bluuebunny/crossref_metadata_2025 huggingface dataset:
Lymphocyte Transformation in Syphilis: an In Vitro Correlate of Immune Suppression In Vivo?
Authors: Musher Daniel M. , Schell Ronald F. , Jones Ronald H. , Jones Alice M.
Published: January 2020

Suppression of cellular immunity during primary and secondary infection may explain, in part, the unusual clinical evolution of syphilis. We have previously shown that lymphocytes from normal subjects undergo blastic transformation when exposed in vitro to
Treponema refringens.
This response was suppressed in patients with syphilis. the suppression being unrelated to serum factors. In the present paper we studied lymphocyte response in vitro to
T. refringens, T. reiter
, and
T. pallidum
as well as to monilia and trychophytins. The response to these antigens was suppressed in patients with syphilis although the response to phytohemagglutinin. pokeweed mitogen, and streptolysin was normal. These data support the hypothesis that human infection with
T. pallidum
is followed by a complex interaction between cellular and humoral immunity, the former being suppressed in primary and secondary stages.
Production, Isolation, and Partial Characterization of Three Foot-and-Mouth Disease Virus Temperature-Sensitive Mutants
Authors: Richmond J. Y.
Published: January 2020

Three high temperature-sensitive (
ts
) mutants of foot-and-mouth disease virus were characterized by their relative abilities to grow at 33 or 38.5 C, to kill infant mice, to infect guinea pigs, and to produce foot-and-mouth disease in steers. Mutants
ts
-24 and
ts
-42 did not grow at 38.5 C; both may have produced considerable quantities of noninfectious virus particles at 33 C. A third mutant,
ts
-22, appeared “leaky” because it multiplied to a limited extent during prolonged incubation at the nonpermissive temperature. Mutant
ts
-42 was pathogenic for infant mice, whereas
ts
-22 and
ts
-24 were essentially apathogenic. Mice were protected against the lethal effects of the wild-type (
wt
) virus if injected 1 week earlier with
ts
-22, apparently as a result of specific antibody development. One-half of the guinea pigs injected with the mutant viruses showed lesion development, but only at the site of injection. Antibody development was also much less than in those animals injected with the
wt
virus. The onset of FMD in steers was delayed and the severity of the disease was diminished after intradermalingual injection of the mutant viruses.
In Vitro Studies on Rickettsia-Host Cell Interactions: Intracellular Growth Cycle of Virulent and Attenuated
Rickettsia prowazeki
in Chicken Embryo Cells in Slide Chamber Cultures
Authors: Wisseman C. L. , Waddell A. D.
Published: January 2020

Upon entry into the cytoplasm of irradiated chicken embryo cells in slide chamber cultures infected over a 2-h period, yolk sac-grown virulent (Breinl strain) and attenuated (E strain)
Rickettsia prowazeki
underwent indistinguishable reproducible intracellular growth cycles. They promptly entered an exponential growth phase, without detectable lag and without microscopic evidence for any unusual early replicative phase. The generation time for both strains was 8.8 to 8.9 h at 34 C. During most of this period, the state of the organisms and growth were very similar from one cell to another. The exponential-growth phase continued for at least 36 to 48 h, when the rickettsiae became too numerous to count by microscopic examination. Between about 36 and 48 h, cells packed with rickettsiae began irregularly to break down and release organisms. These began to initiate new infection cycles in previously uninfected cells over many hours, as demonstrated by the rise in percentage of cells infected, yielding a highly disordered infected culture with different cells containing rickettsiae in diverse stages of growth. The organisms underwent regular minor changes in morphology, similar to those seen in bacterial cultures, in the first infection cycle. As the cells became packed with rickettsiae, the microorganisms regularly diminished in size to become minute coccobacillary to coccoid forms. However, the rickettsiae in the second and subsequent infection cycles in aging cultures often assumed filamentous or swollen bizarre forms. Only the first infection cycle conformed closely to the concept of a one-step growth cycle. A set of terms is proposed and defined for the infection cycle.
Studies on Gonococcus Infection IX. In Vitro Decreased Association of Pilated Gonococci with Mouse Peritoneal Macrophages
Authors: Blake Milan , Swanson John
Published: January 2020

Pili, in addition to enhancing attachment of gonococci to tissue culture cells, appear to reduce association (attachment/ingestion) of
Neisseria gonorrhoeae
with mouse peritoneal macrophages in vitro.
In Vitro
N
-Nitrosodimethylamine Formation by Some Bacteria
Authors: Hashimoto Shusuke , Kawai Yasuo , Mutai Masahiko
Published: January 2020

It was found that human pathogenic bacteria and some species of intestinal bacteria in rats have the ability to catalyze the formation of
N
-nitrosodimethylamine from dimethylamine and nitrate in vitro.
Effect of Temperature on Survival and Growth of Infectious Pancreatic Necrosis Virus
Authors: Tu Kuen-Ching , Spendlove Rex S. , Goede Ron W.
Published: January 2020

Infectious pancreatic necrosis virus was stable for 10 days at 4 C in stream and well water, after which the virus had a half-life of 7.5 days. At 15 C, the virus was stable for 5 days, and then had a half-life between 5 and 6 days. Viral antigen in infected cells developed much more slowly at 4 C than at 20 C. Infected cells released infectious viral particles at temperatures as low as 4 C. Nutrition had a greater effect on the production of infectious virus at 4 C than at 20 C.
Genetic instability of M protein and serum opacity factor of group A streptocci: evidence suggesting extrachromosomal control
Authors: Cleary P P , Johnson Z , Wannamaker L
Published: January 2020

The M antigen, a primary determinant of virulence in group A streptococci that is expressed biologically as resistance to phagocytosis, is known to undergo a variety of phenotypic changes both in vivo and in vitro. These changes are nonrandom and can occur at a high frequency. Using the previously described relationship between the serum opacity reaction (associated with certain strains) and the presence of the M antigen, the phenotypic instability of the M antigen was analyzed. The results support the conclusion that M protein synthesis and the serum opacity reaction are directly or indirectly controlled by the same gene or by genes which are linked and can segregate as a unit. Moreover, growth conditions and the curing agents rifampin and ethidium bromide had a discernible influence on the segregation of clones unable to exhibit serum opacity factor and to resist phagocytosis by human leukocytes. Serial transfer of stationary-phase cultures of four strains of group A streptococci significantly increased the number of colonies negative for the serum opacity reaction and the M antigen. For two of four strains both ethidium bromide and rifampin also increased the segregation of colonies with this phenotype. In light of these experiments and the necessary controls, the possible influence of plasmids or bacteriophage in regulating M protein synthesis is discussed.
Factors affecting filamentation in Candida albicans: changes in respiratory activity of Candida albicans during filamentation
Authors: Land G A , McDonald W C , Stjernholm R L , Friedman L
Published: January 2020

Glucose metabolism and respiration of Candida albicans were compared under conditions which permitted either maximal filamentous or maximal yeast growth. Changes in metabolism were monitored by comparing the quantities of ethanol produced, CO2 evolved, and oxygen consumed. Filamenting cultures produced more ethanol and less CO2 than yeasts, with oxygen consumption in the former concomitantly slower than that of the latter. Studies involving cofactors and inhibitors associated with electron transport imply that a transfer of electrons away from flavoprotein is required for maintenance of yeast morphology. Conditions consistent with a buildup of reduced flavoprotein, however, favored filament formation. These changes were expressed metabolically as a shift from an aerobic to a fermentative metabolism. The results presented are consistent with hypotheses correlating filament production with changes in carbohydrate metabolism and an interruption of electron transfer within the cell.
Establishment of a nonproductive herpes simplex virus infection in rabbit kidney cells
Authors: Kelleher J J , Varani J , Nelson W W
Published: January 2020

A nonproductive infection of rabbit kidney cells was established with a type 2 strain of herpes simplex virus after incubation of the virus-infected cells at 41 C. Although infectious virus could not be recovered from cells disrupted by freeze-thawing or sonication after incubation at 41 C, spontaneous reactivation of virus growth occurred in 84% of the cultures after lag periods of variable length when cultures of viable cells were transferred to 37 C and incubated. Forty-one percent of the cultures had lag periods of 4 or more days, and 24% had lag periods of 7 or more days. The longest lag period was 45 days. A similar infection was established in WI-38 cells, but attempts to establish the infection in human kidney cells was not successful. This nonproductive infection is being used to study the effects of various physical and chemical agents on herpes simplex virus in a latent state.
Biochemical and immunological properties of ribonucleic acid-rich extracts from Francisella tularensis
Authors: Andron LA I I , Eigelsbach H T
Published: January 2020

Ribonucleic acid (RNA)-rich extracts derived from the attenuated strain of Francisella tularensis (strain LVS) protected Swiss mice against lethal challenge with F. tularensis strain 425 but not against strain SCHU S4. No killed preparation, including an RNA-rich extract from SCHU S4 itself, offered protection against strain SCHU S4 in contrast to the high level of protection offered against this strain by vaccination with live strain LVS. The protective activity observed against strain 425 was sensitive to ribonuclease but not to Pronase. Protective activity is not a general property of bacterial RNA, since RNA-rich extracts from Staphylococcus aureus offered no protection against tularemia, although disc gel electrophoresis showed similar kinds and amounts of RNA in preparations form F. tularensis and S. aureus. Furthermore, inability to localize activity to a specific region in sucrose gradients suggests a structural rather than an informational role for the RNA in such extracts. RNA-rich extracts from F. tularensis but not from S. aureus were efficient inducers of F. tularensis opsonins in mouse serum, suggesting one mechanism by which such extracts confer protection.
Partial purification and properties of somatic antigen spontaneously released from Vibrio cholerae
Authors: Pike R M , Chandler C H
Published: January 2020

The supernatant fluids from cultures of Vibrio cholerae grown for 40 h in an dialyzable medium were dialyzed, concentrated, and fractionated on agarose columns. The fractions containing most of the antigen which inhibited the vibriocidal activity of homologous antiserum were pooled, dialyzed, and concentrated to provide material with about 100 times the specific activity of the original culture supernatant. This material, containing 12 to 20% protein, 11 to 19% carbohydrate, and about 16% unbound lipid, had a mean lethal dose for mice of about 500 mug. This partially purified antigen absorbed all the vibriocidal antibody from homologous antiserum against live cultures and produced a single line of precipitation in gel diffusion tests with the same antiserum.
Growth and cytopathology of Mycoplasma synoviae in chicken embryo cell cultures
Authors: Aldridge K E
Published: January 2020

Mycoplasma synoviae was tested for its ability to grow and induce cytopathogenic changes in chicken embryo cell cultures. M. synoviae grew to high titers by day 5 in the presence of chick cells, but showed no growth in the tissue culture medium alone even though it was enriched with nicotinamide adenine dinucleotide and swine serum. Infected chick cell cultures showed a progressive cytoplasmic degeneration on successive days of examination. Early changes involved cytoplasmic granularity and mild vacuolation. On the last day of examination the cytoplasm of most cells was completely degenerated and some showed nuclear degeneration. M. synoviae was shown to be cytophilic for the chick cell membranes where the mycoplasmas reproduced and formed microcolonies which, on successive days, increased in size. The attachment site on the chick cell membrane was shown to be neuraminidase sensitive.
Rhipicephalus sanguineus: vector of a new spotted fever group rickettsia in the United States
Authors: Burgdorfer W , Sexton D J , Gerloff R K , Anacker R L , Philip R N , Thomas L A
Published: January 2020

A rickettsia related to but distinct from the spotted fever agent, Rickettsia rickettsii, has been detected in 167 (18.9%) of 884 Rhipicephalus sanguineus taken off dogs in central and northern Mississippi. The organisms could readily be isolated in male meadow voles (Microtus pennsylvanicus), where it produced massive infections in the tissues of tunica vaginalis. It was practically nonpathogenic for male guinea pigs, although inoculation of these animals with infected tunica vaginalis of voles afforded in 30 of 38 instances solid immunity to challenge with virulent R. rickettsii. The Rhipicephalus rickettsia grew well in monolayers of chicken embryo fibroblast, Vero, mouse L, and HeLa cells. Cytopathogenic effects were minimal unless large concentrations of rickettsiae were used as inocula. It also could be established in embryonated hen eggs but only after injection of massive doses of L cell-propagated organisms. Serological tests (complement fixation, microagglutination and/or micro immunofluorescence) indicated that the newly described Rickettsia belongs to the spotted fever group but differs from R. rickettsii, R. akari, and R. conorii. Antigenic differences were also demonstrated by direct fluorescence microscopy as well as by vaccine potency and mouse-toxin neutralization tests.
Competition between Chlamydia psittaci and L cells for host isoleucine pools: a limiting factor in chlamydial multiplication
Authors: Hatch T P
Published: January 2020

L cells (mouse fibroblasts) supported the multiplication of the obligately intracellular parasitic bacterium Chlamydia psittaci (strain 6BC) when incubated in fresh growth medium (medium 199 + 5% fetal calf serum). When incubated in the medium supernatant from a 24-h-old culture of uninfected L cells (24-h used medium), uninfected cells did not divide and infected cells did not provide an adequate environment for the multiplication of C. psittaci, which persisted in a noninfectious latent state within the host cells. The failure of both L cells and chlamydiae to divide resulted from an overall reduction in the rate of protein synthesis by both host and parasite brought about by an insufficiency of the essential amino acid isoleucine in 24-h used medium. The concentration of isoleucine required to activate minimal growth of C. psittaci also minimally stimulated uninfected L cells to divide. The addition of cycloheximide to 24-h used medium also activated the latent chlamydial infection because it stimulated the incorporation of host protein-derived isoleucine into chlamydial protein. The results suggest that the chlamydial parasite and the L-cell host compete for the isoleucine in the soluble pool of the host cell and that the parasite is capable of sequestering isoleucine for its own biosynthetic needs only when the concentration of isoleucine in the host pool rises above the level required to maintain the hose in the stationary state. Extrapolation of the results obtained with the L cell-C. psittaci model system to natural latent chlamydial infections is discussed.
Intrinsic and chemically produced microheterogeneity of Staphylococcus aureus enterotoxin type C
Authors: Metzger J F , Johnson A D , Spero L
Published: January 2020

Staphylococcus aureus enterotoxins C1 (SEC1) and C2 (SEC2) produced from 50-liter quantities of crude culture supernatants were purified chromatographically in a neutral or acid milieu. Microheterogenity of SEC1 was markedly increased by treatment of the purified toxin with alkali, and new more acidic charged species appeared. SEC2 was more heterogenous than any of the other S. aureus enterotoxins and was affected only slightly by treatment with alkali. Prolonged incubation of the organism during production of the SEC2 produced changes in charged species that may be related to a bacterial deamidase, since similar changes were not seen with alkaline treatment of the purified toxin. Although SEC1 and SEC2 showed complete identity immunologically, they are separate, distinct toxins, and alkali treatment of SEC1 did not produce SEC2.
Sensitive assay for detection of toxin-induced damage to the cytoplasmic membrane of human diploid fibroblasts
Authors: Thelestam M , Möllby R
Published: January 2020

A sensitive assay was developed for detection and quantitation of subtle permeability changes in the cytoplasmic membrane of human diploid fibroblasts. Release of the non-metabolizable amino acid [1-14C]alpha-aminoisobutyric acid (AIB; molecular weight (103) from the cytoplasm of prelabeled cells was used as an indicator of toxin-induced membrane damage. An optimal procedure for labeling these cells was designed after varying the conditions with regard to pH, temperature, concentration of AIB, composition of medium, and incubation time. Toxin-induced release of AIB was compared with release of a previously described nucleotide label, [3H]uridine. Melittin from bee venom and the polyene antibiotics filipin and amphotericin B in low concentrations induced a strikingly greater release of AIB than of nucleotide label. The sensitivity of this assay was furthermore demonstrated by treatment with the following bacterial cytolysins: phospholipase C and theta-toxin from Clostridium perfringens, alpha-, beta-, delta-, and gamma-toxins from Staphylococcus aureus, and streptolysin S from Streptococcus pyogenes. In spite of their different modes of action, all these membrane-active toxins at low concentrations induced a significant release of AIB label. For an equal release of nucleotide label, several times higher concentrations were required.
Antigenic heterogeneity among pyocins of Pseudomonas aeruginosa
Authors: Allen J C , Kelly P C
Published: January 2020

We investigated the effect of FeSO4 on phagocytosis-associated, increased oxidative metabolism via the hexose monophosphate shunt, with special attention to its effect on H2O2 levels. The availability of glutathione peroxidase and glutathione reductase for H2O2 disposal and hexose monophosphate shunt stimulation also are evaluated. The results show an impairment of phagocytosis-associated hexose monophosphate shunt activity together with an increase both of resting and phagocytosing formate oxidation. These apparently paradoxical findings are resolved by demonstrating a direct enhancement of formate oxidation by FeSO4 in a cell-free system. In addition, measurement of H2O2 concentrations via scopoletin fluorescence shows reduction of H2O2 by FeSO4. There is no effect on either glutathione peroxidase or glutathione reductase activities. These data suggest that one mechanism of FeSO4 impairment of microbicidal activity is by its removal of H2O2.
Sequential appearance of salivary antibodies after oral immunization of axenic mice
Authors: Ebersole J L , Molinari J A , Platt D
Published: January 2020

The purpose of the present investigation was to examine the production of specific salivary antibodies after oral immunization of axenic mice (ICR/CD-1) with formalinized Escherichia coli (ATCC 11775). Three aspects of the humoral response were studied: (i) the sequential appearance of anti-E. coli antibodies; (ii) classes of antibodies produced in response to the antigen; and (iii) antibody specificity. Antibody levels were determined by passive hemagglutination with soluble lipoplysaccharide and bacterial agglutination, using preparations of somatic O and flagellar H antigens. A short latent period of 1 to 3 days was observed when saliva samples were assayed for anti-lipopolysaccharide and anti-O antibodies. The salivary antibody titers peaked at 11 days after initiation of the immunization regimen. Only two of six mice exhibited a change in serum antibody levels against these antigens. The predominant class of early antibody in saliva was immunoglobulin (Ig)G; however by 7 days IgA WAS found to comprise the major portion of specific immunoglobulins. Serum antibodies directed against falgellar antigenic determinants were primarily of the IgM class, whereas the salivary antibodies were IgG in nature.
Serological studies of actionomyces israelii by crossed immunoelectrophoresis: standard antigen-antibody system for A. israelii
Authors: Holmberg K , Nord C E , Wadström T
Published: January 2020

Standard preparations of crude cytoplasmic and whole cell-associated antigen mixtures of Actinomyces israelii were analyzed by crossed immunoelectrophoresis (CIE), with a standard polyvalent antiserum comprising purified and concentrated immunoglobulin G antibodies to formolized whole cells of A. israelii serotypes 1 and 2. The standard antigens provided four antigen-antibody systems for A. israelii. The immunoprecipitation patterns of the system were compared, and the immunochemical characteristics of individual precipitates were analyzed. Each system contained specific precipitates, but also one or two precipitates which were immunochemically identical to precipitates of the other systems. The standard system for A. israelii based on cytoplasmic antigens was best reproducible and revealed the highest number of immunoprecipitates. These precipitates possessed immunochemical properties which made them suitable for CIE studies. The cytoplasmic antigen mixture of A. israelii was, therefore, adopted as the most suitable for further development of a crossed immunoelectrophoretic system for A. israelii. In subsequent assays the cytoplasmic antigen mixture was raised in rabbit against cell lysates of A. israelii, serotypes 1 and 2. A standard antigen-antibody system for A. israelii was obtained which revealed an immunoprecipitation pattern of 10 distinguishable precipitates. The resolving power and separation by CIE of this standard system for A. israelii was compared with that of crossed immunoelectrofocusing. The results suggest that these methods supplement each other. Crossed immunoelectrofocusing appeared to be a useful tool for separation of specific components of the protein-antigen complex of A. israelii for analytic serology. The CIE in conjunction with a standard reference antigen-antibody system for A. israelii based on cytoplasmic antigens offers great potentialities in diagnostic A. israelii serology.
Unusual sensitivity of rabbit cells to a nonbinding diphtheria toxin fragment
Authors: Cukor G , Moolten F L
Published: January 2020

Normal and transformed rabbit kidney cells are killed by heat-dissociated diphtheria toxin fragments, whereas human (heLa), mouse (L929), and hamster (BHK and 333-8-9) cells are not affected.
Immunization Against Experimental Chagas' Disease by Using Culture Forms of
Trypanosoma cruzi
Killed with a Solution of Sodium Perchlorate
Authors: Kierszenbaum Felipe , Budzko Delia B.
Published: January 2020

Protection against infection with virulent blood (trypomastigote) forms of
Trypanosoma cruzi
was accomplished in mice by immunization with culture (mainly epimastigote) forms killed by treatment with sodium perchlorate. Sodium chloride, used instead of sodium perchlorate, with all other conditions kept the same, failed to kill all the organisms, indicating that the effects of the perchlorate anion were not simply ionic or osmotic, suggesting that they might be chaotropic. A single dose of the immunogen, without adjuvants, was sufficient to significantly protect against the infection. Protection was achieved by either intraperitoneal, intramuscular, or subcutaneous immunization, though the first two routes appeared to be more effective. After challenge, parasitemias were negative in 25, 29, and 17% of the animals immunized intraperitoneally, intramuscularly, and subcutaneously, respectively.
Binding of cholera toxin by various tissues
Authors: Gascoyne N , Van Heyningen W E
Published: January 2020

Under certain conditions, it is possible to confirm the observation by Peterson (1974) that the cholera toxin-binding capacities of tissues from brain and colon mucosa, and from liver and small intestine mucosa, are comparable. Binding of toxin by all tissues except brain is very variable, but is roughtly proportional to their content of the toxin-binding ganglioside galactosyl-N-acetylgalactosaminyl (sialosyl) lactosyl ceramide. It appears that some toxin-binding sites of the mucosa of the small intestin and colon may be masked. It has also been confirmed that there may be some solubilization of toxin-binding material from brain on standing a few days at 4 C, but this is comparatively slight. Some disadvantages of measuring toxin binding by adding small amounts of radioactive toxin to compartively large amounts of tissue are discussed.
Further In Vitro Studies with 5-Fluorocytosine
Authors: Shadomy Smith
Published: January 2020

Susceptibilities of 53 isolates of
Cryptococcus neoformans
and of 15 isolates identified as either
Candida albicans
or
Candida
species to 5-fluorocytosine (5-FC) were measured. Thirteen, or 24.5%, of all isolates of
C. neoformans
were resistant to 5-FC. Eight of these isolates were recovered from patients treated with 100 mg of 5-FC per kg per day, whereas only one was from a patient receiving 150 mg per kg per day. Only one isolate of
C. neoformans
recovered before treatment was resistant. In 14 cases of cryptococcosis treated with 5-FC at one institution, therapeutic failures associated with resistant isolates of
C. neoformans
occurred in 6 of 10 cases receiving 100 mg per kg per day but in only one of 4 cases treated with 150 mg per kg per day. Mean concentrations of 5-FC in serum and cerebrospinal fluid were twofold higher in those patients receiving the larger dose. Of 15 isolates of
Candida
, 5 were susceptible to clinically meaningful concentrations of 5-FC and 8 were totally resistant. Seven of the resistant
Candida
isolates were isolated before treatment, and selection of resistant isolates during treatment was not observed. Resistant isolates were associated with three of five therapeutic failures. Treatment with 5-FC at 100 mg per kg per day was successful in four of nine patients with systemic candidiasis.
Scanning-Beam Electron Microscopy of Cell Wall-Defective Staphylococci
Authors: Fass Robert J. , Carleton Judith , Watanakunakorn Chatrchai , Klainer Albert S. , Hamburger Morton
Published: January 2020

Staphylococci and their derived wall-defective forms (WDS) were studied with Gram stain, phase microscopy, and the scanning-beam electron microscope. Staphylococci were smooth, spherical, and relatively uniform in size. Stable WDS had corrugated surfaces and were larger; those prepared with lysostaphin were indistinguishable from those prepared with methicillin. During induction of WDS in methicillin-containing hypertonic broth, WDS were first observed after 7 hr of incubation and progressively, thereafter, increased in number. They were larger than the stable WDS and varied more in size and shape. Microscopically, “wisps” were seen to consist of WDS, persistent parent staphylococci, and residual cell membranes.
Virulence of R-Factor-Bearing
Salmonella typhimurium
Authors: Thiele Elizabeth H.
Published: January 2020

Antibiotic-resistant recombinants obtained from mating antibiotic-resistant
Escherichia coli
with virulent, antibiotic-sensitive
Salmonella typhimurium
are generally avirulent. After 32 consecutive transfers, two of four avirulent recombinants regained their virulence without loss of episome-mediated resistance.
Pathological Changes in Brain and Other Target Organs of Infant and Weanling Mice After Infection with Non-Neuroadapted Western Equine Encephalitis Virus
Authors: Aguilar Mary Jane
Published: January 2020

Infant and weanling mice infected experimentally with non-neuroadapted Western equine encephalitis virus exhibited a differing spectrum of target-organ pathology as well as a different clinical response. The infant mice sickened and died within 48 hr. Pathological changes in this group were largely limited to such mesodermally derived tissues as muscle, cartilage, and bone marrow elements. The central nervous system was uninvolved, as were heart, lung, liver, and other body organs. The young adult mice, on the other hand, showed no clinical evidence of disease throughout the 376-hr postinfection period. Nevertheless, after 216 hr they developed acute diffuse meningoenceophalitis of the viral type, with concomitant changes in heart, lung, liver, kidney, and brown fat. The most striking and consistent finding in the infant group was acute necrotizing degeneration of the bone marrow. The most dramatic change in the young adult group was acute necrotizing meningoencephalitis.
Effect of Alkali on the Immunological Reactivity of Lipopolysaccharide from
Salmonella typhimurium
Authors: Čižnár Ivan , Shands J. W.
Published: January 2020

The effect of mild alkaline hydrolysis on the immunological reactivity of
Salmonella typhimurium
lipopolysaccharide (LPS) was studied. Hydrolysis of LPS at 37 C in 0.01 to 0.25
n
NaOH caused a decrease in precipitation of LPS by antiserum. Red cells sensitized with alkali-treated LPS were less responsive to hemagglutination by antiserum than were cells sensitized with heated LPS. Hemagglutination-inhibition studies showed that alkali-treated
S. typhimurium
LPS was antigenically deficient. Alkaline hydrolysis of
S. typhimurium
LPS destroys antigen 5 of the Kauffmann-White scheme by cleavage of
O
-acetyl groups. However, abequose, the immunodominant sugar for antigen 4, is also cleaved from the
O
side chains by alkali, suggesting the loss of more than one antigenic determinant. It is concluded that alkali treatment of LPS to promote the sensitization of red cells may alter the serological specificity and therefore places limitations on its use in serological studies.
Correlation Between Pathogenicity of
Shigella
and Intraperitoneal Survival in Mice
Authors: Nakamura Mitsuru , Jackson Kathleen E. , Cross W. R.
Published: January 2020

Phagocytosis of virulent and avirulent strains of
Shigella
and
Escherichia coli
in the mouse peritoneum was studied. A direct correlation between bacterial virulence and resistance to phagocytosis by peritoneal phagocytes was demonstrated. Virulent strains were less readily cleared and were able to multiply to a limited extent within the peritoneal cavity. An epimerase-deficient, rough mutant of
S. flexneri
2a was highly susceptible to phagocytosis. Restoration of the cell wall structure in these mutants resulted in a significant increase in their resistance to phagocytosis. Susceptibility to phagocytosis in smooth
S. flexneri
was age-dependent. Cells from 16-hr cultures were more resistant to removal from the peritoneum than were cells from 48- and 72-hr cultures.
Relationship Between β-Lactamase Activity and Resistance of
Enterobacter
to Cephalothin
Authors: Farrar W. Edmund , Krause Jane M.
Published: January 2020

The relationship between cephalosporin β-lactamase activity and resistance to cephalothin was investigated in strains of
Enterobacter cloacae
and
E. aerogenes
. β-Lactamase activity was detected in all strains, but a quantitative correlation between amount of β-lactamase activity and level of resistance to cephalothin was not observed. Permeability barriers to cephalothin were observed and varied from strain to strain. β-Lactamase activity was increased by growing organisms in the presence of penicillin G. These enzymes hydrolyzed cephalosporins more rapidly than penicillins. Penicillinase-resistant penicillins, especially those of the isoxazolyl series, effectively inhibited
Enterobacter
β-lactamase. A synergistic antibacterial effect was observed when organisms were exposed to cephalothin and oxacillin in combination, and the resistance of even very small inocula to cephalothin was reduced by addition of oxacillin. Oxacillin probably exerts its effect by inhibiting β-lactamase at an intracellular site. Intracellular β-lactamase may make an important contribution to the resistance of even small inocula of gram-negative bacilli to cephalosporin and penicillin antibiotics. Although β-lactamase plays a significant role in the resistance of
Enterobacter
to cephalothin, other factors, such as permeability barriers, also participate in determining the level of resistance.
Intracellular
Pasteurella pseudotuberculosis:
Multiplication in Cultured Spleen and Kidney Cells
Authors: Richardson Marvis , Harkness Tamar K.
Published: January 2020

Pasteurella pseudotuberculosis
multiplied within rabbit cells in primary culture. Spleen cells from rabbits were either dispersed mechanically, exposed to the organism immediately after cell preparation, and grown as a pellet or the cells were dispersed enzymatically and grown as a monolayer for 4 to 6 days before the bacteria were introduced. Intracellular multiplication proceeded at a logarithmic rate for 1 to 2 days, with a generation time of about 70 min in pelleted cells and 4 to 5 hr in monolayered cells. Under the conditions employed, the wild-type virulent strain and an avirulent mutant multiplied at similar rates. Atmosphere, constituents of the medium, and multiplicity of infection influenced intracellular proliferation. The organism also proliferated in kidney cells. Microscopic observation of stained cells indicated limited growth of the pathogen in spleen cells at 37 C. In kidney cells, the pasteurellae localized in compartments; frequently, a single compartment with masses of proliferating organisms almost filled the cytoplasm.
Lymphocyte Transformation in Repeated Gonococcal Urethritis
Authors: Kraus Stephen J. , Perkins Goldie H. , Geller Ruth C.
Published: January 2020

In an attempt to ascertain whether cell-mediated hypersensitivity develops in the course of a naturally acquired gonorrhea infection, lymphocytes from men with gonococcal urethritis were cultured in vitro with a gonococcal antigen. The lymphocyte response was quantitated by a radioactive assay of deoxyribonucleic acid synthesis. Lymphocytes from subjects without gonorrhea were cultured in a similar manner to determine the specificity of the reaction. The recurrent nature of many gonococcal infections allowed a concurrent evaluation of whether the intensity of the in vitro lymphocyte response is related to the history of previous exposure to the antigen concerned. This study revealed a significantly greater lymphocyte response to the gonococcal antigen in those with gonorrhea infections than in the nongonorrhea subjects (
P
< 0.01). The intensity and timing of the response were also consistent with specific lymphocyte stimulation.
Monospecific Equine Antiserum Against Cholera Exo-Enterotoxin
Authors: Finkelstein Richard A.
Published: January 2020

An antiserum specific for
Vibrio cholerae
exo-enterotoxin was produced by immunization of a horse with purified choleragenoid, a natural cholera toxoid. The serum has a high titer against the toxin antigen in passive hemagglutination tests and a respectable antipermeability factor activity. It also passively protected against choleragen-induced mouse foot edema. The serum was found to be useful for assaying toxin antigen in crude and refined products by in vitro tests such as radial immunodiffusion, Lf, and quantitative precipitin titrations. Based upon experimental observations, the serum was defined as containing 1,000 flocculating units of anticholera toxin antibody per ml. A flocculating dose, or Lf, of choleragen approximates 1 μg, and that of choleragenoid is 0.625 μg. Formalin toxoids behaved like the parent toxin in these tests. The serum contains approximately 2.2 mg of antibody protein per ml, which appears to be largely, if not entirely, of the Ig(T) type. It is suggested that this serum, which is available in considerable supply, be considered for use as a reference cholera antitoxin. The horse developed symptoms of anaphylactic shock during immunization, suggesting the need for caution in projected studies on toxoid-induced immunity in man.
Cell Wall Component Which Affects the Ability of Serum to Promote Phagocytosis and Killing of
Staphylococcus aureus
Authors: Shayegani Mehdi , Hisatsune Kazuhito , Mudd Stuart
Published: January 2020

The role of various cell wall components of nonencapsulated
Staphylococcus aureus
in phagocytosis and killing was studied. Adsorption of human serum with
S. aureus
cell walls, or trypsin-digested cell walls, reduced the rate of phagocytosis and killing of
S. aureus
by human-blood leukocytes when compared to unadsorbed serum. When the various components of the cell walls were used for adsorption, only the intact mucopeptide was found to remove these factors. Products of digestion of this mucopeptide with several enzymes were found to be inactive when used for adsorption of human serum. Other components tested were teichoic acids α, β, and combinations of both and protein A. When used in equivalent amounts, these were found to have no effect on the removal of serum factors necessary for phagocytosis and intracellular killing of
S. aureus
.
Serospecificity and opsonic activity of antisera to Legionella pneumophila
Authors: Johnson W , Pesanti E , Elliott J
Published: January 2020

A high-molecular-weight surface component (F-1 fraction) has been isolated from the four serogroups of Legionella pneumophila. Antibody raised against live organisms was found by microagglutination assay to be specific for the homologous serogroup. Agglutinating activity of antiserum was markedly diminished after absorption with the homologous, but not heterologous, F-1 fraction. In addition, it was found that L. pneumophila organisms were not interiorized by rat alveolar macrophages or mouse peritoneal macrophages in the absence of antiserum, whereas homologous antiserum effectively opsonized the organisms. The opsonizing activity of serogroup-specific antisera was eliminated by absorption of the antisera with the homologous, but not heterologous, F-1 fraction. These data indicate that the serogroup-specific antigen of L. pneumophila resides in the F-1 fraction and that antibody to the F-1 fraction is required for phagocytosis of L. pneumophila by mammalian phagocytes.
In vitro studies of rickettsia-host cell interactions: ultrastructural changes induced by Rickettsia rickettsii infection of chicken embryo fibroblasts
Authors: Silverman D J , Wisseman C L
Published: January 2020

Secondary chicken embryo fibroblasts infected with the Sheila Smith strain of Rickettsia rickettsii and grown in monolayer culture undergo rapid morphological alterations. Transmission electron microscopic examination of cells at intervals after infection showed several progressive host cell lesions, including widespread dilatation of the rough endoplasmic reticulum and outer nuclear envelope and the accumulation of electron-dense material within the cisternae of intracellular membranes. Dilatation of the rough endoplasmic reticulum is a common, early reversible manifestation of other forms of cell injury. However, the severity of the damage to the host cell resulting from the progressive distention of intracellular membranes and the subsequent formation of small segments of membrane-bound host cytoplasm within the cisternae of these membranes is unknown. Early in the infection cycle, the rickettsiae were found free in the host cell cytoplasm, within invaginations of the nuclear envelope, occasionally free in the space between the outer and inner nuclear membranes, and in the host nucleoplasm, but not within cisternae formed by swollen endoplasmic reticulum. As a consequence of intracisternal swelling and fusion of intracellular membranes later in the infection cycle, the majority of the rickettsiae were found surrounded by host cytoplasm bound by host-derived internal membranes and appeared to persist in this state until cell lysis. The overall cytopathological changes in cells infected with R. richettsii appear dramatic and, from other studies in our laboratory, are significantly different from those observed in cells infected with Rickettsia prowazekii.
Host defenses in experimental scrub typhus: role of normal and activated macrophages
Authors: Nacy C A , Osterman J V
Published: January 2020

Resident peritoneal macrophage from BALB/c mice were infected in vitro with Rickettsia tsutsugamushi strain Gilliam, and rickettsial growth was estimated by microscopic examination of Giemsa-stained cells. Both number of infected macrophage per culture and number of intracellular rickettsiae per cell increased with time during culture. Treatment of rickettsiae with immune serum before infection macrophage cultures reduced the number of infected macrophage by 50%. Macrophage treated in vitro with lymphokines were able to suppress rickettsial growth in the absence of detectable antibody and exhibited a 75% reduction in infection compared with normal macrophage. We also obtained activated macrophage from immune mice and found that they were refractory to in vitro rickettsial infection. Macrophage populations activated in vitro or in vivo contained a small percentage of cells which supported unrestrained growth of rickettsiae. These data suggest that an early immunological event in experimental scrub typhus infection may be the development of activated macrophage capable of suppressing rickettsial proliferation before the appearance of circulating antibody.
Macrophages in immunity to syphilis: suppressive effect of concurrent infection with Mycobacterium bovis BCG on the development of syphilitic lesions and growth of Treponema pallidum in tuberculin-positive rabbits
Authors: Hardy P H , Graham D J , Nell E E , Dannenberg A M
Published: January 2020

Paired groups of male rabbits were challenged with Treponema pallidum and Mycobacterium bovis BCG. One group had been sensitized to BCG by inoculation 3 weeks before challenge. All animals were challenged intradermally at multiple sites with T. pallidum alone, BCG alone, and both organisms into the same sites. The resulting lesions were followed clinically and histologically. BCG lesions enlarged more rapidly in sensitized rabbits, but they were otherwise no different from those in the controls. T. pallidum lesions enlarged and regressed simultaneously in both groups, but in the BCG-sensitized animals they became twice as large as those in the unsensitized rabbits. Mixed BCG-T. pallidum lesions showed the greatest differences in the two groups of animals. Like the pure BCG lesions, they enlarged more rapidly in the sensitized rabbits but began to recede after 1 week. The corresponding lesions in the controls enlarged more slowly and reached their maximum size after 3 weeks when the receding lesions in the sensitized animals were much smaller. The most marked histological-histochemical difference between the two groups of animals was in the number and activation of macrophages. These cells were more numerous in the mixed lesions of BCG-sensitized animals than in similar lesions of the controls and more activated as determined by beta-galactosidase staining. Although sparsely distributed, activated macrophages were more numerous in the pur T. pallidum lesions of sensitized animals than in those of control animals. Silver-stained sections revealed fewer treponemes in mixed lesions of sensitized animals than in the mixed lesions of control animals. Quantitation of treponemes in pure T. pallidum versus mixed lesions was determined in two groups of rabbits challenged intratesticularly. The total number of treponemes per testis in the mixed lesions of BCG-sensitized rabbits was significantly less than the number in the mixed lesions of control animals, and also less than the number in pure T. pallidum lesions of both groups of animals.
Respiratory syncytial virus infection in inbred mice
Authors: Prince G A , Horswood R L , Berndt J , Suffin S C , Chanock R M
Published: January 2020

Respiratory syncytial virus infected the nose and lungs of each of 20 strains of inbred mice, with viral titers varying 100-fold from least permissive to most permissive strains. Viral titers appeared to be under genetic control, but did not correlate with the H-2 haplotype.
Isoelectric focusing of Chlamydia trachomatis
Authors: Kraaipoel R J , van Duin A M
Published: January 2020

HeLa-229 cells and the elementary bodies of Chlamydia trachomatis had a net negative electrical surface charge at neutral pH when measured by isoelectric focusing. Inclusion-forming and non-inclusion-forming elementary bodies focused in one band at pI 4.64.
Enhanced hydrogen peroxide release from macrophages stimulated with streptococcal preparation OK-432
Authors: Saito H , Tomioka H
Published: January 2020

Wheat germ lectin was found to be a potent triggering agent for hydrogen peroxide release from mouse peritoneal macrophages. Macrophages stimulated by intraperitoneal injection of OK-432, a lyophilized attenuated streptococcal preparation, were highly responsive to wheat germ lectin.
Effect of chlorpromazine on the secretory activity of Escherichia coli heat-stable enterotoxin
Authors: Abbey D M , Knoop F C
Published: January 2020

The effect of chlorpromazine on the net intestinal accumulation of fluid induced by Escherichia coli heat-stable (ST) enterotoxin in an infant mouse model was examined. Chlorpromazine, when administered with ST enterotoxin, caused a highly significant decrease in net intestinal fluid accumulation. The inhibition of ST activity was dose dependent with various concentrations of chlorpromazine (P less than 0.001). A significant inhibition of toxic activity was also observed when chlorpromazine was administered before (P less than 0.02) or after (P less than 0.05) ST enterotoxin challenge. No significant differences in fluid accumulation were observed between control mice treated with buffer alone and those treated with only chlorpromazine. These data indicate that chlorpromazine markedly decreases the net intestinal fluid accumulation induced by E. coli ST enterotoxin. Further studies on the potential use of chlorpromazine in both the prophylaxis and the treatment of diarrheal diseases appear warranted.
Neutrophil chemotaxis in patients with Staphylococcus aureus furunculosis
Authors: Cates K L , Quie P G
Published: January 2020

Neutrophil chemotaxis was evaluated in patients with staphylococcal furunculosis using a modified Boyden chamber assay. Neutrophil chemotactic response to Staphylococcus aureus-derived chemotactic factor was compared with response to Escherichia coli-derived chemotactic factor and zymosan-activated serum. Twenty-one patients with active furunculosis were compared with 29 patients with a history of furunculosis but no recent infection and with 29 healthy control subjects. Chemotactic response to the staphylococcal chemotactic factor was significantly higher in patients with active furunculosis (mean 61.6) than in patients with a history of furunculosis (mean 36.4) or controls (mean 31.4), P less than 0.001. Neutrophils from patients with active staphylococcal infections also had higher chemotactic activity toward E. coli chemotactic factor, but not significantly so (P = 0.09). Chemotactic response to zymosan-activated serum and background neutrophil motility was comparable among the three groups. The increased neutrophil chemotactic response of patients with active infection to bacterial factors, but not zymosan-activated serum, may represent a specific neutrophil response to products of infecting organisms. The differential response of the patients' neutrophils to these attractants supports evidence for the presence of separate categories of chemotaxin receptor on the surface of neutrophils.