Humoral immune response induced by a Prime-Boost vaccine strategy against recombinant PmpD from Chlamydia trachomatis using liposomal formulations with aminoacidic amphiphiles and CpG-ODN as immunostimulants

RUSSI, ROMINA CECILIA; IVANA REIDEL; CEPEDA, PAULA JULIETA; GRIPPO, LUCÍA ; GARCÍA, MARÍA INES; MÜLLER, DIANA MARÍA; VEAUTE, CAROLINA

Congreso; Reunión Conjunta de Sociedades de Biociencias (SAI, SAIC, SAFIS); 2018

Chlamydia trachomatis (Ct) is a frequently sexually transmittedbacterial worldwide. Vaccine development is strongly needed. Theselection of antigen and novel adjuvant play a crucial role in vaccineeffectiveness. Our aim was to evaluate the ability of a primeboost strategy to induce antibodies against Polymorphic membraneprotein D (PmpD). A selected fragment of PmpD containing B- andT-cell epitopes was expressed in Escherichia coli. The coding sequencewas subcloned in a eukaryotic expression vector (pVAX1).Recombinant protein was formulated with cationic liposomes (Lip)with CpG oligodeoxynucleotide (CpG-ODN) or an aminoacidic amphiphile(AA) as immunostimulants. Female Balb/c mice were immunizedwith a first intradermal dose of nude plasmid. Two proteinboosters were administered, every three weeks, by intranasal andsubcutaneous route, simultaneously. Mice were divided in groupsreceiving: Lip+CpG-ODN+rPmpD, Lip+AA+rPmpD, rPmpD alone,Lip+CpG-ODN or Lip+AA. Mice were bleed before starting the protocoland ten days after the last dose. Sera anti-rPmpD IgG, IgG1and IgG2a antibodies were assessed by indirect ELISA (OD450nm,mean±SEM). Liposome suspensions were stable with a mean particlesize from 209.0 to 248.7nm. Anti-rPmpD IgG were higher inLip+CpG-ODN+rPmpD(0,52±0,16) and Lip+AA+rPmpD(0.41±0.14)immunized mice compared to Lip+CpG-ODN(0,19±0,03) andLip+AA(0.11±0.01) (p