Achievement of serum immunoglobulin depletion in rodents by injections of anti-immunoglobulin antibodies.
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Animals↗
Biomedical subjects
O Denis
Publications and source records attributed to O Denis.
[Primary anorectal malignant melanomas. 2 cases].
Two cases of primary ano-rectal melanoma are reported. Primary melanoma of the anorectum is an uncommon and highly malignant disease (the survival rate is about 7 to 12 percent at 5 years). The tumour may be difficult to diagnose when it is not pigmented (16 to 53 percent of the cases). At histological examination the diagnosis is impossible in 30 percent of the cases. It is facilitated after local excision by immune markers (vimentin, PS 100, HMB 45 immunostaining). Radical abdominal perineal resection may cure patients with less than 2 mm wide lesions. The few cases of long term survival have resulted from radical surgery. For larger lesions staged IV or V by Breslow's method conservative local approach by excision achieves local palliation. Radiation is a palliative therapy in extensive tumours. Combined chemotherapy with fotemustine and dacarbazine may be attempted in case of metastatic spread.
Aged↗
Resting B cells can act as antigen presenting cells in vivo and induce antibody responses.
Although it is well established that B lymphocytes are able to present antigen in vitro, the ability of small resting B cells to act as antigen presenting cells in vivo remains controversial. In this report we have studied the antigen presentation and the antibody response induced by mouse B cells after in vivo or in vitro targeting antigens to membrane Ig (mIg), using rat mAbs. Our results show that injection of these mAbs coupled to 2,4-dinitrophenyl (DNP) strongly enhances the IgG1 antibody response against DNP and rat Ig. T cell depleted spleen cells pulsed in vitro with rat Ig without specificity for B cells induced an antibody response when re-injected into mice, this response being much higher if the antigen was specific for mIg. Moreover, purified resting B cells were shown to induce a specific IgG1 response in vivo only when they were cultured with rat mAb against mIgM or mIgD but not with myeloma rat Ig of the same isotype. B cells do not need to be activated to present antigen since the induction of the specific antibody response does not correlate with the mitogenic activity of rat mAb nor with the IgG1 polyclonal synthesis in vivo. These data clearly show that resting B cells can present antigen in vivo and induce an antibody response, and underline the importance of mIgM and mIgD as targets for antigens.
2,4-Dinitrophenol↗
Modulation of oral tolerance to ovalbumin by cholera toxin and its B subunit.
Oral administration to mice of ovalbumin (OVA), if given together with cholera toxin (CT) or its B subunit (CTB) prevented the hyporesponsiveness to OVA subsequently injected parenterally. Oral immunization with CT plus OVA or OVA plus CTB in fact primed the immune system, inducing a stronger response to a subsequent parenteral injection of OVA with complete Freund's adjuvant than in mice prefed only with OVA or with saline. Oral CT plus OVA also induced good serum IgG1 and IgA anti-OVA responses, with slightly (not significant) decreased IgG2a and IgG2b responses. Our in vivo findings agree well with earlier in vitro data from others, including CT inhibition of the Th1 CD4+ T cell subset and with CT effect on B cells (induction of LPS-stimulated IgM+ B cells to undergo increased switch differentiation to IgG1- and IgA-secreting cells).
Adjuvants, Immunologic↗
Evaluation of stool antigen detection for diagnosis of Helicobacter pylori infection in adults.
OBJECTIVE: The aims of this study were to evaluate the performance of Helicobacter pylori stool antigen test in the diagnosis of H. pylori infection. METHOD: The study included 63 out patients attending the ULB-Lothier Clinic between January 1 and July 31, 2002. They underwent an upper endoscopy, as well as biopsies for histological examination and for culture of H. pylori. Stool samples of these patients were collected either the day of the endoscopy or within 24 hours and tested for H. pylori antigen (HpSA Test) RESULTS: The mean age of study patients included 29 men and 34 women was 51(+/- :16) years. H. pylori infection was detected in 29 cases (46 %) by culture and histology, and in 31 cases (49.2 %) by detection of the antigen in the feces. In 27 patients, all methods were positive whereas 5 in they provided discrepant results. Compared to the reference methods (culture and histology), the HpSA test had a sensitivity of 96.5% and a specificity of 91.2%. PPV of 90.3% and NPV of 96.8%. CONCLUSION: The good correlation found between the results of the HpSA test and the methods based on endoscopy supports its use as an alternative to invasive methods of diagnosis of H. pylori infection and therapeutic follow-up.
Adult↗