title: Acute exposure to the abused inhalant, isobutyl nitrite, reduced T cell responsiveness and spleen cellularity.
abstract: Isobutyl nitrite is an inhalant abused principally by male homosexuals. We have reported that subchronic inhalation exposure (45 min/day for 14 days) to 900 ppm isobutyl nitrite was immunosuppressive. In the present study, the effects of acute exposure to the inhalant were examined. Mice were exposed in an inhalation chamber to 900 ppm isobutyl nitrite for 45 min. One day later, spleen cellularity was reduced by 39% without selectively depleting CD4(+) or CD8(+) cells. The numbers of peripheral blood leukocytes and peritoneal cells were also reduced. Following acute inhalation exposure, T cell proliferative responses stimulated with allogeneic cells or anti-CD3 and anti-CD28 antibodies were inhibited, while mitogen-induced responses were not affected. Purified T cells exposed to the inhalant also had compromised responses, suggesting a direct effect on T cells. However, the cumulative effects of multiple exposures were necessary to inhibit T-dependent antibody responses or T cell or macrophage cytotoxicity.
authors.affiliation: Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
authors.forename: G L
authors.initials: GL
authors.lastname: Guo
authors.forename: D
authors.initials: D
authors.lastname: Rose
authors.forename: J T
authors.initials: JT
authors.lastname: Flick
authors.forename: J B
authors.initials: JB
authors.lastname: Barnett
authors.forename: L S
authors.initials: LS
authors.lastname: Soderberg
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D018106:CD28 Antigens / Q000502:physiology; D002452:Cell Count; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D018960:Hyaluronan Receptors / Q000096:biosynthesis; D007166:Immunosuppressive Agents / Q000633:toxicity*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009573:Nitrites / Q000633:toxicity*; D013154:Spleen / Q000187:drug effects* / Q000473:pathology; D013601:T-Lymphocytes / Q000187:drug effects*
chemical_list: D018106:CD28 Antigens; D018960:Hyaluronan Receptors; D007166:Immunosuppressive Agents; D009573:Nitrites; C018086:isobutyl nitrite