Induction of myeloperoxidase deficiency in granulocytes in lead- intoxicated dogs

Lead interferes with heme synthesis in erythrocytes and has a deleterious effect on red cell membranes. We measured myeloperoxidase (MPO) enzyme activity in the granulocytes of dogs fed increasing quantities of lead. Concurrently, iodination capability and in vitro bactericidal activity were measured. Blood lead levels were monitored. Three of 4 dogs poisoned with lead developed significant decreases in MPO enzyme activity in their granulocytes. The decline in MPO activity correlated with cumulative lead toxicity as judged by blood lead levels and clinical signs of lead poisoning. Iodination ability in all 4 dogs decreased with cumulative lead toxicity. After discontinuation of lead administration, recovery of granulocyte MPO activity preceded recovery of iodination ability. This observation suggests the possibility of separate effects of lead on iodination ability and MPO activity. Moderate impairment of bactericidal capacity developed in 3 of 4 dogs with severe lead poisoning. Clinical infections were not observed during the course of the study.</jats:p

Decreased T cell function in mice exposed to chronic, low levels of lead.

The immune responsiveness of mice given low levels of lead acetate (1300 p.p.m.) in their drinking water for 8 weeks was determined. Mean percentages of splenic T and B lymphocytes in lead-exposed mice were slightly lower than in controls. Mean mitogen response to phytohaemmaglutinin and concanavalin A in mice exposed to lead was significantly decreased compared to controls. The response to lipopolysaccharide on the other hand was not significantly mitogenic response to phytohaemagglutinin and concanavalin A is impaired in mice exposed chronically to low concentrations of lead

Induction of myeloperoxidase deficiency in granulocytes in lead- intoxicated dogs

Abstract Lead interferes with heme synthesis in erythrocytes and has a deleterious effect on red cell membranes. We measured myeloperoxidase (MPO) enzyme activity in the granulocytes of dogs fed increasing quantities of lead. Concurrently, iodination capability and in vitro bactericidal activity were measured. Blood lead levels were monitored. Three of 4 dogs poisoned with lead developed significant decreases in MPO enzyme activity in their granulocytes. The decline in MPO activity correlated with cumulative lead toxicity as judged by blood lead levels and clinical signs of lead poisoning. Iodination ability in all 4 dogs decreased with cumulative lead toxicity. After discontinuation of lead administration, recovery of granulocyte MPO activity preceded recovery of iodination ability. This observation suggests the possibility of separate effects of lead on iodination ability and MPO activity. Moderate impairment of bactericidal capacity developed in 3 of 4 dogs with severe lead poisoning. Clinical infections were not observed during the course of the study.</jats:p