Identification of Leukotoxin and other vaccine candidate proteins in a Mannheimia haemolytica commercial antigen

Tucci, Paula; Estevez, Verónica; Becco, Lorena; Cabrera-Cabrera, Florencia; Grotiuz, Germán; Reolon, Eduardo; Marín, Mónica

Besides LKT identification, we delved further into the characterization of the culture supernatant protein profile. By MS we identified other 10 proteins of M. haemolytica. Most of them are periplasmic and outer membrane proteins, which due to their extracellular location and exposure to the host immune system could represent interesting candidates to play a key role in the protection against this pathogen. It is worth mentioning that we also identified a cytoplasmic protein involved in carbohydrate metabolism (Formate C-acetyltransferase). This finding could be explained by some cellular lysis that could occur during bacterial growth and inactivation (Derzelle et al., 2005) , hence we cannot rule out that the culture supernatant may contain some cytoplasmic proteins.