Induction of cellular immunity to a mycobacterial antigen adsorbed on lamellar particles of lactide polymers.

Microspheres prepared from synthetic, biodegradable poly (L-lactide) [PLA] and copolymers of lactide and glycolide such as poly (DL lactide co-glycolide) [PLG] have been widely investigated for controlled delivery of encapsulated vaccine antigens. In this study we describe novel lamellar microparticles produced from PLA to which protein antigens can be adsorbed. These particles when administered to mice, induced strong Th1-type T cell responses to the adsorbed 38 kDa protein antigen from M. tuberculosis characterised by high levels of Interferon-gamma. In addition to proteins, we were also able to adsorb synthetic peptides resulting in specific T cell proliferation. Induction of strong cellular immunity together with the versatility of antigen adsorption to these particles should make such lamellae a useful tool to deliver protective antigens from intracellular pathogens.