Serology and Vaccines, Research Paper Example

The article Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: A comparative serological study focuses on the MERS-CoV infection and possible animal reservoirs. Incidences of infections and their causative agents have not so far been determined. Although there are incidences of human-to-human transmission between case patients and care providers or other people close to them, the source of infection for most patients remain unknown. However, the infection was found in patients with severe acute respiratory infection who had been in contact with goats and dromedary camels. Possible animal reservoirs were investigated through the assessment of specific serum antibodies. The presence of antibodies that are reactive with MERS-CoV in camels suggests that camels could be a reservoir. However, there is also a possibility of cross-reactivity between antibodies for MERS-CoV and other closely related viruses in camels. It also remains unclear whether infected camels play a role in the transmission to humans (Memish et al 2013).

The article Identification of a Receptor-Binding Domain in the S Protein of the Novel Human Coronavirus Middle East Respiratory Syndrome Coronavirus as an Essential Target for Vaccine Development investigates the Middle East respiratory syndrome coronavirus that causes a similar illness like the severe acute respiratory syndrome.  Laboratory research by Du et al (2013) showed that the coronavirus binds to the soluble DPP4 protein and dipeptidyl peptidase4-expressing cells, the receptors for the virus, inducing a neutralizing antibody response. The region in which the virus binds is potential for the development of the MERS-CoV vaccine since it contains the receptor-binding domain. The MERS-CoV and the SARS-CoV are genetically related; thus, their S protein sequences were compared. It was discovered that the two had the same core structures, but different secondary structures; thus, they have different receptors. The implications of this study is that the fact that it was found that the MERS-COV S protein has the viral RBD that mediates its binding to DPP4 is major discovery in the development of vaccines to prevent infections (Gierer et al 2013). Further investigation revealed that the MERS-CoV S-RBD-Fc protein induces a strong, neutralizing antibody response that confers protection against MERS-CoV infection in vaccinated animals.

MERS-CoV is different from the other coronaviruses and currently there is no vaccine (Jiang et al 2013).  Most confirmed cases MERS-CoV display symptoms of severe respiratory illness and approximately 36% of the patients have died. Therefore, there are different therapeutic and preventive strategies being applied to the emergent strains because research is still ongoing to develop vaccines.  Inovio Pharmaceuticals Inc reported positive results in preclinical trials of DNA synthetic Vaccine against MERS-CoV (Memish et al 2013). The vaccine is DNA synthetic and works by using DNA of the pathogen to elicit immune response in the host. It delivers foreign genes into the cells of the host to mimic a natural infection. The immune system then responds like it would respond when infected. However, the infected cell is not infected; the virus cannot replicate, is not alive and cannot spread in the host. The Inovio MERS-CoV vaccine candidate is one-step towards development of vaccine although vaccine development is a long process that requires careful testing. This notwithstanding, there are multiple possibilities for development of a vaccine in the future because there is also another group of scientists from Madrid who genetically engineered a weakened strain of MERS-CoV which could be used for creating vaccines (Gierer et al 2013).  Therefore, research is still ongoing and tests are being carried out to develop a vaccine against MERS-CoV.

References

Du, L., Zhao, G., Kou, Z., Ma, C., Sun, S., Poon, V. K., Jiang, S. (2013). Identification of a Receptor-Binding Domain in the S Protein of the Novel Human Coronavirus Middle East Respiratory Syndrome Coronavirus as an Essential Target for Vaccine Development. Journal of Virology, 87(17), 9939-9942. doi: 10.1128/JVI.01048-13

Gierer S, Bertram S, Kaup F, Wrensch F, Heurich A, Kramer-Kuhl A, Welsch K, Winkler M, Meyer B, Drosten C, Dittmer U, von HT, Simmons G, Hofmann H, Pohlmann S. (2013). The spike-protein of the emerging betacoronavirus EMC uses a novel coronavirus receptor for entry, can be activated by TMPRSS2 and is targeted by neutralizing antibodies. J. Virol. 87:5502–5511

Jiang S, Lu L, Du L, Debnath AK. (2013). A predicted receptor-binding and critical neutralizing domain in S protein of the novel human coronavirus HCoV-EMC. J. Infect. 66:464–466

Memish ZA, Zumla AI, Al-Hakeem RF, Al-Rabeeah AA, Stephens GM.( 2013). Family cluster of Middle East respiratory syndrome coronavirus infections. N. Engl. J. Med. 368:2487–2494.

Reusken, C. B., Haagmans, B. L., Müller, M. A., Gutierrez, C., Godeke, G. J., Meyer, B., … & Koopmans, M. P. (2013). Middle East respiratory syndrome coronavirus neutralising serum antibodies in dromedary camels: a comparative serological study. The Lancet infectious diseases, 13(10), 859-866. http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(13)70164-6/fulltext