SAFETY AND IMMUNOGENICITY OF HSP65-DNA VACCINE DELIVERED BY IN VIVO MUSCULAR ELECTROPORATION IN CYNOMOLGUS MONKEYS
MONIQUE RIBEIRO DE LIMA¹, ANA CRISTINA C.S. LEANDRO¹, ANDREIA LAMOGLIA¹, JOHN L. VANDEBERG¹, CELIO L SILVA¹, MARIA DA GLORIA BONECINI ALMEIDA ¹
1. INI-FIOCRUZ - Instituto Nacional de Infectologia Evandro Chagas, 2. USP-RP - Escola de Medicina Ribeirão Preto Universidade São Paulo, 3. TEXAS-BIOMED - Texas Biomedical Research Instituto
gloria.bonecini@ini.fiocruz.br

Pulmonary tuberculosis (TB) caused by Mycobacterium tuberculosis remains one of the leading worldwide killers among all infectious diseases. A new TB vaccine is urgently need to replace or to be used as a booster for the BCG vaccine. Among the novel vaccine strategies, plasmid DNA-based TB vaccines have received an increasing attention because of their safety and induction of both CD4 ⁺ and CD8 ⁺ T cells. One approach is to increase the efficiency of plasmid-based DNA vaccination by electroporation (EP). Our goal was to determine the safety and immunogenicity induced by hsp65 -DNA vaccine by muscular EP in cynomolgus macaques (CM), a nonhuman primate model that closely resembles humans in clinical and immune response characteristics of M. tuberculosis infection. The vaccine pVAX- hsp65 DNA was derived from the pVAX vector, previously digested with BamHI and NotI by inserting a 3.3-kb fragment corresponding to the M. leprae hsp65 gene and the CMV intron A. The empty pVAX vector was used as control. Eight male CM were subjected to three intramuscular immunization into the quadriceps muscle using the EP technique. Four monkeys were maintained as control. Animals were assessed monthly for vaccine safety and adverse events and daily to identify behavior alterations. Palpebral TST reactions were graded at 24, 48, and 72h with the standard 1 to 5 scoring system. Cellular immune profile was identified before and monthly after each vaccine dose. None of the eight vaccinated animals showed local or systemic alterations; including renal or hepatic alterations during the entire follow up. pVAX-hsp65DNA EP vaccine did not induce TST conversion. A slight decrease of peripheral CD4 ⁺ T cells was observed after 30-and 120 days post-vaccination and CD8 ⁺ T cells​​ were transiently higher at 120 days p.v. pVAX-hsp65DNA did not induce alterations in myeloid DCs, even after the third vaccine dose. However, there was an increment in the plasmocytoid DCs at 60 and 90 days p.v. Transient enhancement of central but not effector memory CD4 ⁺ T cells was induced by pVAX-hsp65DNA EP vaccine. Our results indicated that pVAX-hsp65DNA EP vaccine is safety and induced a cellular immune response. Our group is actually testing the therapeutic and prophylactic efficacy of this vaccine in NHP, using microspheres as delivered systems. According with AERAS there are 14 new vaccines in clinical trial pipeline and several in pre-clinical studies. pVAX-hsp65DNA may be a new TB vaccine candidate in near future.