Table 1.
Plasmodium infection and outcomes modified by gammaherpesvirus co-infection
| Effect of type 1 interferon |
Requirement for cell-mediated immunity |
Requirement for humoral responses |
Effect of overlapping acute viral infection (less than 16 days post-viral infection) |
Effect of a latent viral infection (more than 16 days post-viral infection) |
|
|---|---|---|---|---|---|
|
Plasmodium yoelii XNL (79) C57BL/6 mice |
Inhibits infection by suppressing reticulocytosis (103) | Requires CD4+ T cells to control the primary peak of infection (140) CD8+ T cells may provide some protection against P. yoelii XL (51) |
Requires antibody for control of primary peak of infection (56) | Nonlethal infection becomes lethal (80) due to uncontrolled primary peak of infection | Immunosuppressive effects on humoral responses wanes after 60 days (79) |
|
Plasmodium chabaudi AS (79) C57BL/6 mice |
Suppresses protective IFN-γ production (100) | Requires CD4+ T cells to control the primary peak of infection (140) CD8+ T cells may provide some protection against erythrocytic malaria (120, 142) |
Does not require antibody for control of acute peak of infection (56) Less able to control secondary peaks of infection (59) |
Nonlethal infection remains nonlethal across primary peak of infection | No data |
|
Plasmodium berghei ANKA (FH Amante and CR Engwerda, unpublished data) C57BL/6 mice |
Suppresses CD4+ T-cell responses and control of erythrocytic parasitaemia (100) | CD4+ T cells required for the development of ECM (142) CD8+ T cells trafficking to the brain are pathogenic (121, 122, 144) |
Required for the control of iRBCs for related species Plasmodium berghei NK65 (145) | Protection from death during the inflammatory phase of experimental cerebral malaria (during or just after lytic infection) | No measureable effect on death from ECM (6 weeks post-infection) |
| Plasmodium falciparum | Certain polymorphisms in the IFNAR1 gene have been found to confer protection from cerebral malaria (146) and enhanced susceptibility to severe malarial anaemia (147) | CD4+ T-cell IFN-γ responses are associated with protection from severe disease (148-151) | Antibody response is associated with protection from severe malarial anaemia and control of blood-stage parasitaemia (21, 22, 26, 27) | No data | No data |