SummaryPlant-based expression systems are attractive for the large-scale production of pharmaceutical proteins. However, glycoproteins require particular attention as inherent differences in the N-glycosylation pathways of plants and mammals result in the production of glycoproteins bearing core-xylose and core-α (1,3)-fucose glyco-epitopes. For treatments requiring large quantities of repeatedly administered glycoproteins, the immunological properties of these non-mammalian glycans are a concern. Recombinant glycoproteins could be retained within the endoplasmic reticulum (ER) to prevent such glycan modifications occurring in the late Golgi compartment. Therefore, we analysed cPIPP, a mouse / human chimeric IgG1 antibody binding to the β -subunit of human chorionic gonadotropin (hCG), fused to a C-terminal KDEL sequence, to investigate the efficiency of ER retrieval and the consequences in terms of N-glycosylation. The KDEL-tagged cPIPP antibody was expressed in transgenic tobacco plants or Agrobacterium -infiltrated tobacco and winter cherry leaves. N-Glycan analysis showed that the resulting plantibodies contained only high-mannose (Man)-type Man-6 to Man-9 oligosaccharides. In contrast, the cPIPP antibody lacking the KDEL sequence was found to carry complex N-glycans containing core-xylose and core-α (1,3)-fucose, thereby demonstrating the secretion competence of the antibody. Furthermore, fusion of KDEL to the diabody derivative of PIPP, which contains an N-glycosylation site within the heavy chain variable domain, also resulted in a molecule lacking complex glycans. The complete absence of xylose and fucose residues clearly shows that the KDEL-mediated ER retrieval of cPIPP or its diabody derivative is efficient in preventing the formation of non-mammalian complex oligosaccharides.

Passive immunization with recombinant HCG-specific antibodies may have clinical utility as (i) diagnostic and therapeutic tools for HCG-expressing cancers and (ii) contraceptive measures.

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Conventional method of species identification in Eimeria employs phenotypic characters of the oocysts and the site of infection in the chicken intestine, which are subjective analyses. PCR-based identification of Eimeria spp. is known to be specific and sensitive. We used internal transcribed spacer 1 (ITS-1)-based nested PCR to follow the distribution of Eimeria spp. in the field, which may be of significant value in the management of coccidiosis in chickens. In the present study, intestinal samples of chicks from commercial poultry farms, in India, suspected of having contracted Eimeria infections were analyzed using ITS-1 PCR. The PCR-amplified ITS-1 regions were also sequenced from these samples. Of 26 field samples analyzed, 19 showed the presence of multiple infections of Eimeria spp. Incidence of Eimeria tenella (80%) was found to be highest in these samples followed by Eimeria mitis (53%), Eimeria acervulina (42%), Eimeria brunetti, and Eimeria maxima (23%). Incidence of Eimeria necatrix was found to be the lowest (15%) in the samples analyzed, while none of the samples analyzed showed the presence of ITS-1 sequence from Eimeria praecox. The ITS-1 sequences amplified from Eimeria spp. in the present study showed few variations from the ITS sequences available in the GenBank database. Further studies will be required to determine whether these differences are unique to geographical locations.

Citation Gupta SK, Srinivasan VA, Suman P, Rajan S, Nagendrakumar SB, Gupta N, Shrestha A, Joshi P, Panda AK. Contraceptive vaccines based on the zona pellucida glycoproteins for dogs and other wildlife population management. Am J Reprod Immunol 2011; 66: 51–62 Zona pellucida (ZP) glycoproteins, by virtue of their critical role in fertilization, have been proposed as candidate antigens for the development of contraceptive vaccines. In this review, the potential of a ZP‐based contraceptive vaccine for the management of wildlife population, with special reference to street dogs, is discussed. Immunization of various animal species, including female dogs, with native porcine ZP led to inhibition of fertility, which was associated with the ovarian dysfunction. Immunization of female dogs with Escherichia coli‐expressed recombinant dog ZP glycoprotein‐3 (ZP3) either coupled to diphtheria toxoid or expressed as fusion protein with ‘promiscuous’ T non‐B‐cell epitope of tetanus toxoid also led to inhibition of fertility. To improve the contraceptive efficacy of ZP‐based contraceptive vaccine, various groups are working on improving the immunogen, use of DNA vaccine as prime‐boost strategy, and delivering the zona proteins/peptides presented on either virus‐like particles or entrapped in microsphere. Host‐specific live vectors such as ectromelia virus and cytomegalovirus have also been used to deliver mouse ZP3 in mice. Various studies show the enormous potential of the ZP‐based vaccine for the management of wildlife population, where permanent sterilization may be desirable.