Summary, Conclusions, and Implications
T. D. Luckey in Radiation Hormesis, 2020
Immune competence was increased by exposures to ionizing radiation. Increased DNA repair capabilities occured in lightly exposed humans and animals; these and other cellular repair systems occur in most active cells. Some cells retained immunologic memory for decades. For example, Japanese survivors of atom bombs showed increased lymphocytic mitogen stimulation after 40 years. The biopositive effects of low doses of ionizing radiation in immunity include increased numbers of circulating lymphocytes, faster wound healing following skin incision, increased resistance to lethal doses of ionizing radiation, and decreased infection and cancer morbidity and mortality. The cumulative effect of increased immune competence was to increase the quality of life and the average lifespan. Increased immune competence and cellular repair systems provided partial explanations for the reduced cancer incidence and mortality found following low doses of ionizing radiation.
Mucosal vaccine strategies
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
Apart from the anatomical differences in the dissemination of SIgA antibody responses induced by orogastric and intranasal immunization, respectively, the kinetics of the responses also appear to be markedly different. Several studies have shown that the intestinal immune response after oral immunization is rapid and relatively short-lasting, but it is associated with long-lasting immunologic memory. Data from field trials have shown that after oral cholera vaccination, protection from the acute intestinal IgA response appears to wane after 6–9 months, while overall protection lasts for several years. It has been proposed that the longer duration of protection reflects the ability of IgA memory B cells to elicit a rapid recall response to a renewed exposure to the pathogen and subsequently the capacity to shut off an infection before it causes disease. In both mice and humans, the kinetics of the antibody-secreting cell recall response to a mucosal challenge is rapid; within days, as documented after oral booster vaccinations in previously cholera-vaccinated subjects. These individuals exhibited strong duodenal-specific SIgA antibody-secreting cell responses, peaking after 1 week and decreasing over a 5-month period. Hence, observations like this are consistent with the notion that immunologic memory following oral mucosal vaccination in humans can last for at least 10 years.
Disease Prediction and Drug Development
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam in Introduction to Computational Health Informatics, 2019
The basis of the immune system is the ability to identify the genes within the human-body and foreign proteins. The invading pathogens (bacteria and virus) are recognized and attacked, and their growth is inhibited. Immune system uses blood circulatory system and lymphatic circulatory system to protect the body against foreign-bodies. The immune system also possesses long-term immunological memory that once triggered can protect a body against the same or similar pathogen for a long time. Vaccines use the memory of the immune system to quickly activate the immune defense in the future against the actual attack by the foreign body that could be bacteria or virus. The immune system uses a complex signaling pathway to tag foreign-bodies that are killed by neutrophils (white blood cells) circulating in the blood. Neutrophils also release more signaling molecules such as chemokines and cytokines that bind to foreign-bodies and attract macrophages and natural killer cells.
A standardized extract of Echinacea purpurea containing higher chicoric acid content enhances immune function in murine macrophages and cyclophosphamide-induced immunosuppression mice
Published in Pharmaceutical Biology, 2023
Heggar Venkataramana Sudeep, Kuluvar Gouthamchandra, Illuri Ramanaiah, Amritha Raj, Puttaswamy Naveen, Kodimule Shyamprasad
The term immunity defines the body’s natural defense system against a massive array of diseases and disorders. Surprisingly complicated and advanced among vertebrates, the complex immune system is capable to produce a boundless variety of cells and molecules to block enormous variety of infections and undesirable elements (Patil et al. 2012; Dutt 2013; Sharma et al. 2017). The strategy of avoiding them all may be extraordinarily tricky or difficult and many of the pathogens have mechanisms that allow them to evade the full effects of host defenses. The innate immune responses are generally rapid and independent of immunological memory unlike the adaptive immunity. Innate immune responses include the cellular mechanisms, for example phagocytosis and cytotoxicity, or secretions (cytokines, complimentary factors, antimicrobial peptides, etc.) (Degn and Thiel 2013; Hilchie et al. 2013; Sokol and Luster 2015). Our knowledge of immune functioning is constantly evolving over the years. There exists a paradigm from emerging evidence that the innate and adaptive immunity have mutually interacted and overlapped at times (Gasteiger et al. 2017). With recent advances in the understanding of how cells communicate with each other to signal effector functions, it has become possible to conceive of strategies to manipulate these signaling pathways to influence host responses (Tzianabos 2000). Compounds that can interact with the immune system to upregulate or downregulate specific aspects of the host response can be classified as immunomodulators or biologic response modifiers.
The prevalence of adaptive immunity to COVID-19 and reinfection after recovery – a comprehensive systematic review and meta-analysis
Published in Pathogens and Global Health, 2022
Tawanda Chivese, Joshua T. Matizanadzo, Omran A. H. Musa, George Hindy, Luis Furuya-Kanamori, Nazmul Islam, Rafal Al-Shebly, Rana Shalaby, Mohammad Habibullah, Talal A. Al-Marwani, Rizeq F. Hourani, Ahmed D. Nawaz, Mohammad Z. Haider, Mohamed M. Emara, Farhan Cyprian, Suhail A. R. Doi
This synthesis suggests, for a period of at least 6–8 months after recovery, around 90% of individuals have evidence of SARS-CoV-2 specific memory B and memory CD4+ cells while about half have evidence of CD8+ cells. While the role of T cells in sterilizing immunity is thought to be limited, they are highly associated with ensuring less severe COVID-19 [73,111]. A diminished prevalence of cytotoxic CD8+ cells may imply that viral clearance is delayed in some individuals, in the event of reinfection. However, there is evidence of sustained high prevalence of T follicular helper cells (TFH) [9], a subset of CD4 + T cells that are the most important in helping memory B cells and in the production of neutralizing antibodies and long-term humoral immunity [99]. A high prevalence of memory B cells at ≥6 months also suggests that immunological memory may be long lasting, at least to the time points measured in the included studies.
The current and future role of nanovaccines in HIV-1 vaccine development
Published in Expert Review of Vaccines, 2021
Christopher P. Karch, Gary R. Matyas
HIV-1 has remained a global pandemic since the 1980s. Despite the successes that have occurred with anti-retroviral therapies, it is unlikely that the virus will be eliminated from the population without an efficacious vaccine [1]. The vaccine development process has been ongoing for almost as long as the pandemic has existed; however, the basic biology of the virus has consistently hampered vaccine development [2]. At the most basic level, HIV-1 is a highly diverse retrovirus that has an error prone reverse transcriptase, which leads to high levels of viral diversity [3]. In addition, HIV-1 DNA can be integrated into the genome of infected cells. Furthermore, there is not a complete understanding of the immune responses necessary to prevent an infection [1]. Moreover, HIV-1 infects CD4+ cells, key components of the immune system, further hampering the immune response [4,5]. Classically, vaccines induce immunological memory, which becomes activated during the early stages of infection and results in a rapid clearing of the infection. The high viral diversity and the ability to of the HIV-1 DNA to be integrated into the genome make a broadly efficacious vaccine a difficult target to obtain.
Related Knowledge Centers
- Adaptive Immune System
- Antibody
- Memory B Cell
- Memory T Cell
- Vaccination
- Immune System
- Antigen
- Immune Response
- T-Cell Receptor
- Pathogen-Associated Molecular Pattern