bluuebunny/crossref_metadata_2025 huggingface dataset:
Neonatal mouse protection against infection with multiple group B streptococcal (GBS) serotypes by maternal immunization with a tetravalent GBS polysaccharide-tetanus toxoid conjugate vaccine
Authors: Paoletti L C , Wessels M R , Rodewald A K , Shroff A A , Jennings H J , Kasper D L
Published: January 2020

Most cases of neonatal sepsis and meningitis caused by group B streptococci (GBS) are attributable to one of four major capsular serotypes: Ia, Ib, II, or III. Because resistance to infection with GBS has been correlated with the presence of serum antibodies to the type-specific capsular polysaccharides in both experimental animals and human neonates, efforts have been made to elicit protective immunity with GBS capsular polysaccharide vaccines. However, the GBS capsular polysaccharides alone are not highly immunogenic in either animals or human volunteers. Therefore, we and other investigators have attempted to enhance immunogenicity by coupling individual capsular polysaccharides to a carrier protein. Here we report the synthesis and immunogenicity in rabbits of a GBS type Ib polysaccharide-tetanus toxoid vaccine prepared by the direct, covalent attachment of tetanus toxoid to a selected number of sialic acid residues on the type-specific polysaccharide. In addition, the Ib polysaccharide-tetanus toxoid conjugate vaccine was combined with similar tetanus toxoid conjugates of GBS type Ia, II, and III polysaccharides to form a tetravalent GBS conjugate vaccine. Protective efficacy of the GBS tetravalent conjugate vaccine was demonstrated in a mouse maternal immunization-neonatal challenge model of GBS infection. The results support testing in human subjects of a multivalent GBS conjugate vaccine of this design, with the eventual goal of protecting newborns against GBS infection.
Characterization of transposon mutants of biofilm-producing Staphylococcus epidermidis impaired in the accumulative phase of biofilm production: genetic identification of a hexosamine-containing polysaccharide intercellular adhesin
Authors: Mack D , Nedelmann M , Krokotsch A , Schwarzkopf A , Heesemann J , Laufs R
Published: January 2020

The primary attachment to polymer surfaces followed by accumulation in multilayered cell clusters leads to production of Staphylococcus epidermidis biofilms, which are thought to contribute to virulence in biomaterial-related infections. We isolated Tn917 transposon mutants of biofilm-producing S. epidermidis 13-1, which were completely biofilm negative. In pulsed-field gel electrophoresis no obvious deletions of the mutants were noted. The Tn917 insertions of mutants M10 and M11 were located on different EcoRI fragments but on identical 60-kb SmaI and 17-kb BamHI chromosomal fragments. Linkage of transposon insertions of mutants M10 and M11 with the altered phenotype was demonstrated by phage transduction, whereas the several other mutants apparently represented spontaneous variants. In a primary attachment assay with polystyrene spheres, no significant difference between any of the mutants and the wild type could be detected. Cell clustering as an indication of intercellular adhesion, which is a prerequisite for accumulation in multilayered cell clusters, was not detected with any mutant. These results demonstrate that the mutants were impaired in the accumulative phase of biofilm production. Mutants M10 and M11 did not produce detectable amounts of a specific polysaccharide antigen (D. Mack, N. Siemssen, and R. Laufs, Infect. Immun. 60:2048-2057, 1992), whereas substantially reduced amounts of antigen were produced by the spontaneous variants. Hexosamine was determined as the major specific component of the antigen enriched by gel filtration of biofilm-producing S. epidermidis 1457 because almost no hexosamine was detected in material prepared from the isogenic biofilm-negative transductant 1457-M11, which differentiates the antigen from other S. epidermidis polysaccharide components. Our results provide direct genetic evidence for a function of the antigen in the accumulative phase of biofilm production by S. epidermidis by mediating intercellular adhesion.
Growth of Legionella pneumophila in Acanthamoeba castellanii enhances invasion
Authors: Cirillo J D , Falkow S , Tompkins L S
Published: January 2020

Legionella pneumophila is considered to be a facultative intracellular parasite. Therefore, the ability of these bacteria to enter, i.e., invade, eukaryotic cells is expected to be a key pathogenic determinant. We compared the invasive ability of bacteria grown under standard laboratory conditions with that of bacteria grown in Acanthamoeba castellanii, one of the protozoan species that serves as a natural host for L. pneumophila in the environment. Amoeba-grown L. pneumophila cells were found to be at least 100-fold more invasive for epithelial cells and 10-fold more invasive for macrophages and A. castellanii than were L. pneumophila cells grown on agar. Comparison of agar- and amoeba-grown L. pneumophila cells by light and electron microscopy demonstrated dramatic differences in the morphology and structure of the bacteria. Analyses of protein expression in the two strains of bacteria suggest that these phenotypic differences may be due to the expression of new proteins in amoeba-grown L. pneumophila cells. In addition, the amoeba-grown bacteria were found to enter macrophages via coiling phagocytosis at a higher frequency than agar-grown bacteria did. Replication of L. pneumophila in protozoans present in domestic water supplies may be necessary to produce bacteria that are competent to enter mammalian cells and produce human disease.
Cloning and sequence analysis of a chymotrypsinlike protease from Treponema denticola
Authors: Arakawa S , Kuramitsu H K
Published: January 2020

A clone expressing a Treponema denticola chymotrypsinlike protease from recombinant plasmid pSA2 was identified in a genomic library of T. denticola ATCC 35405. Nucleotide sequencing of the insert identified an open reading frame, designated the prtB gene, which codes for the protease. Two potential inverted repeat sequences are present both upstream and downstream from the prtB gene. The prtB gene would code for a putative protein of 273 amino acids with a calculated molecular mass of 30.4 kDa and an estimated pI of 7.0. The G+C content of the gene is 40.3%. The results of maxicell analysis are consistent with the expression of a 30-kDa protease from the prtB gene. Preliminary characterization of the protease indicated that it was inhibited by the protease inhibitors phenylmethylsulfonyl fluoride, diisopropylfluorophosphate, and N-tosyl-L-phenylalanine chloromethyl ketone but not by N alpha-p-tosyl-L-lysine chloromethyl ketone. Purification of the protease was accomplished with the PinPoint protein purification system following construction of site-directed mutagenized plasmid pXa-3:2. The purified protease degraded human and bovine serum albumins as well as casein. Furthermore, hemolysis of sheep erythrocytes by the protease was observed. Northern (RNA) blot analysis of mRNA extracted from strain 35405 indicated a single 1.9-kb mRNA species containing the prtB transcript. In addition, the results of primer extension analysis indicated that transcription was initiated primarily at a T residue. However, no corresponding -10 and -35 sequences related to Escherichia coli promoter sequences were identified. The availability of the purified protein and its gene will aid in evaluating the potential role of the protease in the physiology and virulence of T. denticola since proteases may play a key role in oral treponemal pathogenicity.
Defective antigen presentation by Mycobacterium tuberculosis-infected monocytes
Authors: Gercken J , Pryjma J , Ernst M , Flad H D
Published: January 2020

In this study we investigated the effect of an in vitro infection with Mycobacterium tuberculosis on the ability of human monocytes to present the soluble antigen tetanus toxoid to T cells. We observed that tetanus toxoid-specific T-cell proliferation was markedly reduced when monocytes were infected with large numbers (bacterium-to-monocyte ratio, 50:1) of both viable and heat-killed mycobacteria. The level of antigen-induced gamma interferon release also was decreased when M. tuberculosis-containing monocytes were used as antigen-presenting cells. However, mycobacterium-infected monocytes did not show or trigger suppressive activity, because the presence of mycobacterium-infected monocytes did not affect the T-cell response induced by tetanus toxoid-pulsed control monocytes. When M. tuberculosis-infected monocytes were fixed with paraformaldehyde, they were not able to serve as antigen-presenting cells even in the presence of untreated accessory monocytes. Moreover, the uptake of both viable and heat-killed M. tuberculosis cells reduced the expression of human leukocyte antigen DR on monocytes. With regard to accessory function, monocytes infected with large numbers of mycobacteria were less efficient as accessory cells than were control monocytes in cultures of T cells activated with pokeweed mitogen. These results indicate that infection with large numbers of M. tuberculosis cells impairs the ability of monocytes to process and/or present soluble antigen and to serve as accessory cells in T-cell activation.
Pseudomonas aeruginosa invades corneal epithelial cells during experimental infection
Authors: Fleiszig S M , Zaidi T S , Fletcher E L , Preston M J , Pier G B
Published: January 2020

Pseudomonas aeruginosa is considered an extracellular pathogen. Using assays to determine intracellular survival in the presence of gentamicin, we have demonstrated that some strains of P. aeruginosa are able to invade corneal cells during experimental bacterial keratitis in mice. Although intracellular bacteria were detectable 15 min after inoculation, the number of intracellular bacteria increased in a time-dependent manner over a 24-h period. Levels of invasion were similar when bacteria were grown as a biofilm on solid medium and when they were grown in suspension. Intracellular bacteria survived in vitro for at least 24 h, although only minimal bacterial multiplication within cells was observed. P. aeruginosa PAK and Escherichia coli HB101 did not cause disease in this model and were not isolated from corneas after 24 h even when an inoculum of 10(8) CFU was applied. Transmission electron microscopy of corneal epithelium from eyes infected for 8 h revealed that intracellular bacteria were present within membrane-bound vacuoles, which suggests that bacterial entry was an endocytic process. At 24 h, the observation of many bacteria free in the cytoplasm indicated that P. aeruginosa was able to escape the endocytic vacuole. The ability of some P. aeruginosa strains to invade corneal epithelial cells may contribute to the pathogenesis or to the progression of disease, since intracellular bacteria can evade host immune effectors and antibiotics commonly used to treat infection.
Site-specific immunity to Leishmania major in SWR mice: the site of infection influences susceptibility and expression of the antileishmanial immune response
Authors: Nabors G S , Farrell J P
Published: January 2020

Inbred strains of mice usually develop either of two divergent patterns of infection in response to Leishmania major. Resistant mice, which develop self-limiting infections, respond immunologically with the activation of gamma interferon-secreting Th1 helper T cells, while nonhealing infections in susceptible mice are characterized by the proliferation of interleukin-4-secreting Th2 cells. Development of these divergent responses is dependent primarily on the strain of mouse infected, although factors such as the infective dose, species, and strain of parasite can also influence the degree of resistance. In this study, we show that a single mouse strain, SWR, can develop totally divergent patterns of infection depending on the site of parasite inoculation. Both SWR mice and highly susceptible BALB/c mice developed progressive, ultimately fatal disease when inoculated in the dorsal skin over the base of the tail. However, SWR mice infected in the hind footpad developed far less severe infections, which were for the most part controlled, whereas BALB/c mice infected in this site developed severe, nonhealing lesions. Production of gamma interferon and interleukin-4 and measurement of immunoglobulin E levels in serum were used to assess the degree of Th1 and Th2 cell activation in infected mice. Cytokine profiles early in infection had characteristics of a mixed Th1-Th2 response and were similar in SWR mice infected at either site. These early cytokine responses were not predictive of the ultimate disease outcome, since lymph node cells from healing mice eventually produced higher levels of gamma interferon than did those from nonhealing mice, and healing mice had lower levels of immunoglobulin E in serum, suggesting a functional bias toward Th1 cell activity in these animals. The differential ability of SWR mice to heal infections at different cutaneous sites provides a new model for the study of resistance to cutaneous leishmaniasis. Unlike traditional models of infection in which resistant and susceptible strains of mice are compared, this model allows for the study of factors that contribute to healing and nonhealing infections in a genetically identical strain of mouse.
T-cell-epitope mapping of the major secreted mycobacterial antigen Ag85A in tuberculosis and leprosy
Authors: Launois P , DeLeys R , Niang M N , Drowart A , Andrien M , Dierckx P , Cartel J L , Sarthou J L , Van Vooren J P , Huygen K
Published: January 2020

Lymphoproliferation and gamma interferon (IFN-gamma) secretion in response to 28 overlapping 20-mer synthetic peptides covering the complete sequence of the mature (295-amino-acid) 85A component of the major secreted, fibronectin-binding antigen 85 complex from Mycobacterium tuberculosis and Mycobacterium bovis BCG (MTAg85A) was examined by using peripheral blood mononuclear cell (PBMC) cultures from healthy tuberculin- and lepromin-positive volunteers and from patients with tuberculosis and leprosy. Peptide recognition was largely promiscuous, with a variety of human leukocyte antigen haplotypes reacting to the same peptides. PBMC from all tuberculin-positive subjects reacted to Ag85, and the majority proliferated in response to peptide 6 (amino acids 51 to 70), peptides 13, 14, and 15 (amino acids 121 to 160), or peptides 20 and 21 (amino acids 191 to 220). PBMC from tuberculosis patients demonstrated a variable reactivity to Ag85 and its peptides, and the strongest proliferation was observed against peptide 7 (amino acids 61 to 80). MTAg85A peptides were also recognized by PBMC from healthy lepromin-positive volunteers and paucibacillary leprosy patients (again in a promiscuous manner), but despite a 90% homology between the 85A proteins of M. leprae and M. tuberculosis, the peptides recognized were different. PBMC from lepromin-positive healthy contacts reacted against peptide 2 (amino acids 11 to 30), peptide 5 (amino acids 41 to 60), and peptides 25 and 26 (amino acids 241 to 270). PBMC from paucibacillary patients reacted preferentially against peptide 1 (amino acids 1 to 20) and peptide 5. Multibacillary patients were not reactive to Ag85 or the MT85A peptides. IFN-gamma production was generally detected simultaneously with positive lymphoproliferative responses, although peptide 1 mostly stimulated proliferation and peptides 27 and 28 mostly elicited an IFN-gamma response. In conclusion, regions 41 to 80 and 241 to 295 demonstrated powerful and promiscuous T-cell-stimulatory properties, resulting in proliferative responses and IFN-gamma secretion, respectively, in the majority of reactive subjects tested in this study. These results could be of value in the development of a subunit vaccine for tuberculosis and leprosy.
Epitopes of the Onchocerca volvulus RAL1 antigen, a member of the calreticulin family of proteins, recognized by sera from patients with onchocerciasis
Authors: Rokeach L A , Zimmerman P A , Unnasch T R
Published: January 2020

RAL1 is an antigen (Ag) encoded by the filarial nematode Onchocerca volvulus, the parasite causing onchocerciasis (river blindness). RAL1 shares 64.4% identity with the autoantigen calreticulin. The striking similarity of the parasite Ag and the human autoantigen has led to the hypothesis that RAL1 may induce a cross-reactive immune response to calreticulin, which in turn may be involved in the pathogenesis of onchocerciasis. To test this hypothesis, we explored the immune response to RAL1 recombinant Ag (RAL1 rAg) and human calreticulin in patients with O. volvulus infection. A total of 86% of the O. volvulus-infected individuals produced antibodies recognizing RAL1 rAg. Antibody reactivity to RAL1 rAg in patient sera was confined primarily to the central and carboxyl-terminal parts of the molecule. No significant correlations were found to associate recognition of RAL1 rAg, or any particular portion thereof, with a particular disease state. Antibodies against RAL1 thus appear to be produced as a general immune reaction to O. volvulus infection and do not necessarily lead to a cross-reacting response with the host protein. In contrast, 33% of the patient sera tested bound recombinant human calreticulin. All of these sera also recognized a polypeptide encompassing the carboxyl-terminal portion of the RAL1 rAg. These results suggest that recognition of an epitope encoded in the carboxyl-terminal portion of RAL1 is at least in part responsible for inducing a cross-reacting immune response to the host protein.
A 48-kilodalton Mycoplasma fermentans membrane protein induces cytokine secretion by human monocytes
Authors: Kostyal D A , Butler G H , Beezhold D H
Published: January 2020

Mycoplasma fermentans is one of several Mycoplasma species that have been reported to stimulate tumor necrosis factor (TNF) secretion from monocytes. This activity has been associated primarily with the mycoplasma membrane fraction. In this article, we have characterized a membrane protein that stimulates TNF and interleukin 1 beta secretion. The TNF-releasing activity partitioned into the Triton X-114 detergent phase, suggesting that the molecules is hydrophobic. The secretion of TNF is elevated in the presence of serum, which suggests that a serum component may play a role in the interaction between this mycoplasma protein and monocytes. Treatment of monocytes with monoclonal anti-CD14 antibody had no effect on the levels of TNF-releasing activity. By using the monocyte Western blot (immunoblot) technique, we have determined the molecular mass of the active molecule to be 48 kDa. This molecule appears to be distinct from the recently described family of variable lipoproteins of M. fermentans. Mycoplasma particulate material treated with proteinase K lost all inducing activity, whereas lipoprotein lipase-treated samples retained some level of activity.
Binding of Legionella pneumophila to macrophages increases cellular cytokine mRNA
Authors: Yamamoto Y , Okubo S , Klein T W , Onozaki K , Saito T , Friedman H
Published: January 2020

Infection of macrophages with Legionella pneumophila induces formation of interleukin 1 beta (IL-1 beta), but the molecular basis of this is not understood. Binding of bacteria to macrophage surfaces is the first step in an infection process. Therefore, we examined whether this step was sufficient to increase the cellular level of mRNAs for IL-1 beta and other cytokines. To assess the effect of binding of L. pneumophila on the steady-state levels of cytokine mRNAs, cultures of thioglycolate-elicited macrophages from L. pneumophila-susceptible A/J mice were treated with cytochalasin D and infected with L. pneumophila and the total RNA was extracted for analysis by reverse transcription-PCR with primers for IL-1 alpha, IL-1 beta, IL-6, tumor necrosis factor alpha, granulocyte macrophage colony-stimulating factor, and beta interferon (IFN-beta). L. pneumophila treatment increased the cellular steady-state mRNA levels of all cytokines except IFN-beta. To determine the specificity of this effect, macrophage cultures were treated with cytochalasin D and either bacterial lipopolysaccharide, bovine serum albumin-sensitized latex, Salmonella typhimurium, or Escherichia coli. Lipopolysaccharide treatment increased all mRNAs, bovine serum albumin-sensitized latex had no significant effect, and treatment with S. typhimurium or E. coli increased all mRNAs except that of IFN-beta. These results suggested that the binding of gram-negative bacteria to the macrophage surface was sufficient to induce a unique pattern of cytokine mRNAs. Additional studies that examined the characteristics of the bacterial ligands involved indicated involvement of both heat-labile and heat-stable surface ligands.
Experimental infection of young chicks with attaching and effacing Escherichia coli
Authors: Sueyoshi M , Nakazawa M
Published: January 2020

Young chicks were inoculated with six different strains of attaching and effacing Escherichia coli isolated from the feces of calves, pigs, chicks, and humans. Colibacilli of some serotypes had colonized the cecum of chicks by 7 days after inoculation. The characteristic lesions associated with bacterial attachment were also seen on the mucosal surface of the cecum. Electron microscopy revealed numerous colibacilli closely attached to the surface membrane of enterocytes. Cell membranes formed cups and pedestals at the base of the attached bacilli. The results of this study support the conclusion that young chicks can be used as a model for the study of the lesions caused by attaching and effacing E. coli strains.
Detection of Coronavirus Strain 692 by Immune Electron Microscopy
Authors: Kapikian Albert Z. , James Harvey D. , Kelly Sara J. , Vaughn Annie L.
Published: January 2020

Utilization of the technique of immune electron microscopy has enabled the detection of a coronavirus in organ culture harvests derived from a washing from an adult with an acute upper respiratory tract illness; convalescent serum was the source of specific antibody.
Radiobacteriolysis: a New Technique Using Chromium-51 for Assaying Anti-
Vibrio cholerae
Antibodies
Authors: Blachman Uzy , Clark W. R. , Pickett M. J.
Published: January 2020

A new method for detecting and quantitating antibodies against
Vibrio cholerae
is described. The reaction involves the release of radiochromium from prelabeled vibrios in the presence of specific antibody and complement. The entire assay can be completed within 5 hr. The method is highly reproducible, immunologically specific, temperature- and complement-dependent, and significantly more sensitive than other methods currently used for titration of anti-
Vibrio cholerae
antibodies. The technique is also potentially applicable to titration of antibodies against other gram-negative bacteria.
Macrophage Migration Technique Using Coccidioidin
Authors: Sinski James T. , Reed Grace L. , Kelley L. M. , LeFebvre R.
Published: January 2020

Guinea pigs sensitized by repeated skin testing with potent, merthiolated coccidioidin, equal to Smith standard, exhibited erythema, edema, and an induration-like reaction to intradermal injection of the preparation. No statistically significant migration inhibition of peritoneal exudate macrophages from these animals was observed.
Interaction of Virulent and Avirulent
Listeria monocytogenes
with Cultured Mouse Peritoneal Macrophages
Authors: Wilder Martin S. , Edberg Joyce C.
Published: January 2020

The interaction between smooth and rough
Listeria monocytogenes
and mouse peritoneal macrophages in culture was investigated. Initially, antibiotics were deleted from the culture medium, and no attempt other than the removal of unphagocytized bacteria by extensive washings was made to control extracellular growth. Under these conditions the monolayers were rapidly destroyed within an 8-h period, and this was associated with increases in the intracellular population of both strains. Extracellular viability counts revealed that washings failed to reduce the bacteria in the medium to less than 10% of the original inoculum. Continuous phagocytosis of
Listeria
which grew logarithmically in the maintenance media appears to account for the observed changes in the number of intracellular bacteria. The data also indicate that it is primarily the free bacteria in the culture medium which are responsible for the cytotoxic effects. In other experiments streptomycin-penicillin solutions were added to the maintenance media after an initial period of phagocytosis. In the presence of antibiotics, the total number of macrophages per field remained relatively constant, and no morphological alterations in the leukocyte cultures were observable. Extensive intracellular multiplication of either strain was not evident in fixed and stained cover slips. Viable intracellular counts reveal that after 24 h there is almost total killing of the rough variant, whereas the smooth strain tended towards complete survival.
Effects of Antithymocyte and Antimacrophage Sera on the Survival of Mice Infected with
Listeria monocytogenes
Authors: Pearson Leonard D. , Osebold John W.
Published: January 2020

Antisera prepared in rabbits against purified mouse thymocytes (antithymocyte serum; ATS) and peritoneal macrophages (antimacrophage serum; AMS) were injected intraperitoneally into Balb/c mice infected with the bacterium
Listeria monocytogenes
. When administered near the initiation of infection, the ATS significantly decreased the survival time of the animals and increased the mortality rate. When ATS was administered 6 days after a sublethal dose of
L. monocytogenes
had been inoculated, an overt disease did not evolve. ATS that significantly potentiated primary listeriosis also had high cytotoxicity titers for thymocytes and lymphoid cells from the peritoneal cavity. Although cytotoxic activity against peritoneal macrophages could be demonstrated in lower dilutions of the ATS, this activity did not appear to correlate with the effects of the sera on listeriosis. The injection of AMS did not enhance the infectious process. In some trials more deaths occurred among mice receiving normal rabbit serum than those receiving AMS. All of the AMS had cytotoxic titers against peritoneal macrophages, and the sera were usually inactive against thymocytes and peritoneal lymphoid cells.
Listeria
was isolated from fatally infected mice with nearly equal success in all of the serum-treated groups, and the serum treatments did not appear to alter the pattern of gross lesions. The afferent limb of the immune response was markedly affected by the presence of antibodies to lymphocytes. However, antibodies reacting with macrophages did not demonstrably enhance the
Listeria
process, which depends upon cellular immunity as the principal means of acquired host defense.
Serotypic Heterogeneity in Isolates of Human Genital T-Mycoplasmas
Authors: Lin Juey-Shin , Kass Edward H.
Published: January 2020

Serological typing of human genital T-mycoplasmas by a complement-dependent mycoplasmacidal test showed that some recent isolates had different serotypic behavior before and after purification, and that the widely distributed prototype strain T960 was composed of at least two different serotypes. These results indicate that T-mycoplasma isolates from human genital tracts are not serologically homogeneous.
Enzyme-Linked Immunosorbent Assays for Cholera Serology
Authors: Holmgren J. , Svennerholm A.-M.
Published: January 2020

The enzyme-linked immunosorbent assay (ELISA) principle of Engvall and Perlmann, which employs antigen-coated tubes and enzyme-labeled anti-immunoglobulins, was elaborated for use in cholera serology. Immunoglobulin class-specific determinations of primary binding titers of antibodies to cholera exotoxin and endotoxin were more sensitive than were neutralization and vibriocidal tests. It was notable that rather high ELISA titers of immunoglobulin M (IgM) antibodies to exotoxin, which lacked neutralizing capacity were registered, whereas corresponding levels of immunoglobulin G (IgG) antibodies were effectively neutralizing. A modified technique permitting measurement of the binding rate of antibody to the solid-phase antigen was introduced as a possible tool for antibody avidity estimation. Such measurements indicated a wide avidity difference between the IgG and the IgM anti-exotoxin antibodies, which could explain their different neutralizing capacities. The observation that increasing binding rate of the IgG antibodies during the course of the primary immune response could compensate for decreasing antibody amount with regard to neutralizing capacity of serum also indicated the importance of antibody avidity for toxin neutralization. Inhibition with soluble antigen permitted quantitative determination of antigen; levels of exotoxin 0.09 μg/ml and of endotoxin to 1.3 μg/ml were measured.
Immune Response of Rats to Group A Streptococcal Vaccine
Authors: Leslie Gerrie A. , Carwile Henry F.
Published: January 2020

Adult female Sprague-Dawley rats were hyperimmunized with group A streptococcal vaccine in an attempt to evaluate this species for its immunological responsiveness to the group A streptococcal carbohydrate. Pronounced hyperproteinemia, generally attributable to hypergammaglobulinemia was produced in 30 to 40% of the animals. The immune response of the rats was extremely variable, yielding precipitating antibody concentrations ranging from <0.1 mg per ml to >26 mg per ml. Antibody levels also varied considerably in the same rat at different times during the immunization routine. The highest concentration of precipitating antibody was 26.3 mg per ml. Evidence is presented to suggest the production of antibodies of restricted heterogeneity and the production of non-streptococcal antibodies during the immune response.
Effect of Vinblastine on the Chemotactic Responsiveness of Normal Human Neutrophils
Authors: Edelson Paul J. , Fudenberg H. F.
Published: January 2020

The effect of vinblastine on the mobility of human neutrophils was studied. Chemotactic responsiveness was decreased by approximately 80 to 95%, as measured in Boyden chambers, whereas random mobility, as measured in glass capillary tubes, was approximately doubled. Chemotactic responsiveness could be partially restored after dialysis of the treated cells, which is not compatible with an action of vinblastine on microtubules. The possibility is considered that this observation is an additional example of the effect of several microtubular binding agents on phenomena mediated at the phagocytic surface.
Shigella flexneri
Inhibition by Acetic Acid
Authors: Baskett Russell C. , Hentges David J.
Published: January 2020

The degree of
Shigella flexneri
inhibition by acetic acid in a chemically defined medium was dependent upon the concentration of undissociated acetic acid in the medium. Under the conditions of the experiments, the critical concentration of undissociated acetic acid that completely inhibited
S. flexneri
multiplication was approximately 0.0018 M. Adjustment of the medium from pH 6.0 to 7.0 after incubation, which reduced the concentration of undissociated acid 10-fold, completely reversed inhibition, and
S. flexneri
attained a viable population equivalent to its population in medium without acetic acid. The effects of acetic acid on cellular processes were also studied. The acid interfered with the intracellular accumulation of glucose and glutamic acid but did not interfere with the accumulation of phosphate. The glucose analogue 3-o-methyl-D-glucose, which is taken up by
S. flexneri
but not metabolized, was used to determine if inhibition resulted from interference with permeation or interference with intracellular accumulation through inhibition of glucose metabolism. Acetic acid did not interfere with the uptake of the glucose analogue by
S. flexneri
, indicating that inhibition probably involves interference with metabolism. Further evidence for this conclusion was obtained from respiration studies with cell-free extracts in the presence and absence of acetic acid. Inhibition of oxygen uptake by acetic acid in the absence of a permeability barrier suggested a metabolic block rather than interference with permeation. The inhibition of oxygen uptake by cell-free extracts occurred at both pH 6.0 and 7.0, indicating that the degree of dissociation of the acid is unimportant regarding interference with metabolism by intracellular material. The degree of dissociation is important, however, regarding uptake of acetic acid by
S. flexneri.
Whole cells were more permeable to the undissociated form of acetic acid than to the dissociated form. The data indicate that acetic acid, when taken up by
S. flexneri
, interferes with the metabolism of glucose by the cells.
Detection and Characterization of Defective Mycoplasmacidal Antibody Produced by Rodents Against
Mycoplasma arthritidis
Authors: Cole B. C. , Ward J. R.
Published: January 2020

A procedure has been developed for the detection of mycoplasmacidal antibody in the serum of rats and mice infected with
Mycoplasma arthritidis.
Antibody activity can apparently be measured only by using resting mycoplasma cells. The reaction is complement dependent and is usually complete within 3 h. Early antibody (5 days) could be detected only within the immunoglobulin (Ig)M fraction, whereas late antibody (42 days) is found within the IgG fraction. The mycoplasmacidal antibody was highly specific and cross reactions were not observed with other mycoplasma species. Antibody activity could be removed from serum by absorption with either viable or nonviable
M. arthritidis.
Cidal antibody produced by rats against other mycoplasma species was active against both resting and multiplying cells. Mycoplasmacidal antibody against
M. arthritidis
was detected in rats 2 days after injection of the organisms and persisted at least through 300 days. Mice usually developed antibodies by 3 days after injection of the organisms and moderate titers have been observed for as long as 487 days. Since viable mycoplasmas can persist in the peripheral circulation in the presence of antibody, it is likely that viable mycoplasma-antibody complexes are also present.
Neutralizing Antibody Response in Bovine Serum and Nasal and Salivary Secretions After Immunization with Live or Inactivated Foot-and-Mouth Disease Virus
Authors: Figueroa Felipe , Ohlbaum Adela , Contreras Guillermo
Published: January 2020

Calves develop nasal and salivary neutralizing antibodies against foot-and-mouth disease virus after nasal inoculation with live virus. Nasal and salivary antibody was not detected after exposure to inactive virus. Serum antibodies were induced by live and inactive virus given subcutaneously. Passively acquired antibodies were detected as long as 7 months after birth.
Association of Group B Coxsackieviruses with Cases of Pericarditis, Myocarditis, or Pleurodynia by Demonstration of Immunoglobulin M Antibody
Authors: Schmidt Nathalie J. , Magoffin Robert L. , Lennette Edwin H.
Published: January 2020

Tests for immunoglobulin M (IgM) antibody to group B coxsackieviruses were performed on sera from 259 patients with a clinical diagnosis of pericarditis, myocarditis, or pleurodynia on whom there were no definitive serological or virus isolation findings to establish a viral etiology, and on 259 “control” patients with clinical diagnoses of viral or mycoplasmal pneumonia or pneumonitis. IgM antibodies to coxsackievirus types B1, B3, B4, B5, and B6 were detected by a micro-immunodiffusion technique, and antibodies to virus type B2 were detected by reduction of neutralizing antibodies with ethanethiol. Of the patients with pericarditis, myocarditis, or pleurodynia, 27% (70) had IgM antibody to group B coxsackieviruses, as compared with 8% in the control group. On retrospective review of the clinical diagnosis, some of the patients in the control group with IgM antibody were found to have had additional clinical findings which could be attributed to a coxsackievirus infection. Coxsackievirus IgM antibody was demonstrable in 30% of 113 patients in the study group for whom virus isolation had been attempted with negative results. The presence of coxsackievirus IgM is discussed in relation to the time of serum collection, age of the patients, and month of onset of illness.
Behavior of
Mycobacterium leprae
in Human Macrophages In Vitro
Authors: Samuel Dorothy R. , Godal T. , Myrvang B. , Song Y. K.
Published: January 2020

Attempts have been made to cultivate
Mycobacterium leprae
in human macrophages in vitro. In 27 out of 55 experiments a two- to ninefold increase (mean 2.31 ± 1.46) in acid-fast organisms were observed over a period of 1.5 to 3 months of cultivation. No such increase was observed with heat-killed bacilli (mean fold increase 0.88 ± 0.19). Macrophages were necessary for obtaining increases. No multiplication was observed on artificial media. A close correlation between increases of acid-fast organisms and changes in viability as determined by the morphology of the bacilli (morphologic index) was found. The increases in acid-fast organisms could be inhibited by anti-leprosy drugs. It is concluded that multiplication of
M. leprae
may take place inside human macrophages in vitro. Multiplication appears not to be dependent on whether the macrophages are derived from lepromatous or tuberculoid patients or healthy individuals. Moreover, multiplication took place both at 33 and 37 C. The applicability of this method is at present limited by the restricted survival of human macrophages in vitro.
Antibody Responses to Meningococcal Polysaccharide Vaccines
Authors: Brandt Brenda L. , Artenstein Malcolm S. , Smith Creed D.
Published: January 2020

Over the past 4 years 19 lots of group C polysaccharide vaccine and five lots of group A polysaccharide vaccine have been tested for their immunogenicity in man. For each lot tested, groups of 18 to 50 men received 50 μg of vaccine subcutaneously. Sera were obtained prior to and 2 weeks after vaccination. The analytical and serological methods used in these studies were Sepharose 4B chromatography for the estimation of molecular size, the radioactive antigen binding assay, and the indirect hemagglutination (IHA) test for measuring the antibody response. Results have shown that the radioactive antigen binding assay is preferable to the IHA test as a measure of antibody response. Group C meningococcal vaccines have been highly stable when stored at 4 C in powdered form. All lots of group C vaccine tested to date have been of equal potency, with molecular weight varying from 520,000 to 2,000,000. Group A polysaccharides have been found to be unstable after 2 years of storage at 4 C. Optimal antibody response to the group A vaccines appears to be directly related to the molecular size of the preparation.
Protection of Rabbits Against Local Vaccinia Virus Infection by
Brucella abortus
and Polyacrylic Acid in the Absence of Systemic Interferon Production
Authors: De Clercq Erik , De Somer Pierre
Published: January 2020

Brucella abortus
and polyacrylic acid, two agents whose interferon-inducing capacity in the mouse has been well established, failed to stimulate circulating interferon production in rabbits, yet protected rabbits against local vaccinia virus infection.
Pathogenicity of
Allescheria boydii
for Mice
Authors: Lupan David M. , Cazin John
Published: January 2020

Allescheria boydii
and its imperfect state,
Monosporium apiospermum
, were studied to determine whether asexual or sexual strains might exhibit different pathogenic potentials for mice. Six different strains of the fungus were inoculated into mice by the intravenous, intracerebral, intraperitoneal, and intranasal routes. Cortisone-treated mice regularly developed infections after inoculation by any of the routes tested. Mice that had not been treated with cortisone were most susceptible to infection by the intravenous route and least susceptible to infection by the intranasal or intraperitoneal route; nevertheless, all animals that did not receive cortisone were considerably more resistant to infection by the fungus than were comparable groups of cortisone-treated animals. Pathogenicity of the fungus appears to be strain dependent and entirely unrelated to its sexual or asexual form. Studies made to determine accurate viable spore counts of the fungus revealed that the highest viable spore count was generally observed using Sabouraud dextrose agar or potato dextrose agar at an incubation temperature of 37 C for a period of 5 days.
Platelet Enhancement of Postphagocytic Destruction of
Listeria Monocytogenes
in Cultured Mouse Peritoneal Macrophages
Authors: Wilder Martin S. , Lubin Donald J.
Published: January 2020

Rabbit platelets enhance the bactericidal capability of cultured mouse peritoneal macrophages against
Listeria monocytogenes.
Dengue Virus Infection of Mice: Morphology and Morphogenesis of Dengue Type-2 Virus in Suckling Mouse Neurones
Authors: Sriurairatna Siriporn , Bhamarapravati Natth , Phalavadhtana Oranuj
Published: January 2020

In dengue type-2 virus-infected neurones of suckling mice, formation of single-membrane vesicles is observed in the distended cisternae of the endoplasmic reticulum mostly of the perinuclear zone around 72 h after inoculation. Electron-dense 50-nm virus particles are arranged in chains in these distended cisternae; some form small crystalloid aggregates. Aberrant particles of different shapes are also seen in the distended cisternae about the same time that the virus particles appear. Parallel filamentous structures are occasionally observed in the cisternae that contain very few virions, either characteristic or aberrant. Increasing cytopathic changes are present after 75 to 96 h. There is an intense vesicular formation. Large numbers of virions and aberrant particles are seen either in the endoplasmic reticulum cisternae or smooth membrane vesicles. They are spread throughout the neurocytoplasm, extending into the dendrites. Dengue virions which are enclosed in fairly intact membrane-bound vesicles are released during cytolysis of the neurones. Morphogenesis of dengue virus type 2 is discussed.
Comparison of the Tissue Receptors for
Vibrio cholerae
and
Escherichia coli
Enterotoxins by Means of Gangliosides and Natural Cholera Toxoid
Authors: Holmgren Jan
Published: January 2020

The in vitro binding properties of enterotoxins of
Vibrio cholerae
and
Escherichia coli
to different pure gangliosides and related neutral glycosphin-golipids were analyzed with a sorbent assay utilizing plastic tubes to which the glycolipid substances had been coupled. It was found that the cholera toxin bound to G
M1
ganglioside better than to the other tested substances G
M3
, G
M3
-NGN, G
M2
, G
D1a
, G
D1b
, G
T
, G
A1
, tetrahexoside-GlcNac and globoside. With this assay using G
M1
-coated tubes it is possible to measure cholera toxin even at concentrations below 1 ng/ml. Also enterotoxin of various
E. coli
strains bound to G
M1
, but the affinity was much less than for cholera toxin. The G
M1
ganglioside, in contrast to the other glycosphingolipids, effectively inactivated cholera toxin as determined with the intradermal and the ileal loop assays; approximately equimolar concentrations of the ganglioside in relation to toxin sufficed. Also, the skin and ileal loop activities of
E. coli
enterotoxins could be inhibited by G
M1
; however, several orders more of the ganglioside were required for such inhibition than for inactivation of the cholera toxin, and the differences between G
M1
and the other substances were less pronounced for
E. coli
toxins. Preincubation of rabbit ileal loops with choleragenoid, a natural toxoid of
V. cholerae
which has binding properties to the G
M1
ganglioside similar to cholera toxin, made the loops resistant to subsequently added enterotoxin of
V. cholerae.
The responsiveness to enterotoxin of
E. coli
was not reduced by this toxoid. A likely interpretation of these data is that the G
M1
ganglioside constitutes or at least contains the structure of functional tissue receptors for the cholera toxin, whereas the weak binding to G
M1
by
E. coli
enterotoxins is probably a pathogenetically insignificant reflection of structural similarities between these toxins and cholera toxin. Consequently, the cholera toxoid by occupying functional intestinal G
M1
receptors for the cholera toxin could inhibit the ileal response to this toxin, but not the response to
E. coli
enterotoxin since the intestinal receptors for the latter toxin are not affected by the cholera toxoid.
Experimental Genital Infection of Male Guinea Pigs with the Agent of Guinea Pig Inclusion Conjunctivitis and Transmission to Females
Authors: Mount David T. , Bigazzi Pierluigi E. , Barron Almen L.
Published: January 2020

Male guinea pigs were inoculated intraurethrally with the agent of guinea pig inclusion conjunctivitis (Gp-ic). Cytoplasmic inclusions were found in superficial epithelial cells of the urethra in smears and stained sections. Gp-ic antigen(s) was detected by immunofluorescent staining of sections. There was no marked urethral exudate, but many animals developed bullous lesions on the glans and the body of the penis and a severe inflammatory lesion of the hind leg. All males demonstrated an antibody response and most of them showed a positive skin test reaction. Venereal transmission to females of Gp-ic infection was shown to occur as determined by detection of inclusions in vaginal smears, antibody response, and positive skin tests.
In Vitro and In Vivo Effects of Endotoxin on Mouse Peritoneal Cells
Authors: Shands J. W. , Peavy D. L. , Gormus B. J. , McGraw J.
Published: January 2020

The in vitro effect of endotoxin (LPS) on unfractionated mouse peritoneal cells and cells fractionated into glass adherent and nonadherent populations was studied. LPS caused blast transformation and deoxyribonucleic acid synthesis in the nonadherent, nonphagocytic cells. There was no evidence of a mitogenic effect on macrophages. Instead, a cytotoxic effect was noted. When incubated with unfractionated peritoneal cells, LPS was still cytotoxic for macrophages, but the mitogenic effect for nonadherent cells was decreased or ablated. The intraperitoneal administration of LPS to mice resulted in an acute inflammatory response with a transient depletion of mononuclear cells. There was no stimulation of division of macrophages. Data were obtained which indicated that local cell division is an important factor in the normal turnover of peritoneal macrophages.
Release of β-Lysin from Platelets by Thrombin and by a Factor Produced in Heparinized Blood
Authors: Tew John G. , Roberts Robert R. , Donaldson David M.
Published: January 2020

Removal of calcium by either citrate, oxalate, or ethylenediaminetetraacetate inhibited coagulation of blood at an early stage and prevented the release of β-lysin from platelets. In contrast, heparin caused platelet agglutination and stimulated β-lysin release in vitro and in vivo. This release was calcium dependent and may have been due to a calcium-dependent reaction in the blood coagulation sequence. Thrombin which by-passed the early calcium-dependent stages of coagulation directly stimulated the release of β-lysin from platelets. However, thrombin alone or in combination with other plasma factors was not as effective in releasing β-lysin as the regular coagulation process. Thrombin's platelet degranulating activity correlated with its β-lysin releasing activity. In contrast to thrombin, staphylococcal coagulase, which also by-passed the calcium-dependent stages of coagulation, coagulated citrated blood without releasing β-lysin. The release of β-lysin has been observed previously in the absence of blood coagulation, but this is the first observation of coagulation without β-lysin release. It is clear that β-lysin is released from platelets during coagulation by the direct action of thrombin and that it may be released in an earlier calcium-dependent reaction.