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M T Auffredou

Publications and source records attributed to M T Auffredou.

25 records · Page 2Linked to original sources
PubMed1985

Functional properties of two human B cell growth factor species separated by lectin affinity column.

The supernatants from PHA-activated normal human T cells (conditioned medium) were fractionated by differential adsorption on Con A-Sepharose columns. The effluent contained both IL 2 activity (tested on the CTL-L2 cell line) and BCGF activity (tested on anti-mu-activated normal B-enriched cells). Absorption of such effluent on PHA-activated T cell blasts removed the IL 2 activity without affecting the BCGF activity. The eluate also displayed BCGF activity (tested on anti-mu-activated B-enriched cells) without detectable IL 2 activity. The two BCGF species isolated by this criteria synergize with semipurified IL 1 to support the anti-mu-induced proliferation of highly monocyte-depleted B cells. Both BCGF species required the presence of anti-mu Ab to support the proliferation of small B cells (at the G0 stage). However, in contrast to crude conditioned medium and to the BCGF present in the effluent, the BCGF present in the eluate was unable to induce the proliferation of unfractionated or large (at the G1 stage) B cells in the absence of anti-mu Ab. These results support the existence of two functionally different human BCGF species, differing at least in their relative sugar content and distinct from IL 2.

Adsorption↗
PubMed1981

Specificity of antibodies to heterologous glomerular and tubular basement membranes in various strains of mice with different H-2 types.

C3H, CBA (H-2k) and NZB (H-2d) mice were immunized with dog insoluble glomerular (GBM) or tubular basement membrane (TBM). The titre of circulating antibodies was sequentially determined and their specificity was analysed using various soluble antigenic fractions. Glomerular and tubular deposits were studied on serial biopsies by direct immunofluorescence. After elution from whole kidneys, IgG fixation on normal mouse kidney sections was analysed by indirect immunofluorescence. After immunization with insoluble GBM, animals from all three strains develop antibodies mainly directed against collagenous antigenic determinants shared by GBM and TBM. After immunization with insoluble TBM, the antibodies are directed in NZB mice against non-collagenous TBM-specific determinants, in C3H mice against collagenous determinants and in CBA mice against both types of antigenic determinants. Thus the ability to respond to the various antigens of GBM and TBM is genetically determined and does not depend only on the major histocompatibility complex.

Animals↗
PubMed1979

Regulation of contact sensitivity to DNFB in the mouse: effects of adult thymectomy and thymic factor.

The contact sensitivity response to DNFB is decreased after adult thymectomy (ATX). This response decreases to 50% of the control response of normal age-matched mice as soon as 3 weeks after ATX and is not further depressed 9 to 16 weeks after ATX. These results suggest that two T cell subsets of different lifespan are involved in the anti-DNFB response. A circulating thymic factor (FTS) is able to restore the contact sensitivity response to DNFB when injected 3 to 9 weeks after ATX but not 16 weeks later. By contrast, FTS has a depressive effect on the contact sensitivity response to DNFB of normal mice through a cyclophosphamide-sensitive T cell subset. These results suggest that FTS regulates DNFB contact sensitivity by acting on a cyclophosphamide-sensitive T cell subset, still present 9 weeks after ATX but absent after 16 weeks. Thus although the T cell defect, causing a depression of the contact sensitivity reaction to DNFB is quantitatively similar 3 and 16 weeks after ATX, its nature is probably different.

Aging↗
PubMed1979

Specificity of antibodies to heterologous glomerular and tubular basement membranes in BALB/c mice.

Balb/c mice were immunized with dog insoluble glomerular basement membrane (GBM) or tubular basement membrane (TBM). The titre of circulating antibodies was sequentially determined and their specificity was analysed using various soluble membrane fractions. Glomerular and tubular deposits were studied on serial biopsies by direct immunofluorescence. After elution, from whole kidneys, IgG fixation on normal mouse kidney sections was analysed by indirect immunofluorescence. The conclusions are the following: (a) after immunization with insoluble GBM, the antibodies are mainly directed against collagenous antigenic determinants shared by GBM and TBM; (b) after immunization with insoluble TBM, the antibodies are mainly directed against noncollagenous TBM-specific antigenic determinants.

Animals↗
PubMedDate not supplied

IL-4 counteracts anti-mu-induced human B cell proliferation: involvement of a cAMP-dependent inhibitory pathway.

In this report we show that IL-4 inhibits DNA synthesis induced by stimulation of human B cells with mitogenic doses of either soluble anti-mu mAb DA44 or phorbol ester. In contrast, earlier steps of anti-mu-induced B cell stimulation, such as RNA synthesis, CD23 expression and IL-6 production, were not inhibited but rather increased in the presence of IL-4. From these results, IL-4 appears therefore to exert two opposite effects on DA44 anti-mu mAb-induced human B cell activation: early steps are stimulated, and later steps inhibited. The results of kinetic analysis were consistent with this model. The inhibitory activity of IL-4 required an active cAMP-dependent pathway since IL-4-mediated inhibition of anti-mu-induced B cell proliferation was abolished in the presence of two specific inhibitors of the cAMP pathway (H8 and 2',5'-dideoxyadenosine which are specific for cAMP-dependent protein kinase and adenylate cyclase respectively). Furthermore, IL-4 induced a delayed and prolonged increase in intracellular cAMP concentrations (observed between 4 and 48 hours of culture), and this strongly suggests that the late inhibitory effects of IL-4 is cAMP-dependent. Moreover, this delayed IL-4-mediated cAMP production is probably sufficient to prevent anti-mu induced DNA synthesis since addition of the cAMP agonist forskolin on day 1 or 2 of culture also suppresses the anti-mu-mediated B cell proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗