Concentration of the inflammatory cytokine IL-8 is significantly elevated in the AH of POAG patients, supporting the hypothesis that immune activation occurs in glaucoma.

The evolution of human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV) as they replicate in infected individuals reflects a balance between the pressure on the virus to mutate away from recognition by dominant epitope-specific cytotoxic T lymphocytes (CTL) and the structural constraints on the virus' ability to mutate. To gain a further understanding of the strategies employed by these viruses to maintain replication competency in the face of the intense selection pressure exerted by CTL, we have examined the replication fitness and morphological ramifications of a dominant epitope mutation and associated flanking amino acid substitutions on the capsid protein (CA) of SIV/simian-human immunodeficiency virus (SHIV). We show that a residue 2 mutation in the immunodominant p11C, C-M epitope (T47I) of SIV/SHIV not only decreased CA protein expression and viral replication, but it also blocked CA assembly in vitro and virion core condensation in vivo. However, these defects were restored by the introduction of upstream I26V and/or downstream I71V substitutions in CA. These findings demonstrate how flanking compensatory amino acid substitutions can facilitate viral escape from a dominant epitope-specific CTL response through the effects of these associated mutations on the structural integrity of SIV/SHIV.

Although there is increasing evidence that individuals already infected with human immunodeficiency virus type 1 (HIV-1) can be infected with a heterologous strain of the virus, the extent of protection against superinfection conferred by the first infection and the biologic consequences of superinfection are not well understood. We explored these questions in the simian immunodeficiency virus (SIV)/rhesus monkey model of HIV-1/AIDS. We infected cohorts of rhesus monkeys with either SIVmac251 or SIVsmE660 and then exposed animals to the reciprocal virus through intrarectal inoculations. Employing a quantitative real-time PCR assay, we determined the replication kinetics of the two strains of virus for 20 weeks. We found that primary infection with a replication-competent virus did not protect against acquisition of infection by a heterologous virus but did confer relative control of the superinfecting virus. In animals that became superinfected, there was a reduction in peak replication and rapid control of the second virus. The relative susceptibility to superinfection was not correlated with CD4 ؉ T-cell count, CD4 ؉ memory T-cell subsets, cytokine production by virus-specific CD8 ؉ or CD4 ؉ cells, or neutralizing antibodies at the time of exposure to the second virus. Although there were transient increases in viral loads of the primary virus and a modest decline in CD4؉ T-cell counts after superinfection, there was no evidence of disease acceleration. These findings indicate that an immunodeficiency virus infection confers partial protection against a second immunodeficiency virus infection, but this protection may be mediated by mechanisms other than classical adaptive immune responses.Superinfection with human immunodeficiency virus type 1 (HIV-1) is the infection of an HIV-seropositive individual with a second heterologous strain of the virus after infection with the first infecting strain is established. There is accruing evidence for HIV-1 intra-and intersubtype superinfection in settings of intravenous drug use, structured treatment interruptions, and with strains that are resistant to antiretroviral drugs (2,4,6,22,26,28,32,39,42,43,52,60,66). Epidemiologic studies have suggested that the frequency of superinfection ranges from rare to as high as 5% per year in high-risk populations (9,10,15,20,24,27,31,40,41,51,59,65,67). However, it remains unclear how readily superinfections occur after exposure of an infected individual to a heterologous strain of virus. Furthermore, the variables that may contribute to susceptibility or resistance to superinfection, such as the timing of exposure to a second virus or the immunologic status of the exposed individual, have not been well defined. It is also uncertain whether superinfection is invariably associated with the loss of HIV containment and clinical deterioration (8,17,21,23,26,27,30,60). Understanding the risks for and the biological consequences of HIV superinfection will not only clarify an important clinical problem, it may also provide important insig...