Use of the mice passive protection test to evaluate the humoral response in goats vaccinated with Sterne 34F2 live spore vaccine

Abstract

The Sterne live spore vaccine (34F2) is the most widely used veterinary vaccine against anthrax in animals. Antibody responses to several antigens of Bacillus anthracis have been described with a large focus on those against protective antigen (PA). The focus of this study was to evaluate the protective humoral immune response induced by the live spore anthrax vaccine in goats. Boer goats vaccinated twice (week 0 and week 12) with the Sterne live spore vaccine and naive goats were used to monitor the anti-PA and toxin neutralizing antibodies at week 4 and week 17 (after the second vaccine dose) post vaccination. A/J mice were passively immunized with different dilutions of sera from immune and naive goats and then challenged with spores of B. anthracis strain 34F2 to determine the protective capacity of the goat sera. The goat anti-PA ELISA titres indicated significant sero-conversion at week 17 after the second doses of vaccine (p = 0.009). Mice receiving undiluted sera from goats given two doses of vaccine (twice immunized) showed the highest protection (86%) with only 20% of mice receiving 1:1000 diluted sera surviving lethal challenge. The in vitro toxin neutralization assay (TNA) titres correlated to protection of passively immunized A/J mice against lethal infection with the vaccine strain Sterne 34F2 spores using immune goat sera up to a 1:10 dilution (rs ≥ 0.522, p = 0.046). This study suggests that the passive mouse protection model could be potentially used to evaluate the protective immune response in livestock animals vaccinated with the current live vaccine and new vaccines.

Immunogenicity of anthrax recombinant peptides and killed spores in goats and protective efficacy of immune sera in A/J mouse model

“…The A/J mouse strain is deficient in the C5 complement component which renders it vulnerable to infection by vaccine-strain Sterne spores 54 , 55 . These mice develop lethal systemic anthrax following infection with Sterne spores in the absence of protective antibodies 20 , 25 , 39 . Experiments with animals were conducted in accordance with ethical principles and guidelines provided by the animal use and care committees of the UPBRC, OBP and University of Pretoria respectively (Protocol number V065/12).…”

“…Induction of antibodies against PA is the main immune response following vaccination of animals with the Sterne live spore vaccine 23 – 25 . The anti-PA antibodies prevent the development of lethal intoxication and is vital for protection against germinating virulent anthrax bacilli 26 .…”

Development of ELISA based on Bacillus anthracis capsule biosynthesis protein CapA for naturally acquired antibodies against anthrax

“…This is in line with data observed by Phaswana et al . [ 60 ] where five individual Boer goats vaccinated with Sterne 34F2 B . anthracis strain showed variable levels of immune response.…”

Effect of simultaneous administration of foot-and-mouth disease (FMD) and anthrax vaccines on antibody response to FMD in sheep

“…CD4 + T cells, which secrete specific interferon γ (IFN-γ) cytokines against anthrax toxins such as LF, play an essential role against infection. Similarly, following exposure to LT and ET, rodent lymphocytes secrete cytokines such as interleukin (IL)-3, IL-4, IL-5, IL-6, IL-10, IL-17, tumor necrosis factor α, IFN-γ, and granulocyte-macrophage colony-stimulating factor [2223].…”