Efficacy of tuberculosis vaccine increased by formulation with a cationic colloid.(Brief Article)

2002 SEP 4 - (NewsRx.com & NewsRx.net) -- by Maria G. Essig, MS, ELS, senior medical writer - Researchers in Europe and the U.S. found that adding a cationic colloid to DNA vaccine formulations increased splenic and pulmonary immune responses to Mycobacterium tuberculosis antigens.

S. D'Souza and colleagues at the Pasteur Institute of Brussels and Vical, Inc., in San Diego, California, used a murine model to evaluate the immunogenic effect of tuberculosis DNA vaccines formulated with saline or one of two types of colloids.

The vaccines consisted of plasmid DNA (pDNA) encoding for M. tuberculosis antigens Ag85A, Ag85B, or the phosphate-binding protein PstS-3. One formulation included aminopropyl-dimethyl-bis-dodecyloxy-propanaminium bromide-dioleoylphosphatidyl-ethanolamine (GAP-DLRIE:DOPE) with the pDNA designed for intranasal administration. For intramuscular delivery, aminopropyl-demethyl-myristoleyloxy-propanaminium bromide-diphyanoylphosphatidyl-ethanolamine (VC1052:DpyPE, Vaxfectin) was formulated with the pDNA.

"These two novel cationic and neutral colipid formulations were previously reported to be effective adjuvants for pDNA-induced antibody responses," commented D'Souza and collaborators.

Vaccination with the VC1052:DpyPE formulation increased Ag85-specific IgG response 3 to 10 times. The vaccine also provoked a rise in levels of splenic interleukin-2 (IL-2) and gamma interferon in response to Ag85. The PstS-3 vaccine VC1052:DpyPE formulation maintained higher cytolytic T-lymphocyte responses over time compared with vaccination with the saline PstS-3 formulation.

The intranasal Ag85A vaccine formulated with GAP-DLRIE:DOPE stimulated a Th1-type cytokine response. In contrast, the saline ...