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The first demonstration of phagocytosis as a property of leukocytes, the immune cells, was from the German zoologist Ernst Haeckel. [14] [15] In 1846, English physician Thomas Wharton Jones had discovered that a group of leucocytes, which he called "granule-cell" (later renamed and identified as eosinophil [16]), could change shape, the phenomenon later called amoeboid movement.
The history of coronaviruses is an account of the discovery of the diseases caused by coronaviruses and the diseases they cause. It starts with the first report of a new type of upper-respiratory tract disease among chickens in the U.S. state of North Dakota, in 1931. The causative agent was identified as a virus in 1933.
Spike (S) glycoprotein (sometimes also called spike protein, [2] formerly known as E2 [3]) is the largest of the four major structural proteins found in coronaviruses. [4] The spike protein assembles into trimers that form large structures, called spikes or peplomers, [3] that project from the surface of the virion.
Engulfment of material is facilitated by the actin-myosin contractile system. The phagosome is the organelle formed by phagocytosis of material. It then moves toward the centrosome of the phagocyte and is fused with lysosomes, forming a phagolysosome and leading to degradation. Progressively, the phagolysosome is acidified, activating ...
For this reason the spike protein has been the focus of development for COVID-19 vaccines in response to the COVID-19 pandemic caused by the virus SARS-CoV-2. [11] [12] A subgenus of the betacoronaviruses, known as embecoviruses (not including SARS-like coronaviruses), have an additional shorter surface protein known as hemagglutinin esterase. [13]
Nidoviruses vary widely in genome size, from arteriviruses with typically 12-15kb genomes to coronaviruses at 27-32kb. Their evolutionary history has been of research interest in understanding the replication of very large RNA genomes despite the relatively low-fidelity replication mechanism of the viral RNA-dependent RNA polymerase (RdRp). [4]
Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria.
A COVID-19 vaccine is intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 . Prior to the COVID-19 pandemic, an established body of knowledge existed about the structure and function of coronaviruses causing diseases like severe acute ...