Ingelvac circoflex

Thirty female BALB/c mice were randomly divided into 5 groups (n = 6). The mice were inoculated subcutaneously with 30 μg and 15 μg of rF5P as Group rF5PH and Group rF5PL, respectively; 50 μL of commercial inactivated Circovac® vaccine (Merial), subunit vaccine Ingelvac CircoFLEX® (Boehringer Ingelheim) and PBS were classified as positive and negative controls, named as Group MLY, BLG and PBS, respectively.
The rF5P was diluted in 50 μL of PBS and then emulsified with 50 μL of Complete Freund’s adjuvant for the first immunization, and subsequently with 50 μL of Incomplete Freund’s adjuvant for booster at an interval of 4 weeks. At 56 days after the first immunization, 3 mice from each group were sacrificed for both lymphocyte proliferation assay and cytokine production. In order to reduce the pain of mice to the greatest extent, cervical dislocation was chosen to kill them. It is the fastest method to make the spinal cord and brain spinal cord disconnected, so that the central nervous system instantly lost control of the whole body, which is in line with the requirements of animal welfare. The rest alive mice received 100 μL of 10^6.5 (TCID₅₀)/mL PCV2 strain DF-1, and they were monitored for the following 28 days. Next, the mice were sacrificed for PCV2 content in different organs. Blood samples were collected from the tail veins each week.

Sera from sows (Large White × Landrace) at a university-owned pig farm in Lower Austria were tested by the IDEXX Swine Salmonella Ab test (IDEXX Europe, Hoofddorp, The Netherlands) prior to the study. The five sows with the lowest sample to positive control (S/P) ratios (S/P ratios: 0.295–0.473, cut-off for positivity: 1.0) were selected and 44 female and male castrated pigs (Large White × Landrace × Pietrain) from those sows were included in the study at the age of four weeks. All piglets underwent routine vaccinations against PCV-2 (Ingelvac CircoFLEX^®, Boehringer-Ingelheim, Ingelheim am Rhein, Germany) at three weeks of age and Mycoplasma hyopneumoniae (M⁺PAC^®, MSD Animal Health, Kenilworth, NJ, USA) in the first and third week of life at the farm. The Salmonella-free status of the piglets at the start of the study was validated by serological testing for Salmonella-specific antibodies by the IDEXX Swine Salmonella Ab test (IDEXX Europe) and by microbiological testing of fecal samples collected on three consecutive days after arrival (study days (SD) −11, −10, −9). Antibody S/P ratios were below the positivity cut-off for piglets (0.25). Additionally, no Salmonella were detectable in the fecal samples of the piglets at the stated time points.

Six groups were created, 16 pigs in each, comprising four vaccinated and two non-vaccinated groups with low and high (L and H) MDA counterparts per treatment type. The two vaccines used were CIRCOVAC^® (CV; Ceva-Phylaxia Ltd., Budapest, Hungary), an inactivated whole virus vaccine and Ingelvac CircoFLEX^® (CF; Boehringer Ingelheim Vetmedica GmbH, Germany), an ORF2 subunit vaccine and used according to the manufacturer’s instructions, at doses of 0.5 and 1.0 mL, respectively, applied intramuscularly (i.m.) at three weeks of age. The unvaccinated positive controls (PC) received 1.0 mL sterile PBS i.m. The resulting groups were then: HMDA/CV; LMDA/CV; HMDA/CF; LMDA/CF; HMDA/PC; and LMDA/PC.

An inactivated subunit vaccine (Ingelvac CircoFLEX®, Boehringer Ingelheim Vetmedica GmbH) was administered at three weeks of age for immunization against PCV-2. The vaccine contained the ORF2 capsid protein of PCV-2 as active component and an aqueous polymer (carbomer) as adjuvant. This protein has been identified as the major immunogenic antigen of PCV-2 inducing a protective response [51 (link), 52 (link)]. The ORF2 sequence was subsequently inserted into a baculovirus expression system using an insect cell line derived from ovaries of the armyworm Sodoptera frugiperda (SF+ cells) as host. The placebo control consisted of insect cell culture supernatant without PCV-2 capsid protein but containing carbomer adjuvant.

Four weekly weaning groups were followed in the study. One group consisted of approximately 500 piglets, of which half were vaccinated with L. intracellularis vaccine at the age of 3 weeks about 7 days before weaning (V = vaccine group). The other half of non-vaccinated piglets served as controls (C = control). The litters were chosen randomly and all piglets in a litter were either vaccinated or served as controls. One vaccine group piglet at a time was lifted from the ground and administered 2 mL of L. intracellularis vaccine (Enterisol Ileitis^®, Boehringer Ingelheim Vetmedica GmbH) directly into the mouth with a drench and injected intramuscularly 1 mL of circovirus vaccine (Ingelvac CircoFLEX^®, Boehringer Ingelheim Vetmedica GmbH) behind its ear. The control group piglets were lifted similarly but only received the circovirus vaccine. Vaccinated piglets were marked with an individually numbered red ear tag in their right ear. Similarly, control piglets received a numbered yellow ear tag in their left ear.