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Antibody-free target cells stimulate chemiluminescence in polymorphonuclear leukocytes: an artifact due to mycoplasma
Abstract:
The generation of toxic oxygen species represents a significant mechanism in the killing of microorganisms and antibody-coated cells by phagocytic cells. We have investigated the possibility that antibody-free target cells stimulate reactive oxygen generation in polymorphonuclear leukocytes (PMNL) using the measurement of luminol-dependent chemiluminescence (CL). It was found that the induction of CL consistently correlated with a mycoplasma contamination of the target cells. Free mycoplasma organisms of two species found frequently as contaminants in cell culture also stimulated CL. Upon artificial infection with mycoplasma, cultured cells acquired the capacity to evoke CL generation in PMNL. Our experiments strongly suggest that the induction of reactive oxygen generation by antibody-free target cells is an artifact due to mycoplasma contamination of the target cell cultures.
Insights
Mycoplasma contamination in cell cultures can artifactually induce reactive oxygen generation in polymorphonuclear leukocytes (PMNL). This study reveals that mycoplasma, not antibody-free cells, triggers this response, impacting research on cellular defense mechanisms.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Phagocytic cells generate toxic oxygen species to eliminate microorganisms and antibody-coated cells.
- Reactive oxygen species (ROS) production is a key component of the innate immune response.
- Investigating ROS generation by antibody-free target cells is crucial for understanding cellular interactions.
Purpose of the Study:
- To determine if antibody-free target cells can stimulate reactive oxygen generation in polymorphonuclear leukocytes (PMNL).
- To elucidate the underlying cause of ROS generation in the absence of specific antibody opsonization.
- To assess the role of potential contaminants in modulating immune cell responses.
Main Methods:
- Utilized luminol-dependent chemiluminescence (CL) to measure reactive oxygen generation in PMNL.
- Co-cultured PMNL with target cells, including those with and without suspected mycoplasma contamination.
- Introduced known mycoplasma species to cell cultures to assess their effect on CL induction.
Main Results:
- Chemiluminescence (CL) induction was consistently observed with mycoplasma-contaminated target cells.
- Free mycoplasma organisms of common contaminant species also stimulated CL in PMNL.
- Artificially infected cells gained the ability to induce CL in PMNL, confirming mycoplasma's role.
Conclusions:
- The observed stimulation of reactive oxygen generation by antibody-free target cells is an artifact.
- Mycoplasma contamination is the likely cause of artifactual ROS generation in cell cultures.
- Researchers should rigorously screen cell cultures for mycoplasma to ensure accurate study of immune responses.