Person:
Lakhashe, Samir

Profile Picture

Email Address

AA Acceptance Date

Birth Date

Research Projects

Organizational Units

Job Title

Last Name

Lakhashe

First Name

Samir

Name

Lakhashe, Samir

Filters

2010 - 20144

Settings

Author's Publications: search.filters.isAuthorOfPublication.c93cf6ea-cf84-4be7-81b4-07eb56b35796

Search Results

Now showing 1 - 4 of 4
  • Thumbnail Image
    Publication
    Passive immunization of macaques with polyclonal anti-SHIV IgG against a heterologous tier 2 SHIV: outcome depends on IgG dose
    (BioMed Central, 2014) Sholukh, Anton M.; Byrareddy, Siddappa N; Shanmuganathan, Vivekanandan; Hemashettar, Girish; Lakhashe, Samir; Rasmussen, Robert A; Watkins, Jennifer D.; Vyas, Hemant Kumar; Thorat, Swati; Brandstoetter, Tania; Mukhtar, Muhammad M; Yoon, John K; Novembre, Francis J; Villinger, Francois; Landucci, Gary; Forthal, Donald N; Ratcliffe, Sarah; Tuero, Iskra; Robert-Guroff, Marjorie; Polonis, Victoria R; Bilska, Miroslawa; Montefiori, David C; Johnson, Welkin E; Ertl, Hildegund C; Ruprecht, Ruth Margrit
    Background: A key goal for HIV-1 envelope immunogen design is the induction of cross-reactive neutralizing antibodies (nAbs). As AIDS vaccine recipients will not be exposed to strains exactly matching any immunogens due to multiple HIV-1 quasispecies circulating in the human population worldwide, heterologous SHIV challenges are essential for realistic vaccine efficacy testing in primates. We assessed whether polyclonal IgG, isolated from rhesus monkeys (RMs) with high-titer nAbs (termed SHIVIG), could protect RMs against the R5-tropic tier-2 SHIV-2873Nip, which was heterologous to the viruses or HIV-1 envelopes that had elicited SHIVIG. Results: SHIVIG demonstrated binding to HIV Gag, Tat, and Env of different clades and competed with the broadly neutralizing antibodies b12, VRC01, 4E10, and 17b. SHIVIG neutralized tier 1 and tier 2 viruses, including SHIV-2873Nip. NK-cell depletion decreased the neutralizing activity of SHIVIG 20-fold in PBMC assays. Although SHIVIG neutralized SHIV-2873Nip in vitro, this polyclonal IgG preparation failed to prevent acquisition after repeated intrarectal low-dose virus challenges, but at a dose of 400 mg/kg, it significantly lowered peak viremia (P = 0.001). Unexpectedly, single-genome analysis revealed a higher number of transmitted variants at the low dose of 25 mg/kg, implying increased acquisition at low SHIVIG levels. In vitro, SHIVIG demonstrated complement-mediated Ab-dependent enhancement of infection (C’-ADE) at concentrations similar to those observed in plasmas of RMs treated with 25 mg/kg of SHIVIG. Conclusion: Our primate model data suggest a dual role for polyclonal anti-HIV-1 Abs depending on plasma levels upon virus encounter.
  • Thumbnail Image
    Publication
    Passive immunization with polyclonal anti-SHIV IgG: partial protection or increased acquisition of heterologous tier 2 SHIV – depending on IgG dose
    (BioMed Central, 2012) Sholukh, Anton M.; Siddappa, NB; Shanmuganathan, V; Lakhashe, Samir; Rasmussen, Robert; Watkins, Jennifer D.; Vyas, Hemant Kumar; Mukhtar, Muhammad Mahmood; Hemashettar, G; Thorat, Swati; Yoon, JK; Villinger, F; Novembre, FJ; Landucci, G; Forthal, DN; Ratcliffe, S; Robert-Guroff, M; Polonis, V; Montefiori, DC; Ertl, HC; Ruprecht, Ruth Margrit
  • Thumbnail Image
    Publication
    R5 Clade C SHIV Strains with Tier 1 or 2 Neutralization Sensitivity: Tools to Dissect Env Evolution and to Develop AIDS Vaccines in Primate Models
    (Public Library of Science, 2010) Wassermann, Klemens J.; Song, Ruijiang; Wang, Wendy; Kramer, Victor G.; Novembre, Francis J.; Villinger, François; Else, James G.; Montefiori, David C.; Watkins, Jennifer D.; Siddappa, Nagadenahalli B.; Lakhashe, Samir; Santosuosso, Michael Robert; Poznansky, Mark; Rasmussen, Robert; Ruprecht, Ruth Margrit
    Background: HIV-1 clade C (HIV-C) predominates worldwide, and anti-HIV-C vaccines are urgently needed. Neutralizing antibody (nAb) responses are considered important but have proved difficult to elicit. Although some current immunogens elicit antibodies that neutralize highly neutralization-sensitive (tier 1) HIV strains, most circulating HIVs exhibiting a less sensitive (tier 2) phenotype are not neutralized. Thus, both tier 1 and 2 viruses are needed for vaccine discovery in nonhuman primate models. Methodology/Principal Findings: We constructed a tier 1 simian-human immunodeficiency virus, SHIV-1157ipEL, by inserting an “early,” recently transmitted HIV-C env into the SHIV-1157ipd3N4 backbone [1] encoding a “late” form of the same env, which had evolved in a SHIV-infected rhesus monkey (RM) with AIDS. SHIV-1157ipEL was rapidly passaged to yield SHIV-1157ipEL-p, which remained exclusively R5-tropic and had a tier 1 phenotype, in contrast to “late” SHIV-1157ipd3N4 (tier 2). After 5 weekly low-dose intrarectal exposures, SHIV-1157ipEL-p systemically infected 16 out of 17 RM with high peak viral RNA loads and depleted gut CD4\(^+\) T cells. SHIV-1157ipEL-p and SHIV-1157ipd3N4 env genes diverge mostly in V1/V2. Molecular modeling revealed a possible mechanism for the increased neutralization resistance of SHIV-1157ipd3N4 Env: V2 loops hindering access to the CD4 binding site, shown experimentally with nAb b12. Similar mutations have been linked to decreased neutralization sensitivity in HIV-C strains isolated from humans over time, indicating parallel HIV-C Env evolution in humans and RM. Conclusions/Significance: SHIV-1157ipEL-p, the first tier 1 R5 clade C SHIV, and SHIV-1157ipd3N4, its tier 2 counterpart, represent biologically relevant tools for anti-HIV-C vaccine development in primates.
  • Thumbnail Image
    Publication
    An Anti-HIV-1 V3 Loop Antibody Fully Protects Cross-Clade and Elicits T-Cell Immunity in Macaques Mucosally Challenged with an R5 Clade C SHIV
    (Public Library of Science, 2011) Hemashettar, Girish; Wang, Wendy; Novembre, Francis J.; Villinger, Francois; Ibegbu, Chris; Patel, Kalpana; Corti, Davide; Agatic, Gloria; Vanzetta, Fabrizia; Bianchi, Siro; Heeney, Jonathan L.; Sallusto, Federica; Lanzavecchia, Antonio; Watkins, Jennifer D.; Siddappa, Nagadenahalli B.; Lakhashe, Samir; Humbert, Michael; Sholukh, Anton M.; Wong, Yin Ling; Yoon, John C.; Ruprecht, Ruth Margrit
    Neutralizing antibodies have been shown to protect macaques against SHIV challenge. However, genetically diverse HIV-1 clades have evolved, and a key question left unanswered is whether neutralizing antibodies can confer cross-clade protection in vivo. The novel human monoclonal antibody HGN194 was isolated from an individual infected with an HIV-1 clade AG recombinant circulating recombinant form (CRF). HGN194 targets an epitope in the third hypervariable loop (V3) of HIV-1 gp120 and neutralizes a range of relatively neutralization-sensitive and resistant viruses. We evaluated the potential of HGN194 to protect infant rhesus monkeys against a SHIV encoding a primary CCR5-tropic HIV-1 clade C envelope. After high-dose mucosal challenge, all untreated controls became highly viremic while all HGN194-treated animals (50 mg/kg) were completely protected. When HGN194 was given at 1 mg/kg, one out of two monkeys remained aviremic, whereas the other had delayed, lower peak viremia. Interestingly, all protected monkeys given high-dose HGN194 developed Gag-specific proliferative responses of both CD4+ and CD8+ T cells. To test whether generation of the latter involved cryptic infection, we ablated CD8+ cells after HGN194 clearance. No viremia was detected in any protected monkeys, thus ruling out virus reservoirs. Thus, induction of CD8 T-cell immunity may have resulted from transient “Hit and Run” infection or cross priming via Ag-Ab-mediated cross-presentation. Together, our data identified the HGN194 epitope as protective and provide proof-of-concept that this anti-V3 loop mAb can prevent infection with sterilizing immunity after challenge with virus of a different clade, implying that V3 is a potential vaccine target.