Murine CD5+, CD8+ normal fetal liver cells enhance an immune response: benzo(a)pyrene-exposed CD5+ fetal liver cells are inhibitors.
The effects of 150 ug benzo(a)pyrene/gm body weight given intraperitoneally to the pregnant mouse at mid-gestation leads to long-lasting (> 18 months post-birth) immune deficiency in the progeny. Although the progeny are immunodeficient their T cell subsets induced marked enhancement and/or inhibition of cell proliferation in an immune response. Earlier we saw a striking increase (up to 7-fold) in CD8(+) cells in the 18 day gestation liver of benzo(a)pyrene-exposed fetuses. We hypothesized that immune deficiency in carcinogen-exposed progeny could be attributed to an increase in classical CD8(+) suppressor T-cells. Surprisingly, however, we found that CD8(+) and CD5(+) (Lyt 1(+)) cells of normal fetal liver enhance cell proliferation in an immune response. However, liver CD5(+) cells from benzo(a)pyrene-exposed fetuses led to a dramatic reduction of the enhancing effect. Thus, as a novel finding, it appears that the profile of CD5(+) cells, under the ontogenic influence of benzo(a)pyrene, transforms from cells that normally augment cell proliferation in an immune response to cells that are inhibitors. On the other hand the functional status of CD8(+) cells is not affected. This change in physiological status of CD5(+) cells may have important implications on T and B cell interactions, and the role of CD5(+)cells in T cell receptor signaling.
Urso
Paul
P
Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, Georgia, USA. paul_urso@bellsouth.net
D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D018956:CD5 Antigens / Q000096:biosynthesis*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005333:Fetus / Q000166:cytology* / Q000187:drug effects / Q000276:immunology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D011247:Pregnancy
D018956:CD5 Antigens; D001564:Benzo(a)pyrene