Education & Certifications
Master of Science, Polytechnic University, Biotechnology/Entrepreneurship (2011)
Bachelor of Science, Yale University, Mol. Biochemistry/Biophysics (2010)
Inactivated influenza vaccine (IIV) is recommended during pregnancy to prevent influenza infection and its complications in pregnant women and their infants. However, the extent to which pregnancy modifies the antibody response to vaccination remains unclear, and prior studies have focused primarily on hemagglutinin inhibition (HI) titers. A more comprehensive understanding of how pregnancy modifies the humoral immune response to influenza vaccination will aid in maximizing vaccine efficacy. Healthy pregnant women and control women were studied prior to, 7 days after, and 28 days after vaccination with IIV. HI titers, microneutralization (MN) titers, and the frequency of circulating plasmablasts were evaluated in pregnant versus control women. Pregnant women and control women mount similarly robust serologic immune responses to IIV, with no significant differences for any influenza strain in postvaccination geometric mean HI or MN titers. HI and MN titers correlate, though MN titers demonstrate more robust changes pre- versus postvaccination. The induction of circulating plasmablasts is increased in pregnant women versus controls (median fold-change 2.60 vs 1.49 [interquartile range, 0.94-7.53 vs 0.63-2.67]; P = .03). Pregnant women do not have impaired humoral immune responses to IIV and may have increased circulating plasmablast production compared to control women.
View details for DOI 10.1093/infdis/jiv138
View details for Web of Science ID 000361285600004
View details for PubMedID 25740957
Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections, and comprise nearly 8% of the human genome. The most recently acquired human ERV is HERVK(HML-2), which repeatedly infected the primate lineage both before and after the divergence of the human and chimpanzee common ancestor. Unlike most other human ERVs, HERVK retained multiple copies of intact open reading frames encoding retroviral proteins. However, HERVK is transcriptionally silenced by the host, with the exception of in certain pathological contexts such as germ-cell tumours, melanoma or human immunodeficiency virus (HIV) infection. Here we demonstrate that DNA hypomethylation at long terminal repeat elements representing the most recent genomic integrations, together with transactivation by OCT4 (also known as POU5F1), synergistically facilitate HERVK expression. Consequently, HERVK is transcribed during normal human embryogenesis, beginning with embryonic genome activation at the eight-cell stage, continuing through the emergence of epiblast cells in preimplantation blastocysts, and ceasing during human embryonic stem cell derivation from blastocyst outgrowths. Remarkably, we detected HERVK viral-like particles and Gag proteins in human blastocysts, indicating that early human development proceeds in the presence of retroviral products. We further show that overexpression of one such product, the HERVK accessory protein Rec, in a pluripotent cell line is sufficient to increase IFITM1 levels on the cell surface and inhibit viral infection, suggesting at least one mechanism through which HERVK can induce viral restriction pathways in early embryonic cells. Moreover, Rec directly binds a subset of cellular RNAs and modulates their ribosome occupancy, indicating that complex interactions between retroviral proteins and host factors can fine-tune pathways of early human development.
View details for DOI 10.1038/nature14308
View details for PubMedID 25896322
Generalized immune activation during HIV infection is associated with an increased risk of cardiovascular disease, neurocognitive disease, osteoporosis, metabolic disorders, and physical frailty. The mechanisms driving this immune activation are poorly understood, particularly in individuals effectively treated with antiretroviral medications. We hypothesized that viral characteristics such as sequence diversity may play a role in driving HIV-associated immune activation. We therefore sequenced proviral DNA isolated from peripheral blood mononuclear cells from HIV-infected individuals on fully suppressive antiretroviral therapy. We performed phylogenetic analyses, calculated viral diversity and divergence in the env and pol genes, and determined coreceptor tropism and the frequency of drug resistance mutations. Comprehensive immune profiling included quantification of immune cell subsets, plasma cytokine levels, and intracellular signaling responses in T cells, B cells, and monocytes. These antiretroviral-treated HIV-infected individuals exhibited a wide range of diversity and divergence in both env and pol genes. However, proviral diversity and divergence in env and pol, coreceptor tropism, and the level of drug resistance did not significantly correlate with markers of immune activation. A clinical history of virologic failure was also not significantly associated with levels of immune activation, indicating that a past history of virologic failure does not inexorably lead to increased immune activation as long as suppressive antiretroviral medications are provided. Overall, this study demonstrates that latent viral diversity is unlikely to be a major driver of persistent HIV-associated immune activation.Chronic immune activation, which is associated with cardiovascular disease, neurologic disease, and early aging, is likely to be a major driver of morbidity and mortality in HIV-infected individuals. Although treatment of HIV with antiretroviral medications decreases the level of immune activation, levels do not return to normal. The factors driving this persistent immune activation, particularly during effective treatment, are poorly understood. In this study, we investigated whether characteristics of the latent, integrated HIV provirus that persists during treatment are associated with immune activation. We found no relationship between latent viral characteristics and immune activation in treated individuals, indicating that qualities of the provirus are unlikely to be a major driver of persistent inflammation. We also found that individuals who had previously failed treatment, but were currently effectively treated, did not have significantly increased levels of immune activation, providing hope that past treatment failures do not have a lifelong "legacy" impact.
View details for DOI 10.1128/JVI.01257-14
View details for Web of Science ID 000338924400037