Indonesian Native Chickens (Ayam Kampung) as a Local Source of Anti-Rabies Antibody: Optimisation of an In-House Indirect ELISA Using Three Commercial Rabies Vaccines as Coating Antigens Sulaiman Ngongu Depamede (1*), Wayan Wariata (1), Made Sriasih (1), Anwar Rosyidi (1), Wirdullutfi Wirdullutfi (2), and Nurul Azizah (3)
1) Faculty of Animal Science, University of Mataram, Jl. Majapahit No. 62 Mataram, 83125, Indonesia
* sulaiman_n[at]unram.ac.id
2) Faculty of Teacher Training and Education, University of Mataram, Jl. Majapahit No. 62 Mataram, 83125, Indonesia
3) Master of Animal Resources Management Program, Faculty of Animal Science, University of Mataram, Jl. Majapahit 62, Mataram 83125.
Abstract
Rabies remains a fatal zoonosis in eastern Indonesia, where affordable serological reagents are scarce. Avian IgY offers a low-cost, non-invasive alternative to mammalian antibodies, yet Indonesian native chickens (ayam kampung), the dominant smallholder poultry, have not been evaluated as antibody donors. This study assessed their humoral response to commercial rabies vaccines and optimised an in-house indirect ELISA using the vaccines as coating antigens. Two hens received an intramuscular cocktail of three inactivated vaccines (Defensor 3, Nobivac Rabies, Rabisin) plus three four-weekly boosters. Sera taken four weeks post-final booster were tested against each vaccine coated at 1:250 and 1:25, and by two-fold serum titration. Both hens seroconverted strongly (positive-to-negative ratios 3.2-17.5). Nobivac-coated wells gave the best signal-to-noise ratio because pre-immune reactivity was lowest (blank-corrected OD450 0.028, vs 0.142 for Defensor 3 and 0.223 for Rabisin), indicating natural antibody binding to vaccine matrix components. A ten-fold increase in coating antigen raised OD450 only 1.0-1.4-fold, showing saturation at 1:250. Four-parameter logistic fitting (R^2 >= 0.997) gave midpoint titres of 1:567 and 1:748, with reactivity above cut-off at 1:12,800. Ayam kampung thus mount a robust anti-rabies response- 1:250 coating with 1:400 serum dilution is proposed as a cost-efficient format.
