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Biomedical subjects

J Dormont

Publications and source records attributed to J Dormont.

At least 73 records · Page 4Linked to original sources
PubMed1980

Depressed primary in vitro antibody response in untreated systemic lupus erythematosus. T helper cell defect and lack of defective suppressor cell function.

The in vitro antibody response of peripheral blood lymphocytes (PBL) from 19 patients with untreated systemic lupus erythematosus (SLE) was compared with that of 20 control patients and 44 normal subjects. Trinitrophenyl polyacrylamide beads (TNP-PAA) were used to induce IgM anti-TNP plaque-forming cells. SLE patients displayed a markedly depressed, and in most instances virtually absent, response. This was not due to an unusual kinetics of the response; nor could it be induced by preincubation of SLE patients' PBL. In co-cultures of SLE patients and normal PBL, the former, with few exceptions, did not exert a suppressive effect. In four patients the anti-TNP response of either unfractionated or T-depleted SLE PBL could be restored by T cells from a normal individual. Conversely in three of these patients, SLE T cells could not support the response of normal B cells, suggesting a T helper cell defect in SLE PBL. Concanavalin A (Con A)-induced suppressor cells of the antibody response could be assayed by two approaches: (a) in responder SLE patients, by the direct addition of Con A to TNP-PAA-stimulated cultures; (b) in seven patients by transfer of Con A-activated cells to the responding culture of a normal allogeneic donor. In both cases SLE PBL were able to exert a suppressive effect to the same extent as normal PBL.

Adult↗
PubMed1980

Age-related impairment of the in vitro antibody response in the human.

We have used trinitrophenyl polyacrylamide beads (TNP-PAA) to induce a primary in vitro antibody response toward TNP in cultures of peripheral blood lymphocytes (PBL) from aged individuals. The response was virtually non-existent whereas PBL from young control individuals were able to respond. Recombination experiments showed that: (1) aged PBL did not suppress the response of young PBL; (2) young T cells enhanced the response of aged (unfractionated or T-depleted) cells; (3) aged T cells were unable to restore the response of young T-depleted cells, in contrast to young allogeneic T cells. Upon stimulation with Concanavalin A (Con A) aged PBL displayed a moderately diminished proliferative response and a normal ability to suppress the anti-TNP response of autologous PBL (in the few responders). However, contrasting with young PBL they could not suppress the anti-TNP response of young allogeneic PBL.

Adult↗
PubMed1980

[Fulminant pneumococcemia in two splenectomized patients (author's transl)].

Two cases (one fatal) of fulminant pneumococcemia in splenectomized patients are reported. One patient had undergone splenectomy for intra-operative injury, the other for Hodgkin's disease. The cases presented here are compared to those we have reviewed from the medical literature. The role of prophylactic antibiotics and polyvalent pneumococcal polysaccharide vaccine is considered in splenectomized patients.

Acute Disease↗
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

Outbreak of trichinosis near Paris.

A localised outbreak of trichinosis occurred in January 1976 in the southern suburbs of Paris. A total fo 125 cases was recorded including 30 children. The prominent symptoms were oedema of the face or eyelids, fever, and myalgia; diarrhoea was unusual and constipation common. An increased blood eosinophil count and raised serum concentrations of muscular enzymes strongly indicated trichinosis. This diagnosis was confirmed later immunologically. The parasite was found in only three out of 32 muscle biopsy specimens but this investigation was made relatively early in the disease. No deaths occurred. In all cases clinical recovery was fast and serum antibody titres were maximum during the first month and decreased slowly. The disease was milder and the recovery faster in children than adults. Epidemiological study suggested that horse meat was responsible for the infection, though no meat could be examined.

Adolescent↗
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

Depressed primary in vitro antibody response in rheumatoid arthritis.

We have studied the primary in vitro antibody response toward a hapten in cultures of peripheral blood lymphocytes from twenty-two patients suffering from regular rheumatoid arthritis (RA). These patients were not receiving immunosuppressive drugs or corticosteroids and had not taken Aspirin or non-steroidal anti-inflammatory agents for at least 72 hr. The control groups included thirty-two healthy subjects and twenty-seven control patients. The mean anti-TNP response of the RA patients was significantly lower than that of both control groups. No pre-existing anti-TNP or IgG response could be detected. A search for suppressor cells in co-cultures of RA and normal lymphocytes was negative. On the contrary, the extent of allogeneic enhancement in such co-cultures was comparable to that observed when control lymphocytes were co-cultured. RA serum added to normal lymphocytes cultures showed a dramatic inhibitory effect in only two out of nine cases. A follow-up study has strongly suggested that RA lymphocytes could increase their in vitro antibody response upon treatment.

Adult↗
PubMed1979

[In vitro study of the primary antibody response of circulating lymphocytes in patients with chronic inflammatory rheumatism].

We have studied the in vitro antibody response to a hapten of peripheral blood lymphocytes from 26 patients with rheumatoid arthritis and 7 ankylosing spondylitis. These patients had never received immunosuppressor drugs before or corticosteroids during the month before the test. They had failed to receive aspirin or non-steroid anti-inflammatory drugs for 72 hours before blood sampling. The control groups included respectively 38 healthy subjects and 24 patients hospitalized for non inflammatory disease. The antibody response of ankylosing spondylitis patients is comparable to that of controls ; on the opposite the response of patients with rhumatoid arthritis is significantly depressed in comparison with the three other groups. The weak response of lymphocytes in arthritis is not due to increased cell death in culture or to modified kinetics of the antibody response or to the appearance of a IgG secondary type response or a in vivo pre-activation. The lymphocytes of arthritis patients do not inhibit the response of normal lymphocytes when they are co-cultured. The observed response is identical to that obtained when control patient lymphocytes are co-cultured with normal lymphocytes. The function of suppressor T cells induced by Con A seems normal in spondylitis and arthritis.

Adult↗
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↗
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↗
PubMed1977

[Primary dissecting aneurysm of the renal artery with hypertension].

Dissecting aneurysms of the renal artery are the most common site of peripheral dissections without aortic involvement. The problems posed by this condition are analysed in the light of a personal cases and 52 in the literature. The onset in a young man of sudden loin pain followed shortly after by hypertension is suggestive of obstruction of a renal artery. The diagnosis can be confirmed only by arteriography, if the findings are sufficiently clearcut, which is not invariably the case. Surgical treatment gives good results and our own case clearly indicates the immediate and definitive relief of hypertension by nephrectomy. However the decision regarding surgery must take into account the possibility of recurrent peripheral lesions and of the possible reversibility of hypertension under the influence of medical treatment.

Adult↗
PubMed1977

Enhancing effect of low dose cyclophosphamide treatment on the in vitro antibody response.

We have studied the effect of cyclophosphamide (CY) administration on the subsequent in vitro antibody response in the mouse. Treatment with a low dose (20 mg/kg) of CY four days before culture results in an increased IgM response to the T-independent antigen trinitrophenylated polyacrylamide (TNP-PAA), without affecting the background response of unstimulated cultures. This suggests that CY treatment eliminates a short-lived suppressor cell, involved in the regulation of the in vitro B cell response. In contrast, the same regimen decreases the ability of nude mouse spleen cells to respond to TNP-PAA, showing that the target of CY-enhancing effect is a mature T cell. The increased response observed in conventional mice should be the result of a balance between the direct suppressive effect of CY on B cells and the elimination of a suppresor T cell, the latter phenomenon being of predominant significance in our conditions. The target of CY-enhancing effect is nonadherent to plastic, but adherent to Sephadex G-10 columns.

Acrylamides↗
PubMed1977

Primary in vitro antibody response from human peripheral blood lymphocytes.

A method for the induction of a primary in vitro antibody response from human peripheral blood lymphocytes is presented. Upon cultivation with trinitrophenyl conjugated polyacrylamide beads (TNP-PAA), an anti-TNP response can be obtained as indicated by the appearance of direct plaque-forming cells from day 5 of culture, with a reproducible peak on day 8. These plaques correspond to cells actively producing antibody of the IgM type, as shown by their inhibition by cycloheximide and by anti-human IgM serum, but not by anti-human Fc gamma serum. Their specificity for the TNP hapten can be demonstrated by the effector cell blockade phenomenon, with highly substituted TNP-human IgG. Although the anti-TNP response induced by TNP-PAA in mouse spleen cell cultures appears T independent the same response in human PBL may involve in addition the participation of T cells, since E-RFC depletion before culture led to a markedly decreased number of plaque-forming cells. A significant response could be obtained from the PBL of all of the 30 normal individuals tested. Importantly, the response was reproducible in its magnitude in the six individuals tested in at least three different experiments. Thus, the in vitro stimulation of human PBL by TNP-PAA can be proposed as a reliable test for the study of human B cell function in a specific primary antibody response.

Acrylamides↗