bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Yersinia pestis infection in rodents after intragastric inoculation and ingestion of bacteria
Authors: Butler T , Fu Y S , Furman L , Almeida C , Almeida A
Published: January 2020

To clarify the pathogenesis of oral plague infection, we studied the susceptibility of three species of rodents to intragastric inoculation of Yersinia pestis, described the pathology and progression of infection, and measured antibody responses to fraction IA antigen of Y. pestis. The 50% lethal doses of bacteria by intragastric inoculation for Mus musculus, Zygodontomys pixuna, and Rattus rattus were log10 = 6.32, 5.46, and 9.62, respectively, which were at least 1,000-fold higher than the values obtained by subcutaneous inoculation. M. musculus was shown to be susceptible to lethal infection also when bacteria were ingested in drinking water. Microscopic pathology was consistent with heavy systemic infection. Quantitative cultures of tissues at different times after intragastric inoculation revealed that infections of blood, liver, and spleen preceded infections of Peyer's patches and mesenteric lymph nodes. Stool cultures were negative. The strain of Y. pestis used for inoculation was killed when exposed to a buffered solution at pH less than or equal to 3. Antibody responses were observed in some of the surviving rodents after intragastric challenge. These results showed that Y. pestis was an effective oral pathogen that produced fatal systemic infections and self-limited infections with immunity but did not produce enteric pathology or lead to fecal excretion of bacteria.
Rescue and serotypic characterization of noncultivable human rotavirus by gene reassortment
Authors: Greenberg H B , Wyatt R G , Kapikian A Z , Kalica A R , Flores J , Jones R
Published: January 2020

Thirty-three of 50 noncultivable human rotavirus strains from a variety of locations were successfully rescued by gene reassortment. The serotype of each of the 33 strains was investigated by a qualitative cytopathic effect neutralization assay. Nineteen strains resembled the previously characterized human rotavirus serotype Wa, whereas three strains were serologically related to the DS-1 strain. Eleven strains appeared to be serotypically distinct from the Wa and DS-1 strains and thus apparently represent one or more new human rotavirus serotypes.
Definition of human rotavirus serotypes by plaque reduction assay
Authors: Wyatt R G , Greenberg H B , James W D , Pittman A L , Kalica A R , Flores J , Chanock R M , Kapikian A Z
Published: January 2020

Twenty different human rotavirus reassortants were characterized serologically by a plaque reduction assay as belonging to one of three distinct serotypes. Fourteen were similar if not identical to our prototype Wa strain; two were like the prototype DS-1 strain, and four belonged to a third serotype for which a prototype has not yet been selected. Hyperimmune sera raised against the three serotypes were required to distinguish among them, since postinfection sera had lower titers and were more cross-reactive than hyperimmune sera. These results confirmed the ability of a qualitative cytopathic neutralization test to predict correctly the Wa or DS-1 serotype. A strain of rhesus rotavirus (MMU 18006) was identified as belonging to the newly defined third serotype. Finally, an attempt was made to correlate previously published serotype analysis by neutralization of fluorescent cell-forming units with the results determined by the plaque reduction neutralization assay.
Natural history of aortic valve endocarditis in rats
Authors: Héraïef E , Glauser M P , Freedman L R
Published: January 2020

Sterile aortic vegetations were produced in rats by introducing a polyethylene catheter through the right carotid artery. The catheter was either left in place throughout the experiments or removed before bacterial challenge. Bacterial endocarditis was uniformly produced by intravenous injection of 10(7) colony-forming units of Staphylococcus aureus or Streptococcus intermedius, whether the catheter was left in place or removed. However, in rats with the catheter left in place, bacterial multiplication within the vegetations with both strains was accelerated, and mortality from Staphylococcus aureus infection was increased. Using 10(7) colony-forming units of serum-resistant Escherichia coli as a test microorganism, we found a marked difference in the production of endocarditis depending upon whether the catheter was left in place or removed before injection; only those animals infected with the catheter in place developed infection. From these experiments in rats, it was evident that the presence of a foreign body has a considerable influence on the ability of bacteria to grow within an intravascular vegetation. In addition, a striking difference in the virulence of the three strains studied was established; Staphylococcus aureus was the most, and E. coli the least, pathogenic.
Production and partial characterization of monoclonal antibodies to Mycobacterium leprae
Authors: Gillis T P , Buchanan T M
Published: January 2020

Monoclonal antibodies to Mycobacterium leprae were produced by the fusion of BALB/c splenocytes and lymph node cells to BALB/c myeloma (NSI/1) cells. Eleven monoclonal antibodies were characterized as to their reactivity with M. leprae and 18 other mycobacterial species by enzyme-linked immunosorbent assay and immunofluorescence. Two monoclonal antibodies reacted only with M. leprae, and the other nine showed unique patterns of reactivity by enzyme-linked immunosorbent assay. One monoclonal antibody (IIH9) reacted with a 68,000-dalton protein present in extracts from M. leprae, M. tuberculosis H37Rv, M. gastri, and M. smegmatis. Potential uses for these antibodies in serological tests and immunochemical analyses are discussed.
Immunological cross-reactivity in the absence of DNA homology between Pseudomonas toxin A and diphtheria toxin
Authors: Sadoff J C , Buck G A , Iglewski B H , Bjorn M J , Groman N B
Published: January 2020

The immunodominant determinant of Pseudomonas toxin A was shown to cross-react with a normally inaccessible determinant in fragment A of diphtheria toxin. Trypsin-treated diphtheria toxin and fragment A of diphtheria toxin inhibited binding of toxin A antibody to whole toxin A, whereas whole diphtheria toxin did not inhibit this reaction. However, even at the lowest stringency no hybridization was detected between diphtheria tox probe and Pseudomonas aeruginosa DNA.
Age-dependent susceptibility of neonatal rats to group B streptococcal type III infection: correlation of severity of infection and response of myeloid pools
Authors: Zeligs B J , Armstrong C D , Walser J B , Bellanti J A
Published: January 2020

A distinct age-dependent susceptibility to group B streptococcus type III (GBS) was demonstrated, utilizing a neonatal rat model. The most dramatic changes in susceptibility occurred within the first 7 days of postnatal life. To further investigate this susceptibility, experiments were performed utilizing two age groups of rats: (i) animals within the first 24 h of life (NB) and (ii) 7-day-old animals (7d). The infective dosage used was 10(4) GBS per g of body weight, a dose lethal to 100% of NB but only to 15% of 7d. The responses of the myeloid cells in the peripheral blood, spleen, and bone marrow were evaluated at intervals during the first 24 h post-GBS infection. The susceptibility of the NB to GBS appeared to be associated with a number of events, including smaller base-line levels of myeloid elements particularly in the bone marrow, a lag of at least 2 h in their initial response to infection, and an inability to maintain the myeloid pools. The band form of neutrophils appeared to be the predominant cell type in both total number and rapidity of response to infection. Moreover, an initial depletion of this band form was seen in both groups, which returned to base-line levels with recovery in 7d but persisted until death in NB animals. Similarly, shifts in numbers of peripheral nucleated erythrocytes appeared to reflect changes in the myeloid storage pools, with numbers of nucleated erythrocytes significantly decreasing in 7d animals with recovery in contrast to persistence in NB until death. Therefore, shifts in these cells in peripheral blood during infection appear to reflect the state of myeloid storage pools which parallel disease outcome.
Protection against group B Neisseria meningitidis disease: preparation of soluble protein and protein-polysaccharide immunogens
Authors: Frasch C E , Peppler M S
Published: January 2020

Although effective polysaccharide vaccines have been developed for meningococcal groups A, C, Y, and W135, the purified group B polysaccharide has proven to be nonimmunogenic. Earlier studies indicated that serotype 2 outer membrane protein vaccines induced bactericidal antibodies in animals and protected them from meningococcal challenge. However, a similar vaccine induced only low levels of antiprotein antibodies in both adults and children (C.E. Frasch et al., in J.B. Robbins et al., ed., Seminars in Infectious Disease vol. 4, p. 263-267, 1982). Methods were therefore developed to produce more immunogenic serotype 2 protein vaccines. We found that, by growing the organism for 65 to 72 h at 32 degrees C, three to four times more outer membrane protein was released into the culture medium than could be extracted from overnight-grown cells. The outer membranes were therefore purified directly from the broth by ultrafiltration followed by ammonium sulfate precipitation. Most of the lipopolysaccharide was selectively removed from the membranes by treatment with the nonionic detergent Brij-96. The Brij-96 was then removed and the resulting vaccine was filter sterilized. Some vaccines were prepared by combining equal parts of detergent-treated membrane protein and high-molecular-weight group B polysaccharide producing highly soluble vaccines. These new vaccines were compared by using an enzyme-linked immunosorbent inhibition assay to an insoluble vaccine (E-06) found to be poorly immunogenic in humans. A human serum with serotype 2 specificity was used in the inhibition assay, and 5 microgram of E-06 was required for 50% inhibition, whereas less than 1 microgram of the soluble vaccines was required. Addition of group B polysaccharide slightly increased the inhibitory capacity of the protein component.
Stage-specific, strain-specific, and cross-reactive antigens of Leishmania species identified by monoclonal antibodies
Authors: Handman E , Hocking R E
Published: January 2020

The fusion of NS-1 myeloma cells with spleen cells from mice chronically infected with Leishmania tropica resulted in nine clones of hybridomas producing monospecific antibodies to membrane antigens of L. tropica. One of the antibodies (L-5-85) bound specifically to the promastigote form of the parasite, and the remaining eight recognized antigens shared by the promastigote and amastigote of L. tropica. Four of the antibodies (L-5-16, L-5-34, L-5-44, and L-2-3F11) detected parasite antigens on the surface of L. tropica-infected macrophages. Common antigens shared by L. tropica, L. mexicana, and L. donovani were identified as well as one antigen apparent on most Leishmania spp. and present also in Crithidia fasciculata. Two monoclonal antibodies (L-5-27 and L-5-41) were found to bind only to strains of L. tropica from simple cutaneous leishmaniasis. A special property shared by these two antibodies was the inhibition of parasite growth in macrophages in vitro.
Lobar pneumonia in rats produced by clinical isolates of Klebsiella pneumoniae
Authors: Domenico P , Johanson W G , Straus D C
Published: January 2020

Transtracheal instillation of clinical isolate Klebsiella pneumoniae serotype 1 (KP1) into the lungs of rats resulted in the production of a characteristic, chronic lobar pneumonia. To further examine this phenomenon, two variants of this organism were employed in this experimental model. These variants differed markedly in capsule size, colony morphology, and in virulence, as determined by mouse lethality tests. The ability of these strains to establish a lobar pneumonia in rats correlated with the virulence of the respective organisms as monitored by intraperitoneal injection in mice. The 50% lethal doses in mice were 4.9 x 10(1) colony-forming units (CFU) for the more virulent KP1 strain (KP1-O) and 1.42 x 10(5) CFU for the less virulent variant (KP1-T). In the rat lung model, marked lung pathology was evident by day 6 with a KP1-O inoculum of 5 x 10(2) CFU, whereas KP1-T caused little or no lung pathology when delivered transtracheally at a concentration of 7 x 10(6) CFU. Two relatively nonvirulent variants of K. pneumoniae serotype 2 were also used in this rat lung model and were found not to produce a lobar pneumonia even when delivered in large doses. These results indicate that a chronic lobar pneumonia can be established in a rat model if the appropriate organism is employed and the virulence of K. pneumoniae injected intraperitoneally into mice is an excellent indicator of an organism's potential to cause lobar pneumonia in rats.
Gram-positive bacteria-induced granulocytopenia and pulmonary leukostasis in rabbits
Authors: Goldblum S E , Reed W P
Published: January 2020

Pneumococci have been shown to induce granulocytopenia and pulmonary leukostasis which might contribute to morbidity and mortality in pneumococcal sepsis. We studied whether other gram-positive species (groups A and B streptococci, Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens) could also induce these phenomena. Rabbits were challenged with nonviable preparations of each species, and all five species induced profound granulocytopenia (mean decrease of 90%) and pulmonary leukostasis. In vitro studies of serum incubated with these species of bacteria showed a mean consumption of total hemolytic complement of 90%, a mean increase of chemotactic activity for granulocytes of 204%, and a mean augmentation of granulocyte adherence of 45% (compared with 18% for the control). Infusion of sonicate-exposed sera induced granulocytopenia in recipient rabbits. Thus, several nonviable gram-positive species can interact with serum to activate the complement system, generate C5a bioactivity, augment granulocyte adherence, and generate a neutropenia-inducing factor. These alterations may contribute to granulocytopenia or pulmonary leukostasis, which may play a role in the morbidity and mortality associated with gram-positive bacterial infections.
Intestinal immunoglobulin A responses in rabbits to a Salmonella typhi strain harboring a Shigella sonnei plasmid
Authors: Keren D F , Collins H H , Baron L S , Kopecko D J , Formal S B
Published: January 2020

Salmonella typhi 5076-IC, which contains a plasmid that encodes the form I antigen of Shigella sonnei and which expresses S. typhi 9 and 12 and S. sonnei form I antigens, was used to immunize rabbits via chronically isolated ileal loops. Intestinal immunoglobulin A activity was detected against S. typhi, S. sonnei form I, and S. typhi strain 5076-IC. Thus S. typhi 5076-IC can effectively elicit mucosal immunoglobulin A to both S. typhi and S. sonnei.
Delayed hypersensitivity to murine cytomegalovirus and its depression during pregnancy
Authors: Chong K T , Mims C A
Published: January 2020

A delayed hypersensitivity skin test for murine cytomegalovirus is described, in which ear swelling is measured after injection of heat-killed virus. The response appeared within 4 days of infection, peaked at 8 days, and remained at high levels for at least 100 days. When live virus was inoculated into the ear of previously uninfected mice, a much greater degree of ear swelling was seen, maximal at 7 days, but without growth of virus in the inoculated ear. Mice infected with avirulent (cell culture-passaged) virus gave greater delayed hypersensitivity responses than with those infected with virulent (salivary gland-passaged) virus. One of the strains of mice that is susceptible to murine cytomegalovirus (C57BL) developed greater delayed hypersensitivity responses than did the resistant strain (C3H). The delayed hypersensitivity response of neonatally infected mice was greatly depressed during pregnancy and lactation.
Activation of macrophages by products of lymphocytes from normal and syphilitic rabbits
Authors: Lukehart S A
Published: January 2020

The production of soluble macrophage-activating factors by lymphocytes from syphilitic and normal rabbits was examined. Culture supernatants of splenic lymphocytes cultured with Treponema pallidum antigens or concanavalin A were incubated with rabbit peritoneal macrophages in vitro. The macrophage monolayers were then washed and infected with log-phase Listeria monocytogenes. Activation of the macrophages by lymphocyte products was measured by the ability of the macrophages to resist intracellular multiplication of Listeria and thus survive infection. Macrophages incubated with supernatants of unstimulated lymphocytes or T. pallidum-stimulated lymphocytes from normal rabbits were unable to resist intracellular multiplication of Listeria. Specifically stimulated lymphocytes from syphilitic rabbits and mitogen-stimulated lymphocytes from both normal and syphilitic rabbits demonstrated a clear ability to produce soluble factors which conferred upon macrophages the ability to limit the intracellular growth of the bacteria. Antigen or mitogen alone was unable to activate the macrophages; the presence of lymphocyte products was required.
Antibody response of infants to cell surface-exposed outer membrane proteins of Haemophilus influenzae type b after systemic Haemophilus disease
Authors: Gulig P A , McCracken G H , Frisch C F , Johnston K H , Hansen E J
Published: January 2020

The immune response of nine infants with Haemophilus influenzae type b meningitis was examined by using a radioimmunoprecipitation procedure designed to detect antibodies directed against cell surface-exposed outer membrane proteins of this pathogen. Using intrinsically or extrinsically radiolabeled intact H. influenzae type b cells with acute- and convalescent-phase human sera in this radioimmunoprecipitation system, we found that all of the infants produced an antibody response directed against several different H. influenzae type b outer membrane proteins. Anti-H. influenzae type b outer membrane protein antibodies present in convalescent sera, but not found in acute sera, were directed against cell surface-exposed H. influenzae type b outer membrane proteins. In contrast, both acute and convalescent sera contained antibody activity directed against numerous H. influenzae type b outer membrane proteins whose antigenic determinants were apparently inaccessible to antibody on intact H. influenzae type b cells. The ability of infants to develop an antibody response to cell surface-exposed, antibody-accessible H. influenzae type b outer membrane proteins indicates that these proteins may have vaccinogenic potential.
Hydrolytic stability of pneumococcal group 6 (type 6A and 6B) capsular polysaccharides
Authors: Zon G , Szu S C , Egan W , Robbins J D , Robbins J B
Published: January 2020

The hydrolyses of the immunologically cross-reactive and constitutionally isomeric group 6 pneumococcal polysaccharides, types 6A and 6B, were investigated by 31P nuclear magnetic resonance spectroscopy, gel filtration through Sepharose 4B, reducing-sugar analysis, and rocket immunoelectrophoresis. Phosphorus nuclear magnetic resonance spectroscopy showed that cleavage of the repeating-unit phosphodiester linkages at pH 10, 60 degrees C was considerably faster (greater than 10(3) ) for the type 6A than the type 6B polysaccharide. Under these reaction conditions, 31P nuclear magnetic resonance kinetic measurements showed that the Na+ form of the type 6A polysaccharide underwent phosphodiester-linkage hydrolysis two times slower than the corresponding Ca+2 form; a stoichiometrically excess amount of Ca+2 caused a 30-fold enhancement of the latter hydrolysis rate. The spectroscopic characterization of phosphorus-containing end groups resulting from hydrolysis of the type 6A polymer provided additional mechanistic information. Heating the type 6A and 6B polysaccharides at 56 degrees C for various times led to gel filtration coefficients of distribution (Kd values) which indicated that the type 6A material underwent size reductions considerably faster than did the type 6B antigen; these increased Kd values qualitatively correlated with the loss of immunochemical reactivity measured by rocket immunoelectrophoresis. The application of a statistical theory to the depolymerization of the type 6A and 6B polysaccharides was consistent with random bond cleavage, as evidenced by the calculated versus measured gel filtration patterns. Although the molecular changes causing the size reductions were not fully elaborated, it was established that the acetal linkages of the type 6A and 6B polysaccharides were comparatively resistant to hydrolysis and that depolymerization by hydrolysis of the phosphodiester linkage was a major factor only in the type 6A structure. It was concluded that the hydrolytic stability of the type 6B antigen would favor its use in the polyvalent pneumococcal vaccine rather than the cross-reactive, but comparatively unstable, type 6A polysaccharide, if all other factors are equal.
Common antigens of Treponema denticola: chemical, physical, and serological characterization
Authors: Jacob E , Nauman R K
Published: January 2020

A sodium deoxycholate-ethanol extractable antigen (DES-Ag) was obtained from four serotypes of Treponema denticola and characterized by chemical, physical, and serological procedures. The cross-reactivity of these antigens was demonstrated by indirect microhemagglutination, immunodiffusion, and immunoelectrophoresis with hyperimmune rabbit antiserum against each of the T. denticola serotypes. Antiserum against two nonoral treponemes, T. phagedenis biotype Reieter and T. pallidum Nichols strain, did not cross-react with the DES-Ag of T. denticola. Chemical analysis of the DES-Ag indicated that proteins (84%) and hexoses (12%) accounted for 96% of the total dry weight of the antigen. Trace amounts of N-acetylglucosamine (0.6%) were also detected. Fatty acids, including palmitic, oleic, and stearic, were identified by gas-liquid chromatography. Polyacrylamide gel electrophoresis of the DES-Ag of each serotype revealed the presence of two bands. The molecular weights of the bands were estimated to be 58,000 and 31,000 by comparing the electrophoretic mobility of the DES-Ag to that of five protein standards of known molecular weights. Although only a single precipitin line was observed by immunodiffusion when each antigen was reacted against its homologous antiserum, two precipitin lines were evident by immunoelectrophoresis. Antiserum against the DES-Ag of T. denticola was shown to agglutinate whole cells of the homologous serotype. Adsorption of this anti-DES-Ag serum with whole cells of T. denticola resulted in the elimination of precipitating antibodies to the DES-Ag by immunodiffusion. It is concluded that the DES-Ag is a component of the outer sheath of T. denticola.
Quantitation of binding and subcellular distribution of Clostridium perfringens enterotoxin in rat liver cells
Authors: Tolleshaug H , Skjelkvåle R , Berg T
Published: January 2020

Binding of enterotoxin from Clostridium perfringens type A was studied in suspensions of parenchymal and nonparenchymal cells from rat liver. In hepatocytes, 1.5 X 10(6) specific binding sites per cell with an association constant of 3.2 X 10(6) M-1 were found. About 1% of the added toxin was nonspecifically bound to the hepatocytes. At concentrations of toxin below 0.1 micrograms/ml, 80% of the toxin density of 7 X 10(6) cells per ml. Binding did not increase after the cells became permeable to the toxin. Subcellular fractionation in a sucrose gradient produced no evidence for binding to parts of the cell other than the plasma membrane. The degree of binding to nonparenchymal cells was less than 10% of the binding to hepatocytes.
Isolation of a fibronectin-binding protein from Staphylococcus aureus
Authors: Espersen F , Clemmensen I
Published: January 2020

Fibronectin ("cold-insoluble globulin") has been suggested to play a role in cell-to-cell and cell-to-substratum adhesions. The 70-kilodalton terminal part of human fibronectin has recently been shown to bind to Staphylococcus aureus. In the present study, a fibronectin-binding protein was purified from sonicated S. aureus strain E2371 by affinity chromatography on fibronectin-Sepharose. The fibronectin-binding protein was isolated from an extract of sonicated S. aureus containing at least 57 different proteins as determined by crossed immunoelectrophoresis in antibodies to sonicated S. aureus. The fibronectin-binding protein was released from fibronectin-Sepharose by carbamide (8 M). No impurities in the final preparation could be detected when tested in crossed immunoelectrophoresis. By polyacrylamide gel electrophoresis in both reduced and unreduced gels, the protein showed two bands with relative molecular masses of 197,000 and 60,000, respectively. A complex between the purified S. aureus protein and fibronectin could be demonstrated by crossed immunoelectrophoresis both in monospecific antibodies against fibronectin and in S. aureus polyspecific antibody.
Development of a vaccine of cross-linked heat-stable and heat-labile enterotoxins that protects against Escherichia coli producing either enterotoxin
Authors: Klipstein F A , Engert R F , Clements J D
Published: January 2020

A vaccine of cross-linked heat-stable (ST) and heat-labile (LT) toxins that protects against heterologous serotypes of strains of Escherichia coli which produce either the LT or ST enterotoxin was developed by conjugating ST to LT by the carbodiimide reaction. Three interrelated factors were found to affect the composition and properties of the final conjugate: (i) the amount of carbodiimide added to the toxins, (ii) the initial ratio of ST to LT, and (iii) the duration of the conjugation reaction. Optimal conjugation conditions were identified as a carbodiimide-to-toxin ratio of 10:1 by weight, an initial molar ratio of ST to LT of 100:1, and a conjugation reaction time of 96 h. This approach yielded a conjugate that contained 96% by moles and 36% by weight pure ST, determined with radioiodinated pure ST, and 34% by weight semi-pure ST, determined by the Lowry protein method. The retained antigenicities of the conjugated toxins, as determined by enzyme-linked immunosorbent assays, was greater than or equal to 82%, and their toxicities, as determined by the Y1 adrenal cell assay for LT and by the suckling mouse assay for ST, were reduced to less than or equal to 0.15%. Immunization of rats with this cross-linked ST-LT vaccine provided strong protection against challenge with either the LT or the ST toxin or with viable heterologous strains which produce these toxins, either singly or together. These observations indicate that conjugation of ST to LT results in a unique new immunogen in that ST acquires immunogenicity as a function of the reaction, LT retains most of its antigenicity, and the toxic properties of each individual toxin are greatly reduced.
Role of antiviral antibodies in resistance against coxsackievirus B3 infection: interaction between preexisting antibodies and an interferon inducer
Authors: Cho C T , Feng K K , McCarthy V P , Lenahan M F
Published: January 2020

An experimental model of coxsackievirus B3 infection in newborn mice was utilized to examine the protective role of antiviral antibodies and an interferon inducer, polyinosinic acid-polycytidylic acid [poly(I:C)]. Subcutaneous administration to the infected mice of specific antiviral antibodies resulted in significant protection against coxsackievirus B3 infection. Antibody-treated animals had shortened viremia, early clearance of virus from tissues, and a reduced mortality rate. Dose response to antibodies was clearly demonstrated. However, the time of antibody administration in relation to the infection cycle was important. The protection was observed if antibodies were given before infection (24 h) or shortly after (2 h) infection. Administration of antibodies 24 h after infection resulted in no protection. The interferon inducer poly(I:C) prolonged the survival time of the infected mice, but this protective effect was incomplete and could only be demonstrated in animals treated before infection (24 h) or shortly after (2 h) infection. Enhanced protection against lethal coxsackievirus B3 infection was achieved in animals treated with a combination of antiviral antibodies and poly(I:C). These data confirm that antibody-mediated immunity plays a significant role in resistance against coxsackievirus B3 infection and suggest that antiviral antibodies may interact with poly(I:C) or work independently to produce an enhanced protective effect.
Serological response to Escherichia coli pili in pyelonephritis
Authors: Rene P , Silverblatt F J
Published: January 2020

The serological response to Escherichia coli pili was studied in 4 adult male patients with pyelonephritis and in 11 uninfected controls. Antibody to the specific pilus antigen of the infecting strain of each patient was measured with indirect immune electron microscopy. Antibody to a cross-reacting antigen of the type 1 pili of heterologous E. coli 346 was quantitated with an enzyme-linked immunosorbent assay. Few antipilus antibodies were found in the serum of control patients with either technique. All pyelonephrine patients developed an increase in specific antipilus antibodies belonging to the immunoglobulins classes G, A, and M. Antibodies to the cross-reacting type 1 pilus antigen were found in the serum of three of the four patients and were predominantly immunoglobulin G. Few or no antipilus antibodies were present in the urine of infected or control patients. These results suggest that a serological response to the pill of infecting organisms develops after pyelonephritis.
Immune response to lactate dehydrogenase-elevating virus: serologically specific rabbit neutralizing antibody to the virus
Authors: Cafruny W A , Plagemann P G
Published: January 2020

A rabbit was immunized with large amounts of the lactate dehydrogenase-elevating virus (LDV) over a 9-month period. The plasma from this rabbit possessed an anti-LDV IgG titer of 1:80,000 as measured by the enzyme-linked immunosorbent assay (ELISA) method and a neutralizing titer of 1:1,000 for the homologous strain of LDV. LDV neutralization at 4 degrees C followed single-hit kinetics. In contrast, mouse anti-LDV IgG in plasma of chronically LDV-infected mice failed to neutralize LDV at 4 degrees C and neutralization at 37 degrees C was slow, biphasic, and inefficient compared with the neutralization caused by rabbit anti-LDV IgG, even though high levels of anti-LDV IgG were detectable in mouse plasma by the ELISA method. Rabbit anti-LDV IgG neutralized one heterologous strain of LDV as rapidly as it did the homologous strain, but failed to significantly neutralize five other strains of LDV, all of which were originally isolated from different mouse strains bearing transplantable tumors. The results indicate clear serological differences between LDV strains. Cross-reactions between the strains, however, were observed by ELISA, using the antibody induced during persistent infection of mice with each LDV strain. Immunoglobulin M (IgM) from mice infected for 15 days with the various strains bound equally to our LDV strain. IgG obtained from 2-month-infected mice also cross-reacted, but to a varying extent which partly correlated with the specificity detected by neutralization. Both rabbit and mouse anti-LDV IgG enhanced the infectivity of LDV at a low multiplicity of infection for primary cultures of peritoneal mouse macrophages.
In Vivo Crevicular Leukocyte Response to a Chemotactic Challenge: Inhibition by Experimental Diabetes
Authors: Golub Lorne M. , Nicoll Gregg A. , Iacono Vincent J. , Ramamurthy Nungavaram S.
Published: January 2020

Diabetes in rats inhibits the migration of neutrophils into the healing gingival crevice, an effect associated with impaired in vitro neutrophil chemotactic activity. We recently described the in vivo response of human and rat crevicular neutrophils to a chemotactic challenge and used this assay in the present study on streptozotocin-induced diabetic rats. Optimal concentrations of two chemotactic agents, casein (0.2 μl, 2 mg/ml) or
N
-formylmethionylleucylphenylalanine (0.2 μl, 10
−4
M), were placed into the gingival crevices of control and diabetic rats (time zero) after the resting neutrophil count was measured. After a 15-min delay, the neutrophil counts and gingival crevicular fluid flow were assessed every 5 min for another 0.5 h. The control rats (
n
= 14) showed an increase in neutrophil counts which reached maximum levels 30 min after the
N
-formylmethionylleucylphenylalanine challenge (“peak” neutrophil response) and decreased dramatically 5 min later. Diabetes of 4 days (
n
= 4), 14 days (
n
= 8), and 20 days (
n
= 5) duration reduced the peak neutrophil response 45, 66, and 71%, respectively. Casein produced the same response as
N
-formylmethionylleucylphenylalanine in control rats. Uncontrolled diabetes of 20 days duration reduced the peak neutrophil response to casein by 83%; diabetics administered insulin on a daily basis showed a reduction of only 34%. The pattern of change in gingival crevicular fluid flow in response to chemoattractants paralleled the neutrophil response. The chemotactic activity of peritoneal neutrophils was assessed in vitro with the agarose gel technique and was found to be correlated (
r
= 0.84;
P
< 0.01) with the in vivo chemotactic response in the same rats. If the same in vivo defect is observed in humans with diabetes (or with other systemic diseases associated with leukocyte dysfunction), this test could be useful diagnostically to rapidly assess neutrophil chemotaxis in lieu of in vitro assays and to identify patients who are unusually susceptible to aggressive periodontal disease.
Kinetics of immunosuppression of sporozoite-induced immunity by Mycobacterium bovis BCG
Authors: Smrkovski L L
Published: January 2020

The data reported in this study demonstrate that the vaccination of NIH/Nmri mice with viable Mycobacterium bovis BCG organisms induces a state of immunosuppression that renders the recipient animals incapable of a protective immune response to the malaria sporozoite vaccine. The expression of this altered protective immune response is dependent upon the dosage of the two live vaccines, as well as upon the sequence of their administration. Data presented here show that the skin test responses (Arthus and delayed type) of BCG-vaccinated mice do not correlate with the suppression of sporozoite immunity. Evidence is also presented to support the hypothesis that the abrogated immune response to sporozoite vaccination induced by BCG is a result of a loss of immunological memory.
Human Antibody Response to Individual Outer Membrane Proteins of
Haemophilus influenzae
Type b
Authors: Loeb Marilyn R. , Smith David H.
Published: January 2020

To evaluate the potential of outer membrane proteins of
Haemophilus influenzae
as a vaccine, sera from 11 healthy persons and from 23 patients convalescing from disease caused by
Haemophilus influenzae
type b were assayed for antibodies to individual outer membrane proteins of a single type b isolate, strain Eag, by a gel radioimmunoassay. All 23 patients, ranging in age from 2 months to 62 years, with 17 patients being 24 months or less, had antibodies to some of these proteins in their sera (range, antibodies to 4 to 17 proteins per patient). Although the intensity and spectrum of the response varied, all patients had antibodies to one particular outer membrane protein and 19 patients had antibodies to another, with those patients 5 years and older having antibodies to more proteins than did infants (≦24 months). In the two cases examined, convalescent sera had greater amounts and broader spectra of antibodies than did acute sera. In addition, 10 of 11 healthy subjects not known to have had systemic
H. influenzae
disease also had antibodies to individual outer membrane proteins, with older children having greater amounts than did their younger siblings and with children showing a different spectrum of response than that for adults. Thus, antibodies to outer membrane proteins are commonly found in humans. Also, these results and those demonstrating that hyperimmune rabbit antisera to strain Eag reacted with each of five type b substrains possessing some different outer membrane proteins indicate considerable cross-reactivity among these proteins. These results encourage continued consideration of outer membrane proteins in a vaccine.
Inhibition by cyclosporin A of rodent malaria in vivo and human malaria in vitro
Authors: Nickell S P , Scheibel L W , Cole G A
Published: January 2020

The development and course of normally lethal parasitemias in mice inoculated intraperitoneally with erythrocytic stages of Plasmodium yoelii or Plasmodium berghei were markedly affected by treatment with the antilymphoid drug cyclosporin A (CS-A). When the first of four daily subcutaneous 25-mg/kg doses of CS-A was given at the time of parasite inoculation, patent infections failed to develop. If begun up to 5 days earlier, this same treatment regimen prolonged the prepatent period, attenuated parasitemia, and reduced mortality. In mice with patient infections, two consecutive daily 25-mg/kg doses of CS-A were sufficient to terminate parasitemias which, after several days, reappeared but were self-limiting. This pattern of apparent cure followed by transient recrudescence remained unaltered even when daily treatment with the same drug dose was continued for 3 weeks. Recrudescence was associated with the emergence of parasite populations that were relatively resistant to CS-A and, in the case of P. yoelii, of reduced virulence. In more limited experiments, CS-A was found to be active in vitro against erythrocytic stages of the human malarial parasite palsmodium falciparum. Depending on the concentration of drug in the culture medium, parasite growth was either prevented or inhibited.
Virulence of Avian Influenza A Viruses for Squirrel Monkeys
Authors: Murphy Brian R. , Hinshaw Virginia S. , Sly D. Lewis , London William T. , Hosier Nanette T. , Wood Frank T. , Webster Robert G. , Chanock Robert M.
Published: January 2020

Ten serologically distinct avian influenza A viruses were administered to squirrel monkeys and hamsters to compare their replication and virulence with those of human influenza A virus, A/Udorn/307/72 (H3N2). In squirrel monkeys, the 10 avian influenza A viruses exhibited a spectrum of replication and virulence. The levels of virus replication and clinical response were closely correlated. Two viruses, A/Mallard/NY/6874/78 (H3N2) and A/Pintail/Alb/121/79 (H7N8), resembled the human virus in their level and duration of replication and in their virulence. At the other end of the spectrum, five avian viruses were restricted by 100- to 10,000-fold in replication in the upper and lower respiratory tract and were clearly attenuated compared with the human influenza virus. In hamsters, the 10 viruses exhibited a spectrum of replication in the nasal turbinates, ranging from viruses that replicated as efficiently as the human virus to those that were 8,000- fold restricted. Since several avian viruses were closely related serologically to human influenza viruses, studies were done to confirm the avian nature of these isolates. Each of the avian viruses plaqued efficiently at 42°C, a restrictive temperature for replication of human influenza A viruses. Avian strains that had replicated either very efficiently or very poorly in squirrel monkeys still grew to high titer in the intestinal tracts of ducks, a tropism characteristic of avian, but not mammalian, influenza viruses. These observations indicate that some avian influenza A viruses grow well and cause disease in a primate host, whereas other avian viruses are very restricted in this host. These findings also provide a basis for determining the gene or genes involved in the restriction of replication that is observed with the attenuated avian viruses. Application of such information may allow the preparation of reassortant viruses derived from a virulent human influenza virus and an attenuated avian virus for possible use in a live attenuated vaccine for prevention of influenza in humans.
Age resistance in bovine babesiosis: role of blood factors in resistance to Babesia bovis
Authors: Levy M G , Clabaugh G , Ristic M
Published: January 2020

In vitro cultivation of Babesia bovis in erythrocyte cultures demonstrated that blood from young animals contains a factor(s) responsible for their resistance to severe babesiosis. This factor is independent of antibody, is present in the serum of all young animals tested, and is dialyzable. The presence of this factor results in inhibition of parasite multiplication and the eventual death of the parasite while inside the erythrocyte.
Antigenic relationships among homologous structural polypeptides of porcine, feline, and canine coronaviruses
Authors: Horzinek M C , Lutz H , Pedersen N C
Published: January 2020

Transmissible gastroenteritis virus of swine (TGEV), feline infectious peritonitis virus (FIPV), and canine coronavirus were studied with respect to their serological cross-reactivity in homologous and heterologous virus neutralization, immune precipitation of radiolabeled TGEV, electroblotting, and enzyme-linked immunosorbent assay using individual virion polypeptides prepared by polyacrylamide gel electrophoresis. TGEV was neutralized by feline anti-FIPV serum, and the reaction was potentiated by complement; heterologous neutralization involved antibody reacting with the peplomer protein (P), the envelope protein (E), and cellular (glycolipid) components incorporated into the TGEV membrane. Electrophoretic analysis of immune precipitates containing [35S]methionine-labeled disrupted TGEV and feline anti-FIPV antibody confirmed the reaction with the P and E polypeptides and showed the nucleocapsid protein (N) in addition. Electroblotting, followed by incubation with antibody, 125I-labeled protein A, and fluorography, disclosed cross-reactions between the three viruses at the N and E levels and revealed differences in the apparent molecular weights of the latter. Enzyme immunoassays performed with standard amounts of immobilized P, N, and E polypeptides of the three viruses showed recognition of the antigens by homologous and heterologous antibody to comparable degrees. These results indicate a close antigenic relationship between TGEV, FIPV, and canine coronavirus due to common determinants on the three major virion proteins. The taxonomic implications of these findings are discussed.
Use of specific antibody to demonstrate glycocalyx, K99 pili, and the spatial relationships of K99+ enterotoxigenic Escherichia coli in the ileum of colostrum-fed calves
Authors: Chan R , Acres S D , Costerton J W
Published: January 2020

The attachment of enterotoxigenic Escherichia coli (ETEC) strain B44 (O9:K30:K99:F41:H-) to the ileal epithelium of newborn colostrum-fed calves was studied by electron microscopy. Stabilization of the bacterial glycocalyx (K30) and pili (K99) by fixation of tissue sections in specific antibody and staining with ruthenium red were used so that the bacterial surface structures could be clearly visualized and their spatial relationship to the intestinal brush border defined. When sections of ileum from infected calves were neither fixed in antibody nor stained with ruthenium red, the ETEC cells colonizing the small intestine were separated from each other and from the brush border by an electron-translucent halo; neither the glycocalyx nor the pili could be clearly resolved. When ruthenium red staining was used, the halo was partially filled by a net of electron-dense fibers composed of pili and condensed glycocalyx which extended to the brush border. Tissue sections reacted with anti-K30 antibody before staining with ruthenium red revealed microcolonies of ETEC surrounded by a discrete electron-dense glycocalyx 0.3 to 1.0 micrometers thick and in tight contact with the epithelial cell surface. When ileal tissue was treated with K99 antibody, the K99 pili were visible as discrete fibers extending from the bacterial cell surface through the glycocalyx. We discuss the role of these cell surface components in pathogenic adhesion and in the formation of protected microcolonies at the surface of the infected ileal epithelium.
Zinc and bacterial adherence
Authors: Sugarman B , Epps L R , Stenback W A
Published: January 2020

Zinc significantly enhances the ability of piliated Gram-negative and Gram-positive bacteria to attach to HeLa cells. This effect is related to the concentration of zinc and degree of bacterial piliation, and is not present with unpiliated organisms. Bacterial viability is not necessary for this effect, and sulfhydryl blockers decrease the response. These data suggest that zinc can bind to bacterial pili and augment bacterial adherence; in this manner, zinc may act as a virulence factor.
Isolation and characterization of coaggregation-defective mutants of Actinomyces viscosus, Actinomyces naeslundii, and Streptococcus sanguis
Authors: Kolenbrander P E
Published: January 2020

Spontaneously occurring coaggregation-defective (COG-) mutants of oral actinomycetes and streptococci were isolated and used to study interactions between cells of these two kinds of bacteria. COG- mutants of each kind of bacteria were isolated by a simple enrichment scheme. Parent strains were mixed with a coaggregating partner strain, coaggregated cells were removed by low-speed centrifugation, and non-coaggregated cells were recycled by the addition of more partner strain cells. COG- mutants constituted up to 10% of the parent strain cell type in the final enriched cell suspension. Unlike their respective parent strains, COG- mutants of Actinomyces viscosus T14V and Actinomyces naeslundii ATCC 12104, and A. naeslundii I exhibited no lactose-reversible coaggregation with certain oral Streptococcus sanguis strains. However, these COG- mutants were not altered in their coaggregations with another S. sanguis strain, H1, a member of a streptococcal coaggregation group that exhibits only lactose-nonreversible coaggregations with oral actinomycetes. Although all coaggregations between S. sanguis H1 and these actinomycetes appear to be alike, examination of a COG- mutant of S. sanguis H1 revealed that, like its parent, it coaggregated with A. viscosus T14V and its COG- mutants, but unlike its parent, it did not coaggregate with the two A. naeslundii strains or their COG- mutants. Thus, it was concluded that at least two types of surface components are important in mediating coaggregation between S. sanguis H1 and actinomycetes. The COG- mutant of S. sanguis allowed detection of these components, which were indistinguishable in previous studies.
Isolation of a variant of Candida albicans
Authors: Buckley H R , Price M R , Daneo-Moore L
Published: January 2020

During the course of Candida albicans antigen production, a variant of this organism was encountered which did not produce hyphae at 37 degrees C. Presented here are some of the characteristics of this variant. It produces hyphae at 25 degrees C on cornmeal agar and synthetic medium plus N-acetylglucosamine and Tween 80. At 37 degrees C, it does not produce hyphae on these media, although C. albicans normally does produce hyphae under these circumstances. In liquid synthetic medium, this variant does not produce hyphae at 37 degrees C. The variant strain was analyzed for DNA, RNA, protein content, and particle size. After 50 to 70 h in balanced exponential-phase growth, particle size distribution was narrow, and there were no differences in the DNA, RNA, or protein content per particle in the two strains. When balanced exponential-phase cultures were brought into stationary phase, both strains contained the same amount of DNA per cell.