Virus Isolates during Acute and Chronic Human Immunodeficiency Virus Type 1 Infection Show Distinct Patterns of Sensitivity to Entry Inhibitors

Abstract

We studied the effect of entry inhibitors on 58 virus isolates derived during acute and chronic infection to validate these inhibitors in vitro and to probe whether viruses at early and chronic disease stages exhibit general differences in the interaction with entry receptors. We included members of all types of inhibitors currently identified: (i) agents that block gp120 binding to CD4 (CD4-IgG 2 and monoclonal antibody [MAb] IgG 1 b12), (ii) compounds that block the interaction with CCR5 (the chemokine RANTES/CCL5, the smallmolecule inhibitor AD101, and the anti-CCR5 antibody PRO 140), (iii) the fusion inhibitor enfuvirtide (T-20), and (iv) neutralizing antibodies directed against gp120 (MAb 2G12) and gp41 (MAbs 2F5 and 4E10). No differences between viruses from acute and chronic infections in the susceptibility to inhibitors targeting the CD4 binding site, CCR5, or fusion or to MAb 2G12 were apparent, rendering treatment with entry inhibitors feasible across disease stages. The notable exceptions were antibodies 2F5 and 4E10, which were more potent in inhibiting viruses from acute infection (P ‫؍‬ 0.0088 and 0.0005, respectively), although epitopes of these MAbs were equally well preserved in both groups. Activities of these MAbs correlated significantly with each other, suggesting that common features of the viral envelope modulate their potencies.Therapy of human immunodeficiency virus type 1 (HIV-1) infection with a combination of antiretrovirals inhibiting the viral enzymes reverse transcriptase and protease can significantly decrease HIV-related morbidity and mortality (49, 62). However, due to the toxicity of these drugs and the emergence of resistant viral variants, alternative treatment strategies are urgently needed (31,33,36). Entry of HIV-1 into target cells requires expression of the receptor CD4 and a fusion coreceptor, most commonly the chemokine receptors CCR5 and CXCR4 (19,66). The entry process proceeds via a cascade of events that provide multiple opportunities for therapeutic intervention, and several agents targeting this process have been developed over recent years. Considerable effort has been put into investigating the interaction of the virus with its entry receptors and the identification of potential antiretrovirals (66). Neutralizing antibodies were among the first agents identified which block viral entry. Direct antiviral activity is attributed to antibodies directed against specific epitopes on the envelope glycoproteins gp120 and gp41, which inhibit viral entry by blocking virion attachment to its receptors or membrane fusion (65). During natural infection the effect of the autologous neutralization response appears to be limited, since the virus rapidly escapes the immune pressure in most individuals (14,15,54,55,67,76,101). Nevertheless, rare potent monoclonal antibodies (MAbs) with broad activity have been isolated from infected individuals. These antibodies define four neutralization-sensitive epitopes within gp120 and gp41; they are characterized by the MAbs IgG 1 b12 (5,...

Identification and characterization of transmitted and early founder virus envelopes in primary HIV-1 infection

“…Previous studies characterized HIV-1 env sequences in acute and early infection by using methods that did not involve SGA and direct sequencing, and, as a result, they did not allow for the precise identification or enumeration of transmitted or early founder envs, their pathways of diversification as genetic units, or their corresponding phenotypes (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). The extent to which differences in experimental approach can impact the interpretation of virus complexity was recently highlighted in a study of acute and early HIV-1 clade C infection (17) and was seen again in the present study in 10 subjects who had been analyzed previously by the HTA method (10).…”

“…Previous reports examined the molecular basis of HIV-1 transmission by analyzing the genetic composition of viruses sampled between 1 and 6 months after infection (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). A common methodological approach in these studies was to derive viral sequences from the plasma or peripheral blood mononuclear cells of patients by bulk or near-limiting dilution PCR amplification of viral nucleic acid [proviral DNA or viral (v)RNA], followed by cloning, sequencing, and phylogenetic analysis (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”

Sensitivity Changes over the Course of Infection Increases the Likelihood of Resistance Against Fusion but Not CCR5 Receptor Blockers

“…A previous study showed that CCR5 and fusion inhibitors were equally potent against acute and chronic infection isolates, although the variants from the two different time points were not obtained from longitudinally collected samples. 26 In contrast, other investigations of longitudinally followed HIV-1-infected subjects demonstrate that sensitivity to coreceptor and fusion antagonists decreases from the chronic to the late phase of disease. [22][23][24][25] One of the major differences with our study and these previous publications is that we examined variants from the early and chronic phase of infection in a highly characterized seroincident cohort with well-defined dates of estimated seroconversion as opposed to comparing variants from the chronic and late stage of disease.…”

“…We and others have shown that over the course of infection, envelopes have decreased sensitivity to CCR5 receptor and fusion inhibitors, [21][22][23][24][25] although this has not been a universal observation in all subjects. 26 Given the extensive changes observed in both the envelope and polymerase gene, it remains unclear if the sensitivity changes are observed only for entry blockers or also against other drugs from different antiretroviral classes. 2,27 Drug resistance may also emerge more frequently among chronic as opposed to early infection variants because longitudinal sensitivity changes may affect replication in the presence of subtherapeutic drug concentrations.…”

Immunogenicity of recombinant human immunodeficiency virus type 1-like particles expressing gp41 derivatives in a pre-fusion state

“…2F5 and 4E10 neutralized 80 and 100%, respectively, of 91 viruses that were cloned directly from newly infected patients that had a negative or indeterminate serology [24]. Recently, it was shown that 2F5 and 4E10 mAbs were more potent in inhibiting viruses from acutely infected individuals than viruses from chronically infected patients [25]. However, experiments revealed that Env -pseudotyped viruses were more sensitive to neutralization than were their classical peripheral blood mononuclear cell (PBMC)-grown viruses, against which these antibodies manifest less potent activity with reduced breadth [23,26].…”