Differential antigenicity of individual Mycoplasma hyorhinis variable lipoproteins.

The Mycoplasma hyorhinis (Mhr) variable lipoprotein (Vlp) family, comprising Vlps A, B, C, D, E, F, and G, are highly variable in expression, size, and cytoadhesion capabilities across Mhr strains. The 'Vlp system' plays a crucial role in cytoadhesion, immune evasion, and in eliciting a host immunologic response. This pilot study described the development of Vlp peptide-based ELISAs to evaluate the antigenic reactivity of individual Vlps against Mhr antisera collected throughout a longitudinal study focused on Mhr strain 38983, reproducing Mhr-associated disease under experimental conditions. Specifically, serum samples were collected at day post-inoculation 0, 7, 10, 14, 17, 21, 24, 28, 35, 42, 49, and 56 from Mhr- and mock (Friis medium)-inoculated cesarean-derived, colostrum-deprived pigs. Significant Mhr-specific IgG responses were detected at specific time points throughout the infection, with some variations for each Vlp. Overall, individual Vlp ELISAs showed consistently high accuracy rates, except for VlpD, which would likely be associated with its expression levels or the anti-Vlp humoral immune response specific to the Mhr strain used in this study. This study provides the basis and tools for a more refined understanding of these Vlp- and Mhr strain-specific variations, which is foundational in understanding the host immune response to Mhr.