Biomedical subjects

S Chollet-Martin

Publications and source records attributed to S Chollet-Martin.

63 records · Page 4Linked to original sources

PubMed1988

Mechanisms by which oxidative injury inhibits the proliferative response of human lymphocytes to PHA. Effect of the thiol compound 2-mercaptoethanol.

The use of normobaric exposure to O2 as a model for in vitro oxidative injury prevented phytohaemagglutinin (PHA)-stimulated human peripheral blood mononuclear cells (PBMC) from undergoing the G0 to G1 transition, but 5 x 10(-6) M 2-mercaptoethanol (2-ME) almost protected the cells from this blockade. The percentage of cells with IL-2 and transferrin-receptors was reduced by the O2 exposure and, like the cell cycle transition, was protected by 2-ME against oxidative injury. By contrast, IL-2 recovery in the supernatants of O2-exposed PHA-stimulated PBMC was enhanced. This enhancement may be due partly to the reduced IL-2 consumption caused by the decreases in IL-2 receptor expression and in proliferation. On the other hand, IL-2 recovery in the supernatants of O2-treated PBMC was always enhanced compared to the IL-2 control recovery after DNA synthesis was blocked in G1/S by mitomycin c, and the G0/G1 transition was protected by 2-ME. Furthermore, PHA-stimulated monocytes exposed to O2 produced more IL-1 than control cells. This enhanced IL-1 production was not modified by 2-ME. These results suggest that oxidative injury reduces the proliferation of PBMC by interfering with the cellular events that lead to the transition from the G0 to the G1 phase of the cell cycle. The protective effects of 2-ME suggest that thiol compounds have a critical role in the early events of the cell cycle. By contrast, exposure to O2 induced increases in the production of both IL-1 and IL-2 that may not be related to alterations in the thiol status of the cell.

Cell Cycle↗

PubMed1987

Functional effects of monoclonal antibodies (mAbs) against human polymorphonuclear (PMN) adherence antigens.

Two mouse monoclonal antibodies (mABs), 25.31 raised against an subunit epitope of LFA1 antigen and Mol against an epitope of the complement receptor type 3 (CR3) were used for investigating their effects on human polymorphonuclear (PMN) functions. The two mABs have an inhibitory effect on PMN adherence. Furthermore, the PMN adherence strength depends upon the support and the adherence induces the capping process of these antigens. Other PMN functions dependent upon adherence were also altered by these two mAbs: random locomotion and that directed by formyl-methionyl-leucyl-phenylalanine (FMLP) or by activated serum, degranulation induced by opsonized or non opsonized zymosan but not by phorbol myristate acetate (PMA), iodination, K562 cell cytotoxicity. Luminol enhanced chemiluminescence of PMN was diminished by both mAbs when PMN were stimulated either by opsonized zymosan or by PMA. Our results confirm other workers' findings, and they are consistent with PMN functional abnormalities observed in children with congenital LFA1, Mol antigens defect.

Antibodies, Monoclonal↗

PubMed1987

Comparison of blocking effects of monoclonal antibodies anti-MO1-alpha and anti-LFA1-alpha on human neutrophil functions.

In order to analyse the role of LFA1 and MO1 on neutrophil functions, the blocking effects of two monoclonal antibodies (MAb), one (anti-MO1) recognizing an epitope of the MO1-alpha chain and the other (25.31) an epitope of the LFA1-alpha chain, were measured. Adherence of 51Cr-labelled control neutrophils was 66 + 8% (mean +/- 1 SD) on plastic nuclon plates; this figure decreased to 33 +/- 5% and 23 +/- 6% of control adherence when the neutrophils had been pretreated with anti-LFA1-alpha (anti-alpha L) and anti-MO1-alpha (anti-alpha M), respectively. On another support (plastic culture chambers), 84 +/- 6% of control neutrophils adhered and the adherence of neutrophils pretreated with anti-alpha L or anti-alpha M was 10% and 43% of the control figure, respectively. These results show that adherence of neutrophils is dependent upon the plastic used. Moreover, inhibition of adhesion by the two MAbs was also dependent upon the support used for the assay, suggesting that MO1 and LFA1 may be surface proteins with different specificities. Both antigens capped upon adhesion, while they were randomly distributed in resting neutrophils. Anti-alpha L inhibited (congruent to 50%) locomotion more than did anti-alpha M (congruent to 25%), without altering chemoattractant-induced shape changes. These results suggest that the two MAbs inhibit chemokinesis but not chemotaxis. Many other adherence-associated functions, such as ingestion of opsonized Klebsiella pneumoniae, and cytotoxicity towards K/562 cells were decreased more by anti-alpha L than by anti-alpha M. In contrast, chemiluminescence and iodination induced by opsonized zymosan were inhibited more by anti-alpha M than by anti-alpha L. Degranulation induced by zymosan or opsonized zymosan was altered by anti-alpha M only, and this alteration involved azurophilic and not specific granules. Chemiluminescence induced by phorbol myristate acetate was inhibited to a greater extent by anti-alpha M than by anti-alpha L, while degranulation induced by phorbol myristate acetate was not altered by either of the two Mabs.

Adult↗

PubMed1987

[Determination, by the immunogold method, of T lymphocyte sub-populations during HIV infections (LAV/HTLV III)].

This study analyzes a method of indirect marking of T lymphocytes subpopulations using a 2nd antibody coupled to colloidal gold particles (Immunogold). There is an excellent correlation between this technique and the classical technique of indirect immunofluorescence. Immunogold enables an easy and rapid count of lymphocytes CD4+ and CD8+ during infections secondary to HIV virus (LAV/HTLV III). The permanent nature of the preparations and the cytological control make this method an interesting tool for the diagnosis and follow-up of patients suffering from AIDS, ARC or only asymptomatic seropositive individuals.

AIDS-Related Complex↗

PubMed1987

[Adhesiveness and membrane glycoproteins of human polynuclear neutrophils].

Clinical and biological features of a recently recognized inherited syndrome are reported. This syndrome, Leukocyte Adherence Deficiency, is characterized by recurrent, life-threatening infections. The increased susceptibility to infectious agents is mainly related in the inability of the leukocytes to adhere to certain surfaces, because all adherence-related functions of the neutrophils that lead to bacterial killing are impaired. Adherence deficiency is due to moderate or severe deficiency of three structurally related glycoproteins (MO1, LFA-1 and gp 150,95). All three glycoproteins are heterodimers and share a common subunit whose absence is the cause of the disease.

Antigens, Surface↗

PubMed1986

Enumeration of the T4 positive and T8 positive lymphocytes in AIDS and related syndromes. Comparison of the immunogold and the immunofluorescence techniques.

Immunofluorescence and immunogold techniques yielded similar results when used to determine the T lymphocyte subsets (T4 and T8 positive cells) in patients with AIDS or AIDS-related complex and in healthy homosexual men seropositive for HTLV III/LAV antibody. In these pathological situations, the advantages of immunogold staining could render this technique useful in a clinical laboratory.

Acquired Immunodeficiency Syndrome↗

PubMed1986

Sarcoid-like lymphocytosis of the lower respiratory tract in patients with active Crohn's disease.

To re-evaluate the relationship between Crohn's disease and sarcoidosis, we compared the numbers and types of cells recovered by bronchoalveolar lavage from normal volunteers and patients with Crohn's disease, with other forms of inflammatory bowel disease, and with sarcoidosis. Patients with Crohn's disease, but not patients with other inflammatory bowel disorders, had an increase in the number of T lymphocytes on the surface of the lower respiratory tract similar to that seen in patients with sarcoidosis. As in sarcoidosis, this lymphocytosis results from an expansion of the T4+ T-lymphocyte subset, is characteristic of patients with active disease only, and is not associated with similar abnormalities in the peripheral blood. Thus, patients with apparently localized Crohn's disease have sarcoid-like lymphocytosis of the lower respiratory tract, a finding that emphasizes the systemic nature of Crohn's disease and the disorder's close relationship to sarcoidosis.

Adolescent↗

PubMed1985

Spectroscopic interference of hemoglobin with neutrophil cytochrome b-245 and its elimination by carbon monoxide.

A cytochrome b, designated as cytochrome b-245, exists in neutrophils and is probably involved in their stimulated oxidative burst. As a rule, its concentration is spectroscopically measured by the height of its alpha-peak at 558-559 nm (dithionite-reduced minus oxidized). Hemoglobin (Hb), which usually contaminates neutrophils isolated from blood, interferes with the spectroscopic measurement of the cytochrome. Hb contamination from less than 0.4 red blood cells per 100 neutrophils leads to over-estimation of the cytochrome by approximately 50%. This interference can be overcome by bubbling CO through neutrophil homogenates heavily contaminated by Hb, prior to the conventional spectroscopic procedure. The cytochrome B-245 concentration obtained in neutrophils by CO bubbling is 7.2 +/- 1.28 pmoles per 10(6) polymorphonuclear neutrophils.

Carbon Monoxide↗

PubMed1985

Cytochrome b-245 in human alveolar macrophages.

To kill microorganisms, phagocytes exhibit an oxidative burst with, in particular, a NADPH-dependent, superoxide-generating system that consists, in polymorphonuclear leukocytes (PMN), of a flavin enzyme and cytochrome b-245 (cyt b-245). We investigated the existence of this cytochrome in human alveolar macrophages (AM) because its presence would support its wide-spread occurrence in phagocytes and would raise the possibility of similarities in the oxygen-dependent killing mechanisms in AM and PMN. Moreover, we compared the amount of cyt b-245 in AM from patients with lung disorders with that from healthy subjects, by a differential spectroscopic measurement of its 558 to 559 nm characteristic band. This spectrum showed that cyt b-245 was present in AM. In AM of healthy subjects, the amount was similar to that found in PMN of blood. In AM of patients with miscellaneous lung diseases and in Am of infected lungs, the data were not modified.

Cytochrome b Group↗