Recombinant Polyvalent Norovirus Vaccine(Beijing Health Guard Biotechnology, Inc.)

To construct the polyvalent recombinant nucleic acid vaccine of Toxoplasma gondii and measure its protective immune effect.

The gene of heat shock protein (HSP70) was amplified by PCR and inserted into the recombinant plasmid of pcDNA3-ROP2-p30 to construct recombinant polyvalent nucleic vaccine (pcDNA3-ROP2-p30-Hsp70). BALB/c mice were immunized with the constructed recombinant nucleic vaccine. CD4+ and CD8+ in the splenic lymphocytes and the lymphocytes in anticoagulant whole blood, the immune indices such as antibodies (IgG, IgM and IgA) and IFN-gamma, TNF, IL-2, IL-4, IL-12 in serum and splenic lymphocytes culture medium were detected, along with the challenge experiment. The protective immune responses that caused by the vaccine was measured by detecting the changes of immune indices of mice and the challenge experiment.

916 bp fragment of HSP70 gene was amplified by PCR. The recombinant polyvalent nucleic vaccine pcDNA3-ROP2-p30-HSP70 that included the whole open reading frame sequence of HSP gene was successfully constructed. The immunization results also showed this polyvalent nucleic vaccine could induce strong cellular and humoral responses by the detection of higher antibody titer in the experimental mice group, the increasing proliferation of CD4+ and CD8+ cells with significant deviations among the groups (F(CD4+) = 45.00, F(CD8+) = 15.01, all P < 0.01) and the apparent up-regulated levels of several cytokines IFN-gamma, IL-2 and IL-12 in serum and cultural supernatant of spleen cells, with more striking effect in serum. As a result of the challenge experiment, the immunized mice showed a longer survival time.

The recombinant nucleic acid vaccine pcDNA3-ROP2-p30-HSP70 possesses a strong immunogenicity and is able to induce an immune protection.

The ever increasing rate of new cases of Lyme disease, the tendency for chronicity in certain forms of the disease and especially the disputable effect of causal therapy resulted in strenuous efforts to develop an effective vaccine. The authors sum up recent experience with vaccination in the U.S.A. and Europe. Two studies in the U.S. during the years 1994 through 1997 included more than 20,000 probands. In one of the studies, coordinated by Steer (10,936 probands), during the first year twenty-two people of the vaccinated group contracted the disease compared to forty-three people of the non-vaccinated, i.e. placebo group. The vaccine efficacy was 49 percent. During the second year of the study, after the third dose of the vaccine, sixteen vaccinated people contracted the disease vs. sixty-six placebo probands. Vaccine efficacy was 76 percent. Its administration was accompanied by mild to moderate local or systemic reaction lasting up to three days. In the next study, coordinated by Sigal (10,305 probands) the vaccine efficacy was sixty-eight percent in the first year and ninety-two percent in the second, respectively. Both studies proved the vaccine to be safe and efficient in Lyme disease prevention. In comparison with these large long-term double-blind, placebo-controlled studies European research results presented to the medical community for the first time in 1998 in Vienna appear to be of lesser value. Recombinant polyvalent vaccine based on OspC lipoprotein isolated from Borrelia burgdorferi sensu lato was used but only eighty volunteers from Aland Islands participated in the study.