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Biomedical subjects

J Louis

Publications and source records attributed to J Louis.

At least 109 records · Page 6Linked to original sources

The spontaneous development of thymocytotoxic antibodies in athymic nude mice and its suppression after transfer of syngeneic thymocytes.

Athymic nude mice early in life spontaneously develop a high level of thymocytotoxic antibodies which have characteristics similar to the thymocytotoxic autoantibodies occurring in young NZB mice. Thymocytotoxic activity was no longer detectable in the serum of nude mice two weeks after the intravenous injection of syngeneic thymocytes, although the levels of spontaneously occurring anti-DNA and anti-hapten antibodies were not affected by the cell transfer.

Animals↗

Complement components, degradation products and immune complexes after kidney transplantation.

Levels of complement components and the presence of immune complexes were determined in blood samples from 23 patients is a function of time after kidney transplantation. During the first three post-transplantation weeks a decrease in the concentration of plasma C3 with a simultaneous increase of one of its breakdown products (C3d) was generally observed. This pattern often accompanied acute rejection episodes beyond 4 weeks after transplantation, while in the absence of complications normal and stable levels prevailed. In contrast, the presence of circulating immune complexes appeared not to correlate with rejection reactions. All 7 cases with detectable immune complexes presented with various concomitant neoplastic (renal carcinoma, Kaposi sarcoma) or infectious diseases (pneumonia, septicaemia, Herpes zoster or Cytomegalovirus infection). Thus, monitoring of plasma C3 and C3d may represent a helpful additional criterion for the assessment of acute rejection in recipients of kidney allografts; the presence of circulating immune complexes, although not correlating with graft rejection, may be taken as a sign of complicating additional disease.

Antigen-Antibody Complex↗

Mechanism for induction of anti-DNA antibodies by bacterial lipopolysaccharides in mice; II. Correlation between anti-DNA induction and polyclonal antibody formation by various polyclonal B lymphocyte activators.

The capacity of various polyclonal B lymphocyte activators (PBA) to induce, in mice, the formation of anti-DNA antibodies was compared with their ability to mediate the release of DNA in circulating blood and to stimulate polyclonal antibody synthesis in vivo. Anti-DNA antibodies or polyclonal antibody synthesis were induced in mice after the injection of at least 10 microgram lipopolysaccaride (LPS) from Salmonella typhimurium, 1 mg dextran sulfate (DS), or 2 mg purified protein derivative of tubercle bacteria RT32 (PPD). Smaller quantities of LPS (0.1 microgram) or DS (500 microgram) were sufficient to cause the release of DNA in circulating blood, whereas PPD was not able to provoke such a release at any concentration used. The association of anti-DNA antibodies with polyclonal antibody synthesis in mice injected with various PBA contrasts with the lack of correlation between the formation of anti-DNA antibodies and the release of measurable amounts of DNA in circulating blood. These results strongly suggest that the induction of anti-DNA antibodies by PBA is a consequence of the polyclonal B lymphocyte activation.

Animals↗

Fate of antigen-binding cells in unresponsive and immune mice.

Antigen-binding cells (ABC) to the antigen human gamma globulin (HGG) were quantitated in lymphoid tissues of A/J mice at various times after the injection of deaggregated HGG (tolerogen), aggregated HGG (immunogen), or saline. The reaction of lymphoid cells with highly labeled HGG was specific to that antigen since binding could be inhibited by excess unlabeled HGG, but not by unrelated non-cross-reacting proteins. Compared with normal mice, there was a marked decrease in the numbers of ABC in the spleens of unresponsive animals evident as early as 12 h after the injection of tolerogen. A marked increase in ABC was observed in the spleens of immunogen-injected mice, beginning at 24 h and reaching a peak at 3 days. In bone marrow, no difference in the number of ABC was found among the three experimental groups until day 20, when a reduction in ABC was observed only in tolerogen-injected mice. No quantitative difference in the thymuses in the experimental groups could be determined because of the paucity of ABC displayed by normal thymus cells.

Animals↗