Influence of Candida albicans glycoprotein on 3-methylcholanthrene induced malignancy in newborn rodents

In the experimental conditions reportedCandida albicans glycoprotein has a stimulating effect on the course of 3-methylcholanthrene carcinogenesis in newborn rodents. Stimulation of 3-methylcholanthrene carcinogenesis in newborn rats was found following injections of 9.5 µg/g and 18.5 µg/g ofCandida albicans glycoprotein. Subcutaneous tumors occurred in the experimental animals earlier, with higher frequency and attained larger dimensions than in the control animals. Similar effects were observed in mice. In the experimental mice there was also a significantly higher number of thymomas. From the evidence presentedCandida albicans glycoprotein appears to act as a cocarcinogenic substance to 3-methylcholanthrene.This work was supported partially byDora Kaplan, Joan Sloan, Cathy Cooper Memorial Funds and the Leo Roon Foundation.     

Increased carbohydrate content in the thymus and spleen in mice receiving Candida albicans orally (occurence of lymphomas)

Following oral administration ofCancida albicans to non — inbred albino mice in the experimental conditions reported, an increased level of carbohydrate was found in the spleen and thymus. Significant increase of carbohydrate content in these organs was found to occur in the third month of the experiment and remained so, during the ten months of its duration with the exception of the fourth and fifth month. The carbohydrate content in other essential organs was in a similar range in the control and experimental animals. No significant differences in protein level in the control and experimental animals were found. This was regarded as an indication that the incresaed carbohydrate level in the thymus and spleen of experimental animals represents their reaction to the pathological influences of metabolic products ofCandida albicans.Appearance of lymphomas was observed between the seventh and tenth month. Three lymphomas were found in sixty four animals which were autopsied. Previously reported occurrence of lymphomas in mice which received injection ofCandida albicans to the spleen, provides circumstantial support that the observed increase of carbohydrate level as reported here in the spleen and thymus represents the pathological reaction towards metabolic products ofCandida albicans and forms the basis of a collapse of the defense system of the experimental animals.Thymus and spleen appear to act synergically in the reported experimental conditions and as a part of enterodefense system. The possibility of relevance of observed pathology to humans is discussed.This work was supported partially byDora Kaplan, Joan Sloan, Cathy Cooper Memorial Funds and the Roon Foundation.     

Occurrence of atypical lymphocytes following intravenous injection of Candida albicans in mice

The occurrence of atypical lymphocytes has been observed in the course of experimental acute infection withCandida albicans in mice. In animals injected intravenously with 2.5 × 10⁶ ofCandida albicans cells, an increased number of monocytes was seen in 24 hours. Monocytes showed toxic vacuolisation in most instances in protoplasm and sometimes in the nuclei. Only a few atypical lymphocytes could be seen at that time. In the following days the number of monocytes diminished and the number of atypical lymphocytes increased. After four days atypical lymphocytes constituted frequently over 20 % of white cells. The autopsy of sacrificed or dead animals with the presence of such elevated percentages of atypical lymphocytes showed enlargement of cervical lymphnodes in all animals. In mice infected with 1.4 × 10³ ofCandida albicans cells, no level higher than 12% of atypical lymphocytes was seen. Pictures were returning to normal with only a few atypical lymphocytes present among the animals which survived for two months after infection withCandida albicans.This work was supported partially byDora Kaplan, Joan Sloan, Cathy Cooper. Memorial Funds and the Roon Foundation.     

Seizure induction by pentylenetetrazol in rodents receivingCandida albicans glycoprotein orally

Oral administration of extracellularCandida albicaus glycoprotein produces increased proneness to seizures in mice and rats when tested with pentylenetetrazol in the experimental conditions reported.Dosages of 0.25 ug/g of body weight in mice and rats applied for a period of five weeks were enough to produce increased proneness to seizures. It appears that the substance is absorbed from the stomach or intestine and also that its detoxication or excretion is at such a slow rate that it accumulates. Introducing to the stomach much larger dosages could cause increased proneness to seizures to be obtained within six hours. Due to the frequent presence ofCandida albicans in humans and the high probability ofCandida albicans glycoprotein production in vivo, it is possible that the level of this substance may accumulate to produce increased proneness to seizures. The states of tenseness, increased sensitivity and hyperactivity could possibly occur in the same pathological process.A renewal of interest in the possible role of intestinal intoxication in human pathology appears to be indicated. Fungi which are harbored in the digestive tract could be the important source of such toxic substances.This work was supported partially byDora Kaplan, Joan Sloan, Cathy Cooper. Memorial Funds and the Roon Foundation.     

Blood changes and fertility derangements following the injection of Candida albicans into the spleen of the experimental animals (occurrence of hypersplenism)

Summary The injection ofCandida albicans (under experimental conditions used here) into the spleens of Wistar rats and Swiss mice produces profound hematological changes which are similar in rats and mice. After injection of the organisms there was steady lowering of the white cells and of the platelets in mice and in rats. Following splenectomy there was a sharp rise of both platelets and white cells in mice and rats. Mild normocytic, normochromic anemia was observed during the experiment. Following the splenectomy the level of hemoglobin returned to normal in fourteen weeks in the rats and in thirteen weeks in the mice. An increased level of reticulocytes and siderocytes was observed during the experiment. The mean value of the spleen weights in the experimental animals was higher than in the controls. Hyperplasia was the constant histological feature of these spleens. Bone marrow was either normal or hyperplastic. plastic. These changes correspond to the picture known in human pathology as hypersplenism. The injected organisms could still be cultured from the spleen about 4–6 months after operation. Attempts to isolate the injected organisms after 6 months were unsuccessful. The experimental mice showed derangement of fertility. Of the forty females mated with normal males only seven became pregnant. The litters were normal, 7–12 babies. Thirty percent of the young died before one month. Many of them showed growth retardation.This work was supported by a Damon Runyon Memorial Fund Grant No. 720.     

Prophylactic Effect of Enterococcus faecalis FK-23 Preparation on Experimental Candidiasis in Mice

The prophylactic effects of heat-killed cells of Enterococcus faecalis FK-23 (FK-23 preparation) on experimental candidiasis were investigated in normal and leukopenic mice. In cyclophosphamide-induced leukopenic mice, oral or intraperitoneal administration of the FK-23 preparation at a daily dose of 1.25 or 5 mg/mouse for 3 consecutive days prior to Candida albicans infection significantly prolonged survival periods of the infected mice, and decreased viable counts of C. albicans recovered from their kidneys. In normal mice, the FK-23 preparation administered at dosages ranging from 0.63 to 10 mg/mouse/day for 3 consecutive days was ineffective, while in leukopenic mice, the FK-23 administered orally caused a facilitated recovery in the number of white blood cells including neutrophils. Furthermore, intraperitoneal administration of the FK-23 preparation into mice augmented the anti-Candida activity of immunocompromised peritoneal exudate cells obtained from the animals. These results suggested the potential usefulness of the FK-23 preparation as a prophylactic agent for the management of patients with opportunistic fungal infections.     

Role of antibodies and effect of BCG vaccination in experimental candidiasis in mice

The role of humoral antibodies and the effect of BCG vaccination were studied in the experimental candidiasis in mice. The antibody suppressed, B-cell deficient animals were prepared by repeated administration of rabbit anti-mouse--antiserum to the new born mice from birth onwards. Such immunodeficient animals along with controls were infected intravenously with Candida albicans, to study the course of candidal infection. It was observed that B-cell-deficient animals were found to be more susceptible to candidal infection than the controls, as indicated by their steady loss of body weight, longer mean time to death and higher viable counts of candidal cells in different organs. The anti-candidal antibodies were absent in all B-cell-deficient animals but present in the controls. These results suggest that antibodies make a contribution in protection against candidal infection in mice. The BCG vaccinated animals were prepared by repeated intravenous administration of BCG to mice and these vaccinated animals along with unvaccinated controls were challenged intravenously with C. albicans, to study the course of candidal infection. It was observed that BCG vaccination prolonged meantime to death and reduced the number of candidal cells in their kidneys.     

Mouse candidiasis

Administration of a Thy-1.2-specific monoclonal antibody to BALB/c mice resulted in a significant decrease in the efficiency of clearance of Candida albicans from the spleen. The rate of clearance of organisms from the spleen of congenic mice was determined by genes in the major histocompatibility complex, as was the magnitude of the inflammatory response in the popliteal lymph node after footpad immunization. These results formally demonstrate the involvement of T cells in host responses to primary candida infection.     

Effect of Candida albicans dsDNA in Gastrointestinal Candida Infection

Neonates are highly sensitive to infections because they are biased to develop Th2 immune responses. When exposed to certain agents, such as DNA vaccines or CpG DNA motifs, neonates are capable to mount adult-like Th1 protective responses. This study investigates the capacity of Candida albicans (C. albicans) dsDNA to induce host resistance in newborn mice against gastrointestinal C. albicans infection. The protective properties of dsDNA are related to an increased number of spleen CD4+ T cells secreting IFN-γ. In infected DNA-treated mice, an enhanced production of IFN-γ by Peyer’s patch cells was observed together with reduced colonization and histopathological changes in the stomach. Our results indicated that C. albicans dsDNA administration in neonates elicited the protective immune response against gastrointestinal Candida infection.     

Occurrence of lymphomas and lupus erythematosus-like syndrome in the course of experimental Candida albicans infection in mice

Occurrence of four lymphomas was seen following injection of 1.4×10³ Candida albicans cells to the spleen of eighty non - inbred albine mice. These neoplastic changes occurred in three to seven months of the duration of the experiment. Extensive invasion of the subcutaneous tissue by the tumor was found in one animal. Two of the animals with lymphoma also had changes in the kidneys compatible with lupus erythematosus and presence of LE cells in the blood. In other animals most frequent and extensive pathological changes were found in the kidneys and in order of frequency were as follows: thickening of the basement membrane, fibrinoid degeneration, presence of hematoxylin bodies, wireloop formation. In total, the presence of positive LE cells in blood was found in seven instances and suggestive LE cells was observed in eight animals. Finding of perisplenitis, exudative pleuritis and pericarditis gave additional support to the resemblance of observed pathological changes with human lupus erythematosus. The fact that occurrence of lymphomas and lupus erythematosus together has been reported in humans provides additional interest to the results reported.Results presented here and previously suggest that there may be more extensive interrelationship among variety of pathological changes observed than is accepted until now. Better understanding of host — parasite relationship ofCandida albicans, and possible other fungi, could advance out knowledge of pathogenesis of these diseases.This work was supported partially byDora Kaplan, Joan Sloan, Memorial Funds and the Roon Foundation.     

The relative contribution of resident pulmonary alveolar macrophage and inflammatory polymorphonuclear neutrophils in host resistance to pulmonary infection by Candida albicans

Cortisone (CA) or cyclophosphamide (Cy) treatment of mice was used to investigate the relative contributions of pulmonary alveolar macrophages (PAM) and inflammatory neutrophils (PMN) in the initial defense against intratracheal challenge (IT) with Candida albicans. Mice treated with either CA or Cy were susceptible to IT challenge with 10–100 x less C. albicans than were untreated mice. Untreated mice rapidly eliminated C. albicans from their lungs with the majority of the organisms being cleared within three hours of challenge. Mice treated with CA initially cleared some of the C. albicans but were unable to clear all the C. albicans as did the untreated mice. Mice treated with Cy were unable to clear C. albicans from their lungs. Candida albicans did not disseminate from the lungs of untreated mice, while in both of the treated groups, C. albicans disseminated to the liver, spleen, brain and kidneys, rapidly killing the treated hosts. Analysis of the changes in cells in lung lavage fluids collected at various times after C. albicans challenge, revealed that large numbers of PMN accumulated in the lungs of both untreated and CA-treated mice, whereas PMN were virtually undetectable in lavage fluids from Cy-treated mice. Resident PAM from untreated mice were able to kill approximately 70 % of 10⁵ C. albicans in a 3 hr in vitro killing assay. By contrast, at similar effector: target ratios, resident PAM from Cy-treated mice killed only about 20% of the inoculum and resident PAM from CA-treated mice were unable to kill C. albicans. PMNs from both untreated and CA-treated mice killed approximately 70% of 10⁵ C. albicans in vitro. The data indicates that both PAM and PMN were critical to the initial clearance of C. albicans from pulmonary tissue. The accumulation of PMN in the lungs appeared to be required for the complete clearance of C. albicans from the lungs yet was not sufficient to inhibit dissemination of C. albicans from the lungs in CA-treated mice. The presence of PAM with in vitro candidacidal abilities appeared to be required for both the clearance of C. albicans and inhibition of dissemination of C. albicans from the lungs. Compromise of either PAM or PMN function can lead to increased pulmonary susceptibility to C. albicans.     

Intestinal Colonization by Candida albicans Alters Inflammatory Responses in Bruton's Tyrosine Kinase-Deficient Mice

The commensal yeast Candida albicans is part of the human intestinal microflora and is considered a “pathobiont”, a resident microbe with pathogenic potential yet harmless under normal conditions. The aim of this study was to investigate the effect of C. albicans on inflammation of the intestinal tract and the role of Bruton''s tyrosine kinase (Btk). Btk is an enzyme that modulates downstream signaling of multiple receptors involved in innate and adaptive immunity, including the major anti-fungal receptor Dectin-1. Colitis was induced in wild type and Btk-/- mice by treatment with dextran sodium sulfate (DSS) and the gastrointestinal tract of selected treatment groups were then colonized with C. albicans. Colonization by C. albicans neither dampened nor exacerbated inflammation in wild type mice, but colon length and spleen weight were improved in Btk-deficient mice colonized with C. albicans. Neutrophil infiltration was comparable between wild type and Btk-/- mice, but the knockout mice displayed severely reduced numbers of macrophages in the colon during both DSS and DSS/Candida treatment. Smaller numbers and reduced responsiveness of Btk-/- macrophages might partially explain the improved colon length of Btk-/- mice as a result of Candida colonization. Surprisingly, DSS/Candida-treated Btk-/- animals had higher levels of certain pro-inflammatory cytokines and levels of the anti-inflammatory cytokine TGF-β were reduced compared to wild type. A clustering and correlation analysis showed that for wild type animals, spleen TGF-β and colon IL-10 and for Btk-/- spleen and colon levels of IL-17A best correlated with the inflammatory parameters. We conclude that in Btk-/- immunocompromised animals, colonization of the gastrointestinal tract by the commensal yeast C. albicans alters inflammatory symptoms associated with colitis.     

Characteristics of DTH suppressor cells in mice infected with Candida albicans

Inoculation of 10⁸ C. albicans intraperitoneally into Balb/c mice at given dosage was reported to induce suppression of antigen-specific delayed-type hypersensitivity. Adoptive transfer of spleen cells into normal syngeneic mice pre-treated with Cyclophosphamide confirmed the existence of suppressor cells in mice. Such cells were sensitive to treatment with anti- serum and complement, non-adherent to Sephadex G-10. A pretreatment of the mice with Cyclophosphamide eliminated DTH suppression. Treatment with antimacrophage agents via intraperitoneal abrogated suppression only if being effected before inoculation of alive 10⁸ Candida albicans.It is concluded that the spleen suppressor cell is a T-lymphocyte whose precursor is Cyclophosphamide-sensitive, requiring the macrophage to be induced.     

Effects of surface active agents on the susceptibility of Swiss mice to Candida albicans

Summary The LD50's ofCandida albicans combined with Plurafac B26, Mulsor 224, Pluronic L62, and Polyethylene Glycol 400 Mono Laurate injected intraperitoneally into female white Swiss mice were calculated by the method ofReed &Muench. Each of the previously mentioned surface-active agent —Candida albicans combinations had a lower LD50 than theCandida albicans control.Plurafac B26 was found to intially decrease the number of leukocytes in the peritoneal cavity and thus enhance the invasiveness ofCandida albicans.     

Studies on defense mechanisms against Candida albicans infection in congenitally athymicnude (nu/nu) mice

The defense mechanisms against Candida albicans infection were studied by using a mouse thigh lesion model in congenitally athymic nude (nu/nu) mice and their normal littermates (nu/+). Nu/nu mice were more resistant to C. albicans infection than nu/+ mice judging from the course of the thigh lesion, the results of CFUs (colony-forming units) of C. albicans in the lesion, and histopathological observations. Histopathological and serological studies revealed that granulocytic cellular infiltration was predominant, and there were few indications of development of cell-mediated immunity to protect Candida infection in Candida-infected nu/nu and nu/+ mice. These results confirmed that lower susceptibility of nu/nu mice to C. albicans infection as compared with nu/ + mice was due to accelerated non-specific defense mechanisms in nu/nu mice, and that cell-mediated or humoral immunity played a minor role in the defense against Candida infection in this experimental model.Furthermore, treatment with high titer of rabbit anti-C. albicans serum was effective to control the number of Candida cells in thigh lesions of BALB/c mice.Above experimental results seem to clearly indicate the great variability of defense manifestation according to the experimental model exployed.     

Immune responses elicited by vaccinations with Candida albicans ribosomes in cyclophosphamide treated animals

This study describes humoral and cell mediated immune (CMI) responses detected in cyclophosphamide (CY) treated animals who were vaccinated with Candida albicans ribosomes and were protected against systemic candidiasis (previous study).Mice treated with CY and vaccinated with C. albicans ribosomes revealed CMI responses towards the ribosomes as measured in vivo by the foot pad swelling test and in vitro by the lymphocyte transformation assay. Both reactions were higher in CY treated and ribosome vaccinated mice than in controls (mice that were only vaccinated). Humoral immune responses were measured by the enzyme linked immunosorbent assay (ELISA). Anti ribosomal antibody titer contrary to the CMI responses was lower in CY treated animals than in non treated controls.These data point to a possible explanation of the mechanisms underlying the ribosomal vaccinations in CY treated hosts, and show the potential of such vaccinations in compromised individuals.     

Amylolytic activity of yeasts

The total amylolytic activity of 14 selected fermentation type I members of the generaSaccharomyces, Zygosaccharomyces, Candida andTorulopsis was studied. Fractions with α-glucosidase activity, the specificty of which was tested for maltose and sucrose, were isolated on carboxymethyl-cellulose from the intracellular contents of two strains ofCandida albicans and one ofCandida stellatoidea. The fraction from the strainCandida albicans 29-3-109, which is more virulent for mice, displayed the greatest α-glucosidase activity, moderate activity was present in the strainCandida stellatoidea 29-64-1, while the lowest activity was found in the less virulent strain ofCandida albicans, 29-3-19.     

In vitro modification of Candida albicans invasiveness

Candida albicans produces germ-tubes (GT) when it is incubated in animal or human serum. This dimorphism is responsible for its invasive ability.The purpose of the present paper is (1) to evaluate the ability of rat peritoneal macrophages to inhibit GT production of ingested Candida albicans, obtained from immunized rats and then activated in vitro with Candida-induced lymphokines; (2) to determinate any possible alteration of phagocytic and candidacidal activities.The phagocytes were obtained from rats immunized with viable C. albicans. Some of them were exposed to Candida-induced lymphokines in order to activate the macrophages in vitro. The monolayers of activated, immune and normal macrophages were infected with a C. albicans suspension during 4 hr.Activated macrophages presented not only the highest phagocytic and candidacidal activities but a noticeable inhibition of GT formation and incremented candidacidal activity.     

The carriage of Candida albicans in the mouths of rats treated with tetracycline briefly or for a prolonged period

Rats given tetracycline in their drinking water for one week were orally inoculated with Candida albicans in the following week. Colonization of the mouth by the fungus resulted, whether the rats continued to receive tetracycline or not, over a period of 22 weeks. Histological changes indicative of oral candidosis were also found both in rats maintained on tetracycline throughout the experiment and in animals given the drug only initially. It is suggested that exposure to tetracycline as tested in this experiment causes a lasting reduction in the rat's ability to expel C. albicans, or an enhancement of the organism's colonizing propensities.     

Suppression of humoral response during the course of Candida albicans infection in mice

This paper aims at demonstrating the non-specific immunosuppression as regards thyme-dependent antigens sheep erythrocytes (SRBC) during the course of Candida albicans systemic infection.Three lots of syngeneic /BALB/c mice, 8–12 weeks of age, were used. The first normal lot was inoculated via the intraperitoneal route with a (SRBC) suspension (4×10⁸ cells ml) in a Hank's balanced saline solution. The primary response of antibodies formed by splenic cells was measured from 4 to 8 days after inoculation using the direct plaque forming cells technique. The second lot was infected by the same route with a suspension of Candida albicans (1×10⁷ cells). Positive retrocultures from the blood and kidneys of these infected mice were obtained. These yeasts cultivated in a Sabouraud medium were harvested after 20 h at 37 °C. Following the same methodology the immune response to SRBC was determined. The serum obtained from infected mice was transferred to a third lot of mice at different intervals during the course of the infection. The immune response to SRBC was done by the direct plaque-forming cells technique. Controls were carried out using normal donors and recipients.A suppression of the immune response was obtained as from the 2nd day of inoculation up to the 28th day. It was not possible to transfer such suppression passively by means of the serum.These results suggest that the systemic infection by Candida albicans induce a non-specific immunosuppression in the organism, already demonstrated in viral infections, bacteria, protozoaria and metazoaria in mammals.In some way, this will contribute to explain the mechanisms of immune response to Candida albicans.