A nano particle vector comprised of poly lactic‐co‐glycolic acid and monophosphoryl lipid A and recombinant Mycobacterium avium subsp paratuberculosis peptides stimulate a pro‐immune profile in bovine macrophages

Aims We evaluated the potential of a nanoparticle (NP) delivery system to improve methods of delivery of candidate peptide‐based vaccines for Paratuberculosis in cattle. Methods and Results Peptides derived from Mycobacterium avium subsp. paratuberculosis (Map), and the pro‐inflammatory monophosphoryl lipid A (MPLA) were incorporated in polymeric NPs based on poly (d,l‐lactide‐co‐glycolide) (PLGA). The PLGA/MPLA NPs carriers were incubated with macrophages to examine their effects on survival and function. PLGA/MPLA NPs, with and without Map antigens, are efficiently phagocytized by macrophages with no evidence of toxicity. PLGA/MPLA NP formulations did not alter the level of expression of MHC I or II molecules. Expression of TNFα and IL12p40 was increased in Map‐loaded NPs. T‐cell proliferation studies using a model peptide from Anaplasma marginale demonstrated that a CD4 T‐cell recall response could be elicited with macrophages pulsed with the peptide encapsulated in the PLGA/MPLA NP. Conclusions These findings indicate PLGA/MPLA NPs can be used as a vehicle for delivery and testing of candidate peptide‐based vaccines. Significance and Impact of the Study These results will assist on more in depth studies on PLGA NP delivery systems that may lead to the development of a peptide‐based vaccine for cattle.