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J Sarracent

Publications and source records attributed to J Sarracent.

10 recordsLinked to original sources
PubMed2004

Monoclonal antibodies against a 62 kDa proteinase of Trichomonas vaginalis decrease parasite cytoadherence to epithelial cells and confer protection in mice.

Trichomonas vaginalis infects the epithelium of the genital tract. The mechanism by which it invades the tissue leading to the disease is not thoroughly understood. However, results of several studies seem to agree that parasite adhesion to epithelium cells is the initial step leading to infection in women. T. vaginalis is associated with high levels of proteolytic activity. The role of some of these proteinases in the development of infection has been demonstrated. The current study establishes the role of a 62 kDa excretion-secretion proteinase in parasite cytoadherence. Monoclonal antibodies (MAbs) against this enzyme were tested for their ability to inhibit this process. Three stable hybrid producers of IgG(1)class MAbs (4D8, 1A8, 3C11) against the 62 kDa proteinase were obtained. Two of them (4D8 and 1A8) showed parasite recognition by immunofluorescence. Parasite cytoadherence to a monolayer of HeLa cells was inhibited by the 4D8, 1A8 and 3C11 antibodies. MAb 4D8 administered 24 h before a challenge with T. vaginalis by the intraperitoneal route was able to protect the majority of mice. Nitric oxide levels in the serum of animals inoculated with MAb 4D8 and challenged with the parasite were significantly different from those recorded in mice treated with an unrelated MAb. These studies show that an appropriate antibody against 62 kDa proteinase can help the host resist a challenge by the intraperitoneal route with T. vaginalis.

Animals↗
PubMed1999

Antiparasite activity of sea-anemone cytolysins on Giardia duodenalis and specific targeting with anti-Giardia antibodies.

The killing activity of sea-anemone cytolysins on Giardia duodenalis was investigated. Three different toxins, sticholysin I and II from Stichodactyla helianthus (St I and St II) and equinatoxin II from Actinia equina (EqtII) were all found to be active in an acute test, with a C50 in the nanomolar range (St I, 0.5 nM; St II, 1.6 nM; and EqtII, 0.8 nM). A method to target the cytolysin activity more specifically towards the parasite cells by using anti-Giardia antibodies was then investigated. Parasite cells were sensitised with a primary murine monoclonal or polyclonal antibody followed by a biotinylated secondary anti-mouse-IgG monoclonal antibody. Subsequently, avidin and a biotinylated EqtII mutant were added, either in two separate steps or as a pre-formed conjugate. When the monoclonal antibody was used, the C50 of biotinylated EqtII was 1.3 nM with sensitised cells and 5 nM with non-sensitised cells, indicating a four-fold enhancement of activity with the cell treatment. Treatment with the polyclonal antibody was somehow more effective than with the monoclonal antibody in an acute test. This indicates that sea-anemone cytolysins can efficiently kill Giardia cells, and that it is possible to improve, to a certain extent, the anti-parasite specificity of these toxins with anti-Giardia antibodies. However, the feasibility of this approach "in vivo" remains to be demonstrated.

Animals↗
PubMed1998

Partial characterization of the epitope on excretory-secretory products of Fasciola hepatica recognized by monoclonal antibody ES78.

This report contains a partial characterization of the epitope recognized by monoclonal antibody (MAb) ES78 produced against excretory-secretory (ES) antigens of Fasciola hepatica. ES78 is currently used for the detection of ES antigens in serum and stool samples of cattle and humans with fasciolosis, using a highly sensitive and specific sandwich enzyme-linked immunosorbent assay (ELISA). The epitope was characterized by periodate oxidation, alkaline borohydride reduction, trichloroacetic acid precipitation, beta-mercaptoethanol treatment, and enzymatic proteolysis. These results, together with those of the 2-site ELISA, lectin immunoassays, and beta-galactosidase digestion, showed that MAb ES78 reacts with a partly protein/partly carbohydrate antigenic determinant that is found on several ES molecules of adult specimens of F. hepatica and contains at least 1 disulfide bond and beta-galactose probably as galactose-beta(1-3)-N-acetylgalactosamine disaccharide.

Animals↗
PubMed1992

Generation of murine triomas secreting bi-specific monoclonal antibodies that recognize HBsAG ad and ay subtypes.

We report the generation of murine triomas by fusing splenocytes from mice previously immunized with HBsAg ay-subtype and a hybridoma, secreting anti-HBsAg ad-subtype monoclonal antibody, which was rendered HGPRT- by induced mutagenesis with N-methyl-N'nitro-N-nitrosoguanidine. The fusion yielded a 83.8% of hybrids showing the antigen specificity of the parental hybridoma and a 16.1% of bi-specific monoclonal antibodies. One of them, coded as 1C8A5, showing a heavy chain isotype (IgG1/IgG2b) was used as capture reagent in an ultramicro-ELISA. As little as 0.78 I.U. of both HBsAg ad- and ay-subtypes could be realiably detected.

Animals↗
PubMed1988

Lysosomal enzyme release from macrophages: a model of food yeast toxicity evaluation.

The role of lysosomal enzyme released by macrophages was examined in relation to the toxic effect caused by food yeast. Mouse peritoneal macrophages exposed to yeast in culture showed marked release of N-acetyl glucosaminidase, beta-galactosaminidase and beta-glucuronidase below the median lethal dose (LD50). LD50 was measured from the dose response curves of the cytoplasmic lactate dehydrogenase enzyme. Saccharomyces cerevisiae showed the highest LD50 followed by Kluyveromyces fragilis and Candida utilis yeast. LD50 values obtained as well as the in vitro lysosomal release by mouse peritoneal macrophages may be relevant to assess the toxic capacity of food yeast intended for human consumption.

Animals↗
PubMed1984

In vivo effect of clofazimine in the lysosomal enzyme level and immune complex phagocytosis of mouse peritoneal macrophages.

The effects of clofazimine on macrophages obtained from mice fed by gavage with various drug concentrations were studied. The results obtained demonstrated an increase in the activity of various lysosomal enzymes and in the amount of labeled immune complexes phagocytosed at drug concentrations of 1 mg/kg and 10 mg/kg body weight. This confirms and extends the effects reported by us of clofazimine's action on the lysosomal apparatus.

Acetylglucosaminidase↗
PubMed1982

The action of Clofazimine on the level of lysosomal enzymes of cultured macrophages.

Mouse peritoneal and calf alveolar macrophage cultures were exposed to various concentrations of Clofazimine, 3 (p-chloroanilino)-10-p-Chlorophenyl 2, 10-dihydro-2-isopropylimino, for 120 hr and an increase of four lysosomal enzymes were found with 0 . 3 micrograms/ml of the drug. In mouse peritoneal macrophage cultures, higher concentrations were toxic. Cycloheximide inhibited the lysosomal enzyme activity increase found. No change in enzymatic activity was observed when a lysosomal enriched granular fraction was incubated with various drug concentrations. Our results strongly suggest that Clofazimine at concentrations close to therapeutic serum levels induces de novo synthesis of lysosomal enzymes in macrophage cultures.

Animals↗
PubMed1982

Phagocytosis and intracellular degradation of 125I-labelled immune complexes by Clofazimine treated macrophage cultures.

Mouse peritoneal and calf alveolar macrophage cultures were exposed to various Clofazimine concentrations for 5 days. Cultures exposed to drug concentrations near the blood therapeutic level phagocytize and digest more immune complexes than control cultures. Our results allow us to suggest that the beneficial action of Clofazimine in lepromatous leprosy could be at least partially mediated by the removal and degradation of circulating immune complexes by macrophages.

Animals↗
PubMedDate not supplied

Effects of antiallergic drugs on cyclic nucleotides in guinea pig ileum and trachea.

In former papers we have provided evidence on the protective effect of disodium cromoglycate (DSCG) and ketotifen (Ke) against the contractions induced by various agonists (histamine, serotonin, acetylcholine, prostaglandins) in ileal and tracheal smooth muscle of guinea pigs. To offer an insight into the mode of action of these antiallergic drugs we quantified concentrations of cyclic AMP and GMP in these tissues. We observed that DSCG (10(-3)-10(-2) M) significantly diminished the concentration of cyclic AMP in ileum and trachea of guinea pigs, but it increased the level of cyclic GMP in ileum. Ketotifen (10(-6)-10(-4) M) does not modify cAMP and cGMP in ileum, however, in trachea it significantly decreases the concentrations of cGMP. We also studied the effects of oxatomide, ICI 74.917 and BRL 10.833 on cyclic nucleotides concentrations in guinea pig ileum BRL 10.833 increases cAMP at a relatively high dose (10(-4) M). ICI 74.917 at the same dose decreases cGMP. Oxatomide (10(-6)-10(-4) M) does not modify concentrations of both nucleotides. Our results demonstrate that these antiallergic drugs do not have a unique effect on cyclic nucleotides. Our findings do not support a relevant role of these nucleotides on the mechanism of action of these antiallergic drugs.

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