Kinetic modeling of Toxoplasma gondii invasion

Björn F C Kafsack, Vern B. Carruthers, Fernando J Pineda

Research output: Contribution to journalArticle

Abstract

The phylum Apicomplexa includes parasites responsible for global scourges such as malaria, cryptosporidiosis, and toxoplasmosis. Parasites in this phylum reproduce inside the cells of their hosts, making invasion of host cells an essential step of their life cycle. Characterizing the stages of host-cell invasion, has traditionally involved tedious microscopic observations of individual parasites over time. As an alternative, we introduce the use of compartment models for interpreting data collected from snapshots of synchronized populations of invading parasites. Parameters of the model are estimated via a maximum negative log-likelihood principle. Estimated parameter values and their 95% confidence intervals (95% CI), are consistent with reported observations of individual parasites. For RH strain parasites, our model yields that: (1) penetration of the host-cell plasma membrane takes 26 s (95% CI: 22-30 s); (2) parasites that ultimately invade, remain attached three times longer than parasites that eventually detach from the host cells, and (3) 25% (95% CI: 19-33%) of parasites invade while 75% (95% CI: 67-81%) eventually detach from their host cells without progressing to invasion. A key feature of the model is the incorporation of invasion stages that cannot be directly observed. This allows us to characterize the phenomenon of parasite detachment from host cells. The properties of this phenomenon would be difficult to quantify without a mathematical model. We conclude that mathematical modeling provides a powerful new tool for characterizing the stages of host-cell invasion by intracellular parasites.

Original languageEnglish (US)
Pages (from-to)817-825
Number of pages9
JournalJournal of Theoretical Biology
Volume249
Issue number4
DOIs
StatePublished - Dec 21 2007

Fingerprint

Invasion
Toxoplasma
Toxoplasma gondii
Parasites
Kinetics
kinetics
parasites
Cell
Modeling
Confidence interval
confidence interval
Confidence Intervals
cell invasion
cells
Cell membranes
Likelihood Principle
Compartment Model
Malaria
Plasma Membrane
mathematical models

Keywords

  • Apicomplexa
  • Compartment model
  • Host-pathogen interaction
  • Invasion
  • Protozoan parasites

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

Cite this

Kinetic modeling of Toxoplasma gondii invasion. / Kafsack, Björn F C; Carruthers, Vern B.; Pineda, Fernando J.

In: Journal of Theoretical Biology, Vol. 249, No. 4, 21.12.2007, p. 817-825.

Research output: Contribution to journalArticle

Kafsack, Björn F C ; Carruthers, Vern B. ; Pineda, Fernando J. / Kinetic modeling of Toxoplasma gondii invasion. In: Journal of Theoretical Biology. 2007 ; Vol. 249, No. 4. pp. 817-825.
@article{aea8318283de44c7847f366f3b7089eb,
title = "Kinetic modeling of Toxoplasma gondii invasion",
abstract = "The phylum Apicomplexa includes parasites responsible for global scourges such as malaria, cryptosporidiosis, and toxoplasmosis. Parasites in this phylum reproduce inside the cells of their hosts, making invasion of host cells an essential step of their life cycle. Characterizing the stages of host-cell invasion, has traditionally involved tedious microscopic observations of individual parasites over time. As an alternative, we introduce the use of compartment models for interpreting data collected from snapshots of synchronized populations of invading parasites. Parameters of the model are estimated via a maximum negative log-likelihood principle. Estimated parameter values and their 95{\%} confidence intervals (95{\%} CI), are consistent with reported observations of individual parasites. For RH strain parasites, our model yields that: (1) penetration of the host-cell plasma membrane takes 26 s (95{\%} CI: 22-30 s); (2) parasites that ultimately invade, remain attached three times longer than parasites that eventually detach from the host cells, and (3) 25{\%} (95{\%} CI: 19-33{\%}) of parasites invade while 75{\%} (95{\%} CI: 67-81{\%}) eventually detach from their host cells without progressing to invasion. A key feature of the model is the incorporation of invasion stages that cannot be directly observed. This allows us to characterize the phenomenon of parasite detachment from host cells. The properties of this phenomenon would be difficult to quantify without a mathematical model. We conclude that mathematical modeling provides a powerful new tool for characterizing the stages of host-cell invasion by intracellular parasites.",
keywords = "Apicomplexa, Compartment model, Host-pathogen interaction, Invasion, Protozoan parasites",
author = "Kafsack, {Bj{\"o}rn F C} and Carruthers, {Vern B.} and Pineda, {Fernando J}",
year = "2007",
month = "12",
day = "21",
doi = "10.1016/j.jtbi.2007.09.008",
language = "English (US)",
volume = "249",
pages = "817--825",
journal = "Journal of Theoretical Biology",
issn = "0022-5193",
publisher = "Academic Press Inc.",
number = "4",

}

TY - JOUR

T1 - Kinetic modeling of Toxoplasma gondii invasion

AU - Kafsack, Björn F C

AU - Carruthers, Vern B.

AU - Pineda, Fernando J

PY - 2007/12/21

Y1 - 2007/12/21

N2 - The phylum Apicomplexa includes parasites responsible for global scourges such as malaria, cryptosporidiosis, and toxoplasmosis. Parasites in this phylum reproduce inside the cells of their hosts, making invasion of host cells an essential step of their life cycle. Characterizing the stages of host-cell invasion, has traditionally involved tedious microscopic observations of individual parasites over time. As an alternative, we introduce the use of compartment models for interpreting data collected from snapshots of synchronized populations of invading parasites. Parameters of the model are estimated via a maximum negative log-likelihood principle. Estimated parameter values and their 95% confidence intervals (95% CI), are consistent with reported observations of individual parasites. For RH strain parasites, our model yields that: (1) penetration of the host-cell plasma membrane takes 26 s (95% CI: 22-30 s); (2) parasites that ultimately invade, remain attached three times longer than parasites that eventually detach from the host cells, and (3) 25% (95% CI: 19-33%) of parasites invade while 75% (95% CI: 67-81%) eventually detach from their host cells without progressing to invasion. A key feature of the model is the incorporation of invasion stages that cannot be directly observed. This allows us to characterize the phenomenon of parasite detachment from host cells. The properties of this phenomenon would be difficult to quantify without a mathematical model. We conclude that mathematical modeling provides a powerful new tool for characterizing the stages of host-cell invasion by intracellular parasites.

AB - The phylum Apicomplexa includes parasites responsible for global scourges such as malaria, cryptosporidiosis, and toxoplasmosis. Parasites in this phylum reproduce inside the cells of their hosts, making invasion of host cells an essential step of their life cycle. Characterizing the stages of host-cell invasion, has traditionally involved tedious microscopic observations of individual parasites over time. As an alternative, we introduce the use of compartment models for interpreting data collected from snapshots of synchronized populations of invading parasites. Parameters of the model are estimated via a maximum negative log-likelihood principle. Estimated parameter values and their 95% confidence intervals (95% CI), are consistent with reported observations of individual parasites. For RH strain parasites, our model yields that: (1) penetration of the host-cell plasma membrane takes 26 s (95% CI: 22-30 s); (2) parasites that ultimately invade, remain attached three times longer than parasites that eventually detach from the host cells, and (3) 25% (95% CI: 19-33%) of parasites invade while 75% (95% CI: 67-81%) eventually detach from their host cells without progressing to invasion. A key feature of the model is the incorporation of invasion stages that cannot be directly observed. This allows us to characterize the phenomenon of parasite detachment from host cells. The properties of this phenomenon would be difficult to quantify without a mathematical model. We conclude that mathematical modeling provides a powerful new tool for characterizing the stages of host-cell invasion by intracellular parasites.

KW - Apicomplexa

KW - Compartment model

KW - Host-pathogen interaction

KW - Invasion

KW - Protozoan parasites

UR - http://www.scopus.com/inward/record.url?scp=36249011458&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=36249011458&partnerID=8YFLogxK

U2 - 10.1016/j.jtbi.2007.09.008

DO - 10.1016/j.jtbi.2007.09.008

M3 - Article

VL - 249

SP - 817

EP - 825

JO - Journal of Theoretical Biology

JF - Journal of Theoretical Biology

SN - 0022-5193

IS - 4

ER -