Expression of hepatitis B virus chimeric proteins in prokaryotic and eukaryotic systems

The particulate form of the core antigen of hepatitis B virus (HBcAg), is highly immunogenic. It has been used as a carrier molecule, for expression and presentation of heterologous viral epitopes on the surface of hybrid core particles, in immunogenicity studies. The aim of this project was to produce a hybrid antigen comprising HBcAg and an immunogenic epitope of human cytomegalovirus (HCMV). A direct comparison was made of amino and carboxyl terminal fusions, by investigating the influence of position of the foreign epitope on antigenicity, immunogenicity and hybrid core particle formation. A part of the HCMV genome, encoding a neutralizing glycoprotein epitope gp58, was inserted at the amino terminus or fused to the truncated carboxyl terminus of HBcAg in separate constructs and expressed in a prokaryotic system (E.coli). At the same time, in order to express the same fusion proteins in a eukaryotic system, the baculovirus expression vector system (BEVS) was selected and as an initial control two recombinant baculoviruses, containing genes encoding HBcAg and hepatitis B surface antigen were isolated by dot blot hybridization. It was realized that work in BEVS would require more time than previously expected therefore further work was only carried out on the prokaryotic system. The HBcAg carboxyl terminal fusion (HBC 3 - 1 4 4 -HCMV) was expressed in high yields in E.coli and assembled into core like particles resembling native HBcAg. A similar fusion in the amino terminus of HBcAg (HCMV-HBC1-183) could not be purified or characterized immunologically, although it formed core like particles. HBc3-144-HCMV displayed HBc antigenicity but HCMV antigenicity could not be detected. Following immunization of rabbits with HBC3-144-HCMV, a high level of anti-HBc specific antibody was produced along with HCMV/gp58 specific antibody. The data presented here provide evidence that the HCMV/gp58 region can be used as a candidate immunogen for an HCMV subunit vaccine and that HBcAg can effectively present this foreign epitope joined to its carboxyl terminus, to the immune system

Contact Tracing: A Forgotten Tool?

Contact tracing is done to interrupt the spread or transmission of the causative agent to others who are in close contact with the index case and are vulnerable by not being immune. Public health experts have relied on contact tracing to reduce the spread of infections throughout history. Now the same method is being used for COVID 19. The healthcare systems in developing countries are ill-equipped to respond to pandemics of this kind. Our healthcare facility effectively employed the traditional contact tracing tool that formed the basis of a strong support system for all those employees who contracted Corona virus infection

Disclosure of Human Immunodeficiency Virus Serostatus to the Patient; Issues for Laboratory Staff

Background: The disclosure of positive HIV status to a patient is not an easy task. In the developed world with established protocols for doing this, it becomes relatively simpler to present the results to the patient. In underdeveloped countries like Pakistan, it is not easy for the laboratory personnel in particular to convey such results to the patient.  Case Presentation: The problem has been discussed in the light of two cases presenting to Shalamar Teaching Hospital. The first case is an example of “Provider referral” and the second one the “Self-referral”. At the end, recommendations are made to effectively handle the situation in an underdeveloped setup like Pakistan. Discussion: Complete knowledge of the disease is an essential requirement for anybody from the pathology department contemplating this responsibility. In addition, all communications should be in the local language and the counselor must be able to address all the questions/concerns raised by the patients and/or their families. The counselor learns the skill more through supervised training rather than a taught course.  Conclusion: This responsibility should be accepted only if the laboratory staff has no other option

Update on Pakistan Polio Eradication Initiative

The global polio eradication initiative (GPEI) was established in 1988 as a result of the declaration of commitment by the World Health Assembly. In Pakistan, National Emergency Action Plan [NEAP] coined the strategies under government directives to play a pivotal role in line with international requirements to make poliomyelitis extinct. At the program’s initiation, there were around 350,000 cases of polio reported annually. The incidence has fallen by 99% due to the immunization of more than 2.5 billion children worldwide. Poliovirus has three serotypes; two have already been eradicated (the last case of poliovirus type 2 was reported in 1999 and of poliovirus type 3 in 2012). Poliovirus transmission has ceased with the exception of Pakistan and Afghanistan. In April 2022, two cases of acute flaccid paralysis due to poliovirus type 1 have been reported in KPK province. In this communication, insight is provided regarding the issues that have contributed to this wild poliovirus resurgence after a 15-month gap and the way forward

Making Infection Prevention & Control Smarter and User-friendly

The editorial provides information about an infection prevention and control mobile application and a corresponding website that has been developed by members of infection control committee of a tertiary care hospital. The features of the mobile app are discussed along with information shared in the form of guidelines that cover various aspects of infection control practices relevant for healthcare workers. The app can be used in different clinical settings in hospital areas by anyone who has an android or Apple phone.

Stigmatization and Resources Allocation-Ethical Dilemmas for HIV Positive Intravenous Drug Users

The burden of disease due to Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS) in Pakistan is on the rise. According to an estimate approximately 0.165 million people in Pakistan are infected with HIV and 17,149 person are currently receiving treatment for HIV/AIDS. The prevalence of HIV is 20% for intravenous Drug Users (IVDUs) while national surveillance data shows rate of infection in most major cities in range of 15-50%. In light of such alarming figures, distribution of resources and stigmatization are two ethical issues that gain attention of not only healthcare providers but also patients. Following is a case with discussion on these ethical issues