Comparison of Humoral Immune Responses Between Heat-Inactivated Brucella Abortus Biovar 3 and Strain Rb51 Vaccines in Indigenous Cattle of Bangladesh

Abstract

Background: Live attenuated Brucella abortus strains 19 and RB51 vaccines have been used as a key method for the control and eradication of brucellosis in cattle worldwide for decades. Due to certain limitations of these live vaccines, research has been undertaken for the development of an ideal more effective and safer vaccine for animals and human brucellosis. Objective: The main objective of this study was to compare the humoral immune responses (HIR) between the heat-inactivated Brucella abortus biovar 3 and attenuated live RB51 vaccines in native cattle of Bangladesh. Materials and Methods: The methods of isolation, identification, preparation of inoculum dose (10 × 1010 cfu/5 ml) and heat inactivation of B. abortus biovar 3 was followed as described earlier. Each of the three B. abortus sero-negative native cows was inoculated with heat-inactivated B. abortus vaccine @ 5.0 ml (10 × 1010 cfu /5 ml)/ cow SC single injection. Similarly, each of five native calves of 6 to 9 months old was inoculated with live attenuated RB51 vaccine (CZ Veterinaria, SA, Spain) @ 2.0 ml (10-34×109) SC as single dose. The sera of cows were collected at 0, 7, 14, 21, 28, 40, 60 and 90 days post vaccination, whereas the sera of the calves were collected at 0, 7, 14, 21, 28, 60, 90, 120, 150 and 180 days post-vaccination. All the collected sera of both the groups were tested to evaluate antibody titer by RBT followed by ELISA with commercial tests kits. Results: The HIR of the cows inoculated with heat-inactivated vaccine showed antibody (Ab) titer started to rise significantly (p < 0.05) from the 14 days (OD 0.2116 ± 0.0397, Ab titer 1:120) and reached a peak level at 28 days (OD 0.319 ± 0.172, Ab titer 1:800) and then started to decline significantly (p < 0.05) from 40 days (OD 0.234 ± 0.0415, Ab titer 1:35) to 60 days (OD 0.094 ± 0.0075, Ab titer 0). The mean Ab titer in calves inoculated with RB51 vaccine showed that Ab titer started to appears insignificantly (p ˃ 0.05) from day 7 (OD 0.094 ± 0.01603) and reached peak level at day 60 days (OD 0.592 ± 0.398), changes are very significant from day 0 (p < 0.05), after 60 days Ab level start to decrease and reach at lowest level at day 150 (OD 0.112 ± 0.0188), Ab level found similar to day 0 (OD 0.0826 ± 0.00517) at 180 days (OD 0.0822 ± 0.00249). Conclusions: The S19 and RB51 are the approved B. abortus vaccine strains have been widely and successfully used with some limitations to prevent bovine brucellosis worldwide. In addition to live attenuated and inactivated vaccines, recombinant genes, proteins, vectors, DNA and recombinant mutant vaccines have also been evaluated for the prevention of brucellosis but further research would be required to develop an ideal vaccine for both the humans and animals.

Humoral Immune Response in Cross-Bred Heifers Immunized With Brucella Abortus Strain Rb51 Vaccine in Military Dairy Farm of Bangladesh

“…These observation supports with the earlier report on RB51 vaccinated adult indigenous cattle and buffaloes in Bangladesh. 28,29 This study has recorded the rise of antibody level from the second weeks of vaccine administration and highest OD (0.223  0.0032) at 60 days after initial vaccination and the peak ODat 90 days (0.313  0.0032) after booster vaccination and then the antibody level started to decline from 120 to 150 days in heifers. These results are in conformity with earlier reports of immunized indigenous adult cattle and buffaloes.…”

“…These results are in conformity with earlier reports of immunized indigenous adult cattle and buffaloes. 28,29 All animals were sero-negative for Brucella antibodies before immunization which indicates that experimental animals were neither infected nor vaccinated, whereas satisfactory immune responses produced after immunization indicates inoculation of vaccine produced satisfactoryHIR in heifers. The antibody titer has been reported to be significantly increased in the vaccinated calves after one month and the titer declined but remained positive up to six months and then negative throughout the 12 months study periods.…”

“…[19][20][21][22] In addition, molecular detection of Brucella sp. from milk of sero-negative cattle, 23 isolation and genetic characterization of B. abortus biovar 3 from dairy cattle, 24,25 haemato-biochemical and therapeutic responses of chronic brucellosis in crossbred dairy cows, 26 comparison of humoral immune response (HIR) in indigenous cattle immunized with heat inactivated B. abortus biovar 3 and RB 51 vaccines 27,28 and HIR between indigenous cattle and indigenous buffaloes immunized with RB 51 vaccine 29 have been reported from Bangladesh.Report on the immunization and immunological response with B. abortus RB51 strain vaccine in cross-bred heifers is lacking in inland literature. Moreover, the complete understanding of the immune response triggered by the worldwide used B. abortus vaccines in cattle is still undefined.…”

Comparison of Humoral Immune Responses Between Cattle and Buffaloes Immunized With Commercial Brucella Abortus Strain Rb51 Vaccine in Bangladesh

“…23,24 Comparison of HIR between heat-inactivated B. abortus biovar 3 and strain RB51 in cattle have been studied in Bangladesh. 25 This paper describes the comparison of HIR of commercial B. abortus strain RB51 vaccine between cattle and buffaloes in Bangladesh.…”