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At least 289 records · Page 16Linked to original sources
PubMed1977

Development of hematopoietic spleen colonies in nonirradiated genetically normal mice.

The question as to whether prior irradiation or injection of cytotoxic drugs is essential for the development of spleen colonies was examined in genetically normal mice. Mixtures of lymph node and bone marrow cells from C57BL mice were injected into (C57BL X CBA-T6T6) F1 hybrid mice without pretreatment. Hematopoietic nodules were observed in the spleens of F1 hybrid mice killed 18 days after injection. The average number of nodules increased linearly with increased numbers of injected bone marrow cells. Hematopoietic stem cells (CFU-S) and dividing cells in the nodules were shown to be of C57BL origin. Histologic examination showed that erythroid cell colonies predominated over granulocytic cell colonies. These results suggest that any kind of treatment that causes the depletion of CFU-S in the spleen of hosts would provide a suitable environment for the production of colonies by transplanted CFU-S.

Animals↗
PubMed1976

IgM-mediated, T cell-independent suppression of humoral immunity.

The immunological unreactive state occurring in (T,G)-A-L nonresponder mice after secondary antigen challenge was investigated. Syngeneic IgM anti-(T,G)-A-L antibody-containing plasma, transferred at the time of the time of primary challenge, induced persistent suppression of autologous specific antibody production. Removal of plasma IgM with goat anti-mu antisera removed the ability of the plasma to supress. The induction and maintenance of the suppressed state were not different in thymectomized or sham-thymectomized animals. Primed animals subjected to graft-vs-host reaction (GVHR) at the time of secondary challenge switched over to IgG production. Animals suppressed by passive antibody transfer reacted to GVHR, at the time of secondary challenge, with specific IgM but not IgG antibody production. Transfused normal spleen cells partially abrogated suppression only when (suppressed) hosts had been lethally irradiated. Spleen cells from antigen-plus-antibody suppressed donors, upon transfer to previously normal, syngeneic hosts, were less immunocompetent than spleen cells from untreated donors. These data are consistent with a model of IgM mediated, T cell-independent persistent suppression of humoral immunity.

Animals↗