Gazdasejtek

Gazdasejtek, or host cells, are the cells that pathogens exploit to reproduce and complete their life cycles. In virology, a host cell is any cell that a virus infects and uses to replicate, assemble viral components, and release new virions. Host cells can be prokaryotic or eukaryotic, with bacteriophages infecting bacterial cells and animal, plant, or fungal viruses infecting their respective hosts.

Entry and replication depend on host factors. The virus must attach to specific receptors on the cell surface and enter the cell; once inside, it co-opts the cell’s transcription and translation machinery, nucleotide pools, and membranes to produce viral proteins and genomes. The replication site and strategy vary by virus: some replicate in the cytoplasm, others in the nucleus; some integrate into the host genome.

Host range and tissue tropism determine which cells can be used by a particular pathogen. This depends on receptor availability, intracellular environment, and immune defenses. Permissive or non-permissive status influences productive infection versus abortive attempts.

Applications and examples: bacteriophages use bacterial host cells; influenza and coronaviruses target respiratory epithelial cells in humans; HIV targets CD4+ cells; plant viruses infect plant cells. In research and medicine, specific host cells or cell lines are used to propagate viruses, study pathogenesis, and produce vaccines or vectors. Common mammalian lines include HeLa, HEK293, and Vero; plant and insect cell cultures serve other systems.

Host cells also mount defenses such as innate immune responses and programmed cell death. Viruses counter these defenses to establish infection.