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Specific Host Restance: The Effector Mechanisms
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Natural killer cells kill a variety of pathological cells Including host cells that have been infected with viruses, cells in allografts, and some cancer cells, especially leukemic cells. They are also capable of destroying some fungi and protozoa. Natural killer cells kill without prior sensitization. Thus, natural killer cell activity may be considered a component of constitutive immunity. Natural killer cells also have receptors for the Fc portion of IgG and can therefore be mobilized as effector cells by antibody through the antibody-dependent cell-mediated cytotoxicity (ADCC) mechanism. In this latter respect they may be considered effectors for the inducible immune system.
Physical Activity and the Prevention and Treatment of Cancer
Published in James M. Rippe, Increasing Physical Activity, 2020
Physical activity can also serve as a valuable tool during rehabilitation and chronic disease management for cancer patients. In one analysis of 26 prospective cohort studies of breast, colorectal, and prostate cancer, a 37% pooled risk reduction of cancer-specific mortality was demonstrated when comparing most-active to least-active patients (24). Importantly, regular physical activity, when compared to other lifestyle factors such as smoking, diet, and alcohol intake, has been shown to have the strongest effect in attenuating the risk of breast cancer recurrence and reducing mortality. Physical activity has been shown to help patients increase longevity and quality of life (25). There are multiple, postulated mechanisms for the physical activity-mediated benefits in tertiary cancers. Regulation of inflammation and natural killer cell function may play a role.
Chronic Exercise and Immunity
Published in James M. Rippe, Lifestyle Medicine, 2019
Melissa M. Markofski, Paul M. Coen, Michael G. Flynn
Natural killer cells are cytotoxic lymphocytes and a major constituent of the innate immune system. They protect against certain tumors and virally infected cells by releasing granules containing proteases and porins that induce apoptosis in the target cell. Yan et al. reported that the proportion of NK cells (CD16+CD56+) in isolated peripheral blood mononuclear cells was higher in older subjects who exercised regularly than those who did not,26 but the NK activity against K562 target cells was not different between these subject groups. Further, there were no differences in either NK cell number or activity between exercisers and non-exercisers in the young and middle-aged groups. In another study, there were no differences in the expression of NKG2D or NKG2A receptors, but young athletes had a greater NK cell activation and degranulation in response to cells from the K562 and .221 cell lines, though not .221-AEH, when compared with young non-athletes.27
Emerging monoclonal antibody therapies in the treatment of metastatic urothelial carcinoma
Published in Expert Opinion on Emerging Drugs, 2023
Rohit K Jain, Avani M Singh, Xuefeng Wang, José A. Guevara-Patiño, Guru Sonpavde
Natural killer cells (NK) are part of the innate immune system which act as a defense system regulated by both inhibitory and activating cell signals. They play an important role in the body’s natural defenses against cancer and have become a growing target in cancer research. Killer-cell immunoglobulin-like receptors (KIR) are NK-cell surface receptors which when ligands bind, act as a checkpoint for NK-cell activation [71]. Human leukocyte antigen-C (HLA-C) molecules are the primary ligands for KIRs and are expressed on normal cells to be recognized as ‘self.’ Some cancer cells are able to express aberrant HLA class-I molecules evading activation of NK-cells [72]. Therapeutically blocking these receptors, and disabling the checkpoint can ultimately lead to enhanced anti-tumor effects of NK-cells [73].
Recalcitrant Herpes Zoster Ophthalmicus in a Patient Discovered to Have Underlying Functional Natural Killer Cell Deficiency
Published in Ocular Immunology and Inflammation, 2022
Brent J. Deibert, Kurtis C. Johnson, Luke W. Desilet, Andrew C. Rorie
Natural killer cells are a vital part of the innate immune response. These cells are especially important in the body’s protection from viral infections. Varicella zoster virus (VZV) is essentially ubiquitous in the aging population. In those who experienced a childhood infection with VZV, known as chicken pox, the virus typically reactivates as the immune system wanes with age and is unable to keep the dormant virus contained. The re-activation of this virus causes the disease shingles, which presents as painful, dermatomal, vesicular lesion. This disease can affect almost every part of the body and is especially problematic when the eye is affected. In cases of immunodeficiency the course of the disease can be altered regarding age of onset or re-occurrence of the disease. Despite appropriate response from the adaptive immune system, deficiencies in cells of the innate response that preform viral surveillance can have a large impact on the disease course that would normally be self-limited.
Hemophagocytic lymphohistiocytosis due to pembrolizumab therapy for adenocarcinoma of the lung
Published in Baylor University Medical Center Proceedings, 2021
James J. Doyle, James A. Hall, Kelsey Reely, Jyothi Dodlapati
The patient became pancytopenic, with platelets reaching a nadir just under 100,000/µL. Vitamin B12 was near low, and he was started on supplementation but remained transfusion dependent. Peripheral smear was unremarkable for hemolysis, though low-density lipoprotein was elevated and haptoglobin was low. His reticulocyte count was depressed, and human immunodeficiency virus, hepatitis panel, parvovirus, cytomegalovirus, and Epstein-Barr virus serologies were negative for an acute infection. Direct antiglobulin testing was negative for an autoimmune source, ferritin peaked at 1303 ng/mL, and triglycerides were 288 mg/dL. He was on chronic warfarin therapy for an atrial arrhythmia, but this was held due to the ongoing anemia. Bone marrow biopsy had variable cellularity without hemophagocytosis. Levels of soluble IL-2 receptor (CD25) and hemoglobin-haptoglobin receptor (CD163) were elevated at 2721 pg/mL and 2425 pg/mL, respectively. Natural killer cell function was normal.