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The effects of inhibitors of cell division on polyclonal stimulation induced either by bacterial lipopolysaccharide (LPS) or by a synthetic adjuvant, MDP, were compared, using different target cells. Doses of colchicine that prevented 3H-thymidine incorporation also prevented the induction of antibodies against TNP and against an altered self antigen: bromelain-treated mouse red blood cells (br-MRBC). Under identical conditions, incubation with cytosine arabinoside (CA) strongly prevented the induction of anti-TNP PFC and to a lesser degree anti-SRBC PFC. However, the number of anti br-MRBC PFC was unchanged even when a dose of CA which inhibits totally the incorporation of 3H-thymidine was used. Our findings inducate that the general term "polyclonal stimulation" may concern at least two different types of cell populations and therefore we strongly stress the importance of choosing similar targets in comparative experiments.

Au cours des années 1910 et 1920, les effets conjugués des idées savantes sur la spécifucité des anticorps, de la croyance profane à l’existence d’un sang syphilitique et de l’importance attribuée à la détection de la syphilis par les autorités sanitaires ont permis de transformer un test diagnostique peu efficace, la réaction de Wassermann, en «fait scientifique» incontestable. Ce fait scientifique établit l’équivalence «individu Wassermann positif = personne infectée par l’agent étiologique de la syphilis, la bactérieTreponema pallidum». Il a ainsi modifié les représentations profanes de la syphilis et les politiques de santé. Tenu pour solide pendant une trentaine d’années, ce «fait scientifique» fut toutefois déstabilisé dans les années 1950 en raison du hiatus croissant entre les résultats accumulés grâce à la diffusion massive du test de Wassermann et les données épidémiologiques sur la prévalence de la syphilis, et de la comparaison entre les résultats de la réaction de Wassermann et ceux des nouveaux tests diagnostiques spécifiques du tréponème. Un pourcentage élevé de personnes «Wassermann positives» fut alors redéfini comme des «faux positifs biologiques», soit des individus souffrant de pathologies autres que la syphilis, mais cependant capables d’induire une réaction Wassermann positive. L’équivalence «personne Wassermann positive = individu infecté parTreponema pallidum» fut remplacée par l’équation «personne Wassermann positive = individu infecté par le tréponèmeoufaux positif biologique». La nouvelle vision de la réaction de Wassermann modifia à son tour les pratiques des professionnels et les représentations que le grand public se fait de la maladie. L’histoire de la détection de la syphilis illustre les interactions complexes entre «faits scientifiques» et «faits sociaux» et l’interdépendance de leur évolution.

Thymus-derived lymphocytes (T cells) exert their regulatory effect (help or suppression) on the antibody production by B cells either by direct cell to cell interaction or by soluble mediators or factors1,2. The low frequency of specific T cells, the heterogeneity of their responses and their relatively short life span have hampered the molecular characterization of the antigen recognition unit of T cells, and its structure is largely unknown. The lymphocyte hybridization technique, which has been found very useful for the production of B-cell hybridomas secreting specific monoclonal antibodies3, has also been used for the generation of homogeneous and stable T-cell hybridomas with unlimited growth potential4,5. So far the only specific effector function demonstrated in the established T hybridomas is the property to generate a factor(s) which suppresses antibody responses6–8. We now describe the establishment of hybrid lines which exhibit characteristic T-cell markers. One of the hybridomas (denoted R-9) releases into the culture supernatant factor(s) with helper activity specific to the synthetic polypeptide (T,G)-A--L and bears surface determinants of the immunoglobulin heavy chain variable region (VH). Such hybrid cell lines are of great value for studies on the nature of the T-cell receptor.

Medico-philosophical reflections were developed in the 19th and the 20th centuries by three consecutive generations of Polish physicians, active in what was later named the Polish School of Philosophy of Medicine. The second generation of this school published its own journal, Medical Critique [Krytika Lekarska], from 1897 to 1907. Medical Critique included numerous articles on the nature of medical knowledge, the reductionism versus holism debate in biology and medicine, the importance of teleologically-oriented approaches in medicine, the influence of theories and of a priori ideas on clinical observations and on ‘clinical facts’, the problem of classification of diseases, the normative and ethical dimension of medicine, and the ion relationships between philosophy, history and medicine. The existence of a journal dealing specifically with theoretical reflections on medicine undoubtedly contributed to the propagation of original work in the philosophy of medicine in Poland.