The reactivity of lymphoid cells from germfree and conventional CDF rats were compared in mixed leukocyte culture (MLC) with both allogeneic rat leukocytes and with human leukocytes as stimulating cells, and in a graft-versus-host (GVH) assay. There was no difference between germfree and conventional rats in any of these systems. Furthermore, the increase in GVH activity after specific immuniza...

While spleen cells from neonatal B10 (H-2b) are reactive (proliferate) in one-way mixed leukocyte culture, cell-mediated lympholysis reactivity does not arise until 7 days of age. When B10 cells are sensitized to B10.D2 (H-2d), cross-killing of third-party B10.BR (H-2k) target is always lower than the specific killing of B10.D2 targets and is not demonstrable until 27 days after birth.

This report describes a search for tumor-specific transplantation antigens in man by testing four sets of identical siblings using the mixed leukocyte transformation reaction. In each case, one member of the set had acute leukemia in relapse. In no instance did the leukemic cells of the patient stimulate the cells of the normal twin, nor did cells from the normal twin stimulate cells from the l...

Cyclosporin A (CY A) is a hydrophobic, undecapeptide, fungal metabolite with potent immunosuppressive effects on T lymphocyte-mediated immune responses. Suppressor T lymphocytes generated during a mixed leukocyte reaction (MLR) performed in the presence of CY A, release a factor that suppresses a primary MLR of responder T cells, which is derived from the same strain as the factor producer but ...

The total hemolytic complement (C) levels in inbred line 7 chicks and adults were lower than C levels in inbred lines 2 and 3 and in outbred chickens of the same age. In all birds, adult levels of C were obtained in 5- to 6-wk-old chickens. Analysis of F1 and F3 generations clearly showed that the C level in chickens was determined by a dominant gene(s) associated with the major histocompatibil...

A mixed leukocyte reaction suppressor factor is produced by spleen cells sensitized in vivo and restimulated in vitro across non-H-2 antigenic barriers. Cells capable of producing this factor appear in the spleens of minor locus-immunized animals later than in animals sensitized to major histocompatibility complex-encoded antigens. However, both H-2 and non H-2-induced factors suppress prolifer...