bluuebunny/crossref_metadata_2025 huggingface dataset:
Diarrhea in gnotobiotic calves caused by the reovirus-like agent of human infantile gastroenteritis
Authors: Mebus C A , Wyatt R G , Sharpee R L , Sereno M M , Kalica A R , Kapikian A Z , Twiehaus M J
Published: January 2020

Gnotobiotic newborn calves were found to be susceptible to infection with the reovirus-like agent of human infantile gastroenteritis (HRVL). Infection was based on (i) seroresponse using immunofluorescence and (ii) fecal shedding of virus particles using electron microscopy. Virus was detected in fecal samples for at least 2 to as long as 7 days after inoculation, although peak virus concentrations were observed on days 1 to 4. Diarrheal illness was observed in seven calves on second to fourth serial passage of HRVL in calves but in none of four animals studied on first passage. Diarrhea began 15 to 30.5 h (mean = 22.3 h) post-inoculation and lasted less than 24 h; three of the seven animals that developed diarrhea were also depressed or anorectic.
Vibrio cholerae adherence and colonization in experimental cholera: electron microscopic studies
Authors: Nelson E T , Clements J D , Finkelstein R A
Published: January 2020

Colonization of the intestinal epithelium by Vibrio cholerae was examined in two model systems, in ligated ileal loops of adult rabbits and in the patent gut of infant rabbits, using both scanning and transmission electron microscopy. Time studies in the adult model showed a lag period of up to 1 h before the attachment of significant numbers of the vibrios. The bacteria appeared initially in small patches on the sides of the villi, predominantly along the transverse furrows. The number of adherent bacteria steadily increased, reaching a maximum between 4 and 7 h, when a dense mat of bacteria several layers thick covered much of the villi. After this time there was a rapid decline in the number of V. cholerae bound. By 12 to 16 h only a few bacteria could be seen on the surface of the villi, which had a rough, patchy appearance at these later times. Globular protrusions, with vibrios attached, may play a role in the clearance of bacteria. Colonization and clearance in the patent intestine of the infant rabbit occurred much as in the adult model. However, the bacteria adhered more uniformly and there was no lag in attachment. In both models the majority of bacteria were aligned horizontally with the epithelial surface, but some were attached in an end-on manner, with their flagella extending into the lumen. The bacteria adhered via their surface coats directly to the tips of the microvilli, except for a few vibrios that were partly embedded into the brush border. Some changes in the microvilli occurred as a consequence of the bacterial attachment.
Murine gastrointestinal tract as a portal of entry in experimental Pseudomonas aeruginosa infections
Authors: Schook L B , Carrick L , Berk R S
Published: January 2020

Peroral administration of viable Pseudomonas aeruginosa into the stomach of mice resulted in an acute systemic infection, with death occurring within 72 h. One strain, ATCC 19660, a non-encapsulated form of P. aeruginosa, had a median lethal dose of 5.3 X 10(6) colony-forming units, whereas two encapsulated strains, ATCC 17933 and 17934, had median lethal dose values of 5.0 x 10(7) and 5.6 x 10(7) colony-forming units, respectively. Each strain required fewer organisms to establish a lethal infection via the stomach than by intravenous or intraperitoneal routes. The non-encapsulated strain, ATCC 19660, did not cause any diarrhea in the infected animals, whereas the two encapsulated strains, although less virulent, caused diarrhea when administered perorally. No signs of necrosis were noted within the gastrointestinal tract; however, hematogenous spread of the organism resulted in a vasculitis associated with the pulmonary vessels and bacterial invasion of the renal tissues. Treatment of animals with antineoplastic drugs 24 h before or simultaneously with peroral challenge resulted in an increased susceptibility to infection.
Specificity of Inhibition of Epithelial Cell Adhesion of
Neisseria gonorrhoeae
Authors: Tramont Edmund C.
Published: January 2020

Inhibition of epithelial cell adhesion (attachment) for individual strains of
Neisseria gonorrhoeae
is antigenically distinct.
Significant contribution of spleen cells in mediating the lethal effects of endotoxin in vivo
Authors: Glode L M , Mergenhagen S E , Rosenstreich D L
Published: January 2020

Two closely related, histocompatible mouse strains that have marked differences in both in vitro and in vivo responses to endotoxin were used to evaluate the contribution of lymphoid cells to the lethal effect of endotoxin. C3H/HeJ mice are endotoxin resistant, whereas C3H/HeN mice are endotoxin sensitive. In vitro spleen cell mitogenic responses to endotoxin were similar in untreated mice and in mice that received sublethal irradiation (450 R) followed by reconstitution with autologous spleen cells. Reconstitution with spleen cells from the related strain produced chimeric animals with spleen cell mitogenic activity like that of the donor strain. When chimeric animals were subjected to a lethal challenge of endotoxin, their response was markedly altered by the transferred lymphoid cells. C3H/HeJ animals reconstituted with C3H/HeN cells became more endotoxin sensitive, whereas C3H/HeJ cells became more endotoxin resistant. These results indicate that spleen cells play a significant, detrimental role in endotoxin-induced lethality.
Comparison of the In Vitro Bactericidal Activity of Human Serum and Leukocytes Against
Bacteroides fragilis
and
Fusobacterium mortiferum
in Aerobic and Anaerobic Environments
Authors: Bjornson Ann B. , Altemeier William A. , Bjornson H. Stephen
Published: January 2020

In aerobic and anaerobic in vitro environments,
Fusobacterium mortiferum
was killed by human leukocytes or serum alone or in combination; clinical isolates of
Bacteroides fragilis
were killed only by leukocytes in the presence of serum.
T cells and protective immunity to Plasmodium berghei in rats
Authors: Brown K N , Jarra W , Hills L A
Published: January 2020

Experiments were carried out in which unfractionated spleen cells, and T lymphocyte subpopulations characterized by certain experimental criteria, were isolated at various times from rats infected with Plasmodium berghei. By adoptive transfer it was shown that unfractionated spleen cells, and T cells alone, could transfer protection to syngenic recipients as early as 11 days after infection of the cell donors. The protection conferred by T cells increased with the duration of the infection in the donors, at least up to 100 days. The additional presence of B cells in transferred lymphocyte populations enhanced their protective capacity over that shown by T cells alone. The role of T cells in protective immunity to malaria is discussed.
Attempts to serologically classify feline caliciviruses on a national and an international basis
Authors: Burki F , Starustka B , Ruttner O
Published: January 2020

A serological classification of five feline calicivirus (FCV) strains of Swiss origin and 13 isolates of Austrian origin was attempted. The antisera used had been prepared in rabbits against the five Swiss strains and in goats against six American strains. Homologous and heterologous neutralization tests were made in tube cultures using sera at dilutions that contained 20 antibody units, in unabsorbed sera at low dilution, and in sera after subjection to three consecutive absorptions with lyophilized feline liver powder. None of these procedures resulted in the delineation of serotypes. A study using 20 antibody units yeilded FCV strains with broad-spectrum antigenicity, which seem promising for vaccination trials and for covering global needs. In addition, readily neutralized strains suitable for epidemiological work on cat sera, and possibly also for measuring humoral response to vaccines, could be recognized. The extent of serum titer variance, after 10-fold variance of virus input, was established as being only two- to threefold. Five Swiss FCV strains have been shown to remain antigenically stable over 10 years of laboratory passage. FCV strains and the procedure using 20 antibody units offered a suitable approach for international comparative work. FCV strains with little cross-neutralization should be subjected to higher antibody concentrations of existing antisera before attempting to create serotypes. Liver powder absorptions, which reduced homologous and heterologous neutralization titers to similar extents, subsequently proved to be unsuitable for use in FCV classification.
Participation of complement in the nonimmune host defense against experimental Haemophilus influenzae type b septicemia and meningitis
Authors: Crosson F J , Winkelstein J A , Moxon E R
Published: January 2020

This study was undertaken to determine whether the terminal complement components (C3-9) are involved in the nonimmune host defense against Haemophilus influenzae type b septicemia and meningitis. Using cobra venom factor, infant rats were depleted of C3 and C5. After intranasal challenge with H. influenzae type b, the complement-depleted rats developed a greater incidence and magnitude of bacteremia and a higher mortality rate. In contrast to the effects on bacteremia, complement depletion did not directly influence either the occurrence of meningitis or bacterial multiplication within the cerebrospinal fluid. These experiments provide evidence that the complement system may be an important mechanism of natural immunity to H. influenzae type b.
Complement in experimental Trypanosoma lewisi infection of rats
Authors: Jarvinen J A , Dalmasso A P
Published: January 2020

The role of complement in host resistance to infection with Trypanosoma lewisi was studied in normal, C4-deficient, and C3-depleted rats. Complement levels were measured in normal rats throughout the course of infection. A drastic reduction of total complement and C4 hemolytic activities occurred, and C3 levels measured immunochemically were decreased. Although total complement and C4 levels were regularly reduced to less than 10% of preinfection levels regardless of parasite numbers, the degree of C3 consumption correlated with the parasitemia. C3 levels varied from 100% of preinfection in rats with light infections to 35% in animals with heavy parasitemias. Recovery to normal levels followed trypanosome elimination from the peripheral blood. The infection had no significant effect on C6 hemolytic activity. Parasitemias and C3 levels in C4-deficient rats did not differ from those of normocomplementemic controls. Depletion of C3 and late-acting components by cobra venom factor during the reproductive or adult stages of infection did not alter the parasitemias. In addition, T. lewisi and immune serum caused complement activation in vitro, which could be inhibited with ethylene glycol-bis-(beta-aminoethyl ether)N,N'-tetraacetic acid or ethylenediaminetetraacetic acid. It is concluded that T. lewisi infection in rats result in activation of the classical complement pathway with extensive consumption of the early-acting components, as well as a low degree of activation of the alternative pathway. However, complement does not appear to play a major role in the control and termination of the infection.
Lymphocyte function in experimental african trypanosomiasis: mitogenic effects of trypanosome extracts in vitro
Authors: Mansfield J M , Craig S A , Stelzer G T
Published: January 2020

Extracts of Trypanosoma brucei and Trypanosoma congolense were incubated in vitro with nonimmune lymphocytes of mice, rats, guinea pigs, and rabbits in order to test for mitogenic effects or for other characteristics of polyclonal B lymphocyte activators. Trypanosome extracts (TE) were not mitogenic for spleen cells of mice, rats, and guinea pigs in vitro, nor did the parasite extracts alter the mitogenic responses of lymphocytes from these animals to known B- and T-cell mitogens. TE also failed to induce polyclonal antibody synthesis in mouse spleen cell cultures in an in vitro antibody response system, in contrast to the effects of bacterial lipopolysaccharide, a known polyclonal B cell activator. Rabbit spleen cell and peripheral blood lymphocyte cultures, however, were stimulated by TE to undergo blastogenesis in vitro. Incubation of rabbit lymphocytes with phytohemagglutinin (PHA) and TE or anti-rabbit immunoglobulin serum and TE revealed an additive effect only in terms of the TE-plus-PHA culture responses; these findings suggest that a non-PHA responsive lymphocyte population, possibly B lymphocytes, is stimulated by TE in rabbits. The relationship of trypanosome-induced lymphocyte mitogenic stimulation to other immunological dysfunctions occurring in chronic African trypanosomiasis is discussed.
Mechanism of fever induction in rabbits
Authors: Siegert R , Philipp-Dormston W K , Radsak K , Menzel H
Published: January 2020

Three exogenous pyrogens (Escherichia coli lipopolysaccharide, synthetic double-stranded ribonucleic acid. Newcastle disease virus) were compared with respect to their mechanisms of fever induction in rabbits. All inducers stimulated the production of an endogenous pyrogen demonstrated in the blood as well as prostaglandins of the E group, and of cyclic adenosine 3',5'-monophosphate in the cerebrospinal fluid. The concentrations of these compounds were elevated approximately twofold as compared to the controls. Independently of the mode of induction, the fever reaction could be prevented by pretreatment with 5 mg of cycloheximide per kg, although the three fever mediators were induced as in febrile animals. Consequently, at least one additional fever mediator that is sensitive to a 30 to 50% inhibition of protein synthesis by cycloheximide has to be postulated. The comparable reactions of the rabbits after administration of different pyrogens argues for a similar fever mechanism. In contrast to fever induction there was no stimulation of endogenous pyrogen, prostaglandins of the E group, and cyclic adenosine 3',5'-monophosphate in hyperthermia as a consequence of exposure of the animals to exogenous overheating. Furthermore, hyperthermia could not be prevented by cycloheximide.
Interaction of inflammatory cells and oral microorganisms. III. Modulation of rabbit polymorphonuclear leukocyte hydrolase release response to Actinomyces viscosus and Streptococcus mutans by immunoglobulins and complement
Authors: McArthur W P , Baehni P , Taichman N S
Published: January 2020

In the absence of antiserum, rabbit polymorphonuclear leukocytes (PMNs) released lysosomal enzymes in response to Actinomyces viscosus (19246) but not to Streptococcus mutans (6715). Antibodies had a marked modulating influence on these reactions. PMN hydrolase release was significantly enhanced to both organisms when specific rabbit antiserum and isolated immunoglobulin G (IgG) were included in the incubations. Immune complex F(ab')2 fragments of IgG directed against S. mutans agglutinated bacteria. Immune complexes consisting of S. mutans and F(ab')2 fragments of IgG directed against this organism were not effective as bacteria-IgG complexes in stimulating PMN release. The intensity of the release response to bacteria-IgG complexes was also diminished when PMNs were preincubated with isolated Fc fragments derived from IgG. Fresh serum as a source of complement components had no demonstrable effect on PMN release either alone or in conjuction with antiserum in these experiments. These data may be relevant to the mechanisms and consequences of the interaction of PMNs and plaque bacteria in the pathogenesis of periodontal disease.
Binding of bacterial endotoxin to murine spleen lymphocytes
Authors: Kabir S , Rosenstreich D L
Published: January 2020

The early events in lipopolysaccharide (LPS)-induced B-cell activation were investigated by studying the binding of 14C-labeled LPS to murine lymphocytes in vitro. In these studies we utilized intrinsically labeled 14C-labeled LPS from Salmonella minnesota or the 14C-labeled glycolipid derived from the Re mutant of S. minnesota (R595). Bone marrow-derived (B) lymphocytes bound more LPS than did thymus-derived (T) lymphocytes. Binding of LPS to murine spleen lymphocytes from strain C3H/HeN was compared with the binding to spleen lymphocytes from strain C3H/HeJ, a strain resistant to certain biological activities of LPS including mitogenesis. Spleen cells from both strains bound LPS equally well, suggesting that unresponsiveness of C3H/HeJ mice to LPS is due to factors other than a defect in binding of LPS. LPS binding to cells appeared to be due to a nonspecific interaction between the lipid moiety of LPS and the lipid components of the cell membrane. Thus, the highly lipophilic, polysaccharide-deficient glycolipid from R595 bound at least 20 times better than did LPS. Furthermore, partial removal of cell surface proteins with trypsin or sialic acids with neuraminidase enhanced glycolipid binding, suggesting that binding is not through a protein- or sialic acid-containing receptor. The binding of glycolipid to lymphocytes was only partially specific since unlabeled glycolipid R595, lipid A, and LPS did not completely inhibit the uptake of 14C-labeled glycolipid R595. In addition, binding could be inhibited by a nonmitogenic phospholipid (phosphatidyl ethanolamine), which also is consistent with a nonspecific lipid-lipid interaction. Experiments were performed to determine the relationship of LPS binding to lymphocyte activation in the lymphocytes. The process of activation of lymphocytes by LPS was a slow one, since LPS was required to be present in culture for at least 24 h in order to obtain significant lymphocyte activation, suggesting that the amounts of LPS bound earlier are either quantitatively or qualitatively insufficient to irreversibly activate the cell.
Humoral immunity in vaginal candidiasis
Authors: Mathur S , Koistinen G V , Horger E O , Mahvi T A , Fudenberg H H
Published: January 2020

Serum antibody titers to Candida albicans were estimated in 37 women with recurrent vaginal candidiasis and in 148 normal American and Finnish subjects, using the passive-hemagglutination technique. The antibody titers ranged from 0 to 16 in normal individuals and 4 to 256 in vaginal candidiasis patients. Antibodies to C. albicans in the sera of vaginal candidiasis patients were found to be the secretory immunoglobulin A type, as determined by gel filtration and double-diffusion tests. The results were confirmed by the indir-ct fluorescent-antibody technique. Our findings suggest that, in vaginal candidiasis, the antibody response is mainly local, consisting of secretory immunoglobulin A, some of which finds its way into systemic circulation.
Basophil hypersensitivity response in rabbits
Authors: Clark J M , Altman G , Fromowitz F B
Published: January 2020

A cutaneous basophil hypersensitivity response has been observed in rabbits immunized with bovine serum albumin and challenged intradermally with this antigen 7 days later. The cellular response appears to be similar to cutaneous basophil hypersensitivity reported in guinea pigs and humans. A basophil response was also observed in rabbits immunized with Staphylococcus aureus and challenged with viable staphylococcal cells 7 days later. A method of observing basophil infiltration in rabbits by means of connective tissue spreads obtained from the subcutaneous connective tissue is described. The rabbit should serve as an excellent model for the study of basophil responses as these animals have a significant basophil component with few if any tissue mast cells which may be confused both morphologically and functionally with the basophil.
Autoimmunity induced by injection of virus-modified cell membrane antigens in syngeneic mice
Authors: Eaton M D , Almquist S J
Published: January 2020

C3H/Bi mice developed autoantibodies after repeated inoculations of isolated membranes from primary tissue cultures of a syngeneic ascites lymphoma in which Newcastle disease virus had grown. This was in addition to the tumor transplantation resistance and cytotoxic antibodies previously demonstrated. The complement-fixing antibodies were completely removed from sera by adsorption with ascites tumor cells but only partially by normal mouse liver powder or C3H/Bi erythrocytes. With continued immunization, antibodies to deoxynucleoprotein and heterophile reagins also appeared. After several months, mice showing these serological reactions died with a wasting disease characterized by loss of lymphoid tissue and scarred, atrophied kidneys. No significant antibody response or autoimmune disease occurred in mice receiving membranes from uninfected syngeneic ascites lymphoma.
In vivo interference in vesicular stomatitis virus infection
Authors: Crick J , Brown F
Published: January 2020

Inactivated defective interfering and complete particles of vesicular stomatitis virus given intracerebrally to adult mice protect them against challenge with homologous virus whether this is given at the same time or several days later. Two separate protective processes appear to be involved. The first, which comes into operation immediately after inoculation, is also effective against heterologous strains of vesicular stomatitis virus, rabies (another rhabdovirus), and a neurotropic strain of foot-and-mouth disease virus. The second, later effect, which is strain specific, appears to be correlated with the appearance of circulating neutralizing antibody. Our results suggest that the protective effect that Holland and his colleagues described using defective interfering particles of vesicular stomatitis virus may also be accounted for by an immunological mechanism rather than one involving interference.
Immunoglobulin and specific-antibody synthesis in vitro by enteral and nonenteral lymphoid tissues after subcutaneous cholera immunization
Authors: Svennerholm A M , Holmgren J
Published: January 2020

An in vitro culture technique with synthesis of 14C-labeled protein has been used to study immunoglobulin and specific-antibody formation by spleen, mesenteric lymph nodes, Peyer's patches, and small intestine of rabbits, which were immunized twice subcutaneously with Vibrio cholerae lipopolysaccharide (LPS) and enterotoxin; saline-injected rabbits served as controls. Newly synthesized immunoglobulin G (IgG), IgA, and IgM were quantitated by liquid scintillation after their isolation by means of affinity chromatography from columns with immunoglobulin class-specific antibodies coupled to Sepharose. Specific antibodies were similarly measured after purification from gels derivatized with LPS or cholera toxin. The isolated antibodies had full biological activity as studied in protection tests. The immunization increased the overall IgM synthesis in the spleen. It also enhanced the production of IgA and IgG in Peyer's patches and of IgA in intestine. Significant synthesis of radiolabeled antibodies against both V. cholerae LPS and enterotoxin was found in spleen as well as in Peyer's patches of immunized animals. Titration with an enzyme-linked immunosorbent assay (ELISA) showed significant levels of IgG as well as IgA antibodies in incubation medium from all the studied tissues, whereas specific IgM was only found for spleen and mesenteric lymph nodes. Simultaneous tissue incubations at 37 degrees C and in an ice bath indicated that the major part of the antibodies registered with the ELISA represented de novo synthesis.
In vitro interaction of Neisseria gonorrhoeae type 1 and type 4 with tissue culture cells
Authors: Brodeur B R , Johnson W M , Johnson K G , Diena B B
Published: January 2020

As a basis for studies of gonococcal pathogenicity, tissue culture cells were infected with type 1 or type 4 Neisseria gonorrhoeae to determine intracellular viability. A simple and objective means of measurement was devised, based on the uptake of tritiated protein and deoxyribonucleic acid precursors by cycloheximide-inhibited cells infected with gonococci. Cycloheximide was found to inhibit protein synthesis by over 97% tissue culture cells at a concentration of 100 microng/ml. In contrast, N, gonorrhoeae was found to be highly resistant to this antibiotic, and protein synthesis was unaffected by concentrations up to 1,000 microng/ml. Extracellular gonococci were eliminated by treatment with high concentrations of penicillin during cycloheximide inhibition and prior to the addition of radioisotope. Levels of protein and deoxyribonucleic acid synthesis by N. gonorrhoeae in the cycloheximide-treated cells were significantly higher in T1-infected cells (RE2, HeLa, or HEp-2) than in the corresponding T4-infected cells. No differences were observed in tissue cell susceptibility to gonococcal infection. Intracytoplasmic localization of N. gonorrhoeae was confirmed by electron microscopy.
Extracellular antigens of Micropolyspora faeni grown in synthetic medium
Authors: Kurup V P , Fink J N
Published: January 2020

Extracellular antigens were prepared by growing Micropolyspora faeni in a new synthetic medium (SMSL), and this antigenic preparation was compared with antigens obtained by the double-dialysis method. These two preparations were tested against pooled sera from farmer's lung patients and rabbits immunized with these antigens by the agar-gel double-diffusion, immunoelectrophoresis, and two-dimensional immunoelectrophoresis methods. The immunological cross-reactivity between M. faeni strains of diverse origin and between other species of thermophilic actinomycetes associated with hypersensitivity pneumonitis was also investigated. The usefulness of two-dimensional immunoelectrophoresis in the comparison and standardization of antigens is discussed.
Novel bacterial structures in human blood: cultural isolation
Authors: Domingue G J , Schlegel J U
Published: January 2020

Evidence for the existence of a novel bacteriological system has been obtained from osmotically lysed and filtered human blood (membrane filters with a pore size of 0.22 micronm) placed in special culture media. These blood filtrates gave rise to ordinary bacteria for 71% of the blood specimens processed from diseased humans and for 7% of those from supposedly normal humans. Morphologically, the bacteria resembled streptococcal, staphylococcal, and gram-positive filamentous (cocco-bacillary) forms. Prior to the appearance of bacteria in the media, large and small "dense bodies" were microscopically observed but disappeared when ordinary bacteria were apparent, Cultures of of unlysed blood as conventionally performed were negative. These organisms may represent an adaptation of certain bacteria to life in the blood.
Escape from antibody-mediated immune suppression in vitro by delayed-type hypersensitivity reaction
Authors: Muscoplat C C , Setcavage T M , Kim Y B
Published: January 2020

Anti-sheep erythrocyte antiserum suppressed the in vitro immune response of swine spleen cells to sheep erythrocytes. Inhibition of the in vitro anti-sheep erythrocyte response was also observed in neonatal spleen cells, which were obtained from piglets recently fed colostrum. Addition of purified protein derivative (PPD) to spleen cell cultures prepared from animals previously sensitized to Mycobacterium bovis reversed the immunosuppression caused by passive antibody. Passive antibody regulation was dose dependent; low doses of anti-sheep erythrocyte antiserum caused enhancement, whereas higher doses resulted in complete inhibition of anti-sheep erythrocyte responses. Addition of PPD to cultures of sensitized cells containing passive antibody resulted in progressively increased antibody responses as the dose of anti-sheep erythrocyte antibody increased. PPD addition also reversed maternal antibody suppression of in vitro 2-week-old neonatal spleen cell responses providing these animals were sensitized with M. bovis at the time of birth.
Role of macrophages in hepatitis induced by Herpes simplex virus types 1 and 2 in mice
Authors: Mogensen S
Published: January 2020

A marked difference was found between herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in the induction of hepatic necrotic lesions in mice inoculated intraperitoneally. Although HSV-2 produced many large, progressive liver lesions in 4-week-old BALB/c mice, HSV-1 only occasionally induced a few, self-limiting foci, which eventually healed. This was reflected in the isolation of HSV from the liver and spleen, two organs that are rich in macrophages. Although HSV-1 could be only temporarily isolated, HSV-2 was found in the two organs until the mice died. On the other hand, no such difference was found in the isolation of virus from the brain, which contains no macrophages, and the mice eventually died from encephalitis. This difference in hepatic involvement caused by the two virus types was found to parallel a marked difference in the restriction of HSV-1 and HSV-2 replication by macrophages as measured by an infectious center assay in vitro. HSV-2 produced 17 times as many infectious centers in infected peritoneal macrophage cultures as did HSV-1. Furthermore, the HSV-2 plaques in the cell overlay were large and increasing in size, whereas the HSV-1 plaques were small and showed regression on prolonged incubation. It was shown that this diversity was unique to the macrophage population and not caused by differences in the uptake of virus by macrophages. This model involving two closely related virus types shows the importance of tissue macrophages in the primary host defense against virus infections.
Production and properties of a staphylococcin genetically controlled by the staphylococcal plasmid for exfoliative toxin synthesis
Authors: Rogolsky M , Wiley B B
Published: January 2020

Previous data from this laboratory showed that certain phage group 2 staphylococci contain a large 56S virulence plasmid containing genes that code for both exfoliative toxin (ET) and a specific staphylococcin. Optimal cultural conditions for bacteriocin production were similar to those found for ET production. The bacteriocin is an extracellular product produced in small quantities that can be neither extracted from cell pellets with 1 M NaCl nor induced with mitomycin C. The staphylococcin is active against a wide variety of gram-positive organisms and also against group 2 staphylococcal strains that have been cured of the plasmid carrying the staphylococcin marker. The bacteriocin is not inactivated by oxidation, mechanical agitation, or boiling for 15 min. It is sensitive to the action of trypsin and Pronase but not lysostaphin and is stable within a pH range of 4 to 9. It has an isoelectric point of approximately 7.7. Removal of the ampholytes and glycerol from electrofocused staphylococcin preparations resulted in total loss of bacteriocin activity.
Biological properties of Shigella flexneri 2A toxin and its serological relationship to Shigella dysenteriae 1 toxin
Authors: O'Brien A D , Thompson M R , Gemski P , Doctor B P , Formal S B
Published: January 2020

A toxin extracted from heat-inactivated, alkaline-treated Shigella flexneri 2a showed biological properties similar to those of Shigella dysenteria 1 toxin. The S, flexneri 2a toxin was lethal to mice, enterotoxic for ileal loops of rabbits, and cytotoxic for HeLa cells. A serological relationship between S. flexneri 2a and S. dysenteriae 1 toxin was shown with cross neutralization tests.
Complement-fixing reactivity of Varicella-Zoster virus subunit antigens with sera from homotypic infections and heterotypic Herpes simplex virus infections
Authors: Schmidt N J , Dennis J , Lennette E H
Published: January 2020

Various subunit antigens of varicella-zoster (V-Z) virus were examined for complement-fixing (CF) activity with sera from homotypic infections and from herpes simplex virus (HSV) infections in which a CF antibody titer rise was demonstrated with crude V-Z antigen. The subunit antigens included nucleocapsids, envelopes, a soluble antigen produced from infected culture fluids by sucrose density gradient centrifugation, a soluble antigen produced by reducing the volume of clarified infected culture fluids, a soluble antigen derived from infected cell lysates, a "viral" antigen consisting largely of enveloped particles with a few nucleocapsids, and a cell membrane-associated antigen. None was more suitable than crude V-Z antigen for serodifferentiation of V-Z virus and HSV infections. The envelope antigen, cell membrane antigen, and the soluble antigen prepared by density gradient centrifugation showed little reactivity with sera from varicella and HSV infections, but gave high antibody titers with sera from zoster infections, suggesting that a secondary V-Z virus infection is required to produce an antibody response to these subunit antigens. Patients with varicella and zoster infections and the selected patients with HSV infections all showed significant CF antibody responses to the other V-Z subunit antigens.
Cholesteryl de-esterifying enzyme from Staphylococcus aureus: separation from alpha toxin, purification, and some properties
Authors: Harvie N R
Published: January 2020

A cholesteryl de-esterifying enzyme found in partially purified preparations of alpha toxin produced by the Wood 46 strain on Staphylococcus aureus has been separated from other staphylococcal proteins and from alpha toxin by isoelectric focusing and gel filtration. Preparations of alpha toxin from Bi-Gel P-60 columns and of the cholesteryl esterase from Bio-Gel P-200 columns showed a high degree of purity, as determined by analytical ultracentrifugation, gel diffusion, immunoelectrophoresis, and polyacrylamide gel electrophoresis. The molecular weight of the cholesteryl esterase determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate was 25,500 and on Bio-Gel P-300 columns it was 175,000, indicating an associating system. The density of the enzyme was lower than expected for simple proteins (about 1.19 g/ml). Chloroform-methanol extracts showed the presence of a neutral lipid that did not contain cholesterol. This material, possibly a glycolipid, might play a role in the stabilization of the enzymatically active protomer. The isoelectric point of the esterase was 9.1. Cholesteryl esterase was labile and lost its activity easily. It could bind reversibly to agarose-containing gels. After elution, it was enzymatically inactive, with an isoelectric point of less than 6.2. The W46M mutant of the Wood 46 strain, which does not produce alpha toxin, also does not produce cholesteryl esterase.
Experiments on lymphocyte-mediated cellular immunity in murine histoplasmosis
Authors: Howard D H , Otto V
Published: January 2020

Peritoneal exudate cells from immunized mice inhibit the intracellular growth of Histoplasma capsulatum. The lymphocyte is the mediator cell of this phenomenon. Lymphocytes from immunized animals are highly activated cells. Supernatants from cultures of immune lymphocytes or from cultures of mitogen-stimulated lymphocytes did not arm macrophages from normal animals to inhibit the intracellular growth of H. capsulatum.
Effects of Cigarette Smoke Components on In Vitro Chemotaxis of Human Polymorphonuclear Leukocytes
Authors: Bridges Raymond B. , Kraal J. H. , Huang L. J. T. , Chancellor M. B.
Published: January 2020

Some ciliostatic components of cigarette smoke were studied as inhibitors of in vitro chemotaxis of human polymorphonuclear leukocytes (PMNs). In comparison to their concentration in an inhibitory level of cigarette smoke, the unsaturated aldehydes acrolein and crotonaldehyde were the most potent inhibitors, whereas nicotine, cyanide, acetaldehyde, and furfural were the next strongest inhibitors. In contrast, sulfide, propionaldehyde, butyraldehyde, and the phenols (phenol and
o
-,
m
-, and
p
-cresol) were relatively weak inhibitors of PMN chemotaxis. Acrolein and crotonaldehyde mimicked whole cigarette smoke in their effects on PMNs by not causing loss of PMN viability, yet their effects were prevented by the addition of cysteine. On the other hand, addition of nicotine, cyanide, acetaldehyde, and furfural to PMN suspensions resulted in a limited loss of cellular viabilities, and their effects on PMNs were not prevented by cysteine. Of the tested components, only cyanide significantly altered PMN glucose metabolism by increasing carbon flow via the glycolytic and hexose monophosphate pathways in a manner similar to that observed with whole cigarette smoke. The results of this study suggest that the unsaturated aldehydes, including acrolein and crotonaldehyde, are major contributors to the inhibitory properties of cigarette smoke. The inhibitory effects of these unsaturated aldehydes are probably due to a direct interaction of these oxidants and/or thiol-alkylating agents with PMNs, yet the glucose metabolism of these cells is unaffected. One interpretation of these data is that PMN chemotaxis is dependent upon particular cellular proteins containing one or more essential thiol group(s) but that these proteins are unrelated to glucose metabolism.
Comparison of Streptomyces albus muramidase-extracted streptococcal antigen with acid-extracted M antigen and with pepsin-extracted T antigen
Authors: Bray J P , Bass J A
Published: January 2020

Purified Streptomyces albus lytic enzyme was used in an attempt to extract type-specific antigen from a type 1, group A streptococcus. The presumably type-specific antigen was purified by ammonium sulfate fractionation followed by chromatography on O-(carboxymethyl)-cellulose columns. Comparison of the enzyme-extracted substance with acid-extracted material showed it to be serologically different from M protein. In addition, the extract obtained by enzyme treatment was resistant to trypsin as well as to the lytic enzyme. It was inactivated partially by pepsin and totally by papain. Comparison of the enzyme extract with pepsin-extracted T antigen showed these two preparations to be serologically identical. Subtle differences in their susceptibility to heat and acid treatment were noted. Immunodiffusion analyses of acid-extracted M protein and pepsin-extracted T protein, as well as with the enzyme extract, clearly established that the M-protein preparation contained a component serologically identical with one of the precipitinogens common to the other two extracts.
Cell-mediated cytotoxicity to herpes-infected cells in humans: dependence on antibodies
Authors: Moller-Larsen A , Heron I , Haahr S
Published: January 2020

Herpes simplex virus type 1 (HSV-1)-infected human skin fibroblasts were used as target cells in a 51Cr release assay, using peripheral blood mononuclear cells from HSV-seropositive and -seronegative donors as effector cells. Cytotoxicity was exerted by ordinarily prepared lymphoid cells but could be reduced by extensive washing of the effector cells. The antibody dependence of the system was shown by the recovery of activity through addition of positive serum or medium used for the early washes of effector cells. Three donors found to be seronegative in the usual serological tests were shown to be seropositive in this test. It is proposed that the assay can be used as a very sensitive serological test.
Immunological responses of mice to lipopolysaccharide: lack of secondary responsiveness by C3H/HeJ mice
Authors: Rudbach J A , Reed N D
Published: January 2020

Mice of the C3H/HeJ strain, which were unresponsive to the biological effects of bacterial lipopolysaccharide (LPS), could not be induced to make specific secondary immunological responses to LPS; they responded to two doses of LPS with a primary response. This lack of secondary responsiveness by C3H/HeJ mice was due to a defect in a single, autosomal, dominant gene. Thus, further evidence was provided that an intact second immunological signal and responsiveness thereto were required to trigger secondary antibody responses in primed animals.
Purification and characterization of group A streptococcal pyrogenic exotoxin type C
Authors: Schlievert P M , Bettin K M , Watson D W
Published: January 2020

Group A streptococcal pyrogenic exotoxin (SPE) type C was partially purified by differential solubility in ethanol and acetate-buffered saline. Toxin prepared in this way consisted of protein and hyaluronic acid. After removal of hyaluronic acid, the toxin remained pyrogenic, enhanced susceptibility of rabbits to letahl endotoxin shock, was stable when treated with acid, base, or pepsin, but was inactivated by heat. Toxin further purified by thin-layer isoelectric focusing was pyrogenic and enhanced the susceptibility of rabbits to lethal endotoxin shock. Purified type C toxin appeared homogeneous when tested by Ouchterlony immunodiffusion and migrated as a single protein band in isoelectric focusing polyacrylamide gels (isoelectric point, 6.7) and sodium dodecyl sulfate-polyacrylamide gels (molecular weight, 13,200). The purified toxin was antigenically distinct from A and B SPE, and antisera raised against the purified toxin neutralized pyrogenic activity. The amino acid composition was determined.
Low sucrose levels promote extensive Streptococcus mutans-induced dental caries
Authors: Michalek S M , McGhee J R , Shiota T , Devenyns D
Published: January 2020

One-tenth percent sucrose significantly promotes dental caries induced by Streptococcus mutans in young gnotobiotic rats. Maximum caries activity was observed in rats provided a purified diet containing 3% sucrose.
Chronic infection with Trypanosoma musculi in congenitally athymic nude mice
Authors: Rank R G , Roberts D W , Weidanz W P
Published: January 2020

Trypanosoma musculi produces a chronic infection with a consistently elevated parasitemia in nude mice. Thymic reconstitution of nude mice restores immunity to the infection.
Immunological analysis of plasma membranes of a T-strain of mycoplasma (Ureaplasma urealyticum)
Authors: Romano N , La Licata R , Scarlata G
Published: January 2020

The cell membranes of a T-strain of mycoplasma, obtained by ultrasonic disruption, were as effective as whole organisms in eliciting metabolism-inhibiting and complement-fixing antibodies. The soluble fraction separated from cell membranes by centrifugation at 35,000 X g showed a minor ability to elicit an antibody response as measured by metabolism inhibition and complement fixation tests. After a further centrifugation at 100,000 X g, the immunogenic activity of the soluble fraction was completely lost. Immunogenic determinants in mycoplasma membranes could also be demonstrated by adsorption tests; cell membranes were more effective than soluble fractions in adsorbing antibody capacity from the immune sera against whole cells. It has been shown by further experiments that cell membranes have at least two major antigenic determinants, which differ either in chemical nature or in capacity to adsorb and evoke antibodies, characterized by different serological behaviors.
Synthesis and cleavage processing of oncornavirus proteins during interferon inhibition of virus particle release
Authors: Shapiro S Z , Strand M , Billiau A
Published: January 2020

The effect of interferon on the rate of synthesis and the cleavage processing of viral proteins in mouse cells, chronically infected with Rauscher murine leukemia virus, has been studied by immunoprecipitation of newly synthesized viral proteins from virus-infected cells pulse-labeled with [35S]methionine. Immuno-precipitated, labeled polypeptides were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and then examined by autoradiography. Cleavage processing was studied in the same manner with cells that had been pulse-labeled and then incubated with non-radioactive media for a sufficient time to allow normal cleavage processing to occur. At a concentration that strongly inhibited the release of virus particles, interferon had no effect on the synthesis of proteins carrying antigenic determinants of the major core protein p30 or of the envelope glycoprotein gp69/71. Nor did it affect the post-translational cleavage processing of the precursors to these proteins. Similarly, interferon did not affect labeling or chasing of precursor protein carrying the p15 determinants; labeling of p15 itself could not be studied because it does not contain methionine.
Specific method for the purification of Streptococcus mutans dextransucrase
Authors: McCabe M M , Smith E E
Published: January 2020

A convenient and rapid method for the purification of Streptococcus mutans dextransucrase is described. Affinity chromatography, on a column containing insoluble dextran purified from a culture of S. mutans 6715-49, gave an almost 300-fold purification, with 76% recovery of enzyme. Subsequent hydrophobic chromatography on butyl-agarose increased the overall enzyme purification to more than 1,000-fold, with a 65% recovery of activity. Two components of the dextransucrase activity were separated during hydrophobic chromatography. Both synthesized insoluble glucan as their major product and were capable of synthesizing soluble glucan in the presence of exogenous soluble dextran. However, the major enzyme component, which coeluted with a catalytically inert, dextran-binding protein, was greatly stimulated by exogenous soluble dextran, whereas the second enzyme component was not.
Prevention of recrudescent malaria in nude mice by thymic grafting or by treatment with hyperimmune serum
Authors: Roberts D W , Rank R G , Weidanz W P , Finerty J F
Published: January 2020

Nude mice died when infected with the normally avirulent malarial parasite Plasmodium berghei yoelii. Furthermore, malaria recrudesced in Nu/Nu mice after the termination of acute disease by treatment with clindamycin. Recrudescence was not observed in Nu/Nu mice that had been grafted with thymic tissue or treated with hyperimmune serum. Mice mad B cell deficient by treatment with anti-mu-chain serum also died when infected with P. berghei yoelii. The data suggest that a crucial role of the thymus in preventing recrudescent malaria in this model system is to provide a helper function in the production of protective antibody.
Immune response and latent infection after topical treatment of herpes simplex virus infection in hairless mice
Authors: Klein R J , Friedman-Kien A E , Fondak A A , Buimovici-Klein E
Published: January 2020

Treatment of herpes simplex virus (HSV)-infected hairless mice with a 2% phosphonoacetic acid (PAA) ointment prevented the appearance of virus-induced skin lesions and subsequent central nervous system (CNS) involvement. Treatment started 24 h after infection significantly reduced the intensity of the skin lesions and also prevented CNS involvement. After four to six applications of PAA ointment, a moderate skin erythemia developed, followed by scaling and complete healing 7 days after cessation of the treatment. Mice treated early after HSV infection had low or undetectable levels of virus-specific antibodies but were completely resistant to reinfection. Early treatment prevented the development of a latent ganglionic infection, but treatment initiated 24 h after infection could not prevent the establishment of the latent infection. PAA-treated and HSV-infected mice with nondetectable levels of antibodies did not develop, with a single exception, a latent ganglionic infection unpon reinfection. The cell-mediated immune response determined by levels of [14C]thymidine incorporation in Ficoll-Hypaque-purified spleen lymphocytes cultures was low in PAA-treated mice; it increased slightly after challenge infection but was strong in mice that proved to harbor a latent HSV infection in the ganglia.