Vaccination of calves with yeast‐ and bacterial‐expressed paramyosin from the bovine lungworm Dictyocaulus viviparus

Abstract

Summary Previously, vaccination of cattle with Escherichia coli‐expressed bovine lungworm paramyosin (EcPMY) adjuvanted with Quil A resulted in considerable reduction in worm burden and larvae shedding (Strube et al., 2015). To further evaluate the protective potential of PMY, cattle vaccination trials were performed using either E. coli‐ (EcPMY) or Pichia pastoris‐expressed PMY (PpPMY) with different adjuvants (Matrix‐Q™ or Quil A). Combinations EcPMY+Matrix‐Q™ (trial 1), PpPMY+Matrix‐Q™ (trial 2) and PpPMY+Quil A (trial 3) were tested against challenge infections with 2000 Dictyocaulus viviparus larvae. Even though GM worm burden and larvae shedding was lower in almost all vaccinated groups, there were high variations between individuals hampering significant differences. However, in all vaccinated groups, lungworms were significantly shorter compared with those in controls. In vitro stimulation of peripheral blood mononuclear cells (PBMC) with recombinant (r)PMY revealed no significant proliferation following vaccinations or challenge infection. All vaccinated cattle showed a significant rise in specific antibodies, particularly IgG and its subclass IgG1, and detected the native lungworm PMY in immunoblots starting 2 weeks after the first vaccination. The use of a different rPMY‐adjuvant combination or combined vaccination with additional recombinant antigens might be a promising future approach towards a new vaccine against lungworms in cattle.

Biological function of Dictyocaulus viviparus asparaginyl peptidase legumain-1 and its suitability as a vaccine target

“…Increased IgA levels have been found in bronchoalveolar lavage fluid of D. viviparus-infected calves, suggesting that this Ig subclass may play an important role in local immunity (Scott et al 1996). IgM values fluctuated both in the vaccinated and control animals, which might be due to an immunological response against copurified P. pastoris antigens or an unspecific antibody binding to rLEG-1 and/or the hexa-His-tag as discussed by Joekel et al (2015). Regarding IgE, no titre was measurable at all, which corresponds to the findings of Strube et al (2015) and Joekel et al (2015) who suspect IgE to be bound on surfaces of, e.g.…”

“…IgM values fluctuated both in the vaccinated and control animals, which might be due to an immunological response against copurified P. pastoris antigens or an unspecific antibody binding to rLEG-1 and/or the hexa-His-tag as discussed by Joekel et al (2015). Regarding IgE, no titre was measurable at all, which corresponds to the findings of Strube et al (2015) and Joekel et al (2015) who suspect IgE to be bound on surfaces of, e.g. basophilic granulocytes and consequently not measurable in serum.…”

“…Since natural infection with D. viviparus evokes a protective immunity in the cattle host, the development of a recombinant subunit vaccine appears well-suited and would be highly beneficial for prophylaxis of parasitic bronchitis. Previous vaccine trials with recombinant D. viviparus paramyosin have proved promising regarding their impact on worm burden, worm length and thus worm development, and larvae shedding (Joekel et al 2015; Strube et al 2015). The presented study aimed to investigate the suitability of recombinantly expressed LEG-1 as a bovine lungworm vaccine candidate.…”

“…Measurement of weight gain and parasitological parameters (larvae shedding, worm burden and worm size) as well as analysis of immune response to rLEG-1 by enzyme-linked immunosorbent assay (ELISA) were performed as described previously (Joekel et al 2015) with the modification that ELISA detection of immunoglobulin subclasses IgG, IgG1, IgG2, IgA and IgM was performed with 1:10 000 diluted secondary antibodies. In addition, immunoblots against whole adult lungworm lysate as antigen were performed as described by Joekel et al (2015) except that 64 µ g crude antigen was loaded per lane and cattle sera were 1:25 diluted. As positive control, 0·2 µ g rLEG-1 was detected with 1:50 diluted anti-rLEG-1 rabbit antiserum.…”

Helminth Vaccines in Ruminants

“…In an attempt to overcome these issues, several attempts were made to develop recombinant subunit vaccines, with limited success. Vaccination with recombinant acetylcholinesterase, 6 paramyosin, 7,8 or asparaginyl peptidase legumain-1 9 with different adjuvants did not result in significant and/or reproducible reduction in worm numbers or larval shedding.…”