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Cytomegalovirus-infected adherent cells interact synergistically and antagonistically with Staphylococcus aureus
T Paulin1, O Ringdén, R Wahren
1Department of Clinical Immunology, Karolinska Institute, Huddinge Hospital, Stockholm, Sweden.
Abstract:
Cytomegalovirus (CMV) has been shown to exert suppressive effects on the immune response but also to have mitogenic properties. A bacterial product, protein A from Staphylococcus aureus (SpA) was chosen to study possible interactions in vitro between bacterial products and adherent cells incubated with infectious CMV and ultraviolet light (UV)-inactivated CMV. Small amounts of infectious CMV potentiated SpA-induced DNA synthesis and Ig secretion measured by induction of plaque-forming cells (PFC). The reason for this may be that CMV in small amounts may act in synergism with the non-specific mitogen SpA. UV-inactivated CMV did not influence these responses except for a markedly enhanced PFC induction with SpA in lymphocytes from seronegative individuals. This remarkable synergism with SpA was also seen in enriched B cells. No synergism was seen in lymphocytes from seropositive donors. Large amounts of infectious CMV markedly reduced SpA-induced immune responses. Preliminary data suggest that the immunosuppressive effects are mediated by an interleukin 1 inhibitory factor. CMV was not shown to be a polyclonal B-cell activator but may, possibly in small amounts, act as such together with bacterial products, which would explain certain autoimmune phenomena. To conclude, CMV could in interaction with a bacterial product generate both synergistic and suppressive effects on immune response.
Insights
Cytomegalovirus (CMV) can enhance or suppress immune responses when interacting with bacterial products like Staphylococcus aureus protein A (SpA). Small amounts of CMV may synergize with SpA, while large amounts suppress immune activity.
Area of Science:
- Immunology
- Virology
- Microbiology
Background:
- Cytomegalovirus (CMV) exhibits both immune-suppressive and mitogenic properties.
- Bacterial products, such as Staphylococcus aureus protein A (SpA), are known immune modulators.
- Interactions between viral and bacterial components can significantly impact immune cell function.
Purpose of the Study:
- To investigate the in vitro interactions between Cytomegalovirus (CMV) and Staphylococcus aureus protein A (SpA).
- To determine how infectious and inactivated CMV affects SpA-induced immune responses in lymphocytes.
- To explore the potential synergistic or suppressive effects of CMV on bacterial product-mediated immune activation.
Main Methods:
- Incubation of adherent cells with infectious and UV-inactivated CMV.
- Measurement of SpA-induced DNA synthesis and immunoglobulin (Ig) secretion.
- Assessment of plaque-forming cell (PFC) induction in lymphocytes, including enriched B cells.
- Analysis of responses in lymphocytes from both seronegative and seropositive individuals.
Main Results:
- Small amounts of infectious CMV potentiated SpA-induced DNA synthesis and Ig secretion (PFC induction).
- UV-inactivated CMV enhanced SpA-induced PFC induction in lymphocytes from seronegative individuals and enriched B cells, but not seropositive donors.
- Large amounts of infectious CMV markedly reduced SpA-induced immune responses.
- Preliminary findings suggest immunosuppression may involve an interleukin-1 inhibitory factor.
Conclusions:
- Cytomegalovirus (CMV) can exert both synergistic and suppressive effects on immune responses in the presence of bacterial products like SpA.
- CMV, particularly in small quantities, may act synergistically with bacterial products, potentially contributing to autoimmune phenomena.
- The interplay between CMV and bacterial products highlights complex immune modulation relevant to host defense and disease.