The lipopeptide, Pam2Cys-Ser-(Lys)4: an alternative adjuvant to Freund's adjuvant for the immunisation of chicken to produce egg yolk antibodies

By Erhard, M.H. - Schmidt, P. - Hofmann, A. - Bergmann, J. - Mittermeier, P. - Kaufmann, P. - Wiesmuller, K.H. - Bessler, W.G. - Losch, U.

This study describes an alternative adjuvant for the immunisation of chicken. The lipopeptide, Pam3Cys-Ser-(Lys)4(PCSL), has been demonstrated to be a very potent adjuvant, by immunisation with the hapten methyl phosphoric acid paraaminophenyl 1,2,2-trimethylpropyl diester, with coronavirus, with rotavirus and with the Escherichia coli K99 pilus antigen. The antibody titres in chickens that received PCSL were compared with those in animals that received Freund's complete adjuvant/Freund's incomplete adjuvant (FCA/FIA). Antigen-dependent differences in antibody titres could be shown. The optimal dosage for PCSL was 250 microgram per injection. Whereas injection of FCA/FIA resulted in chronic inflammatory alterations, mostly accompanied with granulomatous reactions, no long-term tissue damage could be found with PCSL. When PCSL was used as the adjuvant, the total immunoglobulin Y (IgY) levels in chicken sera were constant during the immunisation period (20.2mg/ml, SD +/- 1.3), and were significantly different (p < 0.0001) from those in chickens given FCA as adjuvant (26.6mg/ml, SD +/- 4.9). IgY concentrations in the egg yolks showed no significant differences in both groups (PCSL-13.7mg/ml, SD +/- 3.7; FCA-13.5mg/ml, SD +/- 4.2), and were significantly lower (p < 0.0001) than the IgY serum levels.