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Impaired T lymphocyte colony formation in infectious mononucleosis: evidence for both monocyte and lymphocyte defects
Abstract:
PHA-induced T lymphocyte colony formation in semi-solid agar culture was studied in mononuclear cells (MC) and non-adherent cells (NAC) from the blood of patients with infectious mononucleosis (IM). Colony formation expressed as number of colonies per 10(6) E-RFC or as number of colonies per ml of blood was depressed by about 90% during the first weeks of disease, but returned to normal levels during the convalescence period. Addition to the agar culture of conditioned medium prepared from adherent blood MC or normal donors partly restored colony formation by both MC andNAC from patients with IM in the acute stages, suggesting a subnormal production of conditioning factors by cocultured adherent cells. In line with this finding adherent cells from patients with acute disease failed to produce a conditioned medium which optimally supported the growth of T lymphocyte colonies from NAC of normal donors. When mononuclear cells from patients with IM were mixed with normal donor lymphocytes prior to agar seeding, colony formation by the normal cells was reduced by 10--65%. It is concluded that mononuclear cells from patients with IM have a reduced capacity to form T lymphocyte colonies in agar medium. This reduction possibly reflects a lack of production of colony stimulating factors from monocytes, but also increased activity of T lymphocyte colony suppressor cells.
Insights
T lymphocyte colony formation is significantly reduced in patients with infectious mononucleosis (IM). This impairment stems from both reduced colony-stimulating factors and increased suppressor cell activity, impacting immune response during IM.
Area of Science:
- Immunology
- Cell Biology
- Virology
Background:
- Infectious mononucleosis (IM) is a viral illness primarily affecting T lymphocytes.
- Understanding T lymphocyte dysfunction in IM is crucial for managing the disease and its complications.
Purpose of the Study:
- To investigate T lymphocyte colony formation in patients with infectious mononucleosis (IM).
- To elucidate the mechanisms underlying T lymphocyte colony formation defects in acute IM.
Main Methods:
- Assessing phytohemagglutinin (PHA)-induced T lymphocyte colony formation in semi-solid agar culture.
- Analyzing mononuclear cells (MC) and non-adherent cells (NAC) from IM patients.
- Evaluating the role of adherent cells and conditioned media in T lymphocyte growth.
Main Results:
- Colony formation was depressed by approximately 90% in acute IM, normalizing during convalescence.
- Conditioned media from adherent cells of IM patients partially restored colony formation, indicating reduced production of growth factors.
- Normal T lymphocyte colony formation was suppressed when co-cultured with IM patient cells, suggesting increased suppressor cell activity.
Conclusions:
- Mononuclear cells from IM patients exhibit a reduced capacity for T lymphocyte colony formation.
- This defect is likely due to impaired production of colony-stimulating factors by monocytes and enhanced activity of T lymphocyte suppressor cells.
- These findings highlight a dual mechanism of immune dysregulation in infectious mononucleosis.