Persistence of anti-donor allohelper T cells after neonatal induction of allotolerance in mice.

BALB/c mice rendered tolerant to A/J alloantigens by neonatal injection of 10(8) (A/J X BALB/c)F1 spleen cells develop an autoimmune disease associated with a polyclonal activation of donor B cells. To study the mechanisms leading to donor B cell activation in tolerant mice, we prepared mixed lymphocyte cultures (MLC) between splenic T cells from neonatally injected mice and donor-type (A/J X BALB/c)F1 or third-party (C57BL/6 X BALB/c)F1 B cells. T cells from tolerized mice were unable to generate cytotoxic T lymphocytes, to proliferate or to secrete interleukin (IL)2 after stimulation with donor alloantigens in MLC.

Compartments and the topography of leg afferent projections in Drosophila.

The legs of Drosophila are covered with mechanosensory bristles, innervated by sensory neurons that project to the CNS in a very orderly manner. We examined this afferent projection by staining the sensory neurons associated with identified bristles in wild-type, engrailed and scute flies. We observe that anterior neurons project to an anterior region of the ventral neuropil, while posterior neurons project to a more posterior region.

Hyperactivity of donor B cells after neonatal induction of lymphoid chimerism in mice.

Balb/c mice made chimaeric by neonatal injection of semi-allogeneic (A/J x Balb/c)F1 hybrid spleen cells develop anti-DNA and rheumatoid factor-like antibodies in the context of hypergammaglobulinaemia with marked elevation of IgG1 and IgE serum levels. Chimaeric mice also display increased levels of antibodies to different haptens and to tobacco mosaic virus (TMV). The allotypic marker of the A/J strain is present on anti-DNA and anti-hapten antibodies.