The theory of evolution predicts that the rate of adaptation of a population is a function of the amount of genetic variation present in the population. This has been experimentally demonstrated in Drosophila populations in which genetic variability was increased either by mass hybridization of two gene pools, or by X-irradiation.--Mutator genes in...
Multiple families of cytotoxic molecules [Lymphotoxin (LT)] have been identified in phytohemagglutinin (PHA-P) activated human lymphocyte supernatants and lymphocyte homogenates, using gel filtration chromatography on Sephadex G-150. These macromolecules have molecular weights of 80-90,000, 50,000, and 10-15,000 daltons and have been termed LT2, LT...
Recent studies by various authors suggest that variation in gene regulation may be common in nature, and might be of great evolutionary consequence; but the ascertainment of variation in gene regulation has proven to be a difficult problem. In this study, we explore this problem by measuring alcohol dehydrogenase (ADH) activity in Drosophila melano...
The present studies demonstrate that a portion of lymphotoxin (LT) cell-lytic activity present in supernatants from: 1) lectin (Con A, PHA) stimulated nonimmune; or 2) antigen (soluble or cellular) stimulated immune human lymphocytes in vitro, is associated with immunoglobulin (Ig) or "Ig-like" receptor molecule(s). This concept was supported by th...
Lymphotoxins released by lectin activated human lymphoid cells in vitro are complex and can be resolved by molecular sieving techniques into multiple classes of activity, termed complex, α,β and γ. The classes can be further resolved into sub-classes on the basis of their charge by ion-exchange chromatography and electrophoresis. We found the lytic...
Lymphocytes or purified T cells obtained from the spleens of alloimmune C57BL/6, DBA/2, or C3H/DiSn mice, when placed on monolayers of lectin-coated allogeneic (L-929 or 3T3) fibroblasts, release into the supernatant various forms of cell lytic material. One form appears to be a high m.w. complex containing an antigen-binding receptor(s) that is hi...
The present studies investigate the physicochemical and immunologic properties of cell-lytic molecules released in vitro by nonadherent C57/BL/6 splenocytes or nylon wool-enriched T cell populations activated on monolayers of PHA coated L-929 cells. The findings reveal that cell-lytic molecules released by these lymphoid cells are physically hetero...
High levels of cytotoxic activity (lymphotoxin-like (LT) detectable on L-929 cells was obtained in serum-free culture supernatants when non-adherent murine splenic lymphocytes or nylon wool-enriched T cells were cultured on monolayers of mitogen- (PHA) coated allogeneic or xenogeneic stimulator cells in vitro. Levels of lytic activity were lower in...
During the last 20 years the anatomical plasticity of the brain in response to sensory stimulation has been clearly demonstrated. This paper reviews the effects of environments rich in sensory stimulation versus those which are stimulus poor. Effects have been noted at all levels from the gross anatomical to the electromicroscopic. As compared to t...
Antisera produced in rats by immunization with alloimmune murine C57Bl/6 anti-P815 splenic lymphocytes or purified T cells activated in vitro by coculture with phytohemagglutinincoated L-929 cells were found to inhibit the in vitro cytolytic action of in vivo and in vitro alloimmune C57Bl/6 anti-P815 cytotoxic T cells in a 4-hr chromium-51 release ...
