In vivo immunosuppression in broiler chickens witb spontaneous infectious stunting syndrome

Abstract

Cellular and and humoral immune response were assessed in broiler chickens with spontaneous infectious stunting syndrome (ISS). Celluiar immunity was measured by delayed hypersensitivity response to 2, 4- dinitrochlorobenzene (DNCB) and phytohaemagglutinin- purified (PHA-p) tests. In DNCB test, the mean increase in skin thickness and induration sites were significantly lower in infected bIrds. Similarly, the mean increase in skin thickness and induration sites were also significantly lower in infected birds than those of controls in PHA-p test. In ISS- infected birds, marked reduction in size of all lymphoid organs was observed with lymphocytolysis and/or depletion of lymphoid cell populatiofl. The mean antibody titres in the stunted birds immunized with Ranikhet disease virus as antigen, were significantly lowered. The results clearly demonstrated that the causative agent(s) of ISS, produced immunosuppression in broiler chickens.