Table 1.
Relations between coinfecting viruses and HIV-1
| Virus | Mechanisms | Potential effects on HIV-1* |
|---|---|---|
| HBV | Several anti-HBV drugs are also HIV-1 RT inhibitors | HBV treatment also decreases HIV replication; emergence of HIV-1 RT-resistant mutants |
| HCV | Systemic immune activation | Facilitation of HIV-1 replication |
| GBV-C | CCR5 and CXCR4 downregulation; induction of RANTES and SDF-1 | Suppression of HIV-1 replication |
| HTLV-1 | LTR transactivation; induction of CC chemokines | Facilitation of HIV-1 replication; suppression of HIV-1 R5 replication |
| HTLV-2 | Induction of CC chemokines; decreased systemic immune activation | Suppression of HIV-1 replication |
| HIV-2 | Cross-reactive immune response; induction of CC chemokines | Decreased HIV-1 acquisition; suppression of HIV-1 R5 replication |
| JCV | Suppression of Tat functions | Suppression of HIV-1 replication in vitro |
| Measles virus | Induction of RANTES; blockage of CD4 T-cell cycle | Suppression of HIV-1 replication |
| HSV-2 | Genital ulceration; increased LTR transactivation | Increased HIV-1 transmission; facilitation of HIV-1 replication |
| CMV | Increased HIV-1 load in semen; induction of chemokines, virokines, and viroceptors | Increased HIV-1 transmission; variable results were reported for the net effect |
| HHV-6 | Induction of RANTES, virokines, LTR transactivation, CD3 and CD46 downregulation | Decreased replication of HIV-1 R5 ex vivo; net effect on HIV-1 replication in vivo to be studied |
| HHV-7 | Downregulation of CD4 | Decreased replication of HIV-1 R5 ex vivo; net effect on HIV-1 replication in vivo to be studied |
| HHV-8 | Chemokines and virokines | Net effect of HIV-1 replication in vivo to be studied |
*
In vivo, some of the potential effects of coinfecting microbes on HIV-1, especially those that were identifi ed in in vitro system only, may be masked (eg, due to several opposite signals triggered by the same or different microbes, or by other host factors that determine HIV disease). CMV—cytomegalovirus; GBV-C—GB virus C; HBV—hepatitis B virus; HCV—hepatitis C virus; HHV—human herpesvirus; HSV—herpes simplex virus; HTLV—human T-cell leukemia virus; JCV—JC virus; LTR—long terminal repeat; RANTES—regulated upon activation, normal T-cell expressed and secreted; RT—reverse transcriptase; SDF—stromal cell-derived factor.