Mixed immune response induced in rodents by two naked DNA genes coding for mycobacterial glycosylated proteins.

Two genes of Mycobacterium tuberculosis, apa (Rv1860) and pro (Rv1796), coding for two glycosylated excreted proteins have been injected to mice and guinea pigs. They produce an extended immunological response of Th1 and Th2 types. Despite the fact that mycobacterial glycosylation is necessary for a high level of delayed-type hypersensitivity (DTH) reaction, plasmids bearing each of the two genes induced an elevated level of DTH sensitization. An inverse relation between the CpG-N hexamer cluster frequency and the protective effect of injected genes is described. A comparison of the strength of several eukaryotic promoters based on the diameter of the DTH reaction shows that CMVIE followed by the ubiquitin promoter are the most efficient among those tested. A significant protective effect (0.7 log unit CFU) in mice was found for the apa gene while the pro gene had no effect.