Transcriptome Analysis in Human Breast Milk and Blood after Inactivated or Attenuated Influenza Immunization

Abstract

Background. The goal of this study was to identify transcriptomic signatures (RNA-Seq) in human peripheral blood mononuclear cells (PBMCs) and breast milk lymphocyte cells (BMLCs) in response to trivalent inactivated Influenza vaccine (TIV) or live attenuated Influenza vaccine (LAIV). Methods. We performed a randomized, double-blind study in breastfeeding women who received either LAIV and intramuscular placebo, or TIV and intrana-sal placebo. A subset of subjects with available samples (LAIV, n = 10 and TIV, n = 6) was used for this study. Human milk was collected on days 0, 2, 8, and 28, and blood amples were collected on days 0 and 28. PBMC and BMLC RNA was extracted for NA-Seq and differentially expressed (DE) gene analysis. Results. We identified a total of 382 DE BMLC genes in the LAIV group, most f which were up-regulated at day 28. DE genes were preferentially involved in innate mmune signaling pathways including cytokine-cytokine receptor interaction, TNF ignaling, and NF-kappa B signaling. For TIV, 3 DE genes were identified of which 2 IL1A and IL1B) overlapped with LAIV Response time trends for co-expressed gene lusters by vaccine group showed that LAIV generally induced an early (day 2) up-reg-lation of innate immune signaling pathway genes, while TIV induced peak innate mmune signaling gene responses ahead of LAIV (day 8 vs. day 28). A group of known nterferon-alpha/β-inducible genes (IFIT3, OAS3, IFI44L, MX1, OAS2, IFIT1, IFI6) howed higher responses at day 2 for TIV but stronger peak levels by day 28 for the AIV group (Fig 1). While no such innate immune signaling responses were observed n PBMCs at day 28, we identified an up-regulation of IgG gene (IGHG1 and IGHG3) xpression in the TIV group (Fig 2). Conclusion. We observed increased innate immune signaling responses in BMLC ut not in PBMC at day 28 for the LAIV group. We hypothesize that breastfeeding xtends the innate response to LAIV via mucosal immunity. Gene cluster time trends ndicated an earlier innate immune signaling response for TIV The day 28 increase in GHG3 gene expression levels in TIV group PBMCs was correlated with corresponding ncreases in serum ELISA IgG titers for the Influenza B antigen (Fig 3). Additional tudies are required to investigate the Differences in innate response signaling seen for MLC and PBMC in this study. [Figure Presented].