal Zone residents of the same age. In the populations we studied, various modes of transmission and mechanisms of immunity likely explain the differences which we observed in antibody prevalence and titer to these two enteric pathogens.
Immunoregulation in disseminated histoplasmosis: characterization of the surface phenotype of splenic suppressor T lymphocytes
Authors: Watson S R , Bullock W E
Published: January 2020

C57BL/6 and C3H/HeJ mice were infected intravenously with 6 X 10(5) yeast-phase Histoplasma capsulatum organisms. After 1 week, splenocytes from both mouse strains showed diminished antibody responses to sheep erythrocytes in vitro; these cells also were able to suppress the response of normal syngeneic cells. Passage of splenocytes from infected mice through a nylon wool column yielded a population enriched for T cells that exerted suppressor activity, although to a smaller extent than did unfractionated cells. Treatment of the T-cell-enriched population from both strains of mice with either anti-Thy 1.2 or anti-Ly 2 and complement resulted in a loss of this immunosuppressive ability. In addition, anti-I-Jk antiserum was effective in ablating the suppressive effect of C3H/HeJ nylon wool-passed spleen cells. The conclusion drawn from these experiments is that the T cells from H. capsulatum-infected animals which are capable of modulating the in vitro plaque-forming cell response to sheep erythrocytes bear Ly 2 and I-J determinants on their surfaces.
Type-specific protection of neonatal rats from lethal group B streptococcal infection by immune sera obtained from human volunteers vaccinated with type III-specific polysaccharide
Authors: De Cueninck B J , Eisenstein T K , McIntosh T S , Shockman G D , Swenson R M
Published: January 2020

Sera obtained from human volunteers at 6 weeks after vaccination with highly purified type III polysaccharide antigen prepared from a group B Streptococcus, strain M732, were found to protect neonatal rats from otherwise lethal infection by the homologous strain. The specific antibody content of the sera, expressed in micrograms of antibody protein per milliliter, was determined by an enzyme-linked immunosorbent assay in conjunction with quantitative precipitin analysis. For two sera studied in detail, the protective dose of antibody for 50% of the animals was 0.4 micrograms. Immune serum obtained from a volunteer who received type II polysaccharide vaccine was not protective against type III infection. Absorption of anti-type III serum by quantitative precipitation of antibodies with type III polysaccharide completely removed the passive protective activity of the serum. The results show that antibodies induced in humans by purified type II polysaccharide give serotype-specific protection in an animal model of neonatal infection.
Temperature-sensitive mutants of Pseudomonas aeruginosa: isolation and preliminary immunological evaluation
Authors: Hooke A M , Arroyo P J , Oeschger M P , Bellanti J A
Published: January 2020

The immunogenicity of two temperature-sensitive (ts) mutants of Pseudomonas aeruginosa immunotype 1, isolated and characterized for the development of a safe, live vaccine strain, was evaluated in a mouse protection model. One mutant, A/10/25, had a limited "coasting" property (i.e., continued replication for two divisions) at the nonpermissive temperature (36 degrees C), whereas the other mutant, E/9/9, continued replication for five generations after transfer to 36 degrees C. Groups of 3- to 5-week-old ICR mice were immunized intraperitoneally with various doses of the two ts mutants; at various times thereafter, the mice were challenged intraperitoneally with lethal doses of the parental wild type. The more extensive coaster, E/9/9, induced 100% protection at immunizing doses lower than those required for A/10/25 to induce the same protection (1 x 10(8) to 2 x 10(8) and 6 x 10(8) colony-forming units, respectively). Both ts strains induced significant protection for up to 5 weeks after immunization. The results of these studies suggest that the use of P. aeruginosa ts mutants might provide a novel approach to the prevention of P. aeruginosa colonization of patients with cystic fibrosis.
Pseudomonas aeruginosa exotoxin A inhibits proliferation of human bone marrow progenitor cells in vitro
Authors: Stuart R K , Pollack M
Published: January 2020

Pseudomonas aeruginosa exotoxin A, a potent inhibitor of eukaryotic protein synthesis, is produced in vivo during human infection. We tested the hypothesis that exotoxin A may be responsible for the leukopenia which sometimes accompanies pseudomonas disease by examining the in vitro toxicity of exotoxin A for human bone marrow granulocyte-macrophage progenitor cells (colony-forming units in culture [CFU-c] in the soft agar cloning system. Colony formation by freshly obtained marrow cells from five normal subjects was inhibited by exotoxin A in a concentration-dependent manner. The mean 50 and 100% inhibitory concentrations of toxin were 1.4 x 10(-10) and 1.4 x 10(-8) M, respectively, and significant inhibition was observed at a toxin concentration as low as 1.4 x 10(-13) M in two subjects. The inhibitory effect of exotoxin A on colony formation was specifically neutralized by antiserum to exotoxin A. Although mouse CFU-c were somewhat less sensitive to exotoxin A in vitro compared with human CFU-c, exotoxin A produced significant leukopenia in vivo in mice. These data suggest a possible mechanism for the leukopenia which sometimes occurs in human pseudomonas disease.
Mechanism of Host Defense Suppression Induced by Viral Infection: Mode of Action of Inosiplex as an Antiviral Agent
Authors: Ohnishi Haruo , Kosuzume Hiroshi , Inaba Hitoshi , Okura Masatsugu , Morita Yasunobu , Mochizuki Hidenori , Suzuki Yasuo
Published: January 2020

The mechanism of influenza virus (INFV)-induced immunosuppression and the mode of inosiplex action against INFV infection were studied. INFV suppressed both anti-lipopolysaccharide and anti-sheep erythrocyte antibody production in mice. INFV infection caused viral mRNA synthesis and increased total RNA synthesis in lymphocytes, but total mRNA synthesis was decreased. The translational ability of INFV-infected lymphocytes was also suppressed. Thus, INFV seemed to cause suppression of both mRNA synthesis and the translational ability of lymphocytes, resulting in suppression of lymphocyte functions. Inosiplex potentiated antibody production against sheep erythrocytes but not against lipopolysaccharide in normal and INFV-infected mice. Adamantanamine did not produce such a potentiating effect. The lymphocytes obtained from INFV-immunized and inosiplex-treated mice conferred resistance against INFV infection. This resistance was partially inhibited by anti-Thy 1.2 antibody treatment of the lymphocytes. In an adoptive cell transfer system, inosiplex treatment of T-cell donors potentiated antibody production when a non-immunosuppressive carrier (human serum albumin) was used. When an immunosuppressive carrier (INFV) was used, inosiplex treatment of either B-cell donors or T-cell donors increased antibody production. Direct introduction of inosiplex into lymphocytes by a cell fusion technique stimulated anti-sheep erythrocyte antibody production more effectively than the addition of inosiplex to cultures. Inosiplex increased total RNA and total mRNA syntheses in phytohemagglutinin-treated lymphocytes. In INFV-infected lymphocytes, inosiplex decreased syntheses of total RNA, total mRNA, and viral mRNA and restored translational ability. From these results, we concluded that inosiplex penetrates into lymphocytes and suppresses viral RNA synthesis and that it supports lymphocyte functions by promoting RNA synthesis and translational ability, both of which are necessary for hosts.
Effect of anti-pilus antibodies on survival of gonococci within guinea pig subcutaneous chambers
Authors: Lambden P R , Heckels J E , Watt P J
Published: January 2020

Guinea pigs were immunized with either alpha or beta pili from Neisseria gonorrhoeae P9 before the inoculation of subcutaneous chambers with a mixture of variants having alpha, beta, gamma, or delta pili. Animals immunized with alpha pili showed significant protection, but those immunized with beta pili did not. The degree of protection could be correlated with the cross-reactivity of the antibodies produced to the heterologous pilus types.
Monoclonal antibodies to cytomegalovirus: rapid identification of clinical isolates and preliminary use in diagnosis of cytomegalovirus pneumonia
Authors: Goldstein L C , McDougall J , Hackman R , Meyers J D , Thomas E D , Nowinski R C
Published: January 2020

Two monoclonal antibodies which react specifically with cells infected by cytomegalovirus (CMV) are described. One antibody, 6-E3, reacts with a 72,000-dalton protein that appears early in infection and remains localized in the cell nucleus. The other antibody, 6-C5, reacts with an 80,000-dalton protein that appears late in infection and remains localized in cytoplasmic inclusion bodies. Both monoclonal antibodies react with conventional laboratory strains of CMV and can be used in immunofluorescence assays to identify clinical isolates of CMV in culture. Preliminary tests on lung tissues from patients with CMV pneumonia show that only antibody 6-C5 detects CMV infection in primary clinical specimens. A comparison of culture, histological, and immunological methods demonstrates that the monoclonal antibodies possess sufficient specificity and sensitivity to warrant their continued development as immunodiagnostic tools for the detection of CMV infection in both tissue culture and tissues obtained directly from patients.
Monocyte-mediated damage to Rhizopus oryzae hyphae in vitro
Authors: Diamond R D , Haudenschild C C , Erickson N F
Published: January 2020

Clinicopathological correlations from human cases and experimental animal studies suggest that neutrophils are critical components of the host response to mucormycosis but that other cellular defense mechanisms appear to be important as well. Since our previous studies demonstrated that Rhizopus oryzae hyphae which are too large to be ingested completely can be damaged and probably killed by human neutrophils, we studied the antihyphal activity of human monocytes. As with neutrophils, light and electron microscopic studies indicated that monocytes attached to hyphae and appeared to destroy them in the absence of serum. As judged by our previously described assay for the leukocyte-induced inhibition of [14C]uracil uptake by hyphae, quantitative damage to hyphae by monocytes was 40.8 +/- 2.2% in 54 experiments. Neither attachment to nor damage of hyphae by monocytes was augmented by the presence of 10% human serum. As with neutrophils, monocyte-mediated damage of R. oryzae was significantly decreased by some inhibitors of oxidative metabolism and scavengers of the potentially microbicidal oxidative leukocyte products, which included 10(-4)M sodium azide, 10 (-3) M sodium cyanide, catalase, 10(-3) M histidine, 10(-3) M tryptophan, and 10(-4) M 1,4-diazobicyclo[2.2.2]octane but not superoxide dismutase, 1.4 X 10(-2) M dimethyl sulfoxide, and 4.0 X 10(-1) M mannitol. Moreover, monocytes from three patients with chronic granulomatous disease failed to damage hyphae at all. In contrast to our previous data for neutrophils, polyanions (10(-5) M polyaspartic or polyglutamic acid) did not inhibit monocyte-mediated hyphal damage. Thus, monocytes can damage and probably kill R. oryzae hyphae by oxidative mechanisms and so may be involved in host defense mechanisms against mucormycosis.
Interaction of
Escherichia coli
with Different Fimbriae and Polymorphonuclear Leukocytes
Authors: Björkstén Bengt , Wadström Torkel
Published: January 2020

The effects of
Escherichia coli
strains with various fimbriae on bacteria-polymorphonuclear leukocyte (PMN) interactions were studied. Strains of
E. coli
were cultivated at 37°C to express and at 18°C to suppress the formation of fimbriae. The presence of fimbriae was confirmed by electron microscopic studies and hemagglutination and salt aggregation tests. Fimbriated
E. coli
strains were more readily PMN associated than the nonfimbriated strains in the absence of opsonins, confirming the results of previous studies. However, the PMN chemiluminescence (CL) induced by the various strains in the absence of serum opsonins depended on the type of fimbriae they expressed. Strains with type 1 fimbriae expressing mannose-sensitive hemagglutination induced 5 to 15 times more CL than the same strains grown at 18°C, i.e., not expressing this type of fimbriae. For strains showing mannose-resistant hemagglutination, the differences between fimbriated and nonfimbriated variants of the same strains grown at 37 and 18°C, respectively, were less pronounced. Analysis of enterotoxigenic strains expressing colonization factor antigen I (CFA/I) fimbriae showed that these induced only 25 to 33% of the CL induced by the same
E. coli
strains not expressing CFA/I, whereas enterotoxigenic strains expressing CFA/II fimbriae induced 100 to 200% of the CL induced by the nonfimbriated variants. Although less CL was induced by bacteria with CFA/I fimbriae than by nonfimbriated variants, this situation was reversed when the microorganisms were opsonized. Thus, CFA/I fimbriae, while enhancing adhesion to cells, induce less activation of PMN-killing mechanisms in a serum-free environment. These findings may be relevant for the virulence in certain body sites, since CFA/I fimbriae, while facilitating adhesiveness, may protect the bacteria from PMN killing. Our findings indicate that PMN interactions with fimbriated
E. coli
in the host defense may be complex. Certain fimbriae may indeed be advantageous to the bacteria, enabling them to interact with PMNs without activating the bactericidal oxidative metabolism.
Toxoplasmosis in immunoglobulin M-suppressed mice
Authors: Frenkel J K , Taylor D W
Published: January 2020

Mice challenged with a pathogenic strain of Toxoplasma gondii develop fatal infections. However, if such mice are initially treated with sulfadiazine (SD), they develop immunity and survive with chronic infections. The role of antibody (Ab) in establishing protective immunity against acute parasitemias and in maintaining chronic infections was investigated using B-cell-deficient (immunoglobulin M-suppressed), T-cell-deficient (athymic), and normal BALB/c mice. All mice not receiving SD treatment rapidly died (mean 7.5 days) after infection, but the majority (80%) of intact mice developed immunity during SD treatment and survived for over 5 months with chronic toxoplasmosis. Athymic mice rapidly died (mean 6.0 days) after the removal of SD treatment. Although all SD-treated immunoglobulin M-suppressed mice eventually died, they lived considerably longer (18 to 83 days) in the complete absence of antitoxoplasma Ab than unprotected mice (7 to 9 days). Histopathological sections of liver, lung, brain, and other tissues showed that toxoplasma organisms gave rise to fatal lesions in all nonsurviving animals. The injection of Ab into acutely infected and athymic mice imparted no protection, but transfer of antitoxoplasma Ab (titer greater than 1:8,000) to immunoglobulin M-suppressed mice after SD treatment resulted in elimination of the parasites in 50% of the mice. Results of this study suggest that Ab may not be decisive in acute infections, but may be important in controlling long-term toxoplasmosis.
Chlamydia trachomatis
Infection of Mouse Trophoblasts
Authors: Banks Joyce , Glass Robert , Spindle Akiko I. , Schachter Julius
Published: January 2020

Chlamydia trachomatis
(strains L2 and DE) were found to infect fertilized mouse ova in vitro. Inclusions were found in the trophoblast, but not in the embryo.
Fate of vaccines of Propionibacterium acnes after phagocytosis by murine macrophages
Authors: Pringle A T , Cummins C S , Bishop B F , Viers V S
Published: January 2020

Stationary-phase (48 h) cells of Propionibacterium acnes VPI 0009, a potent stimulator of the reticuloendothelial system, persist unchanged within phagocytes for at least 24 h after ingestion. In contrast, exponential-phase (12 h) cells of the same strain (which do not induce splenomegaly) are extensively degraded within 5 h of phagocytosis. Suspensions of P. granulosum VPI 6500, which fails to induce splenomegaly in mice, also show considerable degradation after phagocytosis. Stationary-phase cells of strain VPI 0009 treated with sodium metaperiodate or with trichloroacetic acid, although without ability to induce splenomegaly, resist destruction almost as well as untreated vaccines. However, bacteria inactivated by acetic anhydride show about 50% breakdown in 24 h.
Binding of human C-reactive protein to bacteria
Authors: Mold C , Rodgers C P , Kaplan R L , Gewurz H
Published: January 2020

The binding of C-reactive protein to a variety of species of bacteria with potential clinical significance was studied to assess the potential function of C-reactive protein in nonimmune defense against infection. Purified, radioiodinated human C-reactive protein bound to all Streptococcus pneumoniae tested and to some viridans streptococci, but not to group A or group B streptococci or to any of eight different gram-negative rods and cocci.
Prediction of antigenic determinants and secondary structures of the K88 and CFA1 fimbrial proteins from enteropathogenic Escherichia coli
Authors: Klemm P , Mikkelsen L
Published: January 2020

Recently the amino acid sequences of the K88ab and the CFA1 fimbrial proteins from enteropathogenic Escherichia coli have become available. To elucidate the immunological interrelationships among the K88 family of antigenic variants, and to estimate the nature and position of the antigenic determinants in the K88 and CFA1 proteins, the positions of these features in the amino acid sequences have been predicted. This has been done by computerized algorithms, incorporating such factors as hydrophilicity and secondary structural potential. Some of the predicted determinants of K88 show good correlation with the known sequence differences between the antigenic variants of this protein. The presented results point to a possible use of synthetic vaccines against fimbriated pathogenic E. coli strains.