To study the possibility of immunization against Cryptosporidium baileyi Current, Upton et Haynes, 1986 with the attenuated anticoccidial vaccine, Paracox™ and oocysts of C. parvum Tyzzer, 1912, chickens were inoculated orally with either 3 x 10’ vaccine oocysts or 8 x I O5 C, baileyi or C. parvum oocysts at 1 week of age. The inoculation with Paracox™ vaccine and C. parvum oocysts was repeated at 2 and 3 weeks of age. Uninfected birds served as controls. All animals with the exception of one uninfected group were challenged orally with either 8 x 105 C. baileyi or 3 x 10s Eimeria tenella Railliet et Lucet, 1891 oocysts at 4 weeks of age. Sera were collected at 4 weeks of age, and were examined by ELISA using C. baileyi antigens. Birds inoculated with C. parvum oocysts did not shed C. parvum oocysts in their faeces, but anticryptosporidial antibodies could be detected in the sera. The total oocyst output of C. parvum inoculated chickens was 17% of that of previously uninfected birds after the oral challenge with C. baileyi. Considering that antibodies play no or only a minor role in resistance to C. baileyi, these results suggest that inoculation of chickens with C. parvum oocysts stimulated also cellular immune response. Based on the relative body weight gain, faecal scores, oocyst output, mortality, and caecal lesions in the birds immunized with Paracox™ vaccine and challenged with E. tenella, the vaccination induced only a moderate protection against the reinfection. The results of crossimmunization of chickens with Eimeria spp. and C. baileyi suggest that attenuated anti-eimerian vaccines do not induce any protection against cryptosporidial infection.
There are many strategies to control leishmaniasis, but majority of them are inadequate. Killed Leishmania vaccine (KLV) has been applied for its immunogenicity in human and mouse model. Bacillus Calmette-Guerin (BCG) as adjuvant is an immunemodulator inducing humoral and cellular immune responses during zoonotic cutaneous leishmaniasis (ZCL). Both KLV and BCG have been applied for their immune responses in hosts for controlling leishmaniasis. In this study, KLV and BCG were applied to inhibit replication and visceralization of Leishmania major in BALB/c mice. Mice were injected with KLV and BCG, followed by infection with promastigotes of L. major. Six weeks after infection, a small nodule appeared, which was followed by development of a large lesion and visceralization. Effects of KLV and BCG, physiopathological changes, lesion size, delay of lesion formation, proliferation of amastigotes inside macrophages and detection of amastigotes in target organs were studied. Results showed that the KLV had anti-leishmanial activity by reducing lesion size on late infection. In KLV and BCG group, the average number of amastigotes in macrophages was lower than in other groups. Significant reductions in number of amastigotes in both spleen and lymph node were observed, indicating lower visceralization of Leishmania parasites in these target organs. No significant changes were presented in body weights, survival rates and degrees of splenomegaly in test group. It can be concluded that application of KLV and BCG had acceptable efficacy in reduction of skin lesions size and proliferation of parasites, even though a few side-effects were observed. It is indicated that KLV/BSG may have ability to modulate host immune responses against Leishmania parasites and to reduce pathophysiology of the disease during infection.
First step in developing an epitope-based vaccine is to predict peptide binding to the major histocompatibility complex (MHC) molecules. We performed computational analysis of unique available EgA31 sequence to locate appropriate antigenic propensity positions. T-cell epitopes with best binding affinity values of < 50% inhibitory concentration were selected using different available servers (Propred and IEDB). Peptides with 100% population coverage were selected. A DNA fragment corresponding to the furin linker enriched in Golgi apparatus was inserted sequentially between each epitope sequences in a synthetic DNA in order to cleave the chimeric protein into four separated peptides. Subsequently, the synthetic DNA was cloned into the pGEX4T-1 and pEGFP-N1 vectors and GST-ChEgA31 was expressed in E. coli strain BL21-DE3. The recombinant protein was detected by western blotting using an HRP-conjugated polyclonal anti-GST antibody. Fusion protein purified by affinity chromatography was used to raise antisera in rabbits. Results in agar gel immunodiffusion assay indicated induction of specific antibodies against multiepitope antigen in the tested rabbits. Cytokine assay was carried out in C57Bl/6 mice and the levels of cytokines were analyzed by sandwich ELISA. Interestingly, production of specific IFN-γ was prominently higher in mice immunized with GST-ChEgA31 and pEGFP-ChEgA31 (650-1 300 pg/ml) compared to control groups. No difference was observed in the level of IL-10 and IL-4 in immunized and GST control group. Challenge study with 500 live protoscolices of Echinococcus granulosus on immunized mice demonstrated protectivity level (50-60%). Based on our results, it appeared that the chimeric protein in the study was able to stimulate T-helper cell-1 (Th1) development and high level of cell mediated immunity in mice.
The circulating antibody profiles of rabbits infested or immunized with Sarcoptes scabiei var. canis were compared. Crossed immuno-electrophoretic analysis showed that infested hosts produced serum antibody to 12 proteins (antigens) in an extract made from sarcoptic mite bodies. In contrast, rabbits immunized with an extract made from mite bodies produced antibody to 20 Sarcoptes proteins (antigens). SDS-PAGE/immunoblot analysis revealed that serum from immunized rabbits contained antibodies that bound strongly to proteins of 25 and 39-52 kD that were only barely visualized by antibodies in serum from infested rabbits.