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M C Crevon

Publications and source records attributed to M C Crevon.

6 recordsLinked to original sources
PubMed1979

[Exploration of humoral immunity in man using blood lymphocytes cultures (author's transl)].

New methods allow the study of humoral immunity in man using blood lymphocyte cultures. A primary in vitro antibody response can be induced, characterized by the appearance of antibody forming cells, and its pattern is as follows: stringent culture requirements, which have been so far obtained in few laboratories; the kinetics of the response, with a peak on day 7--8; and exclusively IgM response; a T-cell requirement. Among these methods, the model we have described has the advantage of allowing a reproductible response in a given individual. The in vitro study of humoral immunity has limitations, the most apparent of which is that it addresses itself to only one lymphoid population, that in peripheral blood, easily accessible. It presents several advantages, as compared to an in vivo study after injection of an antigen: absence of ethical problem; the necessity of only one blood sample, at a given time, avoiding the interference of a treatment started after the test; the possibility of performing successive primary stimulations for a longitudinal study.

Acrylamides↗
PubMed1979

Macrophage requirement for the in vitro response to an insolubilized T-independent antigen.

The role of macrophages in the in vitro response of mouse spleen cells to the insolubilized, T-independent antigen trinitrophenylated polyacrylamide (TNP-PAA) is demonstrated by the following points. The response is abolished by filtration on Sephadex G-10 and can be restored by the addition of splenic adherent cells, deficient in either B or T cells, or by 2-mercaptoethanol (2ME). It is suppressed upon elimination of phagocytic cells by silica, and restored by 2-ME. 2-ME can restore a normal response from zero, in cultures depleted of both adherent and phagocytic cells, and is efficient in the absence of mature T cells. Experiments in microcultures show that large numbers of macrophages can stimulate a supra-optimal response from B cells. This response is only obtained in the presence of the antigen, and is specific for TNP. These results show that microphages, probably by their polyclonal B-cell activator (PBA) property, play a role in the specific response to TNP-PAA. This prompts us to discuss the respective roles in the B-cell response of this PBA activity and of the interaction of the antigen with the specific B-cell receptors.

Animals↗
PubMed1979

Regulation of the primary in vitro antibody response in human peripheral blood lymphocytes: different effects of mitogen-induced and spontaneous T suppressor cells.

The specific response of human peripheral blood lymphocyte cultures to TNP-polyacrylamide was suppressed by the addition of concanavalin A (Con A). A dose of Con A (0.5 microgram/ml) could be selected, which induced a reproducible but incomplete suppression independent of the magnitude of the anti-TNP response. Con A-stimulated cells could transfer the suppression to autologous or allogeneic responding cells. The suppressor activity was present in the E-rosette forming cell fraction and was abolished by mitomycin C treatment prior to incubation. With a particular batch of foetal bovine serum, spontaneous suppressor cells were produced which suppressed the response of autologous and allogeneic lymphocytes. In allogenic mixtures, the otherwise enhancing allogeneic effect was replaced by a marked suppression from spontaneous suppressor cells. This suppression was higher than that exerted on autologous lymphocytes, suggesting that an unexpected negative allogenic effect had taken place. Spontaneous suppressors were ineffective when added on day 2 of a culture responding to TNP-polyacrylamide, whereas Con A induced suppressors were fully effective.

Acrylamides↗
PubMed1975

[Differential effect of azathioprine on the activation of B cells].

The in vitro antibody response to most T-independent antigens is inhibited by Azathioprine (Az) only at concentrations of 1-10 mug/ml. In contrast, B cell response to T-dependent antigens and to the T-independent antigen TNP-Polyacrylamide is sensitive to low Az concentrations (10(-2) mug/ml). These data suggest the existence of two different B cell activation processes : a. The activation by B cell mitogens or T-independent antigens with a mitogenic moiety which are Az-resistant; b. The activation by T-dependent antigens or T-independent antigens without a mitogenic moiety which are Az-sensitive.

Animals↗