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The Immunological System and Neoplasia
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
In the previous section, the basic concepts regarding tumor cell development were discussed. In this section, the importance of the immune system for the elimination of these cells will be discussed. The notion that the immune system is able to recognize and destroy continuously arising tumor cells was first proposed by Ehrlich and later eloquently formulated by Burnet (1970) as follows: “The ′ thymus-dependent′ immune system arose from the evolutionary need to counter the development of malignant disease. Wandering cells ancestral to lymphocytes developed the capacity to recognize anomaly (′not-self) on another cell surface and to react destructively on such recognition. “ As soon as this immunosurveillance hypothesis was formulated, it was questioned by several investigators because many observations failed to support this hypothesis. For example, nude or athymic mice and rats, as well as mice and rats thymec-tomized at birth, do not have an increased susceptibility to chemically induced or “spontaneous” tumors, although they tend to develop tumors of the lymphoreticular system more frequently than intact mice.
Phagocytic cells and their functions
Published in Gabriel Virella, Medical Immunology, 2019
Gabriel Virella, John W. Sleasman
Neutrophils and other polymorphonuclear (PMN) leukocytes are “wandering” cells, constantly circulating around the vascular network, able to recognize foreign matter by a wide variety of immunological and nonimmunological mechanisms. Their main biological characteristics are summarized in Table 13.1. Their effective participation in an anti-infectious response depends on the ability to respond to chemotactic signals, ingest the pathogenic agent, and kill the ingested microbes.
Bacteriology in Relation to Immunity And To Diagnosis
Published in Sir Arthur Newsholme, The Story of Modern Preventive Medicine, 2015
In 1884 Metschnikoff (1845—1916) observed that in water fleas the wandering cells of the body surrounded and gradually absorbed into their substance particles of pigment or yeast cells swallowed by the flea. On these and similar experiments he based his theory of phagocytosis, as responsible for securing immunity against infection. It soon became evident that, while body cells were active in the production of immunity, other factors were involved, and much controversy arose between those who regarded the cells of the body and those who thought that the blood serum was responsible for immunity. Later on some reconciliation between the two views became possible, when the discoveries of Denys, Wright and others showed that certain substances in the blood serum prepare invading microorganisms for phagocytosis by the leucocytes.
Hyalocyte functions and immunology
Published in Expert Review of Ophthalmology, 2022
Stefaniya K Boneva, Julian Wolf, Peter Wieghofer, J Sebag, Clemens AK Lange
Already in the 19th century Iwanoff (1865) and Potiechin (1879) postulated that hyalocytes are able to move in an ameboid manner. Consequently, Schwalbe classified hyalocytes in the group of the wandering cells (‘Wanderzellen’), a term, which at that time referred to circulating and migrating macrophages and lymphocytes [38]. Recently, Toco Chui and Rich Rosen identified movement of human hyalocytes with OCT imaging [5] and subsequently employed AOSLO [7] to image and map the movement of hyalocytes in situ (see article 1 in this series of expert reviews on hyalocytes for video display of these features [2]). They elegantly examined key characteristics of macrophage-like cells above the inner limiting membrane (ILM), which are likely to be hyalocytes, in healthy and diseased (see article 3 in this series [3]) human eyes. This was possible in part because these cells can be visualized directly due to their location anterior to the ILM. They found that human hyalocytes are distributed distinctively, age differently, and have clear dynamic characteristics. As such, hyalocytes constantly explore their local environment by extending and retracting their projections within a timeframe of a few minutes, which is consistent with the hypotheses of Iwanoff and Potiechin from years ago [5].