EMBRYONIC STEM CELLS: AN PROMINENT FATE OF HIV VACCINE Harshita Tiwari1, Ashutosh Paliwal1 and Akansha Adhikari2 1.Department of Biotechnology Bhimtal Campus, Bhimtal (Kumaun university Nainital, Uttarakhand) 2. Department of Zoology , P.N.G College (Kumaun university Nainital, Uttarakhand)
Overview ➢
Applications
It is estimated that approximately 8% of Human DNA comprises endogenous retrovirus sequences that presents in either silent or repressive form, and these sequences have many significant roles in the development of embryogenesis, also in the pluripotent nature of embryonic stem cells.
1. To develop HIV vaccine : The silenced proviral sequence in embryonic stem cellls act as antigenic sequence which evoke immune response when introduced into human body.
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Embryonic stem cells repress or silent this sequence by regulatory sequences present in it, which modifies the viral genome at the pro-viral stage at the long terminal region and inhibits the viral transcription.
Humoral Immunity
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This unique property of embryonic stem cells could contribute in the concept of an anti-HIV vaccine development.
Cellular Immunity
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Embryonic stem cells could silence or supress the HIV which further can transfer to somatic cells during differentiation and act as antigenic sequence and produce immunity in the host body.
Pro-viral sequences pass on somatic cells during differentiation
Concept
Step 1
2. To Study the significance of HIV when it becomes endogenous retrovirus as like other Human Endogeneous Reteroviruses
Infection Embryonic stem cells HIV virus
Germ cell
Integrated viral DNA
Step 2
Next generation
Integration
Path ahead
Step 3 LTR
Future prospects ✓To study the immunization with embryonic stem cells which could lead any type of graft rejection however there is less chances of the negative impact of immune response . ✓ This concept could also used against the treatment of other reteroviral diseases including human T leukemia virus.
Post transcriptional Silencing modifications
LTR No transcription
Step 4 Division
Silenced proviral sequences References 1. 2. 3. 4.
Schlesinger, S. et al. (2015). Retroviral transcriptional regulation and embryonic stem cells: war and peace. Molecular and cellular biology, 35(5), 770-777. Satapathy, S. (2016). Provirus Silencing in Stem Cells: The Forbidden Regulators of Cell Fate. Signal Transduction Insights. Yang, B. X. et al. (2015). Systematic identification of factors for provirus silencing in embryonic stem cells. Cell, 163(1), 230-245. Ouyang, X. et al. (2019). Induced Pluripotent Stem Cell-Based Cancer Vaccine. Frontiers in
10. Drukker, M. et al. (2006). Human embryonic stem cells and their differentiated derivatives are less susceptible to immune rejection than adult cells. Stem cells, 24(2), 221-229.