3-Methylcholanthrene induces differential inhibition of humoral and cell mediated immune responses in mice of different ages.
C57B1/6 mice aged 2-3 and 13-14 months were treated i.p. with 3-methylcholanthrene. A single dose of 25 mg/kg reduced primary antibody production to the T-dependent antigen sheep red blood cells by 20% in mice aged 2-3 months and by 90% in 13-14-month-old animals. The same treatment did not reduce antibody production to the T-independent antigen pneumococcal polysaccharide type III in young mice, but reduced this response by 50% in 13-14-month-old animals. Blastogenesis to concanavalin A, phytohemagglutinin and alloantigens, that is mediated by T lymphocytes, was consistently reduced in young animals but only marginally affected, when at all, in 13-14-month-old mice. Blastogenesis to lipopolysaccharide, mediated by B lymphocytes, was reduced in mice of both ages, though in older mice it was affected later than in younger animals. Addition of 3-methylcholanthrene in vitro increased T lymphocyte responses equally in mice of both ages and did not modify B lymphocyte proliferation. Results presented here show that older mice are not necessarily more susceptible to all types of immunosuppression induced by a xenobiotic like 3-methylcholanthrene and that the sensitivity of the different facets of the immune response can change with aging.
Sironi
M
M
Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
Pesenti
E
E
Bernasconi
S
S
Vecchi
A
A
D000367:Age Factors; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D004912:Erythrocytes / Q000276:immunology; D007111:Immunity, Cellular / Q000187:drug effects*; D007519:Isoantigens / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008748:Methylcholanthrene / Q000378:metabolism / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011135:Polysaccharides, Bacterial / Q000276:immunology
D007519:Isoantigens; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial; C026604:pneumococcal polysaccharide, type III; D008748:Methylcholanthrene