Vidisha Minhas is a PhD student at Delhi University. For the past five years, she has been working towards the production of recombinant proteins that has a role in fertilization. She is well versed with techniques like cloning, protein expression and purification, ELISA, indirect immunofluorescence, western blotting, etc. Along with her lab mates, she has cloned around 10 recombinant proteins and tested their immunogenicity and contraceptive efficacy in mice. Some of them have shown promising results and can be considered as potential candidates for development of contraceptive vaccine (CV) for managing wildlife population. She is also working on enhancing the efficacy of antigens by the use of immune potentiator and optimization of antigen delivery system.
Statement of the Problem: Immunocontraception for wildlife management is taking on a new perspective, and many agencies charged with such management decisions are turning to fertility control as a potential humane solution. Contraceptive vaccines based on spermatozoa specific proteins aiming to interfere in sperm-egg interactions have been proposed as one of the strategies for controlling the population of various animal species. Various studies have established that spermatozoa are foreign to immune system of an animal, thus elicits a strong anti-sperm immune response. However, no sperm protein-based contraceptive vaccine has reached field application. In this direction, we have cloned, expressed and purified recombinant protein, bRNase-KK-Sp17C-KK-TT-GnRH-GnRH (Sp17C-GnRH2) and evaluated its immunogenicity and contraceptive efficacy using different adjuvants. Methodology & Theoretical Orientation: Recombinant protein, bRNase-KK-Sp17C-KK-TT-GnRH-GnRH was cloned and expressed in BL21 [DE3] pLysS E. coli cells. The recombinant protein was purified using Ni-NTA affinity chromatography. FVB/J mice were immunized with different combinations of adjuvants and sera were collected to evaluate the antibody titer. After immunization, female mice were put for mating with male mice and pups born per pregnant female were monitored carefully. Results & Conclusion: Immunization of both male and female mice with Sp17C-GnRH2 following three injection schedules, led to high contraceptive efficacy. Interestingly, mating studies of female mice with the male mice wherein both were immunized with Sp17C-GnRH2 revealed complete failure of female mice to conceive. Male mice immunized with Sp17C-GnRH2 led to testicular atrophy and a significant decrease in the diameter and circumference of seminiferous tubules. Further, to reduce the no. of injections, when group of female FVB/J mice were immunized with Sp17C-GnRH2 and Squalene:Arlacel ‘A’ as an adjuvant, there was approximately 90% infertility. Inclusion of killed Mycobacterium indicus pranii in another group of female mice did not make much of a difference in case of immunogenicity. Although, there was also a significant increase in the immune response when female mice were immunized with the same antigen but along with a mixture of PCPP and alum as compared to the group immunized with only antigen and alum following a two injection schedule, but there was no significant increase in the contraceptive efficacy.
Chuan Wang has a strong interest in Tumor Immunology and Cancer Vaccines Development. He has completed his PhD in Cancer Immunology at University of Southampton in 2014. During his PhD, he was working on developing of a novel platform to induce T-cell responses against cancer, which was based on plant viral nanoparticles (PVP). He has identified several HLA-A2+ epitopes derived from novel cancer antigens. He is now working with Dr. Natalia Savelyeva and Prof. Gareth Thomas on development of novel vaccines for HPV negative head and neck cancer.
DNA vaccines represent an attractive and potentially an effective modality to induce immunity against cancer. Recently a linear DNA with closed ends, the so-called doggybone DNA (dbDNATM), has been developed without the use of bacteria. The manufacturing relies on use of Phi29 DNA polymerase to amplify a plasmid template followed by protelomerase TelN to complete individual closed linear DNA. The final DNA product composes of the sequences encoding an antigen of interest, a promoter and a poly A tail, but lacks ‘useless’ bacterial sequences such as antibiotic resistance genes. We compared the ability of dbDNATM vaccine with plasmid DNA vaccine with and without in vivo electroporation to induce adaptive immunity using clinically relevant onco-targets HPV16 E6 and E7. Despite the inability to trigger TLR9, dbDNATM induced similar levels of Th1 CD4 and CD8 T cells as well as antibody immunity against the target antigens, with suppression of established TC-1 tumors. We demonstrated that dbDNATM was able to activate innate immunity via STING, with induction of Th1-inducing cytokines and type I interferons. Collectively, dbDNATM is a highly attractive novel DNA vaccine platform to induce anti-cancer immunity.