Icelandic ovineMycoplasma ovipneumoniaeare variable bacteria that induce limited immune responsesin vitroandin vivo. Issue 10 (October 2018)

• Record Type: Journal Article
• Authors: Einarsdottir, Thorbjorg; Gunnarsson, Eggert; Hjartardottir, Sigridur
• Is Part Of: Journal of medical microbiology. Volume 67:Issue 10(2018)
• Publication Date: 2018-10
• Subjects: Mycoplasma ovipneumoniae -- sheep -- strain typing -- vaccine -- 16S; Medical microbiology -- Periodicals; 616.9041
• DOI: 10.1099/jmm.0.000818
• Languages: English
• ISSNs: 0022-2615

Abstract

Abstract : Purpose. : Mycoplasma ovipneumoniae is a pathogen that causes atypical pneumoniae in sheep and goats. While infection of lambs can induce strong immune responses, typically measured as serum antibodies, experimental vaccines appear to induce lower antibody titres. The purpose of this study was to better understand the bacterium and its interaction with the host, in order to improve the vaccination strategy. Methodology. : We designed primers to compare seven M. ovipneumoniae gene sequences, in addition to the 16S sequence typically used, to estimate the variability between isolates. In addition, we labelled bacteria with a two‐step process to examine whether bacteria could be intracellular as well as on the host surface in vitro . Finally, we vaccinated sheep four times and examined the induction of humoral and cellular responses. Results. : We were able to reliably amplify the seven housekeeping gene sequences to examine variability of the different isolates, and the bacteria could be found intracellularly, as well as on the host cell surface. Four vaccinations of sheep produced only modest humoral and cellular responses in this study, likely due to previous exposure of the animals to mycoplasmas. Conclusions. : The moderate immune responses seen in this study indicate that previous exposure to mycoplasmas is a challenge for vaccination of lambs against M. ovipneumoniae . However, an alternative vaccination strategy, e.g. utilizing a recombinant vaccine, may overcome this vaccination hurdle in endemic regions and we suggest a possible vaccine candidate.