Junin virus-induced delayed-type hypersensitivity suppression in adult mice

Area of Science:

• Immunology
• Virology
• Neuroscience

Background:

• Junin virus (JV) causes lethal meningoencephalitis in suckling mice via a delayed-type hypersensitivity (DTH) response.
• Adult mice are resistant to JV, developing high antibody titers without central nervous system (CNS) pathology.
• JV infection in adult mice may induce DTH depression, explaining their resistance.

Purpose of the Study:

• To investigate the effects of JV infection on the immune response in adult mice.
• To determine if JV infection alters DTH and humoral immunity using sheep red blood cells (SRBC) as a model antigen.

Main Methods:

• Adult mice were infected with Junin virus (JV).
• Delayed-type hypersensitivity (DTH) was assessed using sheep red blood cells (SRBC) as an indicator antigen.
• Humoral immune response was quantified by splenic plaque-forming cell counts.

Main Results:

• JV infection significantly abrogated DTH response to SRBC, irrespective of priming, viral strain, or inoculation route.
• The DTH suppression was dose-dependent and required live, infectious JV.
• Splenic plaque-forming cell counts, indicating humoral response to SRBC, were elevated compared to controls.
• High T-cell percentages in the spleen suggest involvement in DTH suppression.

Conclusions:

• Junin virus (JV) infection induces DTH suppression in adult mice while enhancing humoral immunity.
• The observed immune alterations in adult mice are consistent with their resistance to JV.
• Studying the immune response to SRBC in JV-infected adult mice can elucidate resistance mechanisms.