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Timelapse movie showing the fungus Cryptococcus neoformans (shown in green in the first frame) being expelled from a chicken macrophage via non-lytic expulsion or vomocytosis.

Vomocytosis (sometimes called non-lytic explusion) is the cellular process by which live organisms that have previously been engulfed by a white blood cell are expelled without being destroyed. Vomocytosis was first reported in 2006[1][2] by two groups, working simultaneously in the UK and the USA, based on time-lapse microscopy footage characterising the interaction between macrophages and the human fungal pathogen Cryptococcus neoformans. Subsequently, this process has also been seen with other fungal pathogens such as Candida albicans[3] and Candida krusei.[4] It has also been speculated[5] that the process may be related to the expulsion of bacterial pathogens such as Mycobacterium marinum[6] from host cells. Vomocytosis has been observed in phagocytic cells from mice, humans and birds,[7] as well as being directly observed in zebrafish[8] and indirectly detected (via flow cytometry) in mice.[9] Amoebae exhibit a similar process to vomocytosis whereby phagosomal material that cannot be digested is exocytosed. Cryptococci are exocytosed from amoebae via this mechanism but inhibition of the constitutive pathway demonstrated that cryptococci could also be expelled via vomocytosis[10].

The mechanism of vomocytosis remains unclear although it is known to be influenced by inflammatory signals[11] and rearrangements of the actin cytoskeleton[12] within the host cell. Different morphologies[13] of vomocytosis have been documented and it is possible that the underlying cellular mechanism may vary between them.


  1. ^ Ma, H; Croudace, JE; Lammas, DA; May, RC (7 November 2006). "Expulsion of live pathogenic yeast by macrophages". Current Biology. 16 (21): 2156–60. doi:10.1016/j.cub.2006.09.032. PMID 17084701.
  2. ^ Alvarez, M; Casadevall, A (7 November 2006). "Phagosome extrusion and host-cell survival after Cryptococcus neoformans phagocytosis by macrophages". Current Biology. 16 (21): 2161–5. doi:10.1016/j.cub.2006.09.061. PMID 17084702.
  3. ^ Bain, JM; Lewis, LE; Okai, B; Quinn, J; Gow, NA; Erwig, LP (September 2012). "Non-lytic expulsion/exocytosis of Candida albicans from macrophages". Fungal Genetics and Biology. 49 (9): 677–8. doi:10.1016/j.fgb.2012.01.008. PMC 3430864. PMID 22326419.
  4. ^ García-Rodas, R; González-Camacho, F; Rodríguez-Tudela, JL; Cuenca-Estrella, M; Zaragoza, O (June 2011). "The interaction between Candida krusei and murine macrophages results in multiple outcomes, including intracellular survival and escape from killing". Infection and Immunity. 79 (6): 2136–44. doi:10.1128/iai.00044-11. PMC 3125833. PMID 21422181.
  5. ^ Johnston, SA; May, RC (March 2013). "Cryptococcus interactions with macrophages: evasion and manipulation of the phagosome by a fungal pathogen". Cellular Microbiology. 15 (3): 403–11. doi:10.1111/cmi.12067. PMID 23127124.
  6. ^ Hagedorn, M; Rohde, KH; Russell, DG; Soldati, T (27 March 2009). "Infection by tubercular mycobacteria is spread by nonlytic ejection from their amoeba hosts". Science. 323 (5922): 1729–33. doi:10.1126/science.1169381. PMC 2770343. PMID 19325115.
  7. ^ Johnston, SA; Voelz, K; May, RC (17 February 2016). "Cryptococcus neoformans Thermotolerance to Avian Body Temperature Is Sufficient For Extracellular Growth But Not Intracellular Survival In Macrophages". Scientific Reports. 6: 20977. doi:10.1038/srep20977. PMC 4756366. PMID 26883088.
  8. ^ Bojarczuk, A; Miller, KA; Hotham, R; Lewis, A; Ogryzko, NV; Kamuyango, AA; Frost, H; Gibson, RH; Stillman, E; May, RC; Renshaw, SA; Johnston, SA (18 February 2016). "Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection". Scientific Reports. 6: 21489. doi:10.1038/srep21489. PMC 4757829. PMID 26887656.
  9. ^ Nicola, AM; Robertson, EJ; Albuquerque, P; Derengowski Lda, S; Casadevall, A (2011). "Nonlytic exocytosis of Cryptococcus neoformans from macrophages occurs in vivo and is influenced by phagosomal pH". mBio. 2 (4): e00167–11. doi:10.1128/mBio.00167-11. PMC 3150755. PMID 21828219.
  10. ^ Watkins; Andrews; Wynn; Barisch; King; Johnstin (April 9, 2018). "Cryptococcus neoformans Escape From Dictyostelium Amoeba by Both WASH-Mediated Constitutive Exocytosis and Vomocytosis". Front. Cell. Infect. Microbiol. 8 (108). doi:10.3389/fcimb.2018.00108.
  11. ^ Voelz, K; Lammas, DA; May, RC (August 2009). "Cytokine signaling regulates the outcome of intracellular macrophage parasitism by Cryptococcus neoformans". Infection and Immunity. 77 (8): 3450–7. doi:10.1128/iai.00297-09. PMC 2715691. PMID 19487474.
  12. ^ Johnston, SA; May, RC (12 August 2010). "The human fungal pathogen Cryptococcus neoformans escapes macrophages by a phagosome emptying mechanism that is inhibited by Arp2/3 complex-mediated actin polymerisation". PLoS Pathogens. 6 (8): e1001041. doi:10.1371/journal.ppat.1001041. PMC 2920849. PMID 20714349.
  13. ^ Alvarez, M; Casadevall, A (16 August 2007). "Cell-to-cell spread and massive vacuole formation after Cryptococcus neoformans infection of murine macrophages". BMC Immunology. 8: 16. doi:10.1186/1471-2172-8-16. PMC 1988836. PMID 17705844.