Kinetics of cytokine messenger-rna production in the brains of mice with progressive toxoplasmic encephalitis

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Abstract

C57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised.These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL-1-alpha was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)-alpha and interleukin (IL)-6] were present on day 10, (IL-6) and day 15 (TNF-alpha) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell-associated cytokines, IL-4, a characteristic product of the T helper (T(h))2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM-CSF) which can be produced not only by this cell type but also by T(h)1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)-gamma, present from day 15 post infection, were probably produced by CD8+ T cells, as IL-2 which would indicate T(h)1 cell involvement was only detected 30 days after infection. The continual presence of IFN-gamma and TNF-alpha, cytokines with reported anti-toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection.These results indicate that the CD4+ T(h)2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.

Original languageEnglish
Pages (from-to)2317-2322
Number of pages6
JournalEuropean Journal of Immunology
Volume22
Issue number9
DOIs
Publication statusPublished - Sep 1992

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Encephalitis
Cysts
Cytokines
Messenger RNA
Brain
Infection
Th1 Cells
Tumor Necrosis Factor-alpha
T-Lymphocytes
Astrocytes
Interferon-gamma
Interleukin-6
RNA
Inflammation
Th2 Cells
Interleukin-1alpha
Toxoplasma
Granulocyte-Macrophage Colony-Stimulating Factor
Meningitis
Interleukin-4

Keywords

  • tumor-necrosis-factor
  • central-nervous-system
  • CD8+ t-cells
  • gondii infection
  • gamma-interferon
  • lymphocytes-t
  • factor-alpha
  • ifn-gamma
  • inflammatory response
  • antigen presentation

Cite this

@article{84077c3f2fbe4bf2b0158f32635150a4,
title = "Kinetics of cytokine messenger-rna production in the brains of mice with progressive toxoplasmic encephalitis",
abstract = "C57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised.These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL-1-alpha was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)-alpha and interleukin (IL)-6] were present on day 10, (IL-6) and day 15 (TNF-alpha) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell-associated cytokines, IL-4, a characteristic product of the T helper (T(h))2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM-CSF) which can be produced not only by this cell type but also by T(h)1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)-gamma, present from day 15 post infection, were probably produced by CD8+ T cells, as IL-2 which would indicate T(h)1 cell involvement was only detected 30 days after infection. The continual presence of IFN-gamma and TNF-alpha, cytokines with reported anti-toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection.These results indicate that the CD4+ T(h)2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.",
keywords = "tumor-necrosis-factor, central-nervous-system, CD8+ t-cells, gondii infection, gamma-interferon, lymphocytes-t, factor-alpha, ifn-gamma, inflammatory response, antigen presentation",
author = "HUNTER, {C A} and ROBERTS, {C W} and J ALEXANDER",
year = "1992",
month = "9",
doi = "10.1002/eji.1830220921",
language = "English",
volume = "22",
pages = "2317--2322",
journal = "European Journal of Immunology",
issn = "0014-2980",
number = "9",

}

TY - JOUR

T1 - Kinetics of cytokine messenger-rna production in the brains of mice with progressive toxoplasmic encephalitis

AU - HUNTER, C A

AU - ROBERTS, C W

AU - ALEXANDER, J

PY - 1992/9

Y1 - 1992/9

N2 - C57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised.These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL-1-alpha was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)-alpha and interleukin (IL)-6] were present on day 10, (IL-6) and day 15 (TNF-alpha) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell-associated cytokines, IL-4, a characteristic product of the T helper (T(h))2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM-CSF) which can be produced not only by this cell type but also by T(h)1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)-gamma, present from day 15 post infection, were probably produced by CD8+ T cells, as IL-2 which would indicate T(h)1 cell involvement was only detected 30 days after infection. The continual presence of IFN-gamma and TNF-alpha, cytokines with reported anti-toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection.These results indicate that the CD4+ T(h)2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.

AB - C57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised.These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL-1-alpha was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)-alpha and interleukin (IL)-6] were present on day 10, (IL-6) and day 15 (TNF-alpha) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell-associated cytokines, IL-4, a characteristic product of the T helper (T(h))2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM-CSF) which can be produced not only by this cell type but also by T(h)1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)-gamma, present from day 15 post infection, were probably produced by CD8+ T cells, as IL-2 which would indicate T(h)1 cell involvement was only detected 30 days after infection. The continual presence of IFN-gamma and TNF-alpha, cytokines with reported anti-toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection.These results indicate that the CD4+ T(h)2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.

KW - tumor-necrosis-factor

KW - central-nervous-system

KW - CD8+ t-cells

KW - gondii infection

KW - gamma-interferon

KW - lymphocytes-t

KW - factor-alpha

KW - ifn-gamma

KW - inflammatory response

KW - antigen presentation

U2 - 10.1002/eji.1830220921

DO - 10.1002/eji.1830220921

M3 - Article

VL - 22

SP - 2317

EP - 2322

JO - European Journal of Immunology

JF - European Journal of Immunology

SN - 0014-2980

IS - 9

ER -