Induction of cytotoxic T-cell responses following oral immunization with synthetic peptides encapsulated in PLG microparticles

CTL responses play a critical role in clearing viral infections. We have in vestigated the potential of poly(lactide-co-glycolide) (PLG) microparticles as an oral delivery system for peptides representing CTL epitopes from mea sles virus nucleoprotein. Oral administration of CTL epitopes encapsulated in 50:50 PLG microparticles, resulted in vivo priming of splenic peptide-sp ecific CTL responses. However, the observed CTL lysis was low and cofeeding of encapsulated peptide with cholera toxin as a mucosal adjuvant did not r esult in any significant enhancement of the observed CTL responses. The pro nounced immunostimulatory effect of microparticles, combined with their exc ellent tissue compatibility and biodegradability makes them a valuable deli very system for synthetic peptide immunogens. However, further work is need ed to improve their efficiency via the oral route. (C) 1999 Elsevier Scienc e B. V. All rights reserved.