bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathogenesis of K virus infection in newborn mice
Authors: Greenlee J E
Published: January 2020

Newborn mice were inoculated with a murine papovavirus, K virus, by intracranial, intraperitoneal, oral, and intranasal routes, and the pathogenesis of infection was studied with immunofluorescence, virus assay, and histopathology. Inoculation by each route produced a fatal interstitial pneumonia. Pulmonary vascular endothelium and, to a lesser extent, cells lining hepatic sinusoids were the major sites of viral replication, but intranuclear antigen or inclusions or both were also found in extrapulmonary vascular endothelia, spleens, lymph nodes, and brains. Although K virus produced a predominantly respiratory illness, the virus was less infectious by intranasal than by oral inoculation and did not replicate in respiratory epithelial tissues. The earliest site of K virus replication was the jejunal submucosa, suggesting that in nature K virus may be transmitted by the oral route. Viral antigen was present in brains of animals inoculated by each route and correlated with the duration of viremia. Despite the presence of abundant viral antigen, however, the nervous system remained morphologically normal. The present study indicates that a member of the papovavirus group may produce clinically silent, noninflammatory involvement of the central nervous system during the initial infection of its natural host.
Experimental chlamydial salpingitis in immunosuppressed guinea pigs infected in the genital tract with the agent of guinea pig inclusion conjunctivitis
Authors: White H J , Rank R G , Soloff B L , Barron A L
Published: January 2020

At necropsy indication of spread of infection to fallopian tubes was found in 25 of 41 (60%) female guinea pigs infected in the genital tract with the chlamydial agent of guinea pig inclusion conjunctivitis and immunosuppressed with cyclophosphamide. Eighteen were examined histologically, and the diagnosis of acute salpingitis was confirmed in 10, based on inflammatory reaction, detection of guinea pig inclusion conjunctivitis in tissue, and formation of cysts (pyosalpinx and hydrosalpinx). Infection of fallopian tube tissue was confirmed by indirect immunofluorescence and electron microscopy. Infection of endometrial tissue and peritoneum was also recognized. Data suggested that the immunosuppression mediated by cyclophosphamide resulted in a prolonged genital tract infection and concomitant ascending infection leading to salpingitis.
Appearance of immunoglobulin G Fc receptor in cultured human cells infected with varicella-zoster virus
Authors: Ogata M , Shigeta S
Published: January 2020

After infection with varicella-zoster virus, HeLa and human embryo lung cells developed a receptor for the Fc portion of human and rabbit immunoglobulin G. The receptor was detected by both hemadsorption and immunofluorescence, using antibody-coated erythrocytes and heat-aggregated immunoglobulin G. However, sheep erythrocytes sensitized with F(ab')2 of anti-sheep erythrocyte antibody did not adsorb to the receptor. When cell-free varicella-zoster virus was inoculated into the HeLa cell monolayer, the Fc receptor appeared at first 6 h after infection; varicella-zoster virus antigen in the cytoplasm and detectable cytopathic effects appeared later.
Phosphoenolpyruvate-dependent sucrose phosphotransferase activity in five serotypes of Streptococcus mutans
Authors: Slee A M , Tanzer J M
Published: January 2020

An inducible phosphoenolpyruvate-dependent sucrose phosphotransferase system has been demonstrated in decryptified cell suspensions of the various common serotypes of the cariogenic microorganism Streptococcus mutans.
Respiratory syncytial virus infection in owl monkeys: viral shedding, immunological response, and associated illness caused by wild-type virus and two temperature-sensitive mutants
Authors: Prince G A , Suffin S C , Prevar D A , Camargo E , Sly D L , London W T , Chanock R M
Published: January 2020

Intranasal inoculation of owl monkeys with wild-type respiratory syncytial virus induced upper respiratory tract disease in each of seven animals. The response of owl monkeys to two highly defective, temperature-sensitive, multiple-lesion mutants was then compared to the pattern seen with wild-type respiratory syncytial virus. These mutants, ts-1 NG-1 and ts-1 NG-16, were derived from the ts-1 mutant that had been remutagenized with nitrosoguanidine (NG). Previously the ts-1 NG-1 and ts-1 NG-16 mutants had been shown to be more temperature sensitive and more stable genetically than their ts-1 parent. Both ts-1 NG-1 and ts-1 NG-16 produced infection that was delayed in onsent compared to wild-type virus infection. However, the mutants were shed from the upper respiratory tract for the same period of time and at the same titer as wild-type virus. The serum neutralizing antibody response to infection with the mutants was nearly equivalent to that elicited by wild-type virus. However, the extent of disease induced by the mutants was significantly less than that seen with wild-type virus. These observations suggest that the mutants are potential vaccine condidates and should be subjected to additional in vivo testing in primates and, ultimately, humans.
Purification and characterization of a hemolysin produced by Vibrio cholerae biotype El Tor: another toxic substance produced by cholera vibrios
Authors: Honda T , Finkelstein R A
Published: January 2020

A thermolabile direct hemolysin from an El Tor cholera vibrio strain has been isolated and partially characterized as a simple protein of ca. 20,000 molecular weight. In addition to its hemolytic activity, the hemolysin is cytotoxic, cardiotoxic, and rapidly lethal. In these respects it resembles the thermostable direct hemolysin/cytotoxin/cardiotoxin/lethal toxin of Vibrio parahaemolyticus and certain other bacterial hemolysins, although there are other significant differences. Because identical diseases are produced by both hemolytic and nonhemolytic cholera vibrios, the El Tor hemolysin may be presumed to be pathogenetically irrelevant. These observations raise the question of "When is a toxic substance also a toxin?"
Production of hydroxyl radical by human alveolar macrophages
Authors: Hoidal J R , Beall G D , Repine J E
Published: January 2020

Stimulated human alveolar macrophages were demonstrated to oxidize B-methyl proprionaldehyde (methional) or 2-keto-4-thiomethylbutyric acid to ethylene (C2H4). Agents which are believed to scavenge the hydroxyl radical (.OH), sodium benzoate, and mannitol, as well as scavengers of superoxide anion (O2-) or hydrogen peroxide, decreased C2H4 production, implicaing .OH as the oxidizing radical. Differences in C2H4 rpoduction, as well as oxygen uptake and O2- release between human alveolar macrophages and polymorphonuclear leukocytes, were also documented.
Strain-Dependent Differences in Murine Susceptibility to Coccidia
Authors: Klesius Phillip H. , Hinds Sidney E.
Published: January 2020

Differences in susceptibility of strains of mice to
Eimeria ferrisi
were observed by infecting eight strains of mice with six infectious dose levels and comparing the mortality rate among the strains for a period of 12 days. Mice of the C57BL/6 and HA/ICR strains were susceptible, and those of A/He, AKR, BALB/c, CBA, C3H/Anf, and DBA/2 strains were resistant to coccidial infection. Resistance was a dominant genetic expression, as indicated by the resistant response of F
1
hybrids of susceptible C57BL/6 and resistant CBA, C3H/Anf, or DBA/2 strains. An
E. ferrisi
infection in congenitally athymic nu/nu mice and phenotypically normal heterozygous nu/+ mice was used to determine how thymus-dependent immunoincompetence in cell-mediated immunity of the nu/nu mouse affected resistance to infection in a genetic background of the resistant BALB/c mouse. Results of primary and challenge infections in these two strains of mice suggested that resistance is thymus dependent. Furthermore, impairment of thymus-dependent cell-mediated immunity in resistant AKR mice by treatment with mouse antithymus serum led to partial susceptibility. However, susceptible C57BL/6 and HA/ICR strains are phenotypically normal mice, and previous evidence showed that C57BL/6 mice are not completely immunoincompetent in cell-mediated reactivity to coccidia. Collectively, our data show that cell-mediated immunity is necessary for resistance but may be subjected to modification by genetic expression of the host. The possible role of immune response genes in the control of coccidial immunity is discussed.
Experimental Infection of the Genital Tract of Female Grivet Monkeys by
Mycoplasma hominis
: Effects of Different Routes of Infection
Authors: Møller B. R. , Freundt E. A.
Published: January 2020

In a previous study we produced acute salpingitis and parametritis in grivet monkeys by inoculation of
Mycoplasma hominis
directly into the uterine tubes. With the purpose of examining in the same animal model the effect of more natural routes of infection, six female grivet monkeys were inoculated, two by two, with
M. hominis
by the following methods: (experiment A) into the uterine cavity through the cervical canal; (experiment B) into the uterine cavity by the same route, but after ligature of the isthmus of the uterine tubes had been performed and followed by curettage of the endometrium; and (experiment C) into the cervical epithelium. Whereas the animals in experiment A developed no or only very slight signs of infection, all monkeys in experiments B and C developed pronounced gross and microscopic inflammatory lesions of the uterine tubes and parametria, together with a significant antibody response. It is concluded that ascending
M. hominis
infection of the genital tract must be preceded by mechanical injury of the epithelial barrier, and that subsequent spread of the infection occurs via blood and lymph vessels rather than by the canalicular route. The inflammatory genital tract disease produced experimentally with
M. hominis
in grivet monkeys is very similar in its pathogenesis and pathology to the type of salpingitis caused in humans by microorganisms other than
Neisseria gonorrhoeae
and
Chlamydia trachomatis.
Relationship between host age and susceptibility to oral colonization by Actinomyces viscosus in Sprague-Dawley rats
Authors: Brecher S M , van Houte J
Published: January 2020

The colonization of Actinomyces viscosus strain Ny-1R on the molar teeth of conventional and ex-germfree rats of various ages fed either a high-sucrose diet, a high-glucose diet, or laboratory chow was studied. Conventional rats directly after weaning and up to 30 days of age are less susceptible to experimental infection by strain Ny-1R than are older rats regardless of the test diet. The relationship between host age and susceptibility to infection is also demonstrable in ex-germfree rats fed a high-sucose diet. Host factors responsible for the differences in susceptibility were investigated. The results from these studies do not implicate host antibodies, host indigenous flora, or host saliva. In other studies, it was demonstrated that within the mouths of rats, strain Ny-1R preferentially colonizes in the pits and fissures of the molar teeth rather than on the dorsum of the tongue or on the vestibular mucosa. In short-term experiments, it was found that strain Ny-1R attaches to the first molars of 40-day-old conventional rats to a greater extent than it attaches to the first molars of 20-day-old rats. The differences in attachment and subsequent colonization of strain Ny-1R in 20- and 40-day-old rats may be related to the varying amounts of the reduced enamel epithelium and connective tissue present in the fissures of the molar teeth.
Alternate complement pathway activation by group A streptococci: role of M-protein
Authors: Bisno A L
Published: January 2020

Avirulent strains of group A streptococci readily activate the complement system in normal human serum via the alternate complement pathway (ACP). Virulent M-positive group A streptococci are much less potent as activators of the ACP. The ability of M-positive streptococci to activate the ACP is enhanced by trypsinization or mild peptic digestion. The latter treatment removes the serologically active and antiphagocytic type-specific moieties of M protein, but retains the surface fuzzy layer. The phagocytosis of avirulent streptococci is markedly enhanced by preopsonization in serum chelated with Mg-ethylene glycol tetraacetic acid (classic complement pathway blocked) but not in serum devoid of heat-labile factors. These studies suggest that the function of M protein as a virulence factor may be mediated, at least in part, by its ability to retard interaction of ACP components with structures present on the streptococcal cell surface.
Antibody-induced capping of the intracellular stage of Trypanosoma cruzi
Authors: Leon W , Villalta F , Queiroz T , Szarfman A
Published: January 2020

Intracellular-stage Trypanosoma cruzi were isolated from infected mice. The effect of specific human antibodies on the membrane surface antigens was studied in vitro, using the immunofluorescent technique. The immune serum induced the aggregation of surface antigens, forming polar caps on the amastigotes.
Suppression of antibody response to Leptospira biflexa and Brucella abortus and recovery from immunosuppression after Berenil treatment
Authors: Rurangirwa F R , Tabel H , Losos G J , Tizard I R
Published: January 2020

Zebu cattle infected with either Trypanosoma congolense EATRO 1800 or Trypanosoma vivax EATRO 1721 had suppressed humoral immune responses to Leptospira biflexa injected intravenously and to attenuated Brucella abortus injected subcutaneously. T. congolense infections were more suppressive than T. vivax infections. In cattle infected with T. vivax, the suppression of immune responses to both bacterial immunogens was abrogated when the animals were treated with Berenil at the time of antigen administration. In cattle infected with T. congolense, simultaneous Berenil treatment at the time of vaccination abolished the suppression of immune response to L. biflexa, and lessened but did not abrogate the suppression of immune response to B. abortus.
Interaction of murine cytomegalovirus with separated populations of spleen cells
Authors: Loh L , Hudson J B
Published: January 2020

Mouse spleen cultures were infected with murine cytomegalovirus, either before or after separating the cells into various classes, and the growth of virus and production of infectious centers were measured in each cell class. The separation techniques, which were used in various combinations, comprised: adherence to plastic surfaces; adherence to nylon wool columns; gamma irradiation; and treatment with anti-immunoglobulin serum plus complement. The "macrophage population" took up most of the input virus, as shown by autoradiography of spleen cells infected with radioactive virus. These cells formed infectious centers but replicated the virus only transiently. In contrast, the "B-lymphocyte population" contained a minor cell fraction which was permissive for replication. The "T-lymphocyte population" appeared to be nonpermissive for replication and did not produce infectious centers.
Effects of heat-stable enterotoxin of Yersinia enterocolitica on ion transport and cyclic guanosine 3',5'-monophosphate metabolism in rabbit ileum
Authors: Rao M C , Guandalini S , Laird W J , Field M
Published: January 2020

Strains of Yersinia enterocolitica produce a heat-stable enterotoxin which is positive in the suckling mouse bioassay. Partial purification by a procedure previously worked out for heat-stable Escherichia coli enterotoxin yielded a substance which increases particulate guanylate cyclase activity and short-circuit current and inhibits active Cl-absorption in rabbit ileal mucosa. These effects of Y. enterocolitica enterotoxin are similar to those of heat-stable E. coli enterotoxin, suggesting a common mechanism of action.
Taxonomic relationship of vole agent to Rochalimaea quintana
Authors: Myers W F , Wisseman C L , Fiset P , Oaks E V , Smith J F
Published: January 2020

We investigated the recent claim that the vole agent, a rickettsia-like microorganism isolated from wild voles by Baker in 1946, is actually a strain of Rochalimaea quintana, the etiological agent of trench fever. The two organisms were compared on the basis of percent guanine-plus-cytosine content, genome size, deoxyribonucleic acid-deoxyribonucleic acid hybridization, polypeptide composition, and serological relationships. Although the two organisms do have identical or nearly identical deoxyribonucleic acid base ratios and show some serological cross-reactions, they differ substantially by all of the other criteria employed. They are clearly different, although possibly related, organisms. It remains to be determined whether they can be regarded as two species of the same genus. On the other hand, an Old World strain and a New World strain of R. quintana were indistinguishable from one another by the same criteria.
Disseminated Gonococcal Infection in Mice
Authors: Corbeil Lynette B. , Wunderlich Annette C. , Corbeil Robert R. , Mccutchan J. Allen , Ito James I. , Braude Abraham I.
Published: January 2020

Gonococci do not readily cause disseminated infection in mice. To simulate some of the conditions leading to disseminated gonococcal infection in women, we suspended gonococci in mucin plus hemoglobin and studied the development of gonococcal bacteremia. The mucin-hemoglobin mixture was used because the menstruum appears to be involved in dissemination of gonococci from the genital tract during menstruation. Mice did not die after massive inocula of 10
9
gonococci given intraperitoneally in broth, but when gonococci were suspended in mucin (15%) alone, the 50% lethal dose was 10
8.4
and in 15% mucin plus 4% hemoglobin (M/H), the 50% lethal dose fell to 10
6.6
. Sublethal doses produced local peritonitis and transient bacteremia. With larger inocula the local peritoneal infection progressed to fatal septicemia. Studies of the mechanism by which M/H lowered the 50% lethal dose showed that systemic clearance mechanisms were compromised, but not enough to account for the total decrease in the 50% lethal dose. If gonococci were given intravenously after intraperitoneal inoculation of M/H, sequestration of gonococci in the peritoneal cavity occurred, suggesting an effect on local peritoneal defenses. The effect on neutrophils appeared most significant, since numbers of neutrophils in the peritoneal fluid were decreased in the presence of M/H and neutrophils were destroyed by M/H in vitro. The serum bactericidal system was not affected. We conclude that M/H promotes gonococcal bacteremia by interference with phagocytosis and intracellular killing of gonococci. The model simulates the disseminated gonococcal infection cases in women which follow pelvic inflammatory disease in its progression from local peritonitis to transient or lethal bacteremia and in factors (mucin and hemoglobin) which enhance infection.
Simple and rapid procedure for the selective removal of lysozyme from human saliva
Authors: Germaine G R , Tellefson L M
Published: January 2020

A simple and rapid method is described for the removal of lysozyme from human whole salivary supernatant. Saliva specimens were adsorbed with Micrococcus lysodeikticus. The saliva so treated was depleted of 95% of the lysozyme activity. Changes in total protein, lactoperoxidase, lactoferrin, immunoglobulin A, and the proportions of several anionic proteins were less than 10%. It is concluded that adsorption of saliva with M. lysodeikticus is a suitable procedure for the preparation of saliva that is selectively deficient in lysozyme.
Analysis of the anticomplementary activity in sera of three African patients with parasitic and bacteriological infections
Authors: Loos M , Dierich M P
Published: January 2020

The sera of three different patients from Togo, Africa were investigated with respect to their complement profile. The three patients were suffering from parasitic (Onchocerca volvulus) and bacteriological (Treponema pertenue) diseases. The total hemolytic activity (50% hemolytic complement) was markedly depressed. The analysis of the individual complement components revealed the the titers of C1, C2, C3, and C4 were lowered up to 90%, indicating an activation of the classical pathway of complement. Addition of the patients' sera to normal human serum induced a temperature-dependent consumption of C4 and C2, whereas C3 was not affected. This activity in the patients' sera eluted from a Sephadex-G-200 column with the 19 S peak and could be identified as the activated form of the first component of the complement system. The reason for the presence of activated C1, C1 in the patients' sera resides in the absence of functionally active C1 inactivator.
Enzyme-linked immunosorbent assay for group B streptococcal antibodies
Authors: Rote N S , Taylor N L , Shigeoka A O , Scott J R , Hill H R
Published: January 2020

We report here on the development of enzyme-linked immunosorbent assays (ELISAs) for antibodies to types II and III group B streptococci. Streptococcal antigens were prepared by trichloroacetic acid extraction and fractional alcohol precipitation. Microtiter wells were coated with antigen in 0.1 M carbonate buffer at pH 9.6. Lyophilization was found to be an essential step for efficient binding of the streptococcal antigens. After incubation with antibody-containing rabbit serum, bound antibody was detected with peroxidase-labeled goat anti-rabbit immunoglobulin G. Optimal antigen concentrations were 200 micrograms/ml for type II and 100 micrograms/ml for type III. An ELISA is also described that uses intact bacteria as antigen. Hyperimmune rabbit serum reacted at a titer in excess of 512 against trichloroacetic acid-soluble antigen and 4,096 against whole bacteria. Sera from human subjects were also tested. Most human sera contained antibody which bound to intact bacteria but not to trichloroacetic acid-solubilized streptococcal antigens. Antibody titers in human sera against intact bacteria correlated very well with opsonic antibody activity measured in a chemiluminescence assay.
Effect of rifampin on the immune response in mice
Authors: Bellahsène A , Forsgren A
Published: January 2020

In an investigation of the effect of rifampin on the immune response in mice, the cellular immunity was evaluated with the split-heart allograft technique. The survival time of the heart in animals treated with rifampin at a dose of 20 mg/kg per day from the day of the transplantation until the graft was rejected was longer (33.7 days, P less than 0.001) than that of animals not treated with antibiotics (14.5 days). When rifampin was given at a dose of 5 mg/kg per day for the same period, the mean survival time of allografts was 19.5 days. The number of demonstrable plaques of hemolysis and the humoral antibodies to sheep erythrocytes were also reduced by a human therapeutic dose (20 mg/kg per day). However, the suppression of the humoral immune response was probably of more limited biological significane, suggesting a differential sensitivity to rifampin. In contrast to rifampin, benzylpenicillin had no noteworthy inhibiting effect on the cellular or humoral immune response.
Dengue-2 Vaccine: Viremia and Immune Responses in Rhesus Monkeys
Authors: Scott Robert McN. , Nisalak Ananda , Eckels Kenneth H. , Tingpalapong Markpol , Harrison Venton R. , Gould Douglas J. , Chapple Frank E. , Russell Philip K.
Published: January 2020

Studies were undertaken in Indian rhesus monkeys (
Macaca mulatta
) to determine the safety, potency, immunogenicity, and mosquito infectivity of a small-plaque, temperature-sensitive variant of dengue type 2 (DEN-2) virus, a vaccine candidate. Fifteen monkeys were inoculated subcutaneously with the vaccine virus, ten receiving 10
3.1
plaque-forming units (PFU) and five receiving 10
4.5
PFU. After primary immunization, viremia was detected in only one monkey, a recipient of the higher dose of vaccine. The recovered virus had the same growth characteristics as the vaccine strain.
Aedes aegypti
mosquitoes did not become infected when they were allowed to feed on monkeys that received the lower dose of vaccine. As expected, the immunization produced no evidence of illness in any of the animals. A dose response to vaccine was detected; all five of the high-dose recipients developed neutralizing antibodies, whereas only five of ten low-dose recipients did so. In both groups, neutralizing antibody was often transient. Its presence at 30 days did not always correlate with protection from viremia in those animals challenged 4 to 6 months after vaccination with wild-type DEN-2 virus. However, immunized animals developed anamnestic antibody responses after challenge, and none demonstrated adverse effects to infection. Reimmunization of monkeys 4 months after primary immunization led to the production of low-titered but persistent neutralizing antibody which protected the animals from a wild-type virus challenge.
Transfer factor: a murine model
Authors: Williams M E , Kauffman C A
Published: January 2020

Transfer factor has been studied extensively in humans, but a satisfactory subprimate model has not been established. Using BALB/c mice immunized with complete Freund adjuvant, we show that a low-molecular-weight substance derived from disrupted spleen cells transferred sensitivity to purified protein derivative (PPD) to recipient nonimmunized BALB/c mice. Transfer was confirmed by footpad swelling to PPD in vivo and by splenic lymphocyte transformation to PPD in vitro. In recipients of transfer factor, an inverse correlation was noted between the splenic lymphocyte response to PPD and to concanavalin A. Material obtained from spleens of saline-treated BALB/c mice did not transfer sensitivity to PPD to recipient mice.
Biological and Chemical Characterization of Endotoxin from
Capnocytophaga sputigena
Authors: Stevens R. H. , Sela M. N. , McArthur W. P. , Nowotny A. , Hammond B. F.
Published: January 2020

An endotoxin was isolated from
Capnocytophaga sputigena
strain 4 by a modification of the hot phenol-water method. The extraction procedure yielded a lipopolysaccharide which accounted for approximately 1.5% of the dry weight of the cells. The material was composed of 18.6% lipid (as C
15
fatty acid), 46.5% neutral sugar including 9.6% hexose, 18.3% 6-deoxy sugar, 1.0% 2-keto-3-deoxy sugar, and 4.8% heptose. Hexosamine, protein, and phosphorus were found in quantities amounting to 9.0, 2.9, and 2.0% of the dry weight, respectively. No pentose or nucleic acid was detected. Acid hydrolysis resulted in the release of the constituent sugars and the formation of an insoluble precipitate. The lipopolysaccharide was tested for numerous biological activities characteristic of endotoxins. The pyrogenicity was relatively low; the fever index 40 was 17 μg, and 10 μg was required to give the characteristic biphasic fever response. The toxicity of the extract was very low, with a 50% chicken embryo lethal dose of 15.6 μg and a 50% mouse embryo lethal dose of greater than 8 mg. Similarly, the
C. sputigena
endotoxin had modest effects on leukocytes when compared with endotoxin standards from other organisms. The extract exhibited little or no mitogenicity when tested on mouse spleen lymphocytes. It was not toxic to human peripheral polymorphonuclear leukocytes and caused the release of only a small (13%) portion of lysosomal enzymes. Although the
C. sputigena
lipopolysaccharide caused significant activation of mouse peritoneal macrophages, the dose required was twice that of an
Escherichia coli
endotoxic standard. However, the
Limulus
amoebocyte lysate clotting activity of the lipopolysaccharide was comparable to that of an
Serratia marcescens
lipopolysaccharide standard, and passive hemagglutination tests revealed that 1 μg of the lipopolysaccharide was capable of sensitizing 1 ml of a 2% sheep erythrocyte suspension for agglutination with an antiserum prepared against
C. sputigena
whole cells.
Transduction of staphylococcal enterotoxin B synthesis: establishment of the toxin gene in a recombination-deficient mutant
Authors: Shafer W M , Iandolo J J
Published: January 2020

Cotransduction of enterotoxin B synthesis into a recombination deficient mutant only occurred when the donor contained the pEntB plasmid. Enterotoxin B from chromosomal genotypes could not be established in such hosts. These data suggest that the entB gene is not capable of high-frequency translocation.
Immunosuppressive effect of murine cytomegalovirus
Authors: Loh L , Hudson J B
Published: January 2020

Murine cytomegalovirus suppressed the ability of spleen cells to respond to mitogens in vitro. The degree of suppression was proportional to the multiplicity of infection. This effect could not be explained by cytolysis of lymphocytes, an alteration in the kinetics of the response to mitogen, or a direct competition between virions and mitogen molecules for cell-surface receptors. Nor was it due to simple contact between cell and virus, since ultraviolet-inactivated murine cytomegalovirus failed to suppress the response to mitogens. Reconstitution experiments were performed which involved mixing various combinations of infected and uninfected macrophages and lymphocytes. Under these conditions, it was found that the infected macrophages and lymphocytes. Under these conditions, it was found that the infected macrophages had an impaired capacity to mediate the response ot T lymphocytes to concanavalin A. This suggests that murine cytomegalovirus may cause immunosuppression indirectly by interfering with macrophage function.
Etiology of the liver granulomatous response in Schistosoma mansoni-infected athymic nude mice
Authors: Amsden A F , Boros D L , Hood A T
Published: January 2020

The effect of schistosome infection on the presence and maturation of splenic T lymphocytes in C3H/HeN nu/nu and nu/+ mice was examined. Spleens of uninfected nu/nu mice contained very low numbers (u to 2%) of T lymphocytes. This percentage did not increase throughout the 10 weeks of the infection. Spleens of uninfected nu/+ littermates contained 28.8% T cells, which decreased to 15.0% by week 10 of the infection. Similarly, whereas spleen cells of normal or infected nu/nu mice were nonresponsive to concanavalin A, the initial high response of nu/+ mice gradually diminished. Both nu/nu and nu/+ spleen cells responded well to lipopolysaccharide initially, but by 10 weeks their responsiveness declined. Sera of five infected nu/nu mice contained no antibodies to egg antigens, and one had a low titer (log2 5.0). In contrast, the mean titer of sera from six nu/+ mice was log2 10.7 Nu/+ mice had typical florid lesions, but nu/nu mice mounted sparse granulomatous reactions around eggs in the liver without evidence for hepatocellular damage. Dispersed liver granulomas of nu/nu mice contained 1.2% T and 20.3% B lymphocytes. Lesions of nu/+ mice contained 12.9% T and 18.4% B cells. Eighty percent of the macrophages from nu/nu and nu/+ granulomas displayed high density/avidity Fc receptors. Production of migration inhibition factor-active lymphokine by liver granulomas and spleens of schistosome-infected nu/nu mice is suggestive of the immune role of B cells in the granulomatous inflammation.
Influence of Route of Administration on Immediate and Extended Protection in Rats Immunized with
Escherichia coli
Heat-Labile Enterotoxin
Authors: Klipstein Frederick A. , Engert Richard F.
Published: January 2020

The effect of route of administration, dosage, and number of boosts employed during immunization with the polymyxin-release form of
Escherichia coli
heat-labile (LT) enterotoxin on the degree and duration of protection afforded was evaluated in rats which were challenged by the ligated loop technique. Increasing the boosting dosage by fivefold from 50 to 250 μg resulted in a marked increase in protection against challenge with toxin in rats immunized either just by the parenteral route (i.p./i.p.) or by a parenteral prime, followed by peroral boosts (i.p./p.o.) in rats pretreated with cimetidine to ablate gastric secretions; such was not the case, however, even with a 50-fold increase in dosage in rats immunized just by the peroral route (p.o./p.o.). Four weekly peroral boosts were required to achieve the strongest degree of protection. Increasing the boosting dosage also increased the degree of protection against challenge with viable LT
+
/ST
−
and LT
+
/ST
+
strains (ST indicates heat-stable enterotoxin) in rats immunized by the i.p./p.o., but not by the i.p./i.p., route; no protection was evident against an LT
−
/ST
+
strain. Protection was lost within 3 weeks after immunization in rats immunized by the i.p./i.p. route. In contrast, protection was extended over the 3-month observation period in those immunized by the i.p./p.o. route; the degree of protection was enhanced in rats which received an additional boost at 2 months. These observations establish the fact that immunization with LT is similar to that with cholera toxin in that arousal of the local immune intestinal response by means of peroral immunization provides maximal extended protection.
Binding of cholesterol by sulfhydryl-activated cytolysins
Authors: Johnson M K , Geoffroy C , Alouf J E
Published: January 2020

The binding of cholesterol by pneumolysin, alveolysin, and streptolysin O has been demonstrated. The properties of the cytolysin-cholesterol interaction parallel those of cytolysin-erythrocyte interaction in that the reaction is rapid, temperature independent, decreased at elevated pH, and shows the same specificity with respect to other related sterols. However, oxidized or p-hydroxymercuribenzoate-treated thoxin showed no decrease in cholesterol-binding activity, whereas the ability of cytolysin to bind to erythrocytes was modified by such treatment.
Immunological Characterization of Two Major Proteins Isolated from the Outer Membrane of
Proteus mirabilis
Authors: Bub Felizitas , Bieker Petra , Martin Hans H. , Nixdorff Kathryn
Published: January 2020

Two proteins with apparent molecular weights of 39,000 and 36,000 (
M
r
39,000 and
M
r
36,000, respectively) were isolated from the outer membrane of
Proteus mirabilis
19.
M
r
36,000 was shown to be free of detectable amounts of the
M
r
39,000 protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and free of lipopolysaccharide according to gas chromatographic analyses of 3-hydroxymyristic acid content. The
M
r
39,000 protein contained no detectable amount of lipopolysaccharide and only a trace of
M
r
36,000. Both isolated proteins gave strong reactions in antisera produced to purified
P. mirabilis
19 cell walls (outer membrane proteins in the native state). This suggested that the proteins isolated by our methods essentially retained their native configuration upon resolubilization. Antisera produced in rabbits to the isolated proteins showed strongest reactions with the homologous antigen, but some cross-reactions with the heterologous protein and with
P. mirabilis
19 lipopolysaccharide were observed. These cross-reactions could be attributed to specific responses to traces of the heterologous (contaminant) proteins present in the purified proteins used as immunizing antigens. The
M
r
39,000 and
M
r
36,000 proteins have no major antigenic determinants in common. Reactions with
P. mirabilis
19 lipopolysaccharide in antisera to the outer membrane proteins could be completely removed by absorption of the antisera with the
M
r
36,000 protein.
Iron acquisition by Neisseria meningitidis in vitro
Authors: Archibald F S , DeVoe I W
Published: January 2020

Assays employing iron-limited solid and liquid, defined and complex media were devised to test the iron requirements of Neisseria meningitidis. A variety of tests yielded no evidence for the secretion of a soluble iron-binding substance (siderophore) by the meningococci. The meningococci were unable to use iron bound to some common hydroxamate- and catechol-type siderophores or even compete with them for iron in the growth medium. A total of 20 strains of meningococci, differing widely in their virulence for mice, were similar in ability to acquire iron from a variety of iron-containing substances; the iron in such compounds as hog gastric mucin, citrate, hemoglobin, and myoglobin was easily acquired, whereas the iron in compounds such as ferrioxamine B, ferrichrome,ferritin, Imferon, cytochrome c, FePO4, and [Fe(OH)3]n was not readily available. No correlation was noted between the ability of particular strains to obtain iron from compounds and virulence in mice. Iron complexed or chelated with a number of metabolic organic acids, polyphosphates, and several synthetic polycarboxylic acids was readily available to all strains, even though some of the compounds used had high effective binding constants for iron and all were in 3- or 10-fold molar excess over the iron present. The addition of some of these iron-complexing substances (e.g., citrate and pyrophosphate) in iron-free form made many biologically important iron compounds that are normally inaccessible to the meningococci readily available.
Isolation, characterization, and biological properties of a tuberculin-active peptidoglycan isolated from the culture filtrate of Mycobacterium tuberculosis
Authors: Gupta K C , Landi S
Published: January 2020

A water-soluble tuberculin-active peptidoglycan (TAPG) with a molecular weight of ca. 28,000 to 30,000 was isolated from the culture filtrate of Mycobacterium tuberculosis. TAPG was approximately four to five times more potent than tuberculin purified protein derivative S in guinea pigs sensitized with M. tuberculosis or M. bovis (freeze-dried BCG). It showed little or no cross-reactivity at a dose of 0.1 to 0.4 microgram in guinea pigs sensitized with M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium. TAPG did not show any adjuvant activity when injected in guinea pigs in a water-in-oil emulsion containing ovalbumin. TAPG, in Freund incomplete adjuvant, proved to be an effective immunogen for inducing delayed hypersensitivity in guinea pigs. Chemical analysis of TAPG showed that it contains proline, glutamic acid, alanine, diaminopimelic acid, tyrosine, threonine, glucosamine, and the reducing sugars, arabinose and galactose. In immunoelectrophoretic studies with reference M. tuberculosis H37Rv antiserum, TAPG did not show any precipitin bands.
Cecal toxin(s) from guinea pigs with clindamycin-associated colitis, neutralized by Clostridium sordellii antitoxin
Authors: Rehg J E
Published: January 2020

The cecal contents of guinea pigs with clindamycin-associated colitis contained a heat-labile toxin. This toxin was lethal for guinea pigs and mice, produced vascular permeability in the skin of rabbits, and was cytotoxic in tissue culture. The lethality in mice, vascular permeability in rabbit skin, and cytotoxicity in tissue culture monolayers were neutralized by Clostridium sordellii antitoxin.
Serology and Energetics of Cross-Reactions Among the H3 Antigens of Influenza Viruses
Authors: Underwood P. Anne
Published: January 2020

Reciprocal hemagglutination inhibition titrations were carried out with viruses and antisera of eight field strains of the A3 subtype of influenza A, covering the period from 1968 to 1975. The earlier strains (1968 through 1972) showed asymmetric cross-reactions, with antisera exhibiting more cross-reactions with antecedent strains than with subsequent ones. The later strains, although all were asymmetrically cross-reactive with earlier strains, tended to exhibit distant and variable cross-reactions with each other. The numbers and average affinities of antibody molecules capable of taking part in cross-reactions were calculated from equilibrium filtration experiments. It was found that all the antibody molecules in sera raised against the late strains could combine with earlier viruses, but with reduced affinity. Conversely, only a subset of the antibody molecules in sera raised against early strains could combine with later viruses. The results are discussed in the light of different theories concerning the nature and number of antigenic determinants on the hemagglutinin molecule. They support the existence of a single antigenic area to which all antibody molecules are directed, with differing affinities, rather than the existence of both “common” and “specific” determinants. Thermodynamic measurements on the homologous antigen-antibody reactions indicated that combination was mostly entropy driven. This suggested hydrophobic interaction as the mechanism of combination, i.e., that the complementary regions of antigen and antibody were made up largely or entirely of amino acids with hydrophobic side chains. There was no statistical difference in the magnitude of the entropy term (i.e., the average firmness of binding) among the different virus strains.
Isolation of specific and common antibodies to staphylococcal enterotoxins B, C1, and C2
Authors: Lee A C , Robbins R N , Reiser R F , Bergdoll M S
Published: January 2020

Staphylococcal enterotoxins C1 and C2 elicit the production of antibodies in rabbits that give precipitin reactions with both toxins and gel diffusion plates. These enterotoxins also elicit the production of antibodies that are specific for each of the enterotoxins. Enterotoxin B elicits the production of antibodies in some rabbits that react with enterotoxins B, C1, and C2 in gel diffusion plates and in radioimmunoassay. Antibodies specific for enterotoxin B are produced also. Enterotoxin C1 elicits the production of antibodies that cross-react weakly with enterotoxin B, indicating that the antigenic sites involved in the cross-reactions are not identical in the two toxins. The antibodies have been isolated by affinity chromatography.
Properties of selected rickettsiae of the spotted fever group
Authors: Anacker R L , McCaul T F , Burgdorfer W , Gerloff R K
Published: January 2020

Eight strains of spotted fever group rickettsiae were studied to gain insight into the extent of variation of their properties. Two standard strains of Rickettsia rickettsii and one strain of Rickettsia conorii were included among the eight for comparison. The molar percentage of guanine plus cytosine for each strain did not differ significantly from that for R. rickettsii, 32.6 +/- 0.7%. Two strains caused extended fever in guinea pigs, one strain caused fever of short duration, and the other strains induced little or no fever. Polyacrylamide gel electrophoresis of the detergent-solubilized rickettsial proteins indicated that the protein content of all strains, except the two strains of R. rickettsii, were different, particularly in the molecular weight range of 40,000 to 60,000. Virulent strains produced large clear plaques in Vero cells monolayers; the strains of low virulence generally produced smaller or more turbid, or both, plaques. On the basis of agglutination reactions with rabbit antisera, the eight strains were placed into five serotypes. These results indicate considerable heterogeneity in properties of spotted fever group rickettsiae in the United States.
In Vitro Stimulation of Human Peripheral Blood Lymphocytes by Soluble and Membrane Fractions of Renografin-Purified Typhus Group Rickettsiae
Authors: Bourgeois A. Louis , Dasch Gregory A. , Strong Douglas M.
Published: January 2020

Cell-free extracts of disrupted Renografin-purified
Rickettsia typhi
and
R. prowazekii
were evaluated as antigens in lymphocyte transformation assays for cell-mediated immunity to typhus group rickettsiae in 19 individuals with and 9 without histories of exposure to these organisms. Exposure consisted of clinical disease, vaccination with epidemic typhus vaccine, or occupational exposure to these agents. Both the soluble and membrane fractions of disrupted purified rickettsiae were used, and transformation of peripheral blood lymphocytes (PBL) was determined in microcultures by incorporation of [
3
]thymidine. Of the antigen concentrations tested (1 to 400 μg/ml), 10μg/ml appeared to be the most satisfactory. At this concentration, PBL transformation was highly reproducible and correlated well with donor exposure and the presence of enzyme-linked immunosorbent assay anti-typhus group immunoglobulin G. At higher concentrations, PBL from both exposed and control donors often responded to a lipopolysaccharide-like component present in these preparations. Specific transformation responses to rickettsial fractions were detected in several individuals decades after infection or vaccination, indicating that both fractions contained antigens associated with persisting cell-mediated immunity in humans. Generally, stimulation indexes with the soluble fraction were slightly greater than those obtained with corresponding concentrations of the membrane preparation, and in three individuals transformation was observed only with the soluble fraction. PBL transformation to soluble fractions also appeared to have some species specificity, since PBL from individuals with documented
R. typhi
infections were more responsive to the homologous soluble preparation than to the soluble fraction of
R. prowazekii
. PBL transformation also correlated well with homologous but only poorly with heterologous enzyme-linked immunosorbent assay immunoglobulin G titers.
Microtiter enzyme-linked immunosorbent assay for immunoglobulin G cholera antitoxin in humans: method and correlation with rabbit skin vascular permeability factor technique
Authors: Young C R , Levine M M , Craig J P , Robins-Browne R
Published: January 2020

A microtiter enzyme-linked immunosorbent assay (ELISA) to measure immunoglobulin G cholera antitoxin in human serum has been developed. The ELISA employs commercially available reagents, including cholera enterotoxin and goat anti-human immunoglobulin G. It is specific, sensitive, and reproducible and requires as little as 5 microliter of serum. ELISA, moreover, permits quantitative determination of cholera antitoxin at a single serum dilution of 1:200. A total of 162 pre- and post-challenge sera from 49 volunteers who ingested Vibrio cholerae classical biotype, and 165 sera from 43 volunteers who ingested V. cholerae El Tor biotype, were tested for cholera antitoxin by ELISA and by the rabbit skin vascular permeability factor assay. The correlation between the two assays was statistically significant (P less than 0.001). ELISA for immunoglobulin G cholera antitoxin thus provides a valuable in vitro correlate of in vivo toxin-neutralizing capacity. Microtiter ELISA permits duplicate evaluation of at least 14 sera per 96-well plate including blanks and controls, is readily adapted to use in field studies, and therefore is particularly well suited to seroepidemiological surveys.
Microtiter Enzyme-Linked Immunosorbent Assay for Immunoglobulin G Cholera Antitoxin in Humans: Sensitivity and Specificity
Authors: Robins-Browne Roy M. , Young Charles R. , Levine Myron M. , Craig John P.
Published: January 2020

Serum samples were obtained from 92 informed, community volunteers before and 10, 21, and 28 days after they ingested 10
3
to 10
6
Vibrio cholerae
of Inaba or Ogawa serotype and classical or El Tor biotype as part of a cholera vaccine development program. Pre- and postchallenge sera were examined for neutralizing antibody to cholera toxin by the rabbit skin permeability factor and adrenal cell techniques. Immunoglobulin G-binding antibodies to cholera toxin were quantitated by enzyme-linked immunosorbent assay (ELISA) in serum diluted 1:200. The results obtained in these cholera volunteers were compared with a negative control population comprising 30 people who ingested enteropathogenic
Escherichia coli
or
E. coli
which produced heat-stable but not heat-labile enterotoxin. Although all three antitoxin assays correlated closely with each other in both groups of volunteers, ELISA was more sensitive than either neutralization assay in detecting both subclinical and overt cholera infections. Seroconversion was demonstrated by ELISA in 58 of 66 (88%) volunteers who excreted
V. cholerae
, including 50 of 54 (93%) with clinical cholera, compared with 47 of 66 (71%) and 52 of 66 (79%) by the rabbit skin permeability factor and adrenal cell techniques, respectively. Although ELISA does not measure the toxin-neutralizing activity of antibodies directly, it provides a practical alternative to the rabbit skin permeability factor and adrenal cell assays.