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Biomedical subjects

M F Baudrihaye

Publications and source records attributed to M F Baudrihaye.

8 recordsLinked to original sources
PubMed1986

Restriction of the human in vivo immune response against the mouse monoclonal antibody OKT3.

The murine monoclonal antibody OKT3 (IgG2a) was administered prophylactically to 17 renal allograft recipients (5 mg/day, i.v.), either alone or in association with corticosteroids (0.25 mg/kg/day) and azathioprine (3 mg/kg/day). In all patients the kinetics of the IgM and IgG anti-OKT3 response was monitored by means of immunofluorescence and ELISA. All patients treated with OKT3 alone showed a rapid and strong sensitization that completely neutralized the therapeutic effectiveness of the monoclonal antibody. The anti-OKT3 sensitization was manifested by accelerated OKT3 clearance and abrupt reappearance of circulating OKT3+ cells before the end of treatment. This immune response was significantly delayed and reduced in its incidence and intensity in patients receiving low dose corticosteroids and azathioprine in association to OKT3; mainly IgM anti-OKT3 antibodies that did not accelerate OKT3 clearance were then observed. The fine specificity of the antibodies produced was studied, using patients whole sera and various mouse IgG2a-affinity chromatography-purified serum fractions. The results obtained showed that the anti-OKT3 response was remarkably restricted to two main categories of antibodies: a) anti-idiotypic antibodies that inhibited OKT3 binding to T cells and abrogated its therapeutic activity and b) anti-mouse IgG2a (anti-isotypic) antibodies that did not neutralize OKT3 immunosuppressive activity. These results suggest that OKT3-immunized patients might still be sensitive to the immunosuppressive effect of other anti-T cell monoclonals that do not share the OKT3 idiotype and possibly isotype.

Animals↗
PubMed1984

Unusually restricted anti-isotype human immune response to OKT3 monoclonal antibody.

The unusual anti-mouse immunoglobulin (Ig) sensitization of a renal allograft recipient who was treated prophylactically with the anti-T cell monoclonal antibody OKT3 (IgG2a) is reported. Whereas in most patients, the injection of OKT3 (5 mg/day, i.v. for 13 days) induces the rapid appearance of neutralizing anti-OKT3 antibodies, the patient reported here did not show the signs of conventional anti-OKT3 sensitization. High levels of circulating OKT3 persisted and no OKT3+ lymphocytes reappeared during the whole treatment period. Moreover, no IgG or IgM anti-OKT3 antibodies were detected at any time, using a specific enzyme-linked immunosorbent assay. However, an atypical anti-isotype response was evidenced in this subject whose Ig were shown by indirect fluorescence to bind to normal T cells coated with OKT3 or with other anti-T cell murine monoclonal antibodies carrying the IgG2a isotype (no reactivity was observed with IgG1 or IgG2b molecules). The patient's Ig did not bind to normal T cells coated with F(ab')2 fragments of OKT3 and did not inhibit the binding of OKT3 to its target antigen indicating that they reacted with the Fc fragment of the OKT3 molecule. Additionally, and probably explained by this unusual anti-OKT3 response, the patient's Ig were shown to inhibit the phytohemagglutinin-induced proliferation of normal lymphocytes, to bind under selected in vitro conditions to normal T cells and lastly to enhance the antigenic modulation induced in vitro by OKT3 on its membrane receptor.

Antibodies, Monoclonal↗
PubMed1982

Human in vivo antigenic modulation induced by the anti-T cell OKT3 monoclonal antibody.

The anti-pan T cell monoclonal antibody OKT3 was administered daily for 2 weeks in four human renal allograft recipients. The antibody induced a dramatic and immediate depletion of peripheral T cells followed by an in vivo antigenic modulation of the OKT3-defined membrane antigen: after three injections, OKT3-treated patients showed a limited but significant number of OKT3- cells of T cell nature (as defined by OKT4 and OKT8) which recovered the OKT3 receptor after an overnight in vitro incubation in the absence of the monoclonal antibody.

Antibodies, Monoclonal↗