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[Prevention of lymphatic and hematologic spreading as a pathogenic condition for neural persistence of herpes simplex
1Institut für Medizinische Mikrobiologie und Immunologie der Universität Bonn.
Abstract:
In the experimental model of genital herpes simplex virus (HSV) infection of the mouse--in spite of abundant virus replication on the mucous membranes--no infectious virus can be isolated from the inflamed and swollen draining lymph nodes (DLN), contrary to the positive results in the lumbosacral nerves and their associated ganglia. Attempts to reactivate an abortive infection possibly established in lymph node or spleen cells by stimulation with phytohemagglutinin or lipopolysaccharide rendered no positive results, not even when adult (i.e. at least 6-week old), but immunodeficient mice were used as test animals. On the other hand, isolation of infectious virus from lymph node and--at a lesser rate--from spleen cells was successful in immature 4 to 6-week old mice, particularly when these had undergone pretreatment with cyclophosphamide, silica, antimacrophage serum and/or cortisone; 5 days post infectionem being the date of optimum virus yield. HSV-1 infected mice were more frequently positive than those with HSV-2, and genetically sensitive animals more so than resistant mice. The data indicate that the lymphohaematogenous spread of the virus is inhibited by means of an active defence mechanism, and that unspecific defence factors on the cellular level, probably macrophages and NK-cells, are essentially responsible. This reveals that the lethal generalized infection is prevented and the neural spread can gain its essential role in the pathogenesis of the HSV-infection.
Insights
Herpes simplex virus (HSV) spread to lymph nodes is blocked by the immune system in adult mice, preventing generalized infection and allowing for neural spread. Immature or immunosuppressed mice show susceptibility to lymph node infection.
Area of Science:
- Virology
- Immunology
- Pathogenesis
Context:
- Genital herpes simplex virus (HSV) infection in mice.
- Abundant viral replication occurs on mucous membranes.
- No infectious virus is isolated from draining lymph nodes (DLN) in adult mice.
Purpose:
- To investigate the inhibition of lymphohaematogenous spread of HSV.
- To identify the defense mechanisms preventing generalized infection.
- To understand the role of cellular immunity in controlling HSV dissemination.
Summary:
- In adult mice, HSV replication in mucous membranes does not lead to infectious virus in DLN, contrasting with neural ganglia.
- Attempts to reactivate latent infection in lymph nodes or spleen cells were unsuccessful in adult immunodeficient mice.
- In immature or immunosuppressed mice, HSV was isolated from lymph nodes and spleen, particularly after pretreatment with immunosuppressive agents.
Impact:
- Data suggest active defense mechanisms, involving macrophages and NK cells, inhibit lymphohaematogenous HSV spread.
- This inhibition prevents lethal generalized infection, allowing neural spread to become a primary pathogenic factor.
- Understanding these mechanisms is crucial for developing strategies against HSV pathogenesis.