Study on the Course of Cryptosporidium baileyi infection in chickens treated with interleukin-1 or indomethacin

The effects exerted by human recombinant interleukin-1β (hrIL-1β) and the prostaglandin inhibitor indomethacin on the course of Cryptosporidium baileyi infection in chickens were studied. Daily oocyst shedding was monitored by a quantitative method throughout the experiment. Humoral immune response to C. baileyi was assessed by ELISA at 3 weeks of age while the level of cellular immune response to phytohaemagglutinin-P (PHA-P) by a skin test at 23 days of age. Parenteral application of hrIL-1b decreased oocyst shedding to 62%, but the infection ran a similar course in treated and control birds. The PHA-P skin test demonstrated increased cellular immune reaction in chickens receiving IL-1b, but there was no significant difference in the humoral responses of the two groups as detected by ELISA. On the other hand, indomethacin mixed to the feed lessened oocyst shedding to 13.7% and also shortened its duration. Immunological parameters as reflected by PHA-P skin test and ELISA results indicated enhanced cellular but unaltered humoral immune response. These data suggest that the sys- temic application of interleukin-1 can induce partial protection against C. baileyi in chickens and that prolonged, abundant oocyst shedding is due to an indometha- cin-sensitive immunodepression via the prostaglandin pathway