부산대학교 도서관

The adaptive immune system in mammals acts in a coordinated manner to eliminate environmentally derived pathogens. Humans, mice and rats show within species variation in the levels and ratios of their peripheral CD4[sup +] and CDC[sup 8+] T cells and to a significant degree this variation is under the control of polymorphic genes. Whether genes act separately to specify CD4[sup +] and CD8[sup +] subpopulation levels or whether CD[sup 8+] variation is controlled through gene and environmental action on CD4[sup +] cells or vice versa, is not known. We use a quantitative modelling approach in identical and non-identical female human twins to delineate the lines of control which act upon and between CD4[sup +] and CD8[sup +] subsets. The major findings of the study are: (1) genetic variation controls CD8[sup +] T cell levels through two major routes—the first is via an effect on CD4[sup +] T cells which accounts for the observed co-variation between CD4[sup +] and CD8[sup +] T cells, the second is through direct action on CD8[sup +] T cell levels. (2) No evidence of a gene effect from CD8[sup +] T cells on CD4[sup +] cells is observed. Our findings have implications for the evolution of the complex defence system of which CD4[sup +] and CD8[sup +] T cells are a crucial part and encourage further work towards locating common pleiotropic quantitative trait loci responsible for variation in numbers of T cells. Genes and Immunity (2001) 2, 381-387. [ABSTRACT FROM AUTHOR]