Study of adjuvant effect of fosprenil on immunogenicity of vaccines against parvovirus enteritis and rabies in experiment

To prevent most common viral diseases of small pets, vaccines are most often used that stimulate animal immune system and provide specific protection. Data on the adjuvant properties of well-known and widely used immunomodulator of natural origin, fosprenil, used in veterinary practice as an immunomodulator with antiviral activity for the correction of the immune response in various viral infections, during experimental immunization of BALB/mouse vaccines against dog parvovirus enteritis and rabies are presented in the article. It was shown that fosprenil use in animals at immunostimulating dose (5 pg/mouse) significantly enhances the effect of immunization with both vaccines. So, fosprenil significantly increases the titer of post-vaccination antibodies to standard liquid inactivated vaccine against parvovirus enteritis in dogs. In experiments with the rabies vaccine, it was found that the administration of fosprenil in animals along with vaccine not only contributes to significant increase in the titer of specific antibodies, but also to significant increase in coefficient of protective activity of rabies vaccine. Thus, fosprenil exerts an adjuvant effect on post-vaccination immunity caused by vaccination of mice with rabies and parvovirus enteritis vaccines.

Molecular epidemiology of infections caused by group B Streptococcus in pregnant women and newborns, and development of preventive vaccines

Hypothesis/aims of study. The present analysis was undertaken to summarize current knowledge about molecular properties of group B streptococci (GBS), emphasizing potential targets of vaccines against neonatal GBS infection. Study design, materials, and methods. This review is based on articles published mainly in the last ten years. Results. Epidemiological data on serotypes, multilocus sequence types, clonal complexes of GBS and their relationship are presented. Genetic events in GBS populations indicate significant obstacles to vaccine development. We described key properties of major GBS virulence factors, such as capsular polysaccharide, pili, and cell adhesion molecules, as well as results of experimental immunization on their basis. Conclusion. The population of invasive GBS strains is molecularly and genetically heterogeneous, which complicates selection of vaccine targets. Capsular switching, a low level of immunogenicity and variability of population composition are the most important factors that necessitate the accumulation and monitoring of molecular epidemiological data.

Experimental Immunization Based onPlasmodiumAntigens Isolated by Antibody Affinity

Vaccines blocking malaria parasites in the blood-stage diminish mortality and morbidity caused by the disease. Here, we isolated antigens from total parasite proteins by antibody affinity chromatography to test an immunization against lethal malaria infection in a murine model. We used the sera of malaria self-resistant ICR mice to lethalPlasmodium yoelii yoelii17XL for purification of their IgGs which were subsequently employed to isolate blood-stage parasite antigens that were inoculated to immunize BALB/c mice. The presence of specific antibodies in vaccinated mice serum was studied by immunoblot analysis at different days after vaccination and showed an intensive immune response to a wide range of antigens with molecular weight ranging between 22 and 250 kDa. The humoral response allowed delay of the infection after the inoculation to high lethal doses ofP. yoelii yoelii17XL resulting in a partial protection against malaria disease, although final survival was managed in a low proportion of challenged mice. This approach shows the potential to prevent malaria disease with a set of antigens isolated from blood-stage parasites.

Immunization of Mice with Live-Attenuated Late Liver Stage-Arresting Plasmodium yoelii Parasites Generates Protective Antibody Responses to Preerythrocytic Stages of Malaria

ABSTRACTUnderstanding protective immunity to malaria is essential for the design of an effective vaccine to prevent the large number of infections and deaths caused by this parasitic disease. To date, whole-parasite immunization with attenuated parasites is the most effective method to confer sterile protection against malaria infection in clinical trials. Mouse model studies have highlighted the essential role that CD8+T cells play in protection against preerythrocytic stages of malaria; however, there is mounting evidence that antibodies are also important in these stages. Here, we show that experimental immunization of mice withPlasmodium yoeliifabb/f−(Pyfabb/f−), a genetically attenuated rodent malaria parasite that arrests late in the liver stage, induced functional antibodies that inhibited hepatocyte invasionin vitroand reduced liver-stage burdenin vivo. These antibodies were sufficient to induce sterile protection from challenge byP. yoeliisporozoites in the absence of T cells in 50% of mice when sporozoites were administered by mosquito bite but not when they were administered by intravenous injection. Moreover, among mice challenged by mosquito bite, a higher proportion of BALB/c mice than C57BL/6 mice developed sterile protection (62.5% and 37.5%, respectively). Analysis of the antibody isotypes induced by immunization withPyfabb/f−showed that, overall, BALB/c mice developed an IgG1-biased response, whereas C57BL/6 mice developed an IgG2b/c-biased response. Our data demonstrate for the first time that antibodies induced by experimental immunization of mice with a genetically attenuated rodent parasite play a protective role during the preerythrocytic stages of malaria. Furthermore, they highlight the importance of considering both the route of challenge and the genetic background of the mouse strains used when interpreting vaccine efficacy studies in animal models of malaria infection.