T cell specificity and Cross-reactivity – Implications in Physiology and Pathology

T cell specificity and Cross-reactivity – Implications in Physiology and Pathology
Author: Samuele Notarbartolo
Publisher: Frontiers Media SA
Total Pages: 141
Release: 2024-03-07
Genre: Medical
ISBN: 2832545734

Conventional CD8+ and CD4+ T cells recognize antigens, presented by antigen-presenting cells in the form of short peptides loaded onto major histocompatibility complex (MHC) class I and class II molecules, through their T cell receptor (TCR). Somatic gene rearrangement of the TCR locus and randomization of TCR hyper-variable regions generate the marked diversity of TCRs. Once assembled, the heterodimeric TCR confers specificity to naïve T cells. The naïve T cell repertoire of an individual is established by selection processes in the thymus and cannot be broadened upon antigen recognition by additional somatic mutations. In humans, the estimated number of distinct TCRs in the naïve T cell pool is several orders of magnitude lower than the possible array of peptides that can be generated and accommodated into an MHC molecule. This challenge can be overcome by T cell cross-reactivity, that is the ability of a single TCR to bind multiple peptide-MHC complexes. T-cell cross-reactivity can have both positive and negative consequences. First, it allows for covering a wide range of foreign peptides with a limited repertoire of T cells. Second, it facilitates polyclonal immune responses to a single peptide and increases resistance to escape mutations. Third, it can induce heterologous immunity, that is the generation of memory to a pathogen different from the one against which the immune response has been originally raised. On the contrary, a negative consequence of T-cell cross-reactivity is the possibility of self-antigen recognition, potentially causing autoimmunity. The lower activation threshold of memory T-cells compared to naïve T-cells increases this risk, partially eluding the thymic negative selection checkpoint. Moreover, heterologous immunity can be detrimental when the type of memory T-cell polarization induced by the first pathogen is inappropriate to control the second pathogen.

Live Forever or Die Trying

Live Forever or Die Trying
Author: Thomas J. Mooney
Publisher: Xlibris Corporation
Total Pages: 203
Release: 2011-04-05
Genre: History
ISBN: 1456856456

Initially, I had intended to write this book in the summer of 2006. At that time, my involvement in the Life Extension Movement was growing, my enthusiasm was palpable; trusted friends and colleagues urged me to undertake the project, noting that it would give momentum to a nascent movement that was a mere blip on the political radar screen and bring needed attention to an issue that many thought might never be discussed seriously in a society that considers death an unpleasant but inevitable reality. Even though I agreed with this analysis, I managed to avoid any serious attempt to start a far-reaching debate on the political, social, and economic consequences of radically extending one’s life into the future. After all, I thought, the technology in this field is still at a nascent stage, antiaging research receives few government grants, controversy abounds in the scientific community as to the mere possibility of indefinite life extension; most elected officials are clueless about it and even a majority of the President’s Council on Bioethics is hostile to the idea. But that being said, I never was one to back down from a good fight. I had read much of the scientific work undertaken by a multitude of scientists determined to understand how and why human beings slowly age, and how we can reverse our demise and extend our lives indefinitely. I disagreed with the naysayers who pompously declare that prolonging life will ruin the environment, cause overpopulation, promote wars over scarce resources, as well as those narrow-minded, quasi—pundits who embraced a number of bogus charges and half-truths intended to impede further research into the causes of the terminal disease of aging. I had more than enough evidence to confront the critics, but for some unknown reason, I lost the internal primal spark necessary to fight back. I thought, should I enter a battle that few know about and even fewer care? Instead of hearing a clarion call to act, I became mired in skepticism, doubt and a growing resignation toward terminal apathy. ...

Aging

Aging
Author: Harry R. Moody
Publisher: Pine Forge Press
Total Pages: 508
Release: 2006-01-13
Genre: Psychology
ISBN: 9781412915205

Welcome to the world's most unique and dynamic textbook on aging!Widely praised and adopted in previous editions, the Fifth Edition of Aging once again presents key issues in an engaging and accessible fashion. Organized unlike any other traditional textbook, author Harry R. Moody presents basic concepts followed by controversies, supported by carefully chosen adapted readings. The result is the most captivating introduction to gerontology available today.

Alive and Fixable

Alive and Fixable
Author: Francie Low
Publisher:
Total Pages: 278
Release: 2018-12-13
Genre: Biography & Autobiography
ISBN: 9780998027210

An inspiring memoir about a tragic cycling accident that left Tony fighting for his life and on an arduous journey of recovery. Tearful and funny, the story is told through the eyes of Francie, his wife, who nursed him back to health so he could ride again. Angels from the community surrounded the family with love through casseroles and cookies.

Because To Die, You Have To Be Alive

Because To Die, You Have To Be Alive
Author: Magali Dubreuil Bourguet
Publisher: Babelcube Inc.
Total Pages: 358
Release: 2021-11-19
Genre: Self-Help
ISBN: 1667419587

Warning: this is a book with such positive energy that it is dangerously contagious! Come aboard Miss Rainbow with Oceane and Gaia for a journey beyond all limiting borders whether they are physical or psychological. This is a feel good novel, full of optimism, hope, and positivity, a breath of fresh air (to quote the hundreds of comments already received from readers in France). A story that will allow you to not only travel through many countries but also within you on a journey of self-discovery through philosophical questions mixed in with a modern story in a style that is smooth, simple, honest and full of humor. It is the story of the friendship between two women who take off and stand the test of time in an unconventional adventure. Oceane hits her forties and finds out that she only has about eight months to live and meets Gaia. They both leave aboard Miss Rainbow on a humanitarian and spiritual journey from Toulouse to Kathmandu which will transform their lives as well as the lives of everyone they meet along the way and maybe yours...

Journal ...

Journal ...
Author: Canada. Parliament. House of Commons
Publisher:
Total Pages: 514
Release: 1922
Genre:
ISBN:

Just A Reminder

Just A Reminder
Author: Divine D.
Publisher: FriesenPress
Total Pages: 263
Release: 2020-09-22
Genre: Self-Help
ISBN: 1525551612

“Being a teenage girl is hard in today’s society.” This is the message Divine D. has heard from her students. One student told Divine, “If only there was a book on how to be a teenage, it would make my life easier!” So Divine decided to do just that for her students. By using her twenty years in the field of education, personal life experiences and wealth of knowledge that came from her 46 years on this earth, she wrote 40 Things Every Teenage Girl Needs to Know Before She Becomes an Adult. This book is a wonderful gift for any teenage girl. It has a very positive message that would benefit teenagers going through difficulties or just needing a little reminder of how wonderful they are. Divine uses her expertise as a Catholic school administrator, to bring a Christian twist to all of life’s adventures and bumps in the road. Each chapter ends with a song recommendation message to listen to. One of Divine’s students named the book, Just a Reminder, because all girls need a reminder of how wonderfully awesome they have been made even in times when they forget. In the hopes of improving girls mental health, this is a joyful, happy and positive book sharing delightful and inspiring stories of life in the hopes of making girls lives easier. Believe in yourselves, Girls! With sections including: Mental Health and Well-Being, Body Image and Self-Esteem, Building Foundational Skills for Your Future, Taboo Topics and Getting Help, and Finding Joy in Your Daily Life, teenage girls will be inspired to go out and live their dreams.