ORIGINAL RESEARCH article
Front. Immunol.
Sec. Vaccines and Molecular Therapeutics
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1663259
This article is part of the Research TopicNew Generation Bacterial Vaccines Based on Immune Correlates of ProtectionView all 3 articles
Assessment of immune responses with Brucella abortus S19 vaccine in cattle and buffaloes
Provisionally accepted
Rajeswari Shome*
Y K PRABHAKAR
Gandu Shanmugam
Somy SkariahPraveen Kumar A.MPavan Kalyan NagarajaKirti MeghaNanditha Thimmappa Rajeshwari
M Nagalingam- ICAR - National Institute of Veterinary Epidemiology and Disease Informatics, Bengaluru, India
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Introduction: The Brucella abortus S19 vaccine remains the global reference standard for bovine brucellosis prevention. This study comprehensively evaluated the safety and immunogenicity of S19 at a dose of 4×10⁹colony forming units (CFU) dose in cattle and buffalo calves. Methods: A total of 180 female calves (90 each cattle and buffalo calves) of 4-8 months old were equally distributed across six post-vaccination intervals (15 animals/group/species for DPV intervals such as DPV <21, 21-45, 46-60, 61-90, 91-120, and >120 days).All calves were confirmed seronegative for anti-Brucella antibodies by Rose Bengal Plate Test (RBPT) and indirect ELISA prior to vaccination. Vaccinated animals were monitored for three weeks for adverse effects. Humoral immunity was assessed using RBPT and Standard Tube Agglutination Test (SAT), antibody isotypes IgM/IgG were quantified by indirect ELISA, cytokines such as TNF-α, IL-6, IL-8 and IL-10 were measured by competitive inhibition ELISA, while IL-12, IL-1β and IFN-γ were quantified using high-sensitivity sandwich ELISAs. All the samples were processed by cold centrifugation (4°C) and stored at -20°C until analysis. Results: No local/systemic reactions were observed, confirming safety. Significant humoral responses (p<0.05) peaked at DPV interval <21 (SAT: 640 International Unit /mL), declining gradually but persisting beyond 120 DPV. Cattle calves showed faster IgM-to-IgG switching (p<0.05), with peak IgM (179.2±5.5 vs 163.7±5.9) and IgG (220.6±13.9 vs 187.5±9.5) in cattle versus buffalo calves. Pro-inflammatory cytokines (TNF-α, IL-6, IL-8, IL-12, IL-1β) and IL-10 peaked at DPV interval 46-60 (p<0.05). IFN-γ (Th1 marker) peaked earlier DPV interval 21-45 (cattle 307.7±13.4 pg/mL vs buffalo 274.2±11.7 pg/mL, p<0.05), indicating robust CMI. All comparisons used one-way ANOVA (GraphPad Prism 10) with significance at p<0.05. Conclusion: B. abortus S19 at 4×10⁹CFU/dose safely induces durable humoral and cellular immunity in both species, with cattle mounting faster adaptive responses than buffaloes . The comprehensive immune profile supports its use as an effective vaccination strategy.
Keywords: Brucellosis, Brucella abortus S19, cell-mediated immunity, humoral immunity, innate immunity
Received: 14 Jul 2025; Accepted: 22 Oct 2025.
Copyright: © 2025 Shome, PRABHAKAR, Shanmugam, Skariah, A.M, Nagaraja, Megha, Rajeshwari and Nagalingam. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Rajeswari Shome, rajeswarishome@gmail.com
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