The effect of C. parvum and/or levamisole on tumour growth and spontaneous dissemination was tested in two tumour-host systems, melanoma B16 and LLT in C57BL/6J mice. C. parvum inhibited the growth of LLT and its dissemination to the lungs and the growth of B16 in females in one of the two sub-strains of mice used. Levamisole stimulated the growth of B16 in females in one sub-strain and in both sexes in the other sub-strain of mice. The growth of LLT was not influenced by levamisole but its dissemination to lymph nodes was facilitated. The growth-stimulating effect of levamisole was abrogated by C. parvum in the mice treated with both agents in combination. It is concluded that the effects of non-specific immunomodulators on tumour growth and spread can vary between sub-strains of the same inbred strain of mice bred at different laboratories.

Adjuvants, Immunologic↗

PubMedDate not supplied

The nude mouse. A possible experimental model for investigation of human thyroid tissue.

The effect of transplanting hyperfunctioning human thyroid tissue to athymic, nude mice was explored. The thyroid tissue was obtained from a patient with diffuse, thyrotoxic goiter preoperatively treated with a beta-adrenoreceptor blocker. One transplant was placed in each groin of 4 nude mice. Light microscopy after 4 weeks showed that transplants consisted mainly of typical follicles; capillaries were common at the periphery of the transplant but not in between the follicles. The ultrastructure of the follicle cells in the transplants was similar to that of follicle cells in general. All 8 transplants accumulated 125I as revealed by external counting; the uptake in each transplant 24 h after administration of radioiodine was 4-25% of that in the thyroid of the transplanted mouse. The release of radioiodine, measured during a period of 14 days, from the thyroid of a transplanted mouse was delayed as compared to a nontransplanted control; this indicates that the mouse thyroid activity was suppressed due to hormone production in the transplants. Electron microscopic autoradiography 24 h after injection of 125I showed that protein-bound label in transplants was located mainly in follicle lumens. The radioiodine was incorporated in thyroglobulin as demonstrated by separation of soluble proteins from transplants by sucrose density gradient centrifugation. The present study shows that human thyroid tissue can be transplanted to nude mice with maintained structural and functional properties. Transplantation of human thyroid tissue might be a useful model for studies of thyroid diseases.

Animals↗