RT Journal T1 EVALUATION OF IMMUNOGENICITY AND DOSE DEPENDENT IMMUNE RESPONSE AGAINST COMMON BOVINE ORIGINATED MASTITOGENS IN RABBIT MODEL A1 Bilal Ahmed Shah JF Journal of Animal and Plant Sciences JO JAPS SN 1018-7081 VO 33 IS 3 SP 526 OP 533 YR 2023 FD 2023/06/18 DO DOI https://doi.org/10.36899/JAPS.2023.3.0645 AB

This study evaluated the immunogenicity and dose-dependent immune response of toxinotypes of bovine origin viz Staphylococcus aureus (tst), Streptococcus uberis (Cpn-60 targeted STUB), and Escherichia coli (aggR) in a rabbit model – a step forward towards an effective polyvalent mastitis vaccine. To evaluate the primary and secondary immune response (immunogenicity) against the concentration of 106 cells/mL of each preparation containing subject vaccinal isolates, 24 rabbits were divided randomly into 4 equal groups viz A, B, C and D. Each antigenic preparation was inoculated to the rabbits of group A to C @ 0.2 mL SC while group D served as control (placebo) at day 0 as priming dose and a booster dose at day 7 respectively. The serum antibodies titers were recorded in terms of Optical Density (OD) values at day 0 (pre-inoculation), 7, 14, 21 and 28 (post-inoculation) by iELISA Mastitis Kit (Abbexa, UK). The antibody response was significantly higher (p<0.05) in the post-booster samples at day-14 and day-21 for all the selected isolates. The highest primary antibody response (1.74 ± 0.14) as well as secondary immune response (2.04 ± 0.13) was shown by Strept. uberis (Cpn-60 STUB) in group B on day-14 followed in order by group C and A respectively. Likewise, dose-dependent immune response to composite antigens of 3 different antigenic concentrations of vaccinal isolates: 108 cells/mL; 1010 cells/mL; 1012 cells/mL of each of vaccinal isolates in 18 adult rabbits divided randomly into 3 groups of 6 (A, B and C) respectively for dose standardization was evaluated. Serum samples were collected at weekly intervals following completion of 2nd shot of inocula of each dose for 3 consecutive weeks. The rabbits of group B injected with 1010 cells mL-1 of S. aureus (tst) showed a significantly higher (p<0.05) serum iELISA O.D value (2.97A, a ± 0.10) followed in order by E. coli (aggR) (2.84a ± 0.08) and Str. uberis (cpn60 STUB) (2.78a ± 0.07) at day-14 post-inoculation. This study revealed the concentration of 1010 cells/mL of each subject mastitogens as a standard bacterial load for polyvalent mastitis vaccines with higher and sustained antigenicity in rabbits.

K1 Toxinotypes, polyvalent vaccines, antibody titer, rabbits PB Pakistan Agricultural Scientists Forum LK https://thejaps.org.pk/AbstractView.aspx?mid=2022-JAPS-374