Prevention of reaginic antibody production and anaphylactic gastric ulcer by pesticides and by a polychlorinated biphenyl

Effects of paraoxon, p-nitrophenol, phenyl saligenin cyclic phosphate, and phenol on the rat interleukin 2 system

Two organophosphorus compounds, paraoxon and phenyl saligenin cyclic phosphate, as well as p-nitrophenol and phenol which are structurally related to paraoxon, were tested for their effects on interleukin 2 (IL2) production and responsiveness by rat splenocytes in vitro. Three of the four compounds inhibited mitogen-induced lymphocyte proliferation as well as IL2 production and responsiveness. However, phenyl saligenin cyclic phosphate produced maximal inhibition at a much lower concentration (0.5 microM) than p-nitrophenol (200 microM) or paraoxon (200 microM). Phenol was not inhibitory at any concentration tested (up to 250 microM). Since the production of and response to IL2 are key events in immune responses, compounds which suppress these events can be identified as potential suppressors of host resistance to disease.

Pesticide-containing diets augment anti-sheep red blood cell nonreaginic antibody responses in mice but may prolong murine infection with Giardia muris

The effects of oral ingestion of different pesticides (lindane, phosalone, carbaryl) and of a polychlorinated biphenyl (pyralene) on nonreaginic antibody production in BALB/c mice and also on the duration of Giardia muris infection have been studied using the animal model of this disease. Only lindane and carbaryl produced significant effects on systemic antibody production following oral immunization with sheep red blood cells (SRBC). Lindane ingestion led to a twofold increase in IgG2b antibody titer to SRBC (P less than 0.05) and carbaryl significantly increased both IgG1 and IgG2b titers. No reduction was seen in the synthesis of any antibody class. The effect of feeding with lindane was to increase the duration of giardiasis significantly (P less than 0.002), and these mice developed systemic anti-Giardia antibodies more frequently than Giardia-infected mice on normal diets. These results suggest that in the doses used these pesticides may increase systemic antibody responses to orally ingested antigens, and by inference that spontaneous elimination of giardiasis is independent of the systemic nonreaginic antibody response to the parasite.