Microbiology and Immunology
Please read textbook or other literatures to write a mini-review paper (at least one page for each
question) to address below questions. When you cite literature in your paper, please put the cited
reference into your paper. (10 points for each question)
1. The development of primary and secondary immune responses to an antigen differs
significantly. The primary response may take a week or more to develop fully and
establish memory. The secondary response is rapid and relies on the activation of clones
of memory cells. Would it not be better if clones of reactive cells were maintained
regardless of prior exposure? In this way, the body could always respond rapidly to any
antigen exposure. Would there be any disadvantages to this approach? Why?
2. Jack and Jill were badly burned in an accident at the well and both were taken to the burn
unit of the local hospital. The burns covered only a small area of skin so grafts were
prepared for both patients from the skin of Jack’s thigh. Jack’s graft was successful and
his burn healed completely. Jill, however, rejected the grafted skin. Explain the immune
responses of both patients to these grafts. What treatments could have helped Jill to avoid
rejection of her graft?
Questions 3 and 4:
Please read textbook or other literatures to write a mini-review paper (at least two pages for each
question) to address below questions. When you cite literature in your paper, please put the cited
reference into your paper. (15 points for each question)
3. The 2018 Nobel Prize in Physiology or Medicine is awarded to James P. Allison and
Tasuku Honjo for their discovery of cancer therapy by inhibition of negative immune
regulation. Please search the information from internet or literature and write a summary
for each scientist’s major discovery for them to receive the Nobel Prize on medicine in
2018. How did their discovery contribute to cancer treatment?
4. What is coronavirus disease 2019 (COVID-19)? How does COVID-19 spread and how
can we prevent COVID-19? Please design both molecular and immunological approaches
to detect COVID-19.
Course Name & Number:
Professor’s Name:
Paper due date:
Qn 1. Advantages/Disadvantage(s) of maintaining reactive cell clones despite prior exposure
The clonal section in immunology seeks to expound on how the T-cells or B-cells that recognize antigens that enter the body are selected from the pool of pre-existing cells consisting of varied antigens and are reproduced to generate clones of cells that will be used to eventually eliminate the antigens (Burnet, 2018).
When one suffers an infection, the T-cells and B-cells are activated. Long-term active memory is acquired since the cells automatically undergo clonal selection, increasing their affinity to bind with antigens. It makes it easy for the immune system to eliminate any pathogens if a re-infection occurs even before the disease's symptoms become apparent (Burnet, 2018).
Clonal selection is the mechanism behind the effectiveness of vaccines, which generate artificial immunity known as immunization. In vaccinations, a pathogenic antigen is introduced into the body to stimulate the immune system to respond by developing immunity against the specific pathogen. Vaccines also do not cause the disease as they introduce attenuated pathogens with the inability to replicate. That is the most significant advantage of clonal selection.
The only disadvantage of clonal selection is that there is no cell cloning of all the millions of pathogens that exist. Even those who have undergone prior cloning may keep mutating, thereby changing the structure of their antigens (Moticka, 2015).
Qn 2. Treatments that could have helped Jill to avoid rejection of her graft
In Jack and Jill's case, there was an autologous and allogeneic skin grafting procedure, respectively. It was easy for Jack's skin graft to be successful as the skin on his thigh was the same one used in grafting the area afflicted by the severe burn. In Jack's case, the skin transplant involved transferring his tissues, whose recognition of self-components would rarely invoke an immune response.
However, there was an allogeneic skin graft in Jill's case as Jack’s skin was grafted onto her burned area. There is always a potential for an immune response that inflames and destroys the donor cells, subsequently leading to skin graft rejection. The mechanism of this rejection is explained by the fact that the donor skin's dendritic cells (DCs) are transferred from the graft via the lymphatic vessels infiltrating the recipient’s lymph nodes where they present the donor antigens through the direct pathway and the indirect pathway (Pinto,2017).
The direct pathway is where the T-cells recognize undamaged Major Histocompatibility Complex (MHC) antigens on the donor's dendritic cells. In contrast, the indirect path involves the T-cells recognizing the donor peptides that are bound to their own MHC molecules on the recipient’s dendritic cells. This stimulation of T-cells through direct and indirect pathways is enough to trigger severe rejection of allogeneic skin grafts (Pinto,2017). Studies have also shown that allospecific antibodies result in the rejection of skin grafts by the opsonization of donor cells and the formation of immune multiplexes or by simply killing the allogeneic targets (Kovalev, 2017).
Furthermore, Jill may have rejected the skin graft owing to the activation of her Natural Killer (NK) cells due to the missing self-MHC class I molecules on the donor skin cells resulting in the killing of the allogeneic cells by the production of cytokines such as TNF-α and IFN-γ that support inflammation.
The best treatment approach for Jill would have been the autologous skin grafting since, according to the text, the burns only covered a small area of her skin. It would have been easier for her body to accept the skin graft since it would have come from her own body. Otherwise, there would have been a need to administer immunosuppressive medication to reduce the chances of early rejection of Jack's skin graft (Pinto,2017). Also, Jack's skin graft would only be a short-term solution as her body would still have higher chances of eventually rejecting it.
Qn 3. Contribution of James P. Allison and Tasuku Honjo’s discovery to cancer treatment
In 2018, immunologists James Patrick Anderson and Tasuku Honjo were jointly awarded the coveted Nobel Peace Prize in Physiology or Medicine to research and discover cancer therapy by preventing negative immune regulation.
James P. Allison's recognition stemmed from long years of research on the T-cell (a significant element of the adaptive immune system vital in; regulating immune responses by killing cells that host infection, production of cytokines and stimulation of other immune cells). His molecular immunolo...