bluuebunny/crossref_metadata_2025 huggingface dataset:
Absence of Correlation Between Delayed-Type Hypersensitivity and Protection in Experimental Systemic Candidiasis in Immunized Mice
Authors: Hurtrel Bruno , Lagrange Philippe H. , Michel Jean-Claude
Published: January 2020

We found that in mice which had been immunized intraperitoneally with 2 × 10
8
heat-killed
Candida albicans
cells there was a striking temporal relationship between resistance to systemic challenge with 10
6
living
C. albicans
cells and a number of measurable cellular parameters of the host response. These included the emergence of delayed-type hypersensitivity and the development of granulocytosis. Since it had been shown in previous work that granulocytosis was associated with an increase in resistance when nonspecific immunostimulation was used, we performed experiments to induce delayed-type hypersensitivity without any measurable modification of the granulocyte population. Adoptive transfer of delayed-type hypersensitivity with spleen cells from immune and resistant donor mice did not produce any increase in resistance in normal recipients. When separate groups of mice were immunized intraperitoneally or subcutaneously with varying doses of heat-killed
C. albicans
, we found that doses of less than 10
8
cells did induce significant delayed-type hypersensitivity without any increase in granulocytosis. In such mice, as well as in animals pretreated with immunomodulators before immunization with heat-killed
C. albicans
, the presence of cell-mediated immunity, as measured by the delayed-type hypersensitivity test, was not associated with an increase in resistance against systemic candidiasis. On the contrary, the results suggested that cell-mediated immunity was associated with an increase in the susceptibility of these mice. The same effect on candidiasis susceptibility was observed when animals were immunized with heat-killed filamentous
C. albicans.
Characterization of lipoteichoic acid binding to polymorphonuclear leukocytes of human blood
Authors: Courtney H , Ofek I , Simpson W A , Beachey E H
Published: January 2020

Human polymorphonuclear leukocytes (PMN) were shown to possess specific binding sites for lipoteichoic acid (LTA). LTA binding was reversible and time and temperature dependent. Scatchard plot analysis revealed an apparently single population of 6.6 X 10(6) LTA binding sites per PMN with a dissociation constant of 5.6 microM. Attachment of an avirulent, unencapsulated, M-negative strain of group A streptococci to PMN was inhibited by LTA, but not by other bacterial somatic antigens tested. Occupation of 30% of the LTA binding sites resulted in greater than 70% inhibition of streptococcal attachment to PMN. In contrast, LTA failed to block attachment of Escherichia coli or antibody-coated streptococci, indicating that binding sites for E. coli and the Fc portion of immunoglobulin G are distinct from those for LTA. Immunofluorescent studies demonstrated that LTA remained uniformly bound to PMN membranes for as long as 2 h at 37 degrees C. Cross-linking of PMN-bound LTA with anti-LTA resulted in rapid capping of LTA receptor sites. The results suggest that LTA is a monovalent ligand interacting with mobile receptors in the plasma membrane of PMN.
Effect of monoclonal antibodies on phagocytosis and killing of Toxoplasma gondii by normal macrophages
Authors: Hauser W E , Remington J S
Published: January 2020

Treatment of intact toxoplasma tachyzoites with individual mouse monoclonal antibodies to toxoplasma which are directed against individual membrane-associated antigenic determinants facilitated the phagocytosis of toxoplasma and also prepared the toxoplasma for intracellular destruction by nonelicited mouse peritoneal macrophages. In instances in which the organisms survived intracellularly, their multiplication was significantly reduced. Such monoclonal antibodies should be useful in further elucidating the role of antibody in resistance to toxoplasma and other facultative and obligate intracellular organisms.
Influence of blue-green algae (cyanobacteria) on survival of Legionella pneumophila in aerosols
Authors: Berendt R F
Published: January 2020

The fluid in which blue-green algae (cyanobacteria) (Fischerella sp.) had been grown (algal extract) was investigated for its effect on aerosols of Legionella pneumophila. The bacteria were significantly more stable when suspended in algal extract than in the tryptose-saline solution employed in previously reported experiments. The stabilizing property of the extract disappeared after dialysis, suggesting that a relatively small molecule was involved. The relationship of this observation to the epidemiology of Legionnaires disease is discussed.
Stimulation of nonspecific resistance to infection induced by 6-O-acyl muramyl dipeptide analogs in mice
Authors: Matsumoto K , Ogawa H , Kusama T , Nagase O , Sawaki N , Inage M , Kusumoto S , Shiba T , Azuma I
Published: January 2020

The experimental system utilized in investigating the correlation between the chemical structures of muramyl peptides and their protective activities in the sepsis type of systemic infections caused by Escherichia coli was applied in evaluating the enhancement of resistance to infection induced by 32 synthetic glycopeptide analogs, including 6-O-acyl derivatives and 1-alpha-O-benzyl derivatives of muramyl dipeptide (N-acetyl muramyl-L-alanyl-D-isoglutamine). In assessing the 6-O-acyl derivatives of muramyl dipeptide, we found that the degree of protective activity was attributable to the kinds of fatty acids introduced. Acylation of the 6-hydroxy group on the muramic acid moiety in muramyl dipeptide with natural mycolic acid or a synthetic fatty acid possessing either an alpha-branched or an alpha-branched, beta-hydroxylated group resulted in a decrease in or a disappearance of the protective activity of muramyl dipeptide. Acylation with a normal fatty acid or an iso fatty acid resulted in a retention or enhancement of muramyl dipeptide activity. The activity of acylated derivatives containing linear fatty acids was stimulated by increasing the chain length up to 18 carbon atoms. The highest degree of protective activity occurred with the derivatives acylated with straight-chain fatty acids, particularly with the derivatives acylated with palmitic acid and arachidic acid. Benzylation of the 1-hydroxy group of muramyl dipeptide resulted in a decrease in or a loss of protective activity.
Persistent infection of mouse fibroblasts (McCoy cells) with a trachoma strain of Chlamydia trachomatis
Authors: Lee C K , Moulder J W
Published: January 2020

An in vitro model of persistent infection of mouse fibroblasts (McCoy cells) with a trachoma strain (G17) of Chlamydia trachomatis has been developed. Persistently infected cultures were established by infecting McCoy cells with high multiplicities of chlamydiae. After the first cycle of chlamydial replication, the host cells multiplied more rapidly than the parasites, so that the fraction of inclusion-bearing cells declined to less than 1%. However, after 100 days, the proportion of inclusion-bearing cells rose dramatically, and the cultures alternated between periods of massive host cell destruction by chlamydiae and periods of host cell proliferation. This cycle continued indefinitely as host cell and parasite densities fluctuated periodically. The chlamydiae in the cycling populations were reidentified as the original serotype. No changes in either host cell susceptibility or chlamydial invasiveness were observed in hosts and parasites recovered from persistently infected populations. All evidence suggests that the parasite maintained itself in McCoy cell populations by cell-to-cell transfer and that an equilibrium between host and parasite multiplication was achieved when the persistently infected cultures fluctuated between periods of host cell destruction and proliferation.
Immunological and biological characterization of Coxiella burnetii, phases I and II, separated from host components
Authors: Williams J C , Peacock M G , McCaul T F
Published: January 2020

Coxiella burnetii, phase I and II, cells cultivated in the yolk sac of chicken embryos were separated from host cell components by two cycles of isopycnic Renografin gradient centrifugation. Initial steps in the purification of viable C. burnetii involved differential centrifugation and sedimentation through an aqueous solution of 30% sucrose and 7.6% Renografin. After the first, but not the second, cycle of Renografin gradient centrifugation, the cells were passed through microfilter glass filters which facilitated the removal of host components. The integrity of morphologically different cell variants was maintained during purification procedures by suspending highly purified C. burnetii in phosphate-buffered saline-sucrose solutions. C. burnetii, phases I and II, obtained by these methods appeared to be free from host cell components by serological methods while retaining morphological integrity and infectivity for yolk sacs and experimental animals. Average yields of C. burnetii were 2.83, 1.5, and 0.84 mg (dry weight) per yolk sac of the Ohio strain (phase I), 9 Mile strain (phase I), and 9 Mile strain (phase II), respectively. Recovery of phase I cells averaged about 70%, whereas the recovery of phage II cells was approximately 40%. The temporal sequence of phase I and II antibody response was demonstrated in infected and vaccinated animals. Also, no antibody response in mice and guinea pigs to yolk sac antigens was detectable after two injections of vaccine or viable cells. Importantly, this is the first report of the separation of viable phase II cells of C. burnetii free of host components.
Opsonization in vitro of Giardia lamblia trophozoites
Authors: Radulescu S , Meyer E A
Published: January 2020

The ability of peritoneal rabbit macrophages from immunized and nonimmunized animals to phagocytose Giardia lamblia trophozoites in the presence of serum was studied and compared in an in vitro system. The rabbits which served as the source of immune serum and macrophages were injected repeatedly at multiple sites (intramuscularly, subcutaneously, and intradermally) with a mixture of G. lamblia trophozoites and Freund complete adjuvant. In the presence of normal rabbit serum, a low level of phagocytosis of Giardia trophozoites by normal and immune macrophages was observed. In the presence of hyperimmune rabbit serum, an increased phagocytic activity of both types of macrophages occurred. The opsonic activity was similar whether whole serum or purified immunoglobulin G was used and whether or not these were heat inactivated. G. lamblia trophozoites in suspension were shown to be agglutinated in the presence of hyperimmune serum. Tests employing serial dilutions of hyperimmune serum resulted in a parallel loss of opsonifying and agglutinating activities. It is suggested that opsonization in vivo may play a role in the ability of the host to limit infection by these organisms.
Pathogenesis of a Pichinde Virus Strain Adapted to Produce Lethal Infections in Guinea Pigs
Authors: Jahrling P. B. , Hesse R. A. , Rhoderick J. B. , Elwell M. A. , Moe J. B.
Published: January 2020

A model for studying the pathogenesis of virulent arenavirus infection was developed by adapting Pichinde virus to produce lethal infections of inbred guinea pigs. This adapted Pichinde virus retained low virulence for primates, thus potentially reducing the biohazard to investigators. Whereas all inbred (strain 13) guinea pigs were infected and killed by 3 plaque-forming units or more of adapted Pichinde virus injected subcutaneously, outbred (Hartley strain) guinea pigs were relatively resistant. All infected, inbred guinea pigs died at 13 to 19 days after inoculation, with viremias in excess of 5 log
10
plaque-forming units/ml, severe lymphopenia (<1,000/mm
3
), and elevated serum glutamic oxaloacetic acid transaminase levels. Immunofluorescent antibody examination of tissues and infectivity titrations of tissue homogenates obtained at 3- to 4-day intervals demonstrated significant viral replication in all visceral tissues examined, but not in brain. Livers of all moribund guinea pigs contained moderate to severe hepatocellular necrosis and diffuse fatty change. Splenic red pulp and adrenal cortical tissues were engorged with blood and contained necrotic foci. Pancreatic acinar tissues were atrophied and vacuolated; lung sections typically contained areas of moderate to severe interstitial pneumonia. Inflammatory cells were conspicuously absent from all lesions. The virological and pathological features of adapted Pichinde infection in guinea pigs are remarkably similar to those described for Lassa virus infections in rhesus monkeys and humans, suggesting that this model might provide insight into the pathogenesis and treatment of Lassa fever in humans.
Cultivation of Virulent
Treponema pallidum
in Tissue Culture
Authors: Fieldsteel A. Howard , Cox David L. , Moeckli Randolph A.
Published: January 2020

In a series of seven experiments, the virulent Nichols strain of
Treponema pallidum
was shown to attach and replicate on the surface of tissue culture cells of cottontail rabbit epithelium (Sf1Ep) growing in conventional monolayer cultures under an atmosphere of 1.5% oxygen. Five days after inoculation of 10
6
T. pallidum
, the number of treponemes had increased to between 8 × 10
6
and 2.59 × 10
7
. The viability of harvested organisms ranged from 86 to 97%. The number of
T. pallidum
continued to increase, generally reaching a plateau between days 9 and 12 of incubation, with increases ranging up to 100-fold and averaging 49-fold. There appeared to be a ceiling of multiplication of about 2 × 10
8
irrespective of the inoculum, which ranged from 10
6
to 10
8
T. pallidum.
Concurrent deoxyribonucleic acid assays were performed on the cultures containing
T. pallidum
to obtain further evidence of replication. Significant increases in treponemal deoxyribonucleic acid were observed when the inocula ranged from 10
6
to 10
7
, with the greatest increases, as might be expected, being in the former group. There was also excellent correlation in the amount of deoxyribonucleic acid per treponeme; the averages for the 10
6
, 2.5 × 10
6
, and 10
7
groups were 3.46 × 10
−14
, 3.28 × 10
−14
, and 2.79 × 10
−14
g per treponeme, respectively (3.14 ± 0.72 × 10
−14
g per treponeme). In each experiment, organisms were harvested from the group inoculated with 10
6
T. pallidum
after 7 days of incubation to test for virulence. In all instances, the organisms were virulent; erythematous, indurated, treponeme-containing lesions were produced from an average of six to seven organisms. Scanning electron microscopy revealed that during the course of replication many microcolonies of treponemes formed on the surface of the cells.
Characterization of Salmonella toxin released by mitomycin C-treated cells
Authors: Houston C W , Koo F C , Peterson J W
Published: January 2020

The enzyme-linked immunosorbent assay and the Chinese hamster ovary floating cell assay for cholera toxin have proven to be sensitive and reliable tests for determining the antigenic and biological characteristics of Salmonella toxin, respectively. The addition of mitomycin C to the culture media 3 h after inoculation resulted in increased amounts of Salmonella toxin in culture filtrates but had the reverse effect on cell sonic extracts. Our data suggested that the increased amounts of Salmonella toxin culture filtrates caused by mitomycin C were due to cell lysis, resulting in the release of intracellular toxin, rather than to an increase in the synthesis of Salmonella toxin. The biological activity of Salmonella toxin was heat labile at 100 degrees C. The antigenic structure of the toxin appeared to remain intact after exposure to temperatures as high as 100 degrees C but was altered somewhat when the toxin was subjected to autoclaving. The toxin had an isoelectric point in the pH range from 4.3 to 4.8 and an estimated molecular weight which appeared to be more than 110,000. With the exception of the range for its isoelectric point, its molecular weight, and its low concentration in filtrates and sonic extracts, Salmonella toxin was very similar in biological and antigenic characteristics to cholera toxin. The antigenic and biological assays described here provide an effective basis for extending our study of Salmonella toxin.
Model for Studying Bacterial Adherence to Epithelial Cells Infected with Viruses
Authors: Selinger Daniel S. , Reed William P. , McLaren Leroy C.
Published: January 2020

Measles infection decreased adherence of staphylococci, streptococci, and pneumococci to cultured epithelial cells, whereas adenovirus had no effect. Rhinovirus increased staphylococcal and streptococcal adherence. Influenza A increased or decreased staphylococcal adherence at different times after infection.
Physicochemical surface properties of Escherichia coli strains isolated from different types of urinary tract infections
Authors: Ohman L , Normann B , Stendahl O
Published: January 2020

Escherichia coli strains isolated from three groups of patients with urinary tract infections, such as acute pyelonephritis, acute cystitis, and asymptomatic bacteriuria, were analyzed with respect to their physicochemical surface properties by means of polymer two-phase partitioning in dextran-polyethylene glycol systems and hydrophobic interaction chromatography on Octyl-Sepharose. Strains causing acute pyelonephritis constituted a homogenous group which, depending on the growth conditions, demonstrated smooth-type lipopolysaccharide, elevated negative charge, and liability to hydrophobic interaction, whereas strains isolated from acute cystitis and asymptomatic bacteriuria showed a more heterogenous pattern.
Characterization of the temperature sensitive phenotype of the A/Ann Arbor/6/60 cold-adapted virus and its recombinants
Authors: Murphy B R , Maassab H F , Wood F T , Chanock R M
Published: January 2020

The A/Ann Arbor/6/60 cold-adapted (ca) donor virus had a 38 degrees C shutoff temperature when tested in MDCK tissue culture. ca recombinant viruses bearing all six "internal genes" of the A/Ann Arbor/6/60 ca donor virus and the surface antigens of wild-type virus can manifest a 1,000-fold difference in plaquing efficiency at 38 degrees C. These observations suggest that the A/Ann Arbor/6/60 ca donor genes that specify the temperature sensitive phenotype of the ca recombinants can undergo genetic modification during the production and passage of the recombinants. The NS gene in the ca recombinant virus could be inherited from either parent without influencing the level of temperature sensitivity of the ca recombinant.
Vibrio vulnificus
(Lactose-Positive Vibrio) and
Vibrio parahaemolyticus
Differ in Their Susceptibilities to Human Serum
Authors: Carruthers Mary M. , Kabat William J.
Published: January 2020

Eleven
Vibrio vulnificus
(lactose-positive vibrio) strains were less susceptible to the bactericidal activity of normal human serum or serum treated with magnesium-ethyleneglycol-bis (β-aminoethyl ether)-
N,N
′-tetraacetic acid than were six
Vibrio parahaemolyticus
strains.
Immunogenicity and antigenicity of human coronaviruses 229E and OC43
Authors: Schmidt O W , Kenny G E
Published: January 2020

The immunogenicity and antigenicity of human coronaviruses 229E and OC43 were studied by quantitative immunoelectrophoresis. Three distinct antigens were recognized in both coronavirus strains when T-100-solubilized whole virus was tested by two-dimensional immunoelectrophoresis against homologous rabbit antiserum. No antigens cross-reacted between strains, but the electrophoretic patterns against homologous antiserum were highly similar in that both strains had one electrophoretically fast antigen, one of intermediate mobility, and one of slow mobility. Immunization of rabbits with 10(9) plaque-forming units of virus was required for production of antiserum which recognized the three antigens; lesser amounts gave rise to antisera which recognized only one or two components. Precipitin lines excised from two-dimensional immunoelectropherograms were used successfully as immunogens to prepare monospecific antiserum to each of the antigens of OC43 and 229E. Monospecific antiserum to the slow component of 229E neutralized 229E only, and monospecific antiserum to the slow component of OC43 both neutralized and inhibited hemagglutination of OC43 virus. Human convalescent sera which possessed both complement-fixing and neutralizing antibody also recognized the slow-moving component.
Genetic analysis of resistance to lethal infections of vesicular stomatitis virus in Syrian hamsters
Authors: Fultz P N , Shadduck J A , Kang C Y , Streilein J W
Published: January 2020

Vesicular stomatitis virus (VSV), Indiana serotype, causes a lethal disease in adult Syrian hamsters. Susceptibility to low doses of VSV (10 to 100 plaque-forming units) was shown to be genetically determined by examining six inbred strains. Three strains, LSH, MHA, and CB, were found to be extremely susceptible, with more than 70% of the animals dying within 72 h after intraperitoneal injection. Two strains, MIT and UT2, were intermediately susceptible, with approximately 60% of VSV-infected animals surviving. One strain, UT1, was found to be highly resistant; however, resistance was not acquired until the 4th or 5th week of age, and 100% of VSV-infected neonatal hamsters died. Analyses of F1 hybrid and segregant backcross populations derived from the LSH and UT1 strains suggested that at least three independent genetic loci contribute to phenotypic resistance. One locus resides on the X chromosome; the others reside on autosomes. No obvious linkage to the hamster major histocompatibility complex was detected. F1 hybrids of two highly susceptible strains, CB and MHA, were more resistant than either parental strain, suggesting that alleles of unlinked genes in the susceptible strains interact to produce a partially resistant phenotype. These alleles probably are the cause of the resistance phenotype found in the random-bred LVG strain which shares a common heritage with the CB and MHA strains.
Isolation and characterization of hypertoxinogenic (htx) mutants of Escherichia coli KL320(pCG86)
Authors: Bramucci M G , Twiddy E M , Baine W B , Holmes R K
Published: January 2020

The structural genes for heat-labile enterotoxin (LT) are present on plasmid pCG86. Escherichia coli KL320(pCG86), LT was found to be cell associated. LT was present as a soluble protein in sonic lysates of KL320(pCG86). Thirty-one mutants of KL320(pCG86) that produced increased amounts of extracellular LT were isolated. These hypertoxinogenic (htx) mutants were assigned to four phenotypically distinct classes based on the amounts of cell-associated and extracellular LT in early-stationary-phase cultures. Type 1 and type 2 htx mutants produced significantly increased amounts of cell-associated LT. Type 3 and type 4 htx mutants produced normal or decreased amounts of cell-associated LT was similar to that of the wild type. In the mutants of types 1, 3, and 4, the ratios of extracellular to cell-associated LT were higher than that of the wild type and were characteristic for each strain. Cell lysis or leakage of macromolecular cytoplasmic constituents appeared to be significant for release of LT by mutants of types 1, 3, and 4, because supernatants from cultures of these mutants also contained increased amounts of protein and of the cytoplasmic enzyme glucose 6-phosphate dehydrogenase. In all four representative htx mutants, the hypertoxinogenic phenotypes were dependent on chromosomal mutations. The resident pCG86 plasmids were eliminated from the htx mutants of types 2 and 3. After wild-type plasmid pCG86 was introduced into the cured strains by conjugation, their hypertoxinogenic phenotypes were restored. We conclude that chromosomal loci in E. coli KL320 are important in regulating expression of the LT structural genes of plasmid pCG86.
Effect of uremia on lymphocyte transformation and chemiluminescence by spleen cells of normal and Cryptococcus neoformans-infected mice
Authors: Fromtling R A , Fromtling A M , Staib F , Müller S
Published: January 2020

The effect of uremia on immune incompetence was studied. BALB/c mice were infected with a minimally virulent strain of Cryptococcus neoformans 6 weeks before immune assay. Uremia was induced by intramuscular injection of 0.15 ml of glycerol. Pooled spleen cells from four experimental groups (normal, uremic, infected, and infected and uremic) were assayed by lymphocyte transformation (LT) and luminol-dependent chemiluminescence (CL) 24 h after induction of uremia. A greater response to phytohemagglutinin and concanavalin A stimulation in tests of LT and CL was exhibited by uremic cells than by nonuremic cells; however, the presence of BALB/c uremic serum resulted in lower responses by both LT and CL. Infected mice showed a greater response to mitogens than did noninfected mice, but no significant stimulation in response to heat-killed whole cells of C. neoformans. Spleen cell populations of uremic mice had a lower viability and a different composition of spleen cell subpopulations than did cell preparations from nonuremic mice.
Immunization of rats with heat-labile enterotoxin provides uniform protection against heterologous serotypes of enterotoxigenic Escherichia coli
Authors: Klipstein F A , Engert R F , Clements J D
Published: January 2020

Rats immunized with Escherichia coli heat-labile (LT) enterotoxin, either in the form of the holotoxin derived from a transformed K-12 strain or the polymyxin-release form obtained from human strains which produce LT toxin alone (LT+/ST- [ST is heat-stable toxin)] or together with ST toxin (LT+/ST+), were challenged with viable organisms of 10 different serotypes, 5 LT+/ST- and 5 LT+/ST+. The serum antitoxin response was monitored by enzyme-linked immunosorbent assay, and the degree of protection was determined by challenge in ligated ileal loops. Immunization with the holotoxin provided a strong antitoxin response and protection against all 10 challenge strains. Immunization with toxin from the LT+/ST+ strain provided equally strong protection against all strains, but immunization with toxin from the LT+/ST- strain yielded only a weak antitoxin response, moderate protection against challenge with LT+/ST- strains, and no protection against LT+/ST- strains, increasing by fivefold the immunization dosage of the LT+/ST- toxin failed to enhance protection. These observations (i) establish the fact that immunization with the LT holotoxin provides uniformly strong protection against heterologous serotypes and (ii) indicate that, for reasons which remain to be determined, the immunogenicity of the polymyxin-release LT from an LT+/ST+ strain differs from that of an LT+/ST- strain.
Neuraminidase Activity of
Pasteurella haemolytica
Isolates
Authors: Frank Glynn H. , Tabatabai Louisa B.
Published: January 2020

Neuraminidase activities of
Pasteurella haemolytica
cell suspensions were measured. Type isolates of the 12 established serotypes and bovine and ovine field isolates were included in the study. Neuraminidase activities ranged from 0 to 0.87 U per mg (dry weight) of
P. haemolytica.
Activity levels among the isolates studied were serotype associated.
Organization and expression of genes involved in the production of the K88ab antigen
Authors: Mooi F R , Harms N , Bakker D , de Graaf F K
Published: January 2020

Escherichia coli K-12 minicells were used to study the expression of the genes located on plasmid pFM205, which contains the genetic determinant of the K88ab antigen. Plasmid pFM205 is composed of a 4,3-megadalton large deoxyribonucleic acid fragment derived from the wild-type K88ab plasmid pRI8801 (51 megadaltons) and the cloning vehicle pBR322. The K88ab deoxyribonucleic acid of pFM205 appeared to express six polypeptides with apparent molecular masses of 81, 30, 29, 27, 26, and 17 kilodaltons, respectively. These polypeptides account for approximately 85% of the coding capacity of the cloned deoxyribonucleic acid. The 26-kilodalton polypeptide was found to react with specific anti-K88ab antibodies and therefore represents the K88ab subunit. The K88ab subunit and at least two other polypeptides (81 and 17 kilodaltons) were translated into precursors which were about 2 kilodaltons larger than the mature proteins. Plasmid pFM205 was used to construct deletion mutants. By analyzing these mutants in minicells the genes of the six polypeptides could be located on the physical map of pFM205. It appeared that deletion of the gene of the 81-kilodalton polypeptide resulted in an altered conformation of the K88ab antigen.
Selective induction of immunological tolerance in antiviral T killer cells of inbred mice after treatment with cyclosporin A
Authors: Armerding D
Published: January 2020

Primary anti-influenza A cytotoxic thymus-derived (T) and bone marrow (B) lymphocyte-dependent responses in inbred mice were used as an in vivo model system to study the effects of the immunosuppressive fungus metabolite cyclosporin A (CyA). Five consecutive daily oral applications of CyA, with the first being given 1 or 2 h before virus inoculation of the animals, caused a complete blockage of induction of anti-influenza T killer cells and a partial reduction of cytotoxic B lymphocyte activities. Adoptive cell transfer experiments revealed that incapability to respond was due neither to humoral factors nor to the generation of suppressor cells. The tolerance state appeared to be specific for influenza A; cytotoxic T lymphocytes against allogeneic cell surface determinants could be stimulated in immunosuppressed mice. CyA treatment abolished virus-specific and cross-reactive anti-influenza killer T cell responses. Suppression was of short duration: less than 1 week for B cell-dependent functions, and between 1 and 2 weeks for T killer cell responses. Animals appeared to be normal with regard to both of these cellular activities for 4 weeks after tolerance induction. Thus, the data indicate that CyA exerted preferential effects on killer T cells. Moreover, evidence was presented that CyA treatment during an ongoing influenza infection did not increase sensitivity to that virus. Mice with no measurable cytolytic anti-influenza T killer cell activities but significant B cell responses, although partially diminished by the drug, were completely protected against the lethal effects of influenza infection.
Evidence for Normal Cell-Mediated Immunity in Scrapie-Infected Mice
Authors: Kingsbury David T. , Smeltzer Deborah A. , Gibbs Clarence J. , Gajdusek D. Carleton
Published: January 2020

Comparisons between mixed lymphocyte cultures of splenocytes from scrapie-infected and normal mouse brain-inoculated control mice did not reveal any evidence of an impaired cell-mediated immune response in scrapie-infected mice. Likewise, mixed lymphocyte cultures of splenocytes from scrapie-infected and normal mice demonstrated that infected spleen cells had no scrapie-specific antigens on their surfaces. These data suggested that the absence of a detectable scrapie-specific immune response in infected mice was the result of an absence of an exposed scrapie-specific antigen and not due to any direct effect on the immune system.
Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells
Authors: Redfield D C , Richman D D , Oxman M N , Kronenberg L H
Published: January 2020

Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays.
Phagocytic and chemiluminescent responses of mouse peritoneal macrophages to living and killed Salmonella typhimurium and other bacteria
Authors: Tomita T , Blumenstock E , Kanegasaki S
Published: January 2020

In the presence of luminol, resident as well as thioglycolate-induced and immunized macrophages emitted chemiluminescence more efficiently when the cells were exposed to living Salmonella typhimurium than when they were exposed to the same bacterium killed by ultraviolet light or heat. This phenomenon was observed whether or not the bacterium was opsonized. The different response to living and killed bacteria was also found with Escherichia coli, Pseudomonas aeruginosa, Proteus morganii, and Enterobacter aerogenes, but not with Shigella sonnei, Klebsiella pneumoniae, and Propionibacterium acnes. The results suggest that macrophages respond better to living, motile bacteria than to nonmotile or killed bacteria. The experimental results obtained with motility mutants of S. typhimurium, E. coli, and P. aeruginosa confirm that macrophages exposed to the motile bacteria emit chemiluminescence more efficiently and ingest the motile bacteria at a much faster rate than the nonmotile bacteria.
Immune depression and macroglobulinemia in experimental subchronic trypanosomiasis
Authors: Baltz T , Baltz D , Giroud C , Pautrizel R
Published: January 2020

The effects of subchronic trypanosomiasis upon immune responses were examined in Trypanosoma gambiense infection and in subcurative treatment of T. brucei- and T- equiperdum-infected mice. About 60% of the mice infected with T. gambiense developed a subchronic infection similar to human trypanosomiasis, characterized by the absence of circulating trypanosomes. The animals died between 1 and 12 months after infection with elevated serum immunoglobulin M (IgM) levels (16 times the normal level). After 1 month of infection, the mice showed a normal primary antibody response against sheep erythrocytes, as tested by hemagglutination, despite their high serum IgM levels. After more than 1 month of infection, about 20% of the mice showed depressed hemagglutination titers (25% of control), whereas all relapsed mice that contained circulating parasites showed a pronounced suppression. Elimination of the blood parasites with Berenil treatment restored immune competence, which persisted until the relapse of the animals. Identical results were obtained in T. brucei-infected mice. Berenil treatment abolished the immune depression against sheep erythrocytes, but did not cure the animals, which relapsed with the development of a new state of immune depression. T. gambiense and T. brucei infections were always followed by a marked increase of serum IgM levels. Hypergammaglobulinemia was also induced in relapsing T. equiperdum-infected mice treated with Berenil. No immune depression against sheep erythrocytes could be detected. It appeared that immune depression was not the result of clonal exhaustion (measured by the serum IgM level) but seemed to be closely associated with the presence of living trypanosomes.
Role of Fc fragments in antibody-mediated recovery from ocular and subcutaneous herpes simplex virus infections
Authors: Oakes J E , Lausch R N
Published: January 2020

The contributions of the Fc fragment of virus-specific antibody in the resistance of mice to peripheral herpes simplex virus infection were investigated. Rabbit anti-herpes simplex virus-specific F(ab')2 fragments prepared by pepsin digestion of immune immunoglobulin G (IgG) were found to be inactive in complement-mediated cytolysis while retaining their capacity to neutralize virus infectivity in vitro. When F(ab')2 fragments were passively transferred either before or simultaneously with virus inoculation, they were as efficient as intact IgG was in protecting animals from virus challenge. However, if passive transfer was delayed until 8 h after herpes simplex virus infection, only IgG antibody was protective. The loss of protective activity could not be attributed to a rapid disappearance of F(ab')2 fragments, because comparable levels of F(ab')2 fragments and IgG antibody were maintained in the blood of recipients during the time that antibody mediated its protective effects. The inability of F(ab')2 subunits to activate complement was also not a factor, because complement-deficient A/J mice and complement-sufficient SJL/J mice recovered from herpes simplex virus infection after the passive transfer of IgG. We concluded that the Fc component of the antibody molecule is needed to resolve intracellular infection and that the mechanism by which antibody mediates recovery remains undefined but does not appear to involve virus neutralization or complement activation.
Effects of the composition of peritoneal dialysis fluid on chemiluminescence, phagocytosis, and bactericidal activity in vitro
Authors: Duwe A K , Vas S I , Weatherhead J W
Published: January 2020

Commercial fluid used for peritoneal lavage in peritonitis and in peritoneal dialysis suppressed the activity of peripheral blood leukocytes as measured by chemiluminescence, phagocytosis, and bacterial killing. Suppression was found to be due to the low pH and high osmolality of the fluid. The pH was adjusted to noninhibitory levels in vivo within 30 min, whereas osmolality changes were less rapid and remained at inhibitory levels for fluids of high dextrose concentration (4.25%). Chemiluminescence was the most sensitive assay for inhibitory effects of pH and osmolality, as well as for urea and heparin. The metabolic waste product urea at levels normally found in dialysate and heparin at concentrations routinely added to fluid inhibited only chemiluminescence, whereas creatinine and added insulin were not inhibitory. High fluid volume also resulted in a decrease in efficiency of bacterial killing. These results suggest some changes to be made in the treatment of peritonitis and in peritoneal dialysis.
Nonimmunoglobulin fraction of human milk inhibits bacterial adhesion (hemagglutination) and enterotoxin binding of Escherichia coli and Vibrio cholerae
Authors: Holmgren J , Svennerholm A M , Ahrén C
Published: January 2020

Human milk and colostrum samples were divided into an immunoglobulin and a nonimmunoglobulin fraction by immunosorbent chromatography. The ability of these fractions to inhibit bacterial cell adhesion and enterotoxin receptor binding of Vibrio cholerae and various Escherichia coli isolates was then tested by in vitro assays. The strongest effect was generally seen with the nonimmunoglobulin fractions, which were shown to significantly inhibit E. coli cell adhesion (hemagglutination) mediated by CFA/I, CFA/II, or K88 fimbriae (but not type 1 pili) and V. cholerae hemagglutination, as well as the binding of cholera toxin and E. coli heat-labile enterotoxin to GM1 ganglioside. Also, the immunoglobulin fractions had significant inhibitory activity in some of these systems. The results are interpreted to suggest that human milk and colostrum may contain secreted structure analogs of the cell receptors for some bacterial adhesions and enterotoxins; this might contribute to the protective effect of milk against enteric infections.
Plasmodium knowlesi variant antigens are found on schizont-infected erythrocytes but not on merozoites
Authors: Hommel M , David P H
Published: January 2020

In this report, we demonstrate that the variable antigens present on the surface of Plasmodium knowlesi-infected erythrocytes could not be found on the surface of merozoites. A number of technical problems had to be solved to make such a comparative study possible, including the purification of merozoites by affinity columns and gradient centrifugation, the use of hyperimmune rabbit sera instead of monkey sera, and the use of immunocytological methods (indirect immunofluorescence antibody test and electron microscopy with ferritin-labeled antibodies) instead of the schizont-infected cell agglutination test. To ensure that these new techniques were valid for variant-specific serotyping, we compared two well-characterized variant populations with both the standard and the new methods. The removal of variant antigens from the surface of infected erythrocytes by proteolytic enzymes provides further information on the biochemical nature of these antigens.
Adherence of Acinetobacter calcoaceticus RAG-1 to human epithelial cells and to hexadecane
Authors: Rosenberg M , Perry A , Bayer E A , Gutnick D L , Rosenberg E , Ofek I
Published: January 2020

The ability of Acinetobacter calcoaceticus RAG-1 to adhere to human epithelial cells was investigated and compared with its ability to adhere to a test hydrocarbon (hexadecane). RAG-1, a microorganism originally isolated for growth on hydrocarbon, adhered to epithelial cells when grown under conditions which promote its adherence to hexadecane; similarly, RAG-1 cells adhered poorly to epithelial cells when grown under conditions which cause the cells to possess low affinity towards hexadecane. A mutant derived from RAG-1, MR-481, deficient in its ability to adhere to hydrocarbon, was similarly unable to adhere to epithelial cells. RAG-1 adherence to epithelial cells was not blocked by a number of sugars tested. Streptococcus pyogenes, whose adherence to epithelial cells has been previously attributed to hydrophobic interactions, was also able to adhere to hexadecane. Results suggest that hydrophobic interactions mediate adherence of the strains studied to both epithelial cells and hydrocarbon.
Encapsulated, Coagulase-Negative Strain of
Staphylococcus simulans
Authors: Anderson J. C. , Wilson C. D.
Published: January 2020

An encapsulated strain of
Staphylococcus simulans
(strain 76) isolated from a clinical case of bovine mastitis was demonstrated by the India ink technique, using both a light microscope and an electron microscope. The strain failed to kill mice after intraperitoneal inoculation but resisted ingestion by peritoneal phagocytic cells. The behavior of the strain helps to delineate the antiphagocytic role of the capsule.
Effect of Cycloheximide on the Infective Yield of a Genital Strain of
Chlamydia trachomatis
in McCoy Cells
Authors: Karayiannis Peter , Hobson Derek , Lee Norma
Published: January 2020

The yield of infectious progeny of a genital strain of
Chlamydia trachomatis
in cycloheximide-treated McCoy cell cultures was 11-fold lower than that in untreated monolayers.
Comparison of Plasmid Deoxyribonucleic Acid Contents, Culture Characteristics, and Indices of Pathogenicity Among Selected Strains of
Vibrio parahaemolyticus
Authors: Twedt R. M. , Brown D. F. , Zink D. L.
Published: January 2020

Thirty-one Kanagawa-positive and -negative
Vibrio parahaemolyticus
isolates from patient stools and seafood were examined for plasmid deoxyribonucleic acid content, culture characteristics, and indices of pathogenicity. No significant correlation was found between plasmid deoxyribonucleic acid contents and indices of pathogenicity for the strains tested.
Increased virulence of Neisseria meningitidis after in vitro iron-limited growth at low pH
Authors: Brener D , DeVoe I W , Holbein B E
Published: January 2020

At low pH (6.6) and under conditions of iron limitation, Neisseria meningitidis group B (strain SD1C) exhibited an atypical outer membrane protein profile and an increased relative virulence for the mouse. Cells grown in a buffered medium were effectively deprived of iron by the addition of ethylenediamine-diorthohydroxyphenylacetate. The pH of the medium selected for characteristic colonial morphologies: type M3 predominated at pH 6.6, and type M5 predominated at pH 7.7. A mixed population of M1, M3, and M5 colonies was observed at pH 7.2. Isolated outer membrane proteins were analyzed by sodium dodecyl 99 99 sulfate-polyacrylamide gel electrophoresis, and surface exposed proteins were labeled by the [125I]lactoperoxidase method and subsequently identified by autoradiography. Cells grown at pH 6.6 elaborated a major outer membrane protein (protein III; molecular weight, 69,000), which was also present in the outer membrane of iron-limited cells grown at pH 7.2. At pH 7.2 in an iron-sufficient medium, protein III was present only in small quantities in sodium dodecyl sulfate-polyacrylamide gel was present only in small quantities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. A study of the relative virulence (50% lethal dose) of the meningococcus for C57/BL mice revealed that iron-limited cells grown at low pH had an increased relative virulence 1,200-fold (50% lethal dose, 4.0 CFU) greater than that of cells grown in the same medium but at pH 7.2 and with sufficient iron. These studies indicate that pH and iron can be important factors in the determination of meningococcal virulence.
Endotoxin-induced serum factor kills malarial parasites in vitro
Authors: Taverne J , Dockrell H M , Playfair J H
Published: January 2020

We investigated the possibility that malarial parasites may be killed by nonspecific soluble mediators, such as those in tumor necrosis serum, that are obtained from mice given macrophage-activating agents like Corynebacterium parvum or Mycobacterium bovis BCG, followed by endotoxin. Such sera killed parasites in vitro after overnight incubation; killing was measured directly by using an in vivo infectivity assay. Parasite infectivity was not decreased by incubation in sera from mice given C. parvum or BCG alone (no endotoxin) or by incubation in sera from normal mice given endotoxin. Plasmodium yoelii, its lethal variant, and Plasmodium berghei were equally susceptible to inactivation. Sera obtained from mice given endotoxin during the course of infection with these parasites also contained parasite-killing factor. The activity of this factor appeared to be proportional to parasitemia in that it was higher in the sera from mice infected with the lethal parasites than in the sera from mice with infections which resolved either spontaneously or after vaccination.
Local cell-associated immunity in the Peyer's patches of mouse intestines
Authors: Marneerushapisal V , Rowley D
Published: January 2020

After oral infection of mice with a Salmonella strain, low numbers of organisms could be found in the Peyer's patches of the small intestine. In the course of a few days the organism in the Peyer's patches multiplied to about 10(5) and then were steadily eliminated so that by 10 days, very few organisms could be found in the lymphoid follicles. Because no organisms could be found in the spleen or other organs during this period, it is probable that the decline in numbers was due to killing of the organisms in situ. This development of antibacterial ability was not inhibited by treatment with cyclophosphamide, in contrast to the rapid growth of organisms which occurred in the spleen after intravenous injection in the presence of cyclophosphamide. The difference in behavior between Peyer's patches and the spleen upon treatment with cyclophosphamide is explained in terms of the extent of natural priming of Peyer's patches due to continual contact of the intestine with gram-negative enteric organisms. Once the spleen was primed, cyclophosphamide did not interfere with the elimination of a second challenge with the same organism.