Immune responses in bovines to recombinant glycoprotein D of bovine herpesvirus type 5 as vaccine antigen.

Bovine herpesvirus 5 (BoHV-5) is responsible for outbreaks of meningoencephalitis that cause important economic losses in young cattle. BoHV-5 glycoprotein D (gD5) is essential for attachment and penetration into permissive cells and targeting of host immune systems, inducing strong humoral and cellular immune responses. The aim of this study was to evaluate the vaccinal immune response of vaccines formulated with the recombinant BoHV-5 gD (rgD5) in bovines. For the experiment, 72 heifers were randomly allotted into 6 different groups with 12 animals each. Group 1: vaccine formulated using inactivated BoHV-5 (iBoHV-5) adjuvanted with ISA50V2; Group 2: iBoHV-5 associated with 100 µg of rgD5 adjuvanted with ISA50V2; Group 3: 100 µg of rgD5 adjuvanted with ISA50V2; Group 4: 100 µg of rgD5 adjuvanted with Al(OH)3; Group 5: commercial vaccine; and Group 6: control group. Two doses were administered in a 26-day interval and the third after 357 days from primo vaccination. Cattle vaccinated with the vaccines formulated with iBoHV-5 plus rgD5 showed a significant (p < 0.01) five-fold increase in total immunoglobulin G (IgG) for BoHV-5, BoHV-1, and rgD5 as compared with the commercial and control groups. Also, a significant (p < 0.05) increase in IgG1 and IgG2a levels was induced in serum for rgD5. In addition, these same vaccines showed significant (p < 0.01) four-fold higher titers of BoHV-1 and -5 neutralizing antibodies. The results demonstrated that the rgD5 conserved important epitopes that were able to stimulate bovine humoral immunity response capable of viral neutralization of BoHV-1 and -5, suggesting it as a promising vaccine antigen to be used in vaccine for BoHV-1 and -5 endemic areas.

Production, purification and therapeutic potential of egg yolk antibodies for treating Trypanosoma evansi infection.

The use of avian antibodies has aroused interest in biomedical research due to the numerous advantages compared to mammal's antibodies. Our study aimed to produce and purify IgY immunoglobulins in order to use as an alternative therapy against Trypanosoma evansi. Every 14 days, four New Hampshire chickens were immunized with trypomastigotes of T. evansi, totaling five inoculations. Eggs were collected during 70 days and the extraction of IgY was performed by precipitation through the PEG-6000 method. Characterization and purification of IgY anti-T. evansi were carried out by SDS-PAGE and Western blot, where heavy and light chains were detected. The production of IgY was noted during the whole period, and the average production was 2.87 ± 0.14 at the end of this study. Sample's titration allowed the quantification of specific IgY anti-T. evansi, with antibodies produced showing high avidity indexes. The results indicated that T. evansi is able to generate an immune response in poultry, resulting in a production of specific antibodies. In vivo test showed that IgY treatment resulted in increase of prepatent period, longevity and survival of infected animals, when compared with the positive control, demonstrating an initial, but no curative, trypanocidal activity.

Immune responses of mice against recombinant bovine herpesvirus 5 glycoprotein D.

Glycoprotein D (gD) is essential for attachment and penetration of Bovine herpesvirus 5 (BoHV-5) into permissive cells, and is a major target of the host immune system, inducing strong humoral and cellular immune responses. The aim of this study was to evaluate in mice the immunogenicity of recombinant BoHV-5 gD (rgD5) expressed in Pichia pastoris. Vaccines formulated with rgD5 alone or adjuvanted with Montanide 50 ISA V2; Emulsigen or Emulsigen-DDA was administered intramuscularly or subcutaneously. Almost all formulations stimulated a humoral immune response after the first inoculation. The only exception was observed when the rgD5 was administered subcutaneously without adjuvant, in this case, the antibodies were observed after three doses. Higher titers of neutralizing antibodies were obtained with the three oil-based adjuvant formulations when compared to non-adjuvanted vaccine formulations. The rgD5 vaccine stimulated high mRNA expression levels of Th1 (INF-γ) and pro-inflammatory cytokines (IL-17, GM-CSF). The results demonstrated that the recombinant gD from BoHV-5 conserved important epitopes for viral neutralization from native BoHV-5 gD and was able to elicit mixed Th1/Th2 immune response in mice.