Lymphoid cells from the rodent Praomys (Mastomys) natalensis express antigenic determinants present on mouse and rat lymphocytes.

Recent studies have suggested that Praomys (Mastomys) natalensis might be a suitable model for analyzing the underlying mechanisms of autoimmunity, since a high incidence of autoantibodies to a wide variety of specificities occurs in this rodent which is intermediate in size between the mouse and the rat. Mastomys, also called the "multimammate mouse" or "multimammate rat", more closely resembles the rat than the mouse as regards some anatomical traits, and differs from both common rodents as to others. Because of controversies many years ago, Mastomys was never phylogenetically classified as a genus, but remains a subgenus, designated Praomys (Mastomys) natalensis. We have attempted to determine whether immunological markers differentiated on mouse or rat lymphocytes are present on Mastomys lymphoid cells. It was demonstrated that Mastomys cells (thymus, spleen, lymph node, bone marrow) bear theta determinants of both mouse and rat, express mouse membrane Ig, and bind with anti rat Ia antigens (which cross-react with mouse specificities). Functional markers (helper or suppressor/cytotoxic functions of the mouse or rat) were never found on Mastomys lymphoid cells.

[Stimulation of peripheral guinea pig blood lymphocytes by autologous epidermal cells]. / Stimulation des lymphocytes du sang périphérique chez le Cobaye par des cellules épidermiques autologues.

Using a strictly autologous (and not syngeneic) mixed culture system in the guinea-pig, it was shown that Mitomycin C treated ear epidermal cells (E) were capable of stimulating peripheral blood lymphocytes (L) from the same animal. The proliferative response of the lymphocytes as measured by 3H thymidine incorporation, is optimal on the 5th day of culture, and when the ratio of the concentrations of the two cell populations (L : E) is 1 : 1. The autoreactivity of the lymphocytes varies with the animal.

Lymphocyte activation in penicillin allergy: modification of the response to phytohaemagglutinin by benzylpenicilloylated human albumin.

Lymphocytes from twenty-six subjects, allergic or non-allergic to penicillin, were cultured together with phytohaemagglutinin (PHA) and penicillin. The antigen, benzylpenicilloylated human serum albumin (BPO-HSA), induced an enhanced proliferation with PHA in the allergic subjects, but a decreased proliferation with PHA in the non-allergic subjects treated by penicillin (p less than 0.01). The results are interpreted in terms of B- and T-cell regulations in the immune response of man to penicillin.

Immunofluorescent tracing of cytoplasmic components involved in keratinocyte differentiation.

Sera with epidermal cytoplasmic antibodies (E.C.A.) produced by human subjects after bone marrow transplantation have been studied by indirect immunofluorescen on rabbit lip sections. These sections were used in order to give on a single specimen, areas of mucosa, of parakeratotic and of orthokeratotic epithelium. It has been demonstrated that E.C.A. distinguished the basal cell layer from the upper cell layers on the three areas. Moreover, E.C.A. were not found to react identically on mucosal, parakeratotic and orthokeratotic epithelium. These findings strongly suggest that the target antigens for E.C.A. are molecules involved in keratinocyte differentiation.

Lymphocyte transformation, leucocyte migration, specific IgE, IgG and IgM before, during, and after penicillin treatment without adverse reaction. A follow-up study.

This in vitro follow-up study of the penicillin-induced immune response by a well-tolerated regimen was conducted with an association of four tests: lymphocyte transformation test; leucocyte migration test; passive anaphylaxis on monkey lung tissue; and passive hemagglutination. It showed (1) that previously sensitized subjects (including IgE) tolerated the treatment by pencillin. (2) That the treatment induced either a transient positive conversion of previously negative tests or a negative conversion of previously positive tests. These in vitro findings are in accordance with previously established concepts based upon cutaneous tests and must be taken into consideration when interpretating in vitro diagnosis of penicillin allergy.

[Sensitization to penicillin following cutaneous side-effects of ampicillin]. / Sensibilisation à la pénicilline après accident cutané dû à l'ampicilline

Sensitization to penicillin was determined in vitro in twenty subjects, 30 days after cutaneous side-effects due to ampicillin. The study inclued the detection of anti-penicillin IgE, IgM, a lymphoblastic transformation test and a leucocyte migration test. No difference could be demonstrated between the sensitization 30 days after an ampicillin reaction and the sensitization 30 days after a penicillin reaction.