EFFECT OF ORAL DOSES OF LEAD ON IMMUNE-RESPONSE IN CALVES

Influence of lead on humoral and cellular immune response was studied in healthy crossbred calves (12), divided into 2 groups. Calves of gro up A served as healthy control, and those of group B received lead ace tate @ 5.0 mg/kg body weight (equivalent to 2.73 mg of lead) till the appearance of clinical signs of toxicity. Significant decrease in humo ral immune response to chicken red blood cells was recorded in calves exposed to lead from day 28 onwards. In these calves, phagocytic index of polymorphonuclear cells and delayed hypersensitivity reaction to d initrochloro benzene declined significantly from days 42 and 28 post-e xposure respectively. Erythema, in duration and swelling of the sensit ized area were not intense in calves exposed to lead as compared to he althy calves. Skin biopsy sample taken of the challenge dose of DNCB, revealed moderate cellular infiltration in calves exposed to lead.