Requirements for induction of delayed hypersensitivity in the chicken

Abstract

Delayed hypersensitivity (DH) reactions to bovine serum albumin (BSA) or human gamma globulin (HGG) emulsions in complete Freund's adjuvant (CFA) were elicited in normal and bursectomized (BX) SC and FP chickens of varying ages. Responses in normals could be obtained with doses of BSA as low as 2 μg. Reactivity in agammaglobulinemic BX birds was generally lower than in normal animals. Attempts to increase DH with Bacillus Calmette Guérin pretreatment failed in both normal and BX birds. Cytoxan pretreatment did increase DH in normal but not in BX chickens. Similarly, replacement of whole Mycobacteria with the E. coli water soluble cell wall extracts, “Mur-Nac” and peptidoglycans, was effective in normal chickens but failed in BX birds. Modification of BSA with dodecanoyl side groups allowed the induction of DH by i.v. immunization in normal chickens unlike unsubstituted BSA. When immunization was performed with D-BSA or BSA in CFA, no significant difference was evident. Because of the generally poor health of BX birds, attempts were made to improve their responsiveness by pretreatment with normal chicken Ig or normal chicken spleen cell injections. Such pretreated BX chickens indeed gave higher DH to HGG. Thus, the inability of BX animals to respond to the same modifying influences in DH as did normal birds may have been due to an overall lack of responsiveness rather than to a role of B cell or antibody in these effects.